REPEATABILITY AtlD COMPARISON OF Tl O I-IAZE TESTS

TO MEASURE LEARNING ABILITY IN HORSES

by

CATHERINE ELIZABETli LOKEY, B.S.

A THESIS

IN

ANIMAL BREEDING

Submitted to the Graduate Faculty of Texas Tech University in Partial Fulfillment of the Requirements for

the Degree of

MASTER OF SCIENCE

Approved

Accepted"

May, 1982

' > /^ . I'- ACKNO\vn:.EDGEMENTS

I would like to thank Dr. James C. Heird for his assistance

with this thesis and my graduate studies. The help received from

Dr. Dennis Cogan and Dr. C. Boyd Ramsey in preparing this thesis

is also appreciated. I am deeply indebted to Mr. Steve Brazier,

Ms. Pam Henderson, Ms. Kelly McHugh, Mr. Wes Newman, Ms. Nancy Smith,

Ms. Melinda Weatherbee and Ms. Denise Williams for their assistance

in collecting the data. The friendship and concern of my fellow

graduate students is gratefully acknowledged. Finally, I would like

to thank my parents for their support and encouragement during my

graduate studies.

11

TABLE OF CONTENTS

Page

ACKNOWLEDGEMENTS ii

LIST OF TABLES iv

LIST OF FIGURES v

I. INTRODUCTION 1

II. LITERATURE REVIEW 3

Animal Learning 3

Discrimination 8

Reliability and Comparisons of

Learning Tests 11

Learning in the Horse and Other Domestic Animals 15

III. REPEATABILITY AND COMPARISON OF TWO JMZE TESTS

TO MEASURE LEARITING ABILITY IN HORSES 25

Summary 25

. Introduction 26

Experimental Procedure . . . . . 26

Results and Discussion 31

LITERATURE CITED 54

APPEJTDICES 62

1 1 1

LIST OF TABLES

Table Page

1 CORRELATION COEFFICIENTS FOR TRIALS TO CRITERION AND PERCENTAGE OF CORRECT RESPONSE 42

2 SPEARMAN CORRELATION COEFFICIENTS FOR RANKS ON ODD AND EVEN DAYS ON DISCRIMINATION TESTS 52

APPENDIX TABLES

A. TRAINABILITY M D EMOTIONALITY SCORE FOR EACH HORSE TESTED 63

B. MEAN TRIALS TO CRITERION AND PERCENTAGE OF COPJIECT RESPONSES FOR EACH HORSE BY 5-DAY BLOCKS 64

IV

LIST OF FIGURES

Figure Page

1 MODIFIED T-MAZE 28

2 PERCENTAGE OF CORRECT RESPONSES FOR GROUP 1 BY 5-DAY BLOCKS 34

3 PERCENTAGE OF CORRECT RESPONSES FOR GROUP 2 BY 5-DAY BLOCKS 36

4 NUMBER OF TRIALS TO CRITERION FOR GROUP 1 BY 5-DAY BLOCKS 39

5 NLT ffiER OF TRIALS TO CRITERION FOR GROUP 2 BY 5-DAY BLOCKS 41

6 PERCENTAGE OF CORRECT RESPONSES FOR TRAINABILITY GROUPS BY 5-DAY BLOCKS 44

7 NUMBER OF TRIALS TO CRITERION FOR TRAINABILITY GROUPS BY 5-DAY BLOCKS 45

8 PERCENTAGE OF CORRECT RESPONSES FOR EMOTIONALITY GROUPS BY 5-DAY BLOCKS 48

9 TUMBER OF TRIALS TO CRITERION FOR EMOTIONALITY GROUPS BY 5-DAY BLOCKS 49

CHAPTER I

INTRODUCTION

The horse is unique among livestock species because of the import­

ance of its ability to learn. A horse is worthless without training

regardless of its conformation or athletic ability. Unlike other

fields of animal science which are based on production, the horse in­

dustry is a hobby industry. The horse's primary function is to pro­

vide recreation rather than work or food. In order to perform this

function, the horse must be trainable. For this reason, the study of

learning and behavior is of major economic importance to the horse

industry.

Until recently, most of the research involving horses had concen­

trated on nutrition and physiology. In the mid-1970's, the importance

of equine learning research was recognized and increasing numbers of

studies have been conducted.

In most of the research involving learning behavior in horses,

various types of maze tests were used as measures of learning ability.

Existing research has not shox<m whether maze learning ability is

actually related to learning ability in a practical training situation.

One feature of a sound test is reliability. A reliable test is

one that gives consistent results on successive trials. The reli­

ability of mazes as tests of learning ability in horses has not

been determined.

The objectives of this study were to: 1) determine if a corre­

lation exists between the ranks of the same group of horses given

two types of maze tests - a simple place learning test and a more

difficult discrimination test, 2) compare the repeatability of the

same test using the same group of horses, 3) determine the relation­

ship between subjective trainability scores and performance in a maze

learning situation and, 4) determine if a correlation exists between

emotionality scores based on habituation to a novel stimulus and per­

formance scores in a maze test.

CHAPTER II

LITERATURE REVIEW

Animal Learning

Tarpy and Mayer (1978) have defined learning as an inferred change

in an organism which results from experience and which influences its

subsequent behavior in a relatively permanent manner. This definition

generally agrees with those given by other psychologists (Kimble, 1961;

Tavolga, 1969; Scott, 1972; Hintzman, 1978).

Although man has observed and recorded the behavior of animals

for centuries, the transition from anecdotalism to experimental studies

did not begin until 1894 when C. Lloyd Morgan's Introduction to Compara­

tive Psychology was published (Bitterman, 1979a). Morgan (1894) re­

jected the undisciplined anthropomorphism of the anecdotalists and pro­

posed that systematic and sustained investigation of animal behavior

should replace the accepted method of simply recording random bits of

apparently intelligent behavior.

E. L. Thorndike and I. P. Pavlov ara generally considered to have

had the most profound influence on subsequent animal learning research

(Bitterman, 1979a; Mackintosh, 1974; Fantino and Logan, 1979; Tarpy and

Mayer, 1978). Both of these experimenters recognized the need for con­

trolled objective studies around the turn of the century and each de­

veloped experimental methods fulfilling these requirements.

Thorndike's main thesis, which he first presented in his doctoral

dissertation, was zhat animals did not utilize ideas in problem solving

(Thorndike, 1898). He attacked all "mentalistic" explanations of be­

havior, even accusing Morgan, who was considered to be the most ob­

jective psychologist of the time, of anthropomorphism (Wilcoxin, 1969)

Thorndike later proposed that the behavior of all animals was governed

by what he called the Law of Effect. This principle stated that re­

sponses accompanied or closely followed by satisfaction to the animal

would be more firmly connected to the situation so that they would be

more likely to recur, while responses associated with discomfort would

be weakened and become less likely to occur (Thorndike, 1905). Thorn-

dike's experimental method was to place a hungry animal in a box from

which it could escape by performing a simple task such as pulling a

loop or manipulating a lever. Food was placed outside the box as a

.reward. Thorndike advocated this method because it was objective,

quantitative, reproducible, flexible and adaptable to many species

(Bitterman, 1979a).

During the same time period in which Thorndike's methods were

being accepted in western Europe and America, Pavlovian tradition was

being established in Russia (Bitterman, 1979a). Pavlov, a ohysiolo-

gist,. was studying digestive behavior patterns in dogs. He noticed

that previously neutral stimuli acquired the ability to elicit saliv­

ation when paired repeatedly with the presentation of food. Pavlov

referred to this phenomenon as a "conditioned reflex." He recognized

the significance of this discovery and decided to direct his efforts

to its investigation. His first approach was introspection but it

soon became apparent that this method was flawed. Pavlov decided that

since the nervous system is a biological system, it should be studied

objectively in controlled experimental settings (Hintzman, 1978).

According to Hintzman (1978), the study of animal learning has

been dominated by the behaviorist viewpoint since about 1930. Although

Pavlov's work on conditioned reflexes was conducted beginning in 1902,

it was not translated into English until 1927. The success of the

behaviorist movement in the United States was largely due to the

efforts of John B. Watson, one of its strongest advocates. Watson

was strongly impressed with Pavlov's work and publicized it. The fail­

ings of introspective psychology and the success of Pavlov's work

created a situation in which Watson's philosophies received enthusi­

astic support. Behaviorism proposed that unreliable subj.ective methods

of observation used by the introspectionalists be replaced by objec­

tive methods and that explanations of behavior alluding to mental

states be banned. Watson (1914) stated that the subject matter of

psychology should be limited to overt behavior which was observable

and measurable. The majority of psychologists today have adopted

Watson's basic philosophy, studying overt behavior in a systematic

and objective manner (Tarpy and Mayer, 1978).

Most subsequent learning research has been designed using the

two basic conditioning models developed by Thorndike and Pavlov. Of

the terms used to distinguish between them, the most widely used and

accepted are instrumental and classical conditioning. The operational

distinction between the two paradigms is whether the presentation of

the stimulus is contingent on the subject's response or vzhether it occurs

regardless of behavior. In classical or Pavlovian conditioning, a con­

tingency between the stimulus and the outcome exists, while in instru­

mental conditioning reinforcers are response contingent. Four main

types of instrumental conditioning are reward, punishment, avoidance

and omission (Mackintosh, 1974; Tarpy and Mayer, 1978; Bitterman,

1979a). According to Tarpy (1975), reward training is the most conmionly

used type of instrumental conditioning. In this procedure, a subject

receives positive reinforcement for a correct response. Fantino and

Logan (19 79) define reinforcement as any positive or negative event

that increases the probability that the behavior associated with it

will recur in the future. Typical instrumental experiments usually

include a pretraining phase before the instrumental contingency is im­

posed. This procedure permits preliminary habituation to the experi­

mental apparatus (Mackintosh, 1974). Habituation, which is usually

considered the simplest form of learning, is defined as the decrease of

innate reaction after repeated exposure to a neutral stimulus (Hintz­

man, 1978; Craig, 1981). The procedure of eliminating reinforcement

after the response has been established through training and the be­

havioral result of that procedure are both called extinction. This

process usually results in a gradual decrease in the learned response

(Tarpy, 1975; Rashotte, 1979).

The only objective measure of learning is performance (Tolman,

1955; Kratzer, 1971; Tarpy, 1975). Tarpy (1975) distinguishes between

the two terms by describing learning as the underlying process deter­

mining performance. He also states that performance, and therefore

learning, can be measured by changes in response strength. Indices

of performance frequently used in instrumental learning studies in­

clude rate, latency, frequency, duration, vigor, speed, probability

or persistence of the response (Mackintosh, 19 74; Tarpy, 1975; Fantino

and Logan, 1979). Performance can be measured in a series of discrete

trials or the subject may be allowed to respond at its own rate in a

free operant situation. When discrete trials are used, response

strength is measured by latency, speed or probability (Mackintosh,

1974). Probability of responding is most frequently used in situations

involving a choice in which both correct and incorrect responses are

available (Fantino and Logan, 1979). Many different types of apparatus

have been used to study animal learning. Fantino and Logan (1979)

explain that choosing a measure of learning in any particular situation

depends on several factors: 1) the nature of the behavior required,

2) adaptation to the species being studied, and 3) ease with which be­

havior may be measured. One of the most popular devices used in animal

learning is the maze, which was first mentioned by Small (1899).

Hintzman (19 78) described several variations of the maze, including a

straight alley maze, T-maze and complex maze. Essentially, all

maze designs include starting areas and one or more goals, linked by

pathways of various complexity. The T-maze, which consists of a

start box and a single choice point branching toward two goals,

is the simplest device for choice situations (Mackintosh, 1974). It

also is considered to be ideally suited to discrimination problems

(Mackintosh, 1974; Hintzman, 1978; Fantino and Logan, 1979). Crespi

8

(1942) stated that motivation is an essential factor in any learning

test. He suggested that food is an appropriate reward for a hungry

animal in a maze test. Rate of learning in a T-raaze usually is re­

tarded if the correct alternative is rewarded on less than 100%

of the trials (Hill et al., 1962; Clayton and Koplin, 1964; Sutherland,

1966). Munn (1950) explained that subjects in maze learning studies

usually are trained until they reach a predetermined criterion of per­

formance. According to Stone (1951) the results of any learning study

should be analyzed by graphical means.

Discrimination

An animal discriminates when it responds to one situation based

on reward availability but not to another where there is no reward,

less reward or punishment (Tarpy and Mayer, 1978). Sutherland (1964)

has defined discrimination learning as the process by which an animal

learns to give consistently different responses to two or more stimuli.

Mackintosh (19 74) emphasizes that the distinction between single re­

sponses, as in a straight alley maze, and simple choice behavior does

not coincide with the distinction between non-discriminative and dis­

criminative learning. According to Honig (1969) the primary effect of

discrimination training is the development of differential stimulus

control over behavior by those stimuli involved in the training pro­

cedure. In a discrimination test, some distinguishable property of

the situation is varied systematically and with it the consequences

of the response (Bitterman, 1979b). Restle (1955) explained that the

entire stimulus situation facing a subject in a discrimination learn­

ing trial is a set of cues. A cue, defined by Sutherland and

Mackintosh (1971), is any dimension of difference that could control

the subject's responses in a choice situation. A cue is relevant if

it can be used by the subject to predict where or how reward is to

be obtained; a cue uncorrelated with reward is irrelevant. In solv­

ing a two-choice discrimination problem, the subject learns to relate

its responses currectly to the relevant cues while responding becomes

independent of irrelevant cues (Restle, 1955).

The two methods used to test discriminative learning are simul­

taneous and successive discrimination (Macintosh, 1974; Tarpy and Mayer,

1978). A simultaneous discrimination test involves two or more stimuli

presented simultaneously, offering a choice with reinforcement given

to responses to one of the stimuli. In successive discrimination, the

positive (S+) and negative (S-) stimuli are given sequentially requir­

ing the subject to learn to respond only to S+.

Several different theories of discrimination learning have been

proposed. The continuity theory, developed from the work of Hull

(1943) and Spence (1936, 1952), xvas probably the earliest accepted

theory (Mackintosh, 1965; Tarpy, 1975; Bitterman, 1979b). This theory

states that responding to discriminative stimuli is a function of

their associative strength, which is an algebraic summation of the

conditioned exitation to S+ on rewarded trials and conditioned inhibi­

tion to S- on non-rewarded trials. The continuity theorists believed

that discriminative learning was a gradual process which was continu­

ous and cumulative.

10

Observations made by Lashley (1929) and Krechevsky (1932) that

animals learning a simultaneous discrimination usually perform at

chance levels for many trials before shifting abruptly to virtually

errorless performance resulted in a new theory of discrimination.

Lashley (1929) suggested that the direction of attention is the key

to the solution of discrimination problems. Krechevsky (1932, 1938)

proposed that the pre-solution period of discrimination learning

consisted of a series of attempted solutions which he termed hypoth­

eses since they seemed to be made systematically. Later studies

(Levine, 1959, 1965) also described discrimination learning in terms

of strategies developed by the animal which, when reinforced, would

account for its ultimate improvement in performance.

Other investigators (Mackintosh, 1965; Sutherland and Mackintosh,

1971) criticized the non-continuity theory, state that it implied

that the subject learned about only one cue at a time and could learn

nothing about the relevant stimulus while attending to irrelevant

stimuli. They developed a modified non-continuity, still emphasiz­

ing attention. This theory states that discrimination learning in­

volves two discrete processes: 1) strengthening attention to rele­

vant stimulus dimensions and 2) attaching a particular response to

the relevant stimuli. Bitterman (1979c) noted that discrimination

can be explained entirely on the basis of attention to positive

stimuli but cited examples of tests using negative stimuli alone or

with novel cues which demonstrated aversion to negative stimuli

(Mandler, 1968; Derdzinski and Warren, 1969).

11

Reliability and Comparisons of Learning Tests

Spence (1932) has defined reliability as the amount of agreement

between results from two or more applications of the same test. He

stated that reliability is determined by the consistency with which

it differentiates between various individuals of a groun on different

occasions. Munn (1950) explained that, if a test of learning measures

the same thing in every animal and measures it uniformly from trial

to trial, animals that make high scores will do so consistently.

Leeper's (1932) concept of reliability is the measure of the extent

to which chance factors have been excluded from obscuring the desired

measurement. Heron (1922) also emphasized the relationship of reli­

ability to the predictive value of learning tests.

According to Denenberg and Banks (1962), the importance of

reliability of measurement cannot be overemphasized. They point out

that if behavior is not sufficiently stable to be reproduced, nothing

more than random events has been measured. They also state that re­

liability is a more acute problem in behavioral studies compared to

other branches of science because of the d3n:iamic nature of behavior.

A measure of reliability could be had directly if it were possible to

secure completely independent samples of performance using the same

group of subjects (Tolman and Nyswander, 1927; Leeper, 1932; Denenberg

and Banks, 1962).

According to Munn (1950), many early investigators paid little

or no attention to the problem of reliability, assuming that perform­

ance on any particular learning problem indicated general learning

12

ability. The first study of reliability of animal behavior was con­

ducted by Paterson in 1917 (Leeper, 1932; Munn, 1950). He analyzed

scores on the Watson circular maze and suggested that results from

this test were too unreliable to permit satisfactory measurement of

experimental effects (Paterson, 1917). Numerous studies concerning

reliability of various learning tests were completed in the 1920's

and 30's. Many different methods of testing reliabilitv have been

used but most results have been reported in terms of correlation

coefficients (Munn, 1950).

In a review of reliability tests used prior to 1932, Spence

(1932) listed nine commonly used methods. These included: I) corre­

lation between learning and releaming the same maze, 2) correlation

between results on a maze and another learning problem, 3) correla­

tion of two series of trials separated by a considerable time inter­

val, 4) correlation between scores on various trials, 5) correlations

between scores on different segments of the learning curve, 6) corre­

lations between scores of odd and even trials, 7) correlations between

scores on odd and even blinds in a complex maze, 3) correlation be­

tween errors on the first half and second half of a test, and

9) correlations between results of two different mazes. Spence con­

cluded that the most valid of these methods was a correlation between

two mazes.

Tolman and Nyswander (1927) noted that reliability coefficients

above .60 are rare with results from most studies averaging about .30.

They contend that unless a situation requires accurate ranking of

13

each individual, extremely high reliability coefficients are not

necessary. They suggest that maze tests having relatively low coeffi­

cients are useful when one is interested in differences in mean per­

formance of very large groups or of individuals at two extremes of

the population. These authors have observed that if a group is

close in ability they will be less likely to maintain their respect­

ive ranks consistently. Tolman and Nyswander (1927) disagree with

the results of several studies (Hunter, 1922; Liggett, 1925; Randolph

and Hunter, 1926) which showed relatively low reliability coefficients

and concluded that results from all maze tests should be disregarded.

Several features that Tolman and Nyswander (1927) suggested might be

responsible for low reliability coefficients are: 1) mazes used were

too simple, 2) lack of preliminary training, 3) poor control of moti­

vation, and 4) too few trials used to furnish data. Hunter and Randolph

(1924) used the test-retest method to determine coefficients of corre­

lation human of learning scores on a stylus maze test. They obtained

higher coefficients of correlation with longer intervals between test­

ing and retesting. They also studied rats in a variety of learning

problems, finding the most consistent results with a T-raaze test.

Heron (1930) used the test-retest method in a study of rats in

a multiple T-maze. He found correlations of about .35 between tests.

Heron concluded that animals may forget at different rates between

tests and that keeping all factors constant during two different time

periods is impossible.

14

Validity is another important factor to be considered in the

evaluation of any learning test. A valid test is one that measures

what it is supposed to measure (Hall, 1951; Denenberg and Banks, 1962).

Denenberg and Banks (1962) emphasize the difficulty in evaluating

validity when studying behavior, such as learning or emotionality,

that cannot be directly observed. Hall (1941, 1951) proposed valida­

tion of a test by correlating it with a different test assumed to mea­

sure the same trait. Commins et al (1932) and Hebb and Williams (1946)

pointed out that the most valid ratings of human intelligence are based

on a large number of tasks while many animal studies have regarded re­

sults, from one test as direct indicators of learning ability. Several

authors have suggested that learning ability of animals be evaluated

on several tasks, each requiring a different kind of performance

(Tolman and Nyswander, 1927; Commins et al., 1932; Hebb and Williams,

1946; Kratzer, 1971). Hebb and Williams (1941) note that certain

tests might be measures of motivation or timidity, or a complex of

these factors with intelligence but that they are not interpretable

measures of learning ability in general. Searle (1949) suggested that

"maze bright" animals are not superior in all learning situations but

have traits more adaptable to maze learning. Tolman and Nyswander

(1927) cited the favorable performance of rats compared with humans

to indicate that maze learning is not an index of all types of learn­

ing ability.

Commins et al. (1932) proposed several requirements for research

comparing different types of learning tests. These were: 1) the

15

situations should require similar patterns of adjustment not affected

by interference or general activity level of the subject, 2) motiva­

tion should be similar, 3) animals should have sufficient heterogeneity

to give a spread of scores, 4) the tests used should be reliable, and

5) the problems should be different enough to give a fair distribu­

tion of scores. These requirements were similar to those listed by

Tryon (1931). Commins et al. (1932) compared scores of rats on a Stone

multiple T-maze, Stone light discrimination box, an elevated 12-blind

U-maze and a 20-blind Miles elevated T-maze. They found correlations

between the various mazes, but no relationship was found between per­

formance on the discrimination test and the mazes.

Learning Behavior in the Horse and Other Domestic Animals

Until the mid-1970's, research involving equine behavior was un­

common. Only recently has the value of such work been recognized.

Early interest in horse behavior was generated by reports of

Clever Hans, a trained horse who demonstrated apparently phenomenal

intelligence. Hans could supposedly read and solve various mathe­

matical problems. Controversy between those who believed in the

animal's mental abilities and those who suspected trickery led to

the establishment of an investigative commission in 1911 to settle

the dispute. Pfungst (1965) reported their findings. He reported

that Hans was actually receiving the answers from his handler. When

blindfolded, he correctly answered only 6% of the questions compared

to his previous accuracy of 98%. Pfungst determined that the animal

16

was responding to very slight movements of his handler's head. Karl

Krall who had worked with Hans' ox^er was later able to duplicate

this behavior with Muhamed and Zarif, two Arabians.

Hamilton (1911) compared a horse to humans, monkeys, cats and

dogs in a multiple choice test. Each subject was placed in a com­

partment with four exit doors, one of which was unlocked. The same

door was never unlocked on successive trials. The subject received

food after making a correct response. Only human subjects learned not

to try the door which was previously opened. The horse required more

total responses to achieve 100 goals than did the c^her subjects. In

24% of the trials, the horse repeatedly made unsuccessful attempts

to open a locked door without trying another. Hamilton suggested that

the horse's relatively poor performance might be due to the particular

test given being more suited to the other species tested rather than

the horse's lack of ability.

In 1933, Gardner tested 68 horses, ranging in age from 1 to 20

years, by comparing the rate at which they learned to open a covered

feed box. A decrease in time required to solve the problem (from a

mean of 160 sec. to 5 sec.) over four trials indicated that learning had

occurred. Several of the subjects were retested at various intervals

up to 12 months after the original test and demonstrated retention of

learning. The effects of age, sex and breed on learning also were

considered. Horses from 5 to 14 years of age were more successful

than younger and older animals. Geldings learned more quickly

than mares in th - first trial, but no overall differences were

17

noted. Similar results were reported when effects of breed were

studied; draft horses demonstrated better performance than did light

horses in the first trial only. When cows were tested with the same

problem, it was solved more quickly on the first trial, but, by the

fourth trial, scores were the same for both species.

Gardner's next study (1937a,b) involved a discrimination problem

in which 62 horses and 41 cows were tested over 16 trials. The animals

were presented with three covered feed boxes, two of which were empty.

The box containing feed which alternated between trials was designated

by a black cloth draped over it. Total number of errors on each trial

was recorded. Although both species learned the discrimination, the

horses showed a more rapid initial decrease in number of errors which

was attributed to greater adaptability to the test situation. Position

preferences were noted in both species. Although the younger horses

learned more rapidly than older ones, cows showed no age effects on

performance. Pronounced breed differences were observed among the

cows with Guernsey, Brown-Swiss, and Holstein-Friesian animals making

fewer errors than Jerseys, Shorthorns and Ayrshires. In a subsequent

study. Gardner (1937c,d) tested 44 horses and 31 cows which had learn­

ed the discrimination problem. The conditions in this test were

identical to those in the previous problem except the position of the

discriminative stimulus was changed. Mean errors of both species

were similar to those on the first discrimination after an initial

increase in errors. Breed, age and sex effects were consistent with

the earlier test in both species.

18

Warren and Warren (1962) tested two horses in a series of dis­

crimination reversals combining brightness and spatial cues. Both

animals learned rapidly, averaging two or fewer errors per reversal.

This study showed that the performance of horses on this type of

test was comparable to that of other mammals in previous studies.

Dixon (1966) tested one pony on pattern discrimination, learning

set and memory. The pony reached a 92.5% correct score in the final

test, discriminating between 20 different pairs of patterns. More

rapid learning was observed on each successive pair of patterns. The

pony required 70 sessions to learn the first 10 pairs but only 17

sessions to learn the remaining 10 discriminations. These results

agree with Hebb (1949) who stated that new learning is facilitated

by old. Harlow (1949) explained "learning to learn" by stating that

subjects learn general solutions to frequently encountered problems.

Grizmek (1968) reported handedness in horses. Of the 53 animals

in his study, 77% showed a preference for the foot used in pawing,

67% showed a preference for the foot used to initiate walking, and

23% showed a preference for a lead. Grizmek also, studied the horses'

visual perception by using a goal box based on color. The number of

correct responses varied greatly when different colors were used with

a red goal box resulting in the fewest correct responses. Perform­

ance improved with blue and green; the best results were obtained

with yellow. The study concluded that visual activity in horses is

inferior to that of humans.

19

Miller (1974) also studied horses' color perception in a simple

discrimination test in which the animals were allowed to choose

between a pair of colored buckets at a distance of 9.14 m. Feed was

placed in one of the buckets and their position was reversed at ran­

dom. He reported that horses could distinguish between the following

pairs of colors: black and white; blue and orange; purple and yellow;

and red and green. In a similar test, symbols including a cross,

square, circle, rectangle and triangle were used as the discrimina­

tive stimuli. The symbols were placed on cards in front of the goal

buckets. Miller compared the number of trials required for each

animal to achieve a level of 80% correct responses. He suggested that

such tests might be useful in predicting learning ability in young

horses.

In 1976, Yeates conducted a discrimination test with three half-

sib two-year-old mares. The mares were conditioned to push a flap

for feed reinforcement. No differences were found between animals in

time required to shape the response. After the response had been ac­

quired, distinct differences in response rate which were consistent

throughout the study were observed. The subsequent 21 day discrimina­

tion test included three periods in which auditory, visual and

tactile stimuli were used with a fixed interval schedule of rein­

forcement. Correct responses for the different stimuli were auditory,

69.2%; visual, 56.7%; and tactile, 44%. Higher scores were achieved

when the apparatus was modified to make the test more effortful and

when the animals were put in a free operant situation.

20

Kratzer £t ail (1977) conducted an escape learning test using

37 Quarter Horse yearling geldings in a two-compartment maze. Errors

in making a right hand escape were reduced from 65% to 27% in five

trials. The next phase of the test was a reversal learning which re­

quired the horses to learn to go to the left. Performance on this

pattern did not reach the levels achieved in the right-side escane

trials. However, when adverse stimuli were added to the right side,

performance to the left improved rapidly. Errors dropped from 78%

to 16% in 3 trials. Latency of response decreased during the first

phases of testing but increased significantly with the adverse

stimuli.

Fiske and Potter (1979) tested 26 yearling horses in a 20-day

serial reversal learning discrimination test combining spatial and

brightness cues. The learning curves obtained, using linear regres­

sion analysis of mean trials and mean errors for all 26 horses show

a reduction of trials and errors over time. However, a great deal

of variation among individuals was noted, with a learning ability

index (LAI = 100/mean trials to criteria/mean errors to criteria)

range from 64.4 to 1.3. Mean trial to criterion scores ranged from

13.05 to 30.00 and mean errors ranged from 1.19 to 24.71. A positive

correlation was reported between maze scores and a subjective train-

ability rating for colts and geldings. No significant correlation

was found between trainability scores and any of the measures of per­

formance for fillies. The authors attributed this phenomenon to a

lack of concentration due to estrus behavior.

21

Maze learning, avoidance learning and social dominance were

studied by Haag et al. (1980) using a group of 10 ponies. Rank in the

dominance hierarchy was not correlated with ranks obtained in the

maze and shock avoidance tests. Maze rank was correlated .with three

of the five criteria used to measure avoidance learning. In contrast

to the results of this study, maze and shock avoidance learning were

not found to be correlated in swine (Hammel etal., 1975) or in rats

(Robustelli et al., 1963).

Mader and Price (1980) compared 10 Quarter Horses and 11

Thoroughbreds in a three-choice discrimination test using visual

cues. Quarter Horses learned significantly faster than Thoroughbreds

and performance improved for both breeds in a second discrimination

task. A negative correlation existed between age and rate of learn­

ing. Individual emotionality ratings and learning scores were not

correlated, but Quarter Horses as a group were less reactive than

Thoroughbreds. No correlation was found between social dominance

and learning scores.

Rubin et al. (1980) studied the effect of varying the temporal

distribution of conditioning trials on the horse's learning behavior.

Fifteen ponies were first taught to clear a small jump in response

to a buzzer to avoid a shock. All groups received 10 trials per day

but one group was conditioned every day, another twice a week, and

the third only once a week. The animals conditioned once a week

required fewer sessions to learn the response but their elapsed

learning time was greater. The ponies then were assigned to

22

different groups and taught to back in response to a visual cue to

avoid shock. The schedules for the three groups were the same as

the previous test and the results for the two tests were similar.

A Hebb-Williams closed field maze was used by McCall et al

(1981) to study learning ability in 15 yearling horses. A new prob­

lem was presented each day with eight trials per problem. Perform­

ance was evaluated by the excess entry score method devised by

Pollard and Sampson (1961). The horses made most of their errors

during the first four trials of each problem. The animals were most

successful at solving problems with direct visual solutions. No

significant differences due to sex or prior learning experience were

found. Total excess entry scores and rapidity of learning scores

were not related, suggesting that these criteria measure different

aspects of learning.

Heird (1981) examined the effects of early experience on learn­

ing ability in a simple place-learning T-maze test. He divided 24

yearling fillies into three groups based on the amount of handling

they had experienced. The intermediately handled group required

fewest trials to reach criteria and had the highest percent correct

responses. Borh intermediately and extensively handled groups learned,

while the unhandled fillies showed no improvement in performance over

time. Subjective trainability scores tended to predict group learn­

ing ability, but trainability and trials to criterion were not signifi­

cantly correlated. The author suggested that horses who will later

be exposed to a wide variety of stimuli should be handled more exten­

sively than those who will be exposed to limited stimuli.

23

In a related study, Whitaker (1982) divided 40 horses into five

handling groups and tested them on the same place learning test. Train-

ability scores were given prior to testing and during a post-maze test

under saddle. The results showed that performance had reached an

asymptote for all groups by the 10th day of training, but, in the

initial phase of the test performance was superior in the more handled

groups. Pre-test trainability scores and under saddle scores were

positively correlated but were not related to performance in the maze.

A limited amount of research concerned with learning in other

livestock species has been done. These studies may be more relevant

to learning in horses than those involving laboratory animals because

of the similarities between horses and other farm animals. Baryshnikov

and Kokorina (1946) achieved classical conditioning in dairy cattle

with 11.6 pairings of food reward and conditioned stimulus. They also

reported negative relationships between degree of nervousness and

ability to acquire food-conditioned motor reflexes. Nervousness was

negatively correlated to milk production. In contrast to these re­

sults, Dickson (1967) found that neither temperament nor dominance

value was correlated with milk production.

Wieckert et al. (1966) used a visual discrimination test in a

modified T-maze to evaluate learning ability in 6-month-old dairy

heifers. A performance level of 80% correct responses was attained

after three sessions of 10 trials each. Using a similar test, Dick­

son (1967) reported that calves differed in their ability to remember

and form, visual associations. Albright et al. (1966) used instrumental

24

conditioning to teach cows a homing response with an auditory

stimulus.

Liddell and Anderson (.1931) conditioned sheep and goats to make

reflexive leg movements in response to a metronome paired with elec­

trical shock. Liddell (1954) reported differences in maze learning

ability in twin lambs. Cairns (1966) used a U-maze to test strength

of association between lambs housed with dogs and lambs housed with

ewes. All lambs in the study learned the maze quickly and chose the

species of previous association. Sandler et al. (1968) used crossbred

ewes in a detour problem which was quickly solved by all subjects.

In 1915, Yerkes and Cobum reported the first study of condition­

ing and learning using pigs. They found that pigs could discriminate

between right-left relationships to obtain food. Curtiss (1937)

trained pigs to open food boxers in response to cessation of a buzzer.

Klopfer (1961) reported that pigs have the capacity to utilize non-

visual cues more readily than visual cues. Wieckert and Barr (1966)

reported significant breed and sex differences in learning ability

of pigs in a T-maze. Instrumental conditioning was used by Baldwin

and Ingram (1967) who placed pigs in a cold environment where they

learned to press a switch to obtain a short burst of heat. Baldwin

(1979) used operant techniques to determine environmental preferences

of both pigs and sheep.

CHAPTER III

REPEATABILITY A JD COMPARISON OF TTTO MAZE TESTS

TO MEASURE LEARNING ABILITY IN HORSES

Summary

Sixteen Quarter Horses were divided into two groups after being

sorted by age and sex. After a 10-day pre-conditioning period, each

animal received emotionality and trainability scores. Each group

then completed a series of four 20-day tests. One group of animals

was initially used in a simple place test in a modified T-maze. Dur­

ing the same time period, the other group was involved in a visual

discrimination test. The groups were tested alternately on the two

types of tests in successive test periods with a 10-day extinction

period between each test. A horse that reached a criterion of 11 of

12 correct reponses, with the last eight being consecutive, was re­

tired for the day. Otherwise, 20 daily trials were required. The

discrimination test was clearly more difficult than the place test.

Learning occurred abruptly on the discrimination tests compared to

the gradual improvement in performance observed on place tests.

Animals learned more rapidly and reached higher levels of performance

as the series of tests progressed. Trainability and emotionality

scores tended to predict learning ability but were not significantly

correlated with measures of performance. Correlations of ranks with­

in groups were higher between tests of the same type than comparisons

made between the place and discrimination tests. Comparisons between

25

26

performance of animals grouped by emotionality or trainability scores

on the last 5 days of each test demonstrated significant differences

between these groups. These results suggest that such scores tend

to predict the final level of learning achieved rather than rate of

learning.

Introduction

Learning is a major factor in the economics of the horse industry

because the horse's value increases with training. In recent years,

increased interest in equine learning ability has resulted in a grow­

ing number of learning studies. Many of these tests have used vari­

ous types of mazes to measure learning ability. Many of these studies

are based on the assumption that performance on any type of test

indicates general learning ability. If maze tests are to be of value

in equine learning research, their reliability should be determined.

The objective of this study was to determine whether results obtained

from a series of maze tests, using the same horses, would yield

consistent results.

Experimental Procedure

Experimental Animals. Sixteen Quarter Horses were randomly

assigned to one of two groups after being sorted by sex and age.

Eight mares and eight geldings were used in the experiment. The

animals ranged in age from 1 to 15 years. Seven yearlings, three

2-year-olds, three 3-year-olds and three aged horses were in­

cluded. Two of the yearling geldings were eliminated from the

experiment due to extremely emotional behavior in the maze. One of

these was removed after the preconditioning period: the other com­

pleted Tests 1 and 2 with no evidence of learning. A 6-year-old

mare died during Test 3, leaving the data of 13 animals for analyses.

Test Sequence. After a lO-day preconditioning period, each

animal received subjective emotionality and trainability scores.

Each group then underwent a series of four 20-day tests. One group

of animals was initially used on a simple place test in a modified

T-raaze. During the same time period, the other group was involved

in a discrimination test using the same basic maze with a discrimina­

tive stimulus added at the choice point. The groups were tested

alternately on the two types of tests in successive time periods.

Ten-day extinction periods were included between tests.

Maze Design. A modified T-maze was used in both types of tests

(figure 1). The plywood walls were 2.44 m high to reduce visual dis­

tractions. The branches of the maze contained feed buckets and were

equipped with exit doors, eliminating the need for the horses to re­

trace their paths. The maze was built inside the indoor arena at

the Texas Tech Horse Center so that weather effects and other dis­

tractions would be reduced as much as possible. A brightly painted

sliding panel was placed at the choice point as a visual stimulus

for the discrimination tests.

Preconditioning Period. The 10-day preconditioning period

allowed the horses to become accustomed to the maze and the ration to

be used as reinforcement. The feed consisted of 95% whole oats and

28

4.88m

^ FEED TUBS ^

SWINGING DOORS'

•1.83m-

< 2.44m ».

-1.83m-

DISCRIMINATIVE STIMULUS

4.88m

< 2.44m >

START

' * -1 .22m-*

FIGURE 1. MODIFIED T-MAZE

29

5% molasses. Each animal received about 15 minutes of daily handling

during the preconditioning period. Initially, each animal was led

into the maze and allowed to eat from the bucket before being led

through the exit. An effort was made by the handler to spend equal

amounts of time with each horse in each side of the maze and to

choose between sides in a random manner. After an animal learned to

enter the maze independent of its handler, it was allowed to choose

a side on every other trial and led into the opposite side on the

next trial. This procedure reduced the development of position

preferences.

Emotionality and Trainability Scoring. After completion of the

preconditioning period, emotionality and trainability scores were

assigned to each animal. Emotionality scores were based on reaction

to a novel stimulus which was presented to each animal in a uniform

manner. Persistence of the startle response was used to evaluate

emotionality. Emotionality scores ranged from 1 to 4 with 1 denot­

ing an extremely emotional individual. Each animal also received

a subjective trainability score which was an average of scores from

three raters who were familiar with the subjects. These scores

ranged from 1 to 4 with 1 being an extremely quick learner.

Maze Procedure. The criterion of success used in both types of

test was 11 of 12 correct responses with the last eight being consecu­

tive. Horses who did not reach criterion were retired for the day

after 20 trials. Daily trials were conducted at approximately the

horse's regular feeding time. The horses were tested in a random

order each day (Steel and Torrie, 1980).

30

The score sheet designed for recording each day's results on

the place test is shown in appendix figure A. In this test, feed

was placed in alternate sides of the maze on successive days. Each

horse was brought to the start area and released by the handler.

When the horse had entered a branch of the maze, its response was

recorded as correct or incorrect. The handler then entered the maze,

caught the animal and led it out the exit door. The horses were not

led into the maze or back from the exit doors on the same side each

time.

For the discrimination test:, the daily pattern of correct re­

sponses was determined randomly (Steel and Torrie, 1980). The pattern

was recorded on the daily score sheet (appendix figure 1). The same

basic procedure x as used that was used in the place test. The dis­

criminative stimulus panel was pulled to the side of the correct

response and the feed was moved when the pattern called for the

correct response to change. The same pattern was used for all horses

on the discrimination test on a given day.

Extinction Procedure. Ten-day extinction periods between tests

were conducted to extinguish behavior learned on previous tests.

All runs through the maze during extinction were unrewarded. The

handler released the horse into the maze on alternate trials. On

trials following "free" responses, the handler led the animal to the

opposite side to reduce position preferences. The discrimination panel

was moved in a random pattern (Steel and Torrie, 1980) for the horses

which had just completed the discrimination test. Each horse completed

31

20 total extinction trails ner day, consisting of 10 "free" and 10

"forced" trials.

Statistical Analysis. Trials to criterion and percentage of cor­

rect responses by 5-day groups were analyzed by a completely random­

ized design (Barr et al., 1979). Emotionality and trainability were

analyzed by a split-plot design (Barr et al., 1979). Duncan's mul­

tiple range test was used for mean separations (Steel and Torrie,

1980). Spearman correlations were calculated for rank analyses (Barr

et al., 1979).

Results and Discussion

Percentage of Correct Responses. The mean percentage of correct

responses for each group was determined for each day, for each 5-day

block and for each test. Group 1 had a mean of 73% correct responses

in the first 20-day place test. This mean is lower than those found

on a similar test by I*/hitaker (1982). His five handling groups had

scores which ranged from 77.7 to 85.6% correct responses. Our scores

also were lower than those observed by Heird et al. (1981) in their

intermediate group which achieved 82% correct responses. These higher

scores probably are due to a greater total number of trials in Heird's

and I^itaker's tests. These tests were identical to the place test

used in this study but both investigators used 30 trials per day.

Nonhandled and most handled groups of Heird et al. obtained a lower

percentage of correct responses than the horses in this study, scor­

ing 60 and 67% correct, respectively.

The daily means of Group 1 on Test 1 of this study ranged from

45% correct on day 1 to 91% correct on day 20. These results are

32

consistent with those of the intermediate group of Heird et al. (1981),

which improved from 61% correct on day 3 to 92% correct on day 19.

Although the other groups of Heird et al. (1981) showed some improve­

ment in performance, they failed to yield the usual learning curve.

All of Whitaker's (1982) groups demonstrated an increase in percent­

age of correct responses as a result of practice. The initial in­

crease in percentage of correct responses through day 3, which was

reported by Whitaker (1982) and Fiske and Potter (1979), was not evi­

dent in the present study.

The mean percentages of correct responses by block of Group 1

for each test is shown in figure 2. I^en averaged over 5-day blocks,

percentage of correct responses was lower (P<.05) for block 1 (days

1 to 5) of Test 1 than for block 4 (days 16 to 20), but neither of

these scores differed significantly from those of blocks 2 and 3.

The mean percentage of correct responses for the last block of this

study was 82.9%. These results are comparable to those of I'Jhitaker

(1982) who reported that all of his groups achieved means of 85% or

higher correct responses after day 12.

On Test 2, a discrimination test. Group 1 had a mean of 76.3%

correct responses with mean daily scores ranging from 42% on day 1

to 87.8% on day 17. The mean score for block 1 was significantly

lower than those for blocks 2, 3 and 4 whose mean percentages of

correct responses did not differ (P>.05). These results indicate

that discrimination learning occurs rather abruptly when compared to

the gradual improvement demonstrated on the place test. The horses

33

appeared to hypothesize on the discrimination test. This phenomenon

was first noticed by Lashley (1929) and Krechevsky (1932) and is a

major feature of attention theories of discrimination.

Group 1 achieved a mean of 88.6% correct responses on Test 3,

another place test. Their daily mean scores ranged from 77.5% correct

on day 1 to 94.4% correct on day 20. The mean percentage of correct

responses on block 1 was lower than those for blocks 2, 3 and 4 which

were not different (P>.05).

The early learning in this test compared to the previous two

tests demonstrates the "learning to learn" phenomenon which has also

been reported in horses by Dixon (1966), Fiske and Potter (1979),

and flader and Price (1980) .

Mean percentage of correct responses for Group 1 on their final

test, another discrimination, was 88.7%. Daily mean scores ranged

from 80.8% correct on day 3 to 95.8% correct on day 19, but mean per­

centages of correct responses did not differ (P>.05) between 5-day

blocks on this test, indicating that a high level of performance was

maintained throughout this test.

Mean percentages of correct responses for this group did not

differ (P>.05) between Tests 1 and 2. A significantly higher percent­

age of correct responses was achieved on Tests 3 and 4 which did not

differ.

Group 2 was started on a discrimination test in which they achieved

a mean of 64.4% correct responses. Yeates (1976) reported a compar­

able mean of 56.7% correct in a visual discrimination test under

34

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TEST 3

TEST 4

GROUP 1

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PLACE

(6-10) 2 (11-15) 3

FIVE DAY BLOCKS

(16-20) 4

•DISCRIMINATION

FIGURE 2. PERCENTAGE OF CORRECT RESPONSES FOR GROUP 1 BY 5-DAY BLOCKS

35

operant conditions. Group 2's score was significantly lower than that

of Group 1 on Test 1, indicating that the discrimination was more

difficult than the place test.

Group 2's mean daily scores ranged from 44.2% correct responses

on day 2 to 90.9% correct responses on day 20. This final score is

consistent with the results of Dixon (1966) whose pony achieved 92.5%

correct responses on the final day of a visual discrimination test

using 20 different pairs of patterns.

When analyzed by 5-day blocks, (figure 3) the 49% correct re­

sponses for Group 2 on block 1 of this test was significantly lower

than those on blocks 3 and 4. The mean score of 79.8% correct on

block 4 was higher (P<.05) than those on blocks 1 and 2. Mean scores

on blocks 2 and 3 did not differ. Mader and Price (1980) reported

more rapid learning on a similar test. A criterion of 80% correct

responses on a three choice visual discrimination was reached by

Quarter Horses in 5.4 days and Thoroughbreds in 8.4 days on their

test.

Group 2 reached a mean of 86.4% correct responses on Test 2, a

place test. Mean daily scores on this test ranged from 78% correct

on day 1 to 93% on day 20. These relatively high scores suggest

that previous learning of a more difficult task facilitated learn­

ing on the simple place test.

The mean percentage of correct responses for Group 2 on Test 3

was 89.3% with a mean daily of 62% correct on day 1 to 96% on day 11.

The mean percentage of correct responses for block 1 was significantly

36

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1 (1-5) 1 (6-10) 2 (11-15) 3

PLACE FIVE DAY BLOCKS

DISCRIMINATION

(16-20) 4

FIGURE 3. PERCENTAGES OF CORRECT RESPONSES FOR GROUP 2 BY 5-DAY BLOCKS

37

lower than those on blocks 2, 3 and 4 which did not differ. These

results indicate that learning occurred in the first few days of this

test.

A mean percentage of 86.7% correct responses was achieved on

Test 4 by Group 2. The high score of 94% correct responses was

achieved on day 1 and a low score of 79.2% occurred on day 2 of this

test. No differences (P>.05) were noted between mean scores during the

5-day blocks. A tendency for the percentage of correct responses to

decrease during the 20-day test was noted, perhaps indicating boredom

due to the simple nature of this test.

Group 2 had a significantly lower mean percentage of correct

responses on Test 1 than on the remainder of the tests. Percentage

of correct responses for this group did not differ for Tests 2, 3 and

4. These results, compared with the percentage of correct responses

of Group 1 over the four tests, indicate that learning the more diffi­

cult test initially facilitated the animals' ability to learn.

Trials to Criterion. The mean number of trials to criterion for

each group was calculated for each day, for each 5-day block and for

each test. Group 1 averaged 16 trials to criterion for Test 1 with

daily means ranging from 20.0 on day 1 to 12.2 on day 20. This im­

provement over time represents learning. Heird et al. (1981) showed

a decrease in trials to criterion with his intermediately handled

group. Fiske and Potter (1979) reported mean numbers of trials to

criterion for individuals ranging from 13.05 to 30.00 on a similar

reversal test. Mean number of trials to criterion by block for Group

38

1 on each test is shown in figure 4. Group 1 required more trials

to reach criterion during block 1 (P<.05) than they did in the re­

maining 5-day blocks, which did not differ significantly. Whitaker

(1982) reported no improvement in trials to criterion after day 10.

Results from this study and I^itaker's (1982) test suggest that

learning occurs rapidly on the place test.

Daily trials to criterion for Group 1 on Test 2 ranged from 20

on days 1 to 4 to 14.2 on days 12, 17 and 18 with a mean score of 16.6.

More trials were required to reach to criterion on block 1 than blocks

2, 3 and 4, which did not differ significantly. These results indi­

cate that learning occurred in the first few days of the study. Since

learning occurred sooner and mean trials to criterion were lower than

in Group 2 on Test 1, it can be concluded that, at least with this

measure, previous experience with the simple maze test facilitated

learning the discrimination test. As indicated earlier, this was not

true for the percent correct measure. Lawrence (1952) stated that

animals trained on an easy problem learned to attend more strongly

to relevant stimuli than those initially given a difficult problem.

On Test 3, Group 1 required a mean of 13.5 trials to reach cri­

terion. The mean score for this group on day 18 was 12 trials to cri­

terion, a nearly perfect performance. Mean trials to criterion did

not differ among the 5-day blocks which may indicate that learning

was complete at the end of Test 1 and well remembered.

Group 1 reached a mean of 14.7 trials to reach criterion on Test

4 with no differences (P>.05) between 5-day blocks. Mean number of

39

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TEST 4

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. . . . 1 (1-5) 1 (6-10) 2 (11-15) 3

FIVE DAY BLOCKS

(16-20) 4

PLACE DISCRIMINATION

FIGURE 4 . NU>ffiER OF TRIALS TO CRITERION FOR GROUP 1 BY 5-DAY BLOCKS

trials required to reach criterion on Tests 3 and 4 were signifi­

cantly lower than the number of trials to criterion for Tests 1 and

2 which did not differ. Test 4 did require more mean trials to

criterion than Test 3 for Group 1, demonstrating the greater diffi­

culty of the discrimination task.

Figure 5 shows the mean numbers of trials to criterion by block

for Group 2 on each test. Group 2 shows no improvement in number of

trials to reach criterion during block 1 of Test 1. The mean score

for this entire period was 20, indicating that no individual reached

criterion before day 6 of this test. No significant differences

between mean trials to criterion on blocks 1, 2 and 3 were found.

Number of mean trials required to reach criterion decreased during

days 16 to 20 (P<.05), indicating that learning occurred during this

time period. Fewest mean trials to criterion for this test occurred

on day 20 when the group mean was 12.3.

On Test 2, Group 2 achieved a mean of 14 trials to criterion

with daily means ranging from 16.3 on day 3 to 12.1 on day 7. I'Jhen

analyzed by 5-day blocks, the number of trials required to reach cri­

terion was significantly higher for block 1 than for blocks 2 or 4,

which did not differ (P>.05). Mean niiraber of trials to criterion for

block 3 did not differ significantly from any of the other blocks of

days. These results indicate that learning occurred early in this

test.

Rapid learning was also demonstrated by this group on Test 3.

The mean number of trials to criterion on this test was 14.6. Dailv

41

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TEST1

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(1-5) 1 (6-10) 2 (11-15) 3

PLACE ^ ' ^ ^ ° ^ ^ BLOCKS

DISCRIMINATION

(16-20) 4

FIGURE 5. NUMBER OF TRIALS TO CRITERION FOR GROUP 2 BY 5-DAY BLOCKS

42

mean trials to criterion improved from 20 on day 1 to 11.9 on day 11,

A significantly greater number of trials to criterion were required

for block 1 than blocks 3 or 4. Mean number of trials to criterion

for block 2 did not differ (P>.05) from any other block of days.

Although the mean number of trials to criterion for Test 4 was

higher during the first few days with a high of 14.9 on day 1, no

significant differences among the 5-day blocks were found for this

test. For Group 2, the mean number of trials to criterion for Test

1 was significantly higher than the values for the remaining tests

which did not differ (P>.05). These results support the idea that

initial learning of a difficult task facilitates later learning.

A significant negative correlation between number of trials to

criterion and percentage of correct responses was found on each of

the four tests of this study (table 1). This relationship would be

expected if these are measures of the same traits. Consequently,

most of the results evaluated by trials to criterion support the

findings in the previous discussion section.

TABLE 1. CORRELATION COEFFICIENTS FOR TRIALS TO CRITERION ANT) PERCENTAGE OF CORRECT RESPONSES

Test Correlation coefficient

1 -.78**

2 -.76'^*

3 -.77**

4 -.81**

**P<.01.

43

Trainability Scores. After the pre-conditioning period, each

horse received a trainability score which was an average of sub­

jective scores from three raters. Scores ranged from 1 to 4 with

low scores indicating a greater predisposition to learn.

Simple correlation coefficients were calculated between train-

ability scores, number of trials to criterion and percentage of cor­

rect responses for each test. No significant correlation

was found between trainability scores and either of the measures of

maze performance. Heird (1981) found no correlation between train-

ability scores and trials to criterion. Fiske and Potter (1979) ob­

served negative relationships between trainability scores and both

mean errors and mean trials to criterion for colts and geldings but

not for fillies. They attributed this phenomenon to erratic behavior

during estrus. Whitaker (1982) reported a significant negative corre­

lation between group trainability scores and number of trials to

criterion.

The horses were grouped separately for high and low trainability

scores for comparison of mean of number of trials to criterion and

percentage of correct response for 5-day blocks. The mean scores of

high and low trainability groups for percentage or correct responses

and number of trials to criterion by 5-day blocks are shown in figures

6 and 7. Although differences between groups were not significant,

the animals in the trainable group tended to require fewer trials to

reach criterion and achieve a higher percentage of correct responses

on both types of test. Similar trends were noted by Heird et al. (1981)

44

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TRAINABILITY GROUPS

90

80

70

60

50

90

80

70

60

50

DISCRIMINATION TEST

PLACE TEST

X (1-5) 1 (6-10) 2 (11-15) 3 (16-20) 4

FIVE DAY BLOCKS

LOW TRAINABILITY

HIGH TRAINABILITY

FIGURE 6 . PERCENTAGE OF CORRECT RESPONSES FOR TRAINABILITY GROUPS BY 5-DAY BLOCKS

45

19 TRAINABILITY GROUPS

Z o cc UJ H CC

o

DISCRIMINATION TEST

18

17

16

15

14

13

PLACE TEST

.J < cc

16

15

14

13 (1-5) 1 (6-10) 2 (11-15) 3 (16-20) 4

FIVE DAY BLOCKS

LOW TRAINABILITY

HIGH TRAINABILITY

FIGURE 7. NUMBER OF TRIALS TO CRITERION FOR TRAINABILITY GROUPS BY 5-DAY BLOCKS

/, 6

who suggested that these scores could predict learning over time

rather than individual daily performance.

A higher mean percentage of correct responses (P<.05) was achiev­

ed by the trainable group when scores for block 4 were compared.

These animals also tended to require fewer trials to reach criterion

during this block of days. These results indicate that these sub­

jective scores predict the level at which an asymtote is reached.

Although trainability scores are not related to rate of learning, they

appear to predict the level of performance ultimately achieved. Simi­

lar results of comparisons between performance of horses separated by

emotionality support these conclusions.

Emotionality Score. Several authors (Searle, 1949; Thompson

and Bindra, 1952; Fuller, 1962; Craig, 1981) have suggested that emo­

tionality combined with motivational, physical and intellectual char­

acteristics, may determine performance in a maze-learning situation.

An emotionality score based on reaction to a novel stimulus was assign­

ed to each animal after the pre-conditioning period. Scores ranged

from 1 to 4 with 1 denoting a highly emotional individual.

Simple correlation coefficients were calculated for each test

between emotionality scores, number of trials to reach criterion and

percentage of correct responses. No significant correlation was found

between emotionality scores and maze test performance. A negative

correlation was found between emotionality and trainability scores

(r = -.51, P<.07). \^itaker (1982) reported a negative correlation

(r = -.68, P<.01) between daily emotionality scores and trainability.

4 /

Fiske and Potter (1979) observed a relationship between emotionality

and trainability for colts and geldings but not for fillies. Thomp­

son and Bindra (1952) found no significant difference in emotional­

ity of "maze bright" and "maze dull" rats.

The animals in this study were grouped according to emotional­

ity score and their performance on both types of test was compared.

Their mean number of trials to criterion and percentages of correct

responses were calculated for 5-day blocks. These results are shown

in figures 8 and 9. The highly emotional animals required more tials

to reach criterion (P<.05) than did the less emotional group on the

place test. The less emotional group also achieved a higher percent­

age of correct responses with the difference approaching significance

(P<.08). On a similar test, Fiske and Potter (1979) found a signifi­

cant negative correlation between number of trials to criterion and

emotionality scores for colts and geldings but not for fillies. Al­

though TAjhitaker (1982) found no relationship between group emotion­

ality scores and number of trials to criterion, he reported a signifi­

cant negative correlation between daily individual emotionality scores

and number of trials to criterion.

Although differences between emotionality groups for the discrimi­

nation test were not significant, a tendency for the less emotional

animals to require fewer trials to reach criterion and achieve a higher

percentage of correct responses was observed. Mader and Price (1980)

found a similar relationship between emotionality scores and performance

on a similar test. They observed that Quarter Horses learned a three-

UJ

z O Q. V> UJ cc

I -o Ui a. cc o o

u. O

UJ

(5 < Z UJ O CC UJ

a

90

80

70

60

50

90

80

70

60

43

EMOTIONALITY GROUPS

DISCRIMINATION TEST

PLACE TEST

(1-5) 1 X

(6-10) 2 (11-15) 3

FIVE DAY BLOCKS

(16-20) 4

LOW EMOTIONALITY

HIGH EMOTIONALITY

FIGURE 8 . PERCENTAGE OF CORRECT RESPONSES FOR EMOTIONALITY GROUPS BY 5-DAY BLOCKS

49

cc UJ H E o

o

(0

< CC

19 h

18

17

16

15

14

13

17

1 6 -

EMOTIONALITY GROUPS

DISCRIMINATION TEST

\

PLACE TEST

1 5 -

14 -

13

N

J.

(1-5) 1 (6-10) 2 (11-15) 3

FIVE DAY BLOCKS

(16-20) 4

LOW EMOTIONALITY

HIGH EMOTIONALITY

FIGURE 9 . NUMBER OF TRIALS TO CRITERION FOR EMOTIONALITY GROUPS BY 5-DAY BLOCKS

50

choice discrimination significantly faster than Thoroughbreds. The

Quarter Horses tended to be less reactive but no correlation x>ras

found between individual emotionality and learning scores.

Less emotional animals demonstrated superior performance in the

last 5 days of testing. Mean scores for block 4 were different be­

tween emotionality groups for both trials to criterion and percent­

age of correct responses (P<.001). These results suggest that although

emotionality may not affect rate of learning, less emotional animals

ultimately achieve a higher level of performance on a learning test.

Rank Correlations. Spearman correlation coefficients were calcu­

lated between results of each test. The animals were ranked according

to percentage of correct responses. For Group 1, which started on the

place test, ranks on Test 1 were correlated with those on Test 2

(r = .27, P<.001) and Test 3 (r = .33, P<.001). Ranks for Test 2,

a discrimination test, were correlated with those on Test 3 (r = .25,

P<.006) and Test 4 (r = .41, P<.001).

Rank correlations between test and retest for both types of

tests were consistent with figures mentioned by Tolman and Nyswander

(1927). These early experimenters stated that reliability coeffi­

cients for rats in maze tests usually ranged from .3 to .6. Tryon

(1931) found much higher correlations between learning and releaming

using rats. His correlations between learning and releaming on

three maze tests averaged .81. The rats used in Tryon's (1931) study

were from strains that had been selectively bred for extremes in

D L

ability. Tolman and Nyswander (1972) noted that such extremes of

ability usually result in abnormally high reliability coefficients.

The highest rank correlation for Group 1 was between Tests 2 and

4, the discrimination tests. These results support Tolman and

Nyswander's (1927) suggestion that higher reliability coefficients

are found with more difficult tests.

For Group 1, significant rank correlations were found for each

possible combination of tests except 1 and 4. When calculated by

type, rank correlations between place and discrimination learning

were found for Group 1 (r = .23, P<.001). Tryon (1931a) found a much

higher correlation between two different T-mazes. Again, this differ­

ence probably is due to the extreme nature of his experimental group.

When Spearman correlation coefficients were calculated for Group

2, correlations were found between tests of the same type but no sig­

nificant relationship was found between ranks on different types of

tests. These results may be due to some type of order effect; per­

haps learning by animals learning the difficult problem first is

task-specific. Correlations were found for Group 2 between discrim­

ination tests (r = .33, P<.0001) and between place tests (r = .26,

P<.002).

Spearman coefficients were calculated between ranks on odd and

even days for each group and test. The animals were ranked by trials

to criterion. A high correlation would suggest that the animals'

ranks are consistent throughout a particular test. High correlations

were found between ranks on odd and even days on each of the

52

discrimination tests (table 2). No significant correlations were

found for the place test. This difference might be due to the simple

nature of the maze test, the effects of position preferences on the

place test or a combination of these. Heird et al. (1981) reported

that his nonhandled group showed strong position preferences. This

tendency resulted in inconsistent results since an animal who con­

sistently went to the same side each x>7ould have extremely high and

low scores on alternate days.

TABLE 2. SPEAR IAN CORRELATION COEFFICIENTS FOR RANKS ON ODD AND EVEN DAYS ON DISCRIMINATION TESTS

Group Test Correlation coefficients

1 2 .62**

1 4 .30**

2 1 .74**

2 3 .45**

**P<.01.

Conclusions. Improvement in performance over time was evident

in both the place and discrimination tests, but the discrimination

was clearly more difficult than the place test. Learning occurred

abruptly on the discrimination tests compared to the gradual improve­

ment in performance observed on the place tests. Animals learned

more rapidly and reached higher levels of performance as the series

of tests progressed. Trainability and emotionality scores tended to

predict maze learning ability. Significant differences were

53

demonstrated between performance of animals grouped by emotionality

or trainability scores for the last 5-day period. These results

suggest that such scores tend to predict the final level of learning

achieved rather than rate of learning.

Low but significant correlations of ranks within groups were

higher between tests of the same type than comparisons made between

the place and discrimination tests.

Rank correlations between odd and even days on each test indi­

cated that the animals' ranks within groups were consistent through­

out the discrimination tests but were more variable on the place

tests. This difference is possibly due to the effects of position

preferences on the place test along with its relative simplicity.

LITERATURE CITED

Albright, J. L., W. P. Gordon, W. C. Black, J. P. Dietrich and W. W. Snyder. 1966. Behavioral responses of cows to auditory training. J. of Dairy Sci. 49:104.

Baldwin, B. A. 1979. Operant studies on the behavior of pigs and sheep in relation to the physical environment. J. Anim. Sci. 49:1125.

Baldwin, B. A. and D. L. Ingram. 196 7. Behavioral thermoregula­tion in pigs. Physiol. Behav. 2:15.

Barr, A. J., J. H. Goodnight, J. P. Sail, W. H. Blair and D. M. Chilko. 1979. A user's guide to SAS 79. SAS Institute Inc., Gary, N.C.

Baryshnikov, I. A. and E. P. Kokoring. 1964. Higher nervous activity in cattle. Dairy Sci. 26:97.

Bitterman, M. E. 1964. Phyletic differences in learning. Amer. Psychol. 20:396.

Bitterman, M. E. 1979a. Historical introduction. (In) Bitterman, M. E., V. M. Lolordo, J. B. Overmier and M. E. Rashotte. Animal Learning - Survey and Analysis. Plenum Press, New York.

Bitterman, M. E. 1979b. Discrimination. (In) Bitterman, M. E., V. M. Lolordo, J. B. Overmier and M. E. Rashotte. Animal Learning - Survey and Analysis. Plenum Press, New York.

Bitterman, M. E. 1979c. Attention. (In) Bitterman, M. E., V. M. Lolordo, J. B. Overmier and M. S. Rashotte. Animal Learning -Survey and Analysis.

Cairns, R. B. 1966. Development, ra.aintenance and extinction of social attachment behavior in sheep. J. Compar. and Physiol. Psychol. 62:298.

Clayton, K. N. and S. T. Koplin. 1964. T-maze learning as a joint function of probability and magnitude of reward. Psychon. Sci. 1:381.

Commins, W. D., Q. McNemar and C. P. Stone. 1932. Intercorreiations of measures of ability in the rat. J. Compar. Psy. 14:225.

Craig, J. V. 1981. Domestic Animal Behavior. Prentice-Hall, Inc., Englewood Cliffs, N.J.

54

Crespi, L. P. 1942. Quantitative variation of incentive and per­formance in the white rat. Amer. J. Psychol. 55:467.

Curtiss, Q. F. 1937. Experimental neurosis in the pig. Psychol. Bull. 34:723.

Denenberg, V. H. and E. M. Banks. 1962. Techniques of measurement and evaluation. (In) E. S. Hafez (Ed.) The Behaviour of Domestic Animals. Williams and Wilkins Co., Baltimore.

Derdzinski, D. and J. M. Warren. 1969. Perimeter, complexity and form discrimination learning by cats. J. of Comp. and Phys. Psych. 68:407.

Dickson, D. P. 196 7. A study of social dominance, temperament and learning ability in dairy cattle. Ph.D. Thesis. University of Wisconsin, Madison.

Dixon, J. C. 1966. Pattern discrimination, learning set, and memory in a pony. Paper given at Midwest Psychological Assoc. Convention, Chicago, IL.

Fantino, E. and C. A. Logan. 1979. The Experimental Analysis of Behavior - A Biological Perspective. W. H. Freeman and Co., San Francisco.

Fiske, J. C. and G. D. Potter. 1979. Discrimination reversal learn­ing in yearling horses. J. Anim. Sci. 49:583.

Fuller, J. L. 1962. The genetics of behavior. (In) E. S. Hafez (Ed.) The Behavior of Domestic Animals. Williams and Wilkins Co., Baltimore.

Gardner, L. P. 1933. The responses of horses to the situation of a closed feed box. J. of Comp. Psyc. 15:445.

Gardner, L. B. 1937a. The responses of horses in a discrimination problem. J. of Comp. Psyc. 23:13.

Gardner, L. P. 1937b. The responses of cows in a discrimination problem. J. of Comp. Psyc. 23:35.

Gardner, L. P. 1937c. Responses of horses to the same signal in different positions. J. of Comp. Psyc. 23:305.

Gardner, L. P. 1937d. The responses of cows to the same signal in different positions. J. of Comp. Psyc. 23:333.

Grizmek, B. 1968. On psychology of the horse. In H. Friedrick

(Ed.) Man and Animal: Studies in Behavior. St. Martins Press,

Inc., New York.

56

Haag, E. L., R. Rudman and K. A. Houpt. 1980. Avoidance, maze learning and social dominance in ponies. J. Anim. Sci. 50:329.

Hall, C. S. 1941. Temperament: a survey of animal studies. Psych. Bull. 38:909.

Hall, C. S. 1951. Individual differences In C. P. Stone (Ed.) Comparative Psychology. Prentice-Hall, Inc., Englewood Cliffs, N.J.

Hamilton, G. V. 1911. A study of trial and error reactions in mammals. J. Anim. Behav. 1:33.

Hammell, D. L. , D. D. Kratzer and W. J. Bramble. 1975. Avoidance and maze learning in pigs. J. of Anim. Sci. 40:573.

Harlow, H. F. 1949. The formation of learning sets. Psych. Rev. 56:51.

Hebb, D. 0. 1949. The Organization of Behavior. Wiley Press, New York.

Hebb, D. 0. and K. Williams. 1946. A method of rating animal in­telligence. J. of Gen. Psych. 34:59.

Heird, J. C , A. M. Lennon and R. W. Bell. 1981. Effects of early experience on the learning ability of yearling horses. J. Anim. Sci. 53:1204.

Heron, W. T. 1922. The reliability of the inclined plane problem box as a method of measuring the learning ability of the rat. Comp. Psych. Monog. 1:1.

Heron, W. T. 1930. The test-retest reliability of rat learning scores from the multiple T-maze. J. of Genet. Psych. 38:101.

Hill, W. F. , J. W. Cotton and K. M. Clayton. 1962. Effect of reward magnitude, percentage of reinforcement and training method on acquisition and reversal in a T-maze. J. of Exp. Psych. 64:81.

Hintzman, D. L. 19 78. The Psychology of Learning and Memory. W. H. Freeman and Co., San Francisco.

Honig, W. K. 1969. Attentional factors governing the slope of the generalization gradient. (In) R. M. Gilbert and N. S. Suther­land (Eds.) Animal Discrimination Learning. Academic Press, London.

Hull, C. L. 1943. Principles of Behavior. Appleton-Century, New York.

57

Hunter, W. S. 1922. Correlation studies with the maze in rats and humans. Comp. Psych. Monog. 1:37.

Hunter, W. S. and V. Randolph. 1924. Further studies on the reli­ability of the maze with rats and humans. J. of Como. Psy. 4:431.

Kimble, G. A. 1961. Conditioning and Learning (2nd Ed.). Appleton-Century-Crofts, New York.

Klopfer, F. D. 1961. Early experience and discrimination learning in swine. Amer. Zool. 1:366.

Kratzer, D. D. 19 71. Learning in farm animals. J. of Anim. Sci. 32:1268.

Kratzer, D. D., W. M. Netherland, R. E. Pulse and J. P. Baker. 1977. Maze learning in Quarter horses. J. Anim. Sci. 45:896.

Krechevsky, I. 1932. 'Hypotheses' in rats. Psych. Rev. 39:516.

Krechevsky, I. 1938. A study of the continuity of the problem-solving process. Psych. Rev. 45:107.

Lashley, K. S. 1929. Brain Mechanisms and Intelligence. Univ. of Chicago Press, Chicago, IL.

Lawrence, D. H. 1952. The transfer of a discrimination along a continuum. J. of Comp. and Phys. Psych. 45:511.

Leeper, R. 1932. The reliability and validity of maze experiments with white rats. Gen. Psych. Monog. 11:137.

Levine, M. A. 1959. A model of hypothis behavior in discrimination learning set. Psych. Rev. 66:353.

Levine, M. A. 1965. Hypothesis behavior. ^ A. M. Schrier, H. F. Harlow and F. Stollnitz (Eds.) Behavior of Nonhuman Primates: Modern Research Trends. Academic Press, New York.

Liddel, H. S. 1954. Conditioning and emotions. Scientific Amer. 190:48.

Liddell, H. S. and D. D. Anderson. 1931. A comparative study of the conditioned motor reflex in the rabbit, sheep, goat, and pig. Amer. J. Physiol. 97:339.

Liggett, J. R. 1925. A note on the reliability of the chick's performance in two simple mazes. J. of Genet. Psych. 32:470.

58

Mackintosh, N. J. 1965. Selective attention in animal discrimina­tion learning. Psych. Bull. 64:124.

Mackintosh, N. J. 19 74. The Psychology of Animal Learning. Academic Press, London.

Mader, D. R. and E. D. Price. 1980. Discrimination learning in horses: effects of breed, age, and social dominance. J. Anim. Sci. 50:962.

Mandler, J. M. 1968. The effect of overtraining on the use of posi­tive and negative stimuli in reversal and transfer. J. of Comp. and Phys. Psych. 66:110.

McCall, C. A., G. D. Potter, T. H. Friend and R. S. Ingram. 1981. Learning abilities in yearling horses using the Hebb-Williams closed field maze. J. Anim. Sci. 53:928.

Miller, R. W. 1974. Horse Behavior and Training. Big Sky Books, Bozeman, MT.

Morgan, C. L. 1894. An Introduction to Comparative Psychology. Walter Scott, London.

Munn, N. L. 1950, Handbook of Psychological Research on the Rat. Riverside Press, Cambridge.

Paterson, D. G. 1917. The John Hopkins circular maze studies. Psych. Bull. 13:294.

Pfungst, 0. 1965. Clever Hans. Robert Rosenthal (Ed.) Holt, Rinehart, and Winston, Inc., New York.

Pollard, J. S. and H. Sampson. 1961. Scoring performance in the closed-field test. Australian J. Psychol. 13:92.

Randolph, V. and W. S. Hunter. 1926. A note on the reliability of

the maze as a method of learning in the Angora goat. J. Genet.

Psych. 33:1.

Rashotte, M. E. 1979. Reward training: extinction Bitterman, M 'E V. M. Lolordo, J. B. Overmier and M. E. Rashotte. Animal Learning - Survey and Analysis. Plenum Press, New York.

Restle, F. 1955. A theory of discrimination learning. Psych. Rev.

62:11.

Robustelli, F., J. L. McGough and D. Bouet. 1963. Relationship

between avoidance conditioning and maze learning. Psych. Rep.

13: 103.

59

Rubin, L., C. Oppegard and H. F. Hintz. 1980. The effect of vary­ing the temporal distribution of conditioning trials on equine learning behavior. J. Anim. Sci. 50:1184.

Sandler, B. E., G. A. Van Gelder, W. B. Buck and G. G. Karas. 1968. Effect of dieldrin exposure on detour behavior in sheep. Psychol. Rep. 23:451.

Scott, J. P. 1972. Animal Behavior. The Univ. of Chicago Press, Chicago, IL.

Searle, L. V. 1949. The organization of hereditary maze-brightness and maze-dullness. Genet. Psychol. Monog. 39:279.

Small, W. S. 1899. An experimental study of the mental processes of the rat. Amer. J. Psysiol. 11:133.

Spence, K. W. 1932. The reliability of the maze and methods of its determination. Comp. Psych. Monog. 8:1.

Spence, K. W. 1936. The nature of discrimination learning in animals. Psych. Rev. 43:427.

Spence, K. W. 1952. The nature of the response in discrimination learning. Psych. Rev. 59:89.

Steel, R. G. and J. H. Torrie. 1980. Principles and Procedures of Statistics. McGraw-Hill Book Co., New York.

Stone, C. P. 1927. The reliability of rat learning scores from the multiple T-maze as determined by four different methods. Gen. Psych. Monog. 34:498.

Stone, C. P. (Ed.). 1951. Comparative Psychology. Prentice-Hall, Inc., Englewood Cliffs, N.J.

Sutherland, N. S. 1964. The learning of discrimination by animals. Endeavor. 23:140.

Sutherland, N. S. 1966. Partial reinforcement and breadth of learn­ing. Q. J. Exp. Psych. 18:289.

Sutherland, N. S. and N. J. Mackintosh. 1971. Mechanisms of Animal Discrimination Learning. Academic Press, New York and London.

Tarpy, R. M. 1975. Basic Principles of Learning. Scott, Foresman and Co., Glenview, IL.

Tarpy, R. M. and R. E. Mayer. 1978. Foundations of Learning and Memory. Scott, Foresman and Co., Glenview, IL.

60

Tavolga, W. N. 1969. Principles of Animal Behavior. The Univ. of Chicago Press, Chicago, IL.

Thompson, W. R. and D. Bindra. 1952. Motivational and emotional characteristics of "bright" and "dull" rats. Can. Jour. Psych. 6:116.

Thorndike, E. L. 1898. Animal intelligence: An experimental study of the associative processes in animals. Psychol. Rev. Monog. Suppl. 2:8.

Thorndike, E. L. 1905. The Elements of Psychology. Serler, New York.

Tolman, E. C. and D. B. Nyswander. 1927. The reliability and validity of maze measures for rats. J. Comp. Psych. 7:425.

Tolman, E. C. 1955. Principles of performance. Psych. Rev. 62:315.

Tryon, R. 1926. Effect of the unreliability of measurement on the difference between groups. J. of Comp. Psych. 6:449.

Tryon, R. C. 1931. Studies in individual differences in maze ability. III. The community of function between two maze abilities. Jour. Compar. Psychol. 12:95.

Tryon, R. C. 19 31. Studies in individual differences in maze ability IV. The constancy of individual differences: correlation be­tween learning and releaming. J. Compar. Psy. 12:303.

Warren, J. M. and H. B. Warren. 1962. Reversal learning by horse and raccoon. J. of Genet. Psych. 100:215.

Watson, J. B. 1914. Behavior: An Introduction to Comparative Psychology. Henry Holt and Co., New York.

I^itaker, D. D. 1982. Effects of varying amounts of early handling at weaning and later ages on the subsequent learning ability of two-year-old horses. Ph.D. Dissertation. Texas Tech Univ., Lubbock.

Wieckert, D. A., L. P. Johnson, K. P. Offord and G. R. Barr. 1966. Measuring learning ability in dairy cows. J. Dairy Sci. 49:6 3.

Wieckert, D. A. and G. R. Barr. 1966. Studies of learning ability in young pigs. J. Anim. Sci. 25:1280.

Wilcoxin, H. C. 1969. Historical introduction to the problem of reinforcement. In J. T. Tapp (Ed.) Reinforcement and Behavior. Academic Press, London.

61

Yeates, B. F. 19 76. Discrimination learning in horses. Master's Thesis, Texas A & M Univ., College Station.

Yerkes, R. M. and C. A. Cobum. 1915. A study of the behavior of the pig by the multiple choice method. J. Anim. Behav. 5:185

APPENDIX A

TABLES

62

63

APPENDIX TABLE A. TRAINABILITY AND EMOTIONALITY SCORE FOR EACH HORSE TESTED

Trainability Eraotionalitv Group Horse number score^ score^

4

3

rse number

1

2

3

4

5

6

7

8

9

10

11

12

13

score^

1.3

2.0

3.3

1.7

3.3

3.0

2.3

2.7

2.3

2.7

3.3

1.7

2.3

^Scores ranged from 1 to 4 1 - extremely quick learner, 2 - quick learner, 3 - average learner, 4 - slow learner

Scores ranged from 1 to 4 1 - highly nervous, 2 - nervous, 3 - normal, 4 - quiet

4

4

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69

APPENDIX B: PLACE TEST DAILY RECORDING SHEET

PLACE

Horse

Trial

TEST

No.

Date Feed Location

Correct Incorrect

70

APPENDIX C: DISCRIMINATION TEST DAILY RECORDING SHEET

DISCRIMINATION TEST

Horse

Trial No.

1

2

3

4

5

6

Feed Location

Date

Correct Incorrect

8

9

10

11

12

13

14

15

16

17

18

19

20

APPENDIX D: SUMMARY RECORDING SHEET

Animal // Group # Test

Trainability score

Day

1

Date No. trials to criteria

Emotionality score

Number correct

71

Percent correct

4

5

6

7

8

9

10

11

12

13

14

15

16

17

13

19

20

Emotionality 1) Highly nervous 3) Normal 2) Nervous 4) Quiet

Predisposition to learning (trainability) 1) Ext. quick 3) Average 2) Quick 4) Slow