kahana faust 2002

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Neuropsychologia 40 (2002) 892901

Priming summation in the cerebral hemispheres: evidence fromsemantically convergent and semantically divergent primes

Miriam Faust, Allon KahanaDepartment of Psychology, Bar-Ilan University, Ramat Gan 52900, Israel

Received 31 January 2000; received in revised form 19 January 2001; accepted 31 July 2001

Abstract

Theability to activate andto maintain a large andrelatively undifferentiated semantic field has been thought to be an important component

of lexical semantic processing by the right hemisphere (RH). An implication of this unique propensity of the RH was examined in the

present study that included two divided visual field priming experiments with SOAs of 800 and 2500ms. The experiments investigated the

ability of the RH and the left hemisphere (LH) to summate activation from multiple primes followed by a laterally presented ambiguous

target word. The priming words either converged onto the same semantic representation (i.e. all three words related to either the dominant or

to the subordinate meaning of the target) or diverged onto distinct semantic representations (i.e. two words related to the dominant and one

to the subordinate meaning of the target, or vice versa). Resultsindicated that for either an 800 or 2500 ms stimulus onset asynchrony (SOA)

the LH benefited most from three semantically convergent primes that converged onto the dominant meaning of the ambiguous target word.

There was no facilitation when three subordinate primes preceded the target. When the primes diverged onto different meanings, there

was significant facilitation for the 800 ms SOA only. In contrast, with an 800 ms SOA, the RH benefited only from semantically divergent

primes, that diverged onto alternate meanings of the ambiguous target word. With a 2500 ms SOA, the RH benefited from all combinations

of primes. The discussion focuses on the implications for language processing of the differences between the two hemispheres in the scope

and temporal pattern of the multiple prime effect. 2002 Elsevier Science Ltd. All rights reserved.

Keywords: Hemispheric asymmetry; Visual fields; Multiple priming; Lexical ambiguity

1. Introduction

Although the superiority of the left hemisphere (LH) for

language processing is indisputable, it is now clear that word

meaning access is bilateral. Data from normal brain and from

patients with injury to the RH imply that each hemisphere

processes the meaning of words, although not necessarily in

the same way. The differences between the two hemispheres

in word meaning activation may result in the right hemi-

sphere (RH) having a great deal of influence on language

processing (for reviews see [6,8,13,15,16]). According to the

RH coarse semantic coding theory [6,9], after encountering

a word, the LH engages in relatively fine semantic coding,

strongly focusing activation on a single interpretation of a

word and a few close or contextually appropriate associates,

whereas the RH engages in coarse semantic coding, weakly

and diffusely activating alternative meanings and more dis-

tant associates. The present study examined an important

implication of the coarse semantic coding by the RH: the

Corresponding author. Tel.: +972-3-5318547; fax: +972-3-5350267.

E-mail address: [email protected] (M. Faust).

ability to summate activation from multiple primes that di-

verge onto distinct, unrelated semantic representations (e.g.

money-river-vault as priming stimuli for the target word

bank).

Research on language processing in the two cerebral

hemispheres relies heavily on semantic priming methods,

that allow for the evaluation of RH language processing

independent of the overall superiority of the LH for word

recognition. Taken as a whole, the results of priming studies

reveal qualitatively distinct patterns of priming in the two

hemispheres, suggesting that different semantic information

is most accessible within each hemisphere at different mo-

ments during language processing. Two factors determine

hemispheric differences in semantic access and retrieval:

the nature of semantic relations between words and the time

course of meaning activation [16]. While the LH maintains

a relatively small semantic field, including only closely re-

lated meanings and a single interpretation, the RH weakly

activates a much broader range of related meanings, in-

cluding peripheral and unusual meanings (e.g. metaphoric

interpretations, multiple meanings of ambiguous words, see

[1,2,14]). Furthermore, the range of meaning activation in

0028-3932/02/$ see front matter 2002 Elsevier Science Ltd. All rights reserved.

PII: S 0 0 2 8 -3 9 3 2 (0 1 ) 0 0 1 7 4 - 9


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M. Faust, A. Kahana/ Neuropsychologia 40 (2002) 892901 893

the RH is not just wider, but also less discriminant. While in

the LH, strongly related meanings are activated much more

than weakly related meanings, in the RH weakly related

meanings are also highly activated. Thus, the RH obtains

equal priming from high and low dominant category primes

[19], from a single strongly related associate as from a set

of three weak associates [9], from words related via twosemantic relations as from words related via only one [18],

from contextually relevant as from contextually nonrelevant

meanings of ambiguous words [23,25] and from the domi-

nant and subordinate meanings of ambiguous words [2,16].

The differences between the hemispheres in meaning

availability are usually more pronounced for long stim-

ulus onset asynchronies (SOAs), when strategic and/or

post-access prime processing and inhibition for unrelated

words may only occur within the LH. When relatively long

SOAs were used, larger priming effects in the RH were

found for subordinate meanings of ambiguous words at

750 ms SOA [14], for metaphoric meanings of words at

800 ms SOA [1], for contextually nonrelevant meanings ofambiguous words at 900 ms SOA [23] and 1000 ms SOA

[25], for several weakly related prime words at 700 ms SOA

[9] and for several prime words forming a compound with

the target word at 2000, 7000, 15 000 ms SOA [10].

These results suggest that while LH fine semantic coding

[9] has a clear advantage for most linguistic processes, RH

coarse semantic coding is critical for mediating those aspects

of comprehension which require the simultaneous consider-

ation of more than one plausible meaning, or the sustained

activation of a wide range of word meanings. This unique

ability of the intact RH could account for the difficulties that

RH damaged persons have in appreciating jokes, metaphors,connotations, idioms, sarcasm and indirect requests, which

may depend on the continued activation of multiple mean-

ings [1113]. Thus, these patients seem to behave as if their

intact LH is operating without the semantic support of the

damaged RH [15].

To sum up, the results of semantic priming studies as

well as data collected from brain damaged patients converge

on the idea that the RH contributes to language processing

mainly by subserving widespread activation of word mean-

ings, without subsequent selection. The undifferentiated ac-

tivation of alternative, and sometimes contradictory, inter-

pretations for some indefinite period [14,15,26] may have

significant implications, that have not been explicitly tested

in past research, for the ability of the RH to benefit from

semantically divergent information.

These differences between LH focusing on the most

salient or dominant meaning of a word versus RH main-

taining multiple meanings of words, are relevant to the

processing of both single words and words appearing in a

sentence context [14,23,25]. For every word, even if it is

seemingly unambiguous, there is a large body of divergent

semantic information associated with it. The components of

this semantic information, i.e. the semantic features of the

word, include the definitive properties as well as associa-

tions of the word [6]. Only a subset of all possible semantic

features of a word is relevant in a given context, or, most

salient when there is no context. This is particularly true for

ambiguous words, which may have meaning subsets that

are semantically incompatible with each other. Semantic

processing in the LH may consist of initially activating all

semantic information related to an ambiguous word, thenselecting the dominant or contextually relevant meaning

while actively inhibiting the less frequent or contextually

nonrelevant semantic features [1,14,23,25,31].

In contrast to single words, the selected meaning of

words appearing in sentences is aided by the syntax and

message-level semantics of the sentence. Consequently

only the contextually relevant meanings of the words are

maintained [30]. Earlier studies have shown that the syntac-

tic and message-level semantic components of a sentence

aid in facilitating either the dominant or the subordinate

meaning of target words presented to the RVF/LH even at

relatively longer SOAs [23,25]. For single word primes, at

longer SOAs, no facilitation was found for the subordinatemeaning of target words presented to the RVF/LH [14]. No

systematic studies have been performed to date, however,

on the effect of lists of several single word primes related to

the subordinate meaning of an ambiguous target presented

to the RVF/LH. Thus, one of the questions addressed by a

multiple prime paradigm is how will a list of multiple word

primes related to the subordinate meaning of the target af-

fect target recognition? Will a multiple word list facilitate

an RVF target even at longer SOAs in a manner similar to

that of words embedded in a sentence, or will the LH show

no facilitation for the subordinate meanings at the longer

SOAs in a manner similar to that of single word primesthat are not organized into sentences? For example, primes

consisting of lists of several single words weakly related to

an RVF target, show less facilitation than a strongly related

single word prime [9]. Multiple weak primes, however, do

show strong facilitation for RVF targets when presented in

a sentence structure [22,24]. Consequently, when the SOA

is relatively long, the LH should definitely benefit from

multiple primes that converge on the dominant meaning of

an ambiguous target word, and thus multiply activate the

same subset of dominant semantic features (for discussions

of the effects of multiple primes, see [14,20]). However,

when multiple primes converge on the subordinate meaning

of an ambiguous word, priming may or may not be found

in the LH for relatively long SOAs, depending on whether

the primes are treated as a list of single words or provide

sufficient context for the LH to narrow activation to the sub-

ordinate meaning in a manner similar to that of a sentence

prime.

With regard to lists of divergent primes, the LH may be at a

relative disadvantage. Because of the lack of featural similar-

ity between the different unrelated meanings of an ambigu-

ous word and of the active inhibition of alternative meanings,

the LH may be relatively unable to benefit from semanti-

cally divergent primes that require the sustained availability


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894 M. Faust, A. Kahana/ Neuropsychologia 40 (2002) 892901

of discrete and separable subsets of semantic features, in-

cluding less frequent and incompatible features. Thus, while

the stronger activation of dominant word meanings or se-

mantic features is conducive to most language tasks, the LH

may be at a relative disadvantage when the recognition of an

ambiguous target word depends on the summation of acti-

vation from multiple primes that diverge onto two different,incompatible meanings of an ambiguous word.

In contrast, the RH diffusely activates and maintains large

semantic fields, containing many distantly related semantic

features [1,14,15,17]. The larger, and less discriminant, the

semantic field, the more likely it is to overlap with semantic

fields activated by other input words. Thus, in the RH, the

constellation of features instantiated by one meaning of the

ambiguous word could overlap, at least partly, with that of

the other meanings. Due to the sustained and undifferentiated

activation of alternate, and even incompatible [2], meanings

in this hemisphere, the RH might benefit almost to the same

degree from multiple primes that converge on either the

dominant or subordinate meanings of ambiguous words aswell as from multiple primes that diverge onto two different,

unrelated meanings of ambiguous words.

The current study was conducted to investigate what ef-

fect multiple primes that either converge on the dominant

or subordinate meaning or diverge on both dominant and

subordinate meanings may have on the activation of lexi-

cally ambiguous words presented to the right visual field

(RVF)/LH and the left visual field (LVF)/RH. An earlier

study [5] examined the combinatorial influence of two word

convergent and divergent primes on lexical decision to tar-

gets presented to the central visual field after a relatively

short SOA of 266 ms. The target words were either ambigu-ous or unambiguous for the divergent and convergent con-

ditions, respectively, and the pattern of priming reported for

both convergent and divergent primes was additive. How-

ever, the experimental conditions of that study, i.e. very short

SOAs and central visual field stimulation of primes and tar-

gets do not allow us to conclude which hemisphere and form

of processing was involved. In the present study, a lexical

decision-priming paradigm, which allowed examination of

the relative activation of different sets of meanings in the two

hemispheres, was used. We predicted that at relatively long

SOAs, RVF/LH ambiguous target words following multiple

primes related to the dominant meaning would be facilitated.

The question remains open as to whether multiple primes

that converge on the subordinate meaning will facilitate tar-

get words presented to the RVF. Due to the presence of one

or two primes related to their dominant meaning, ambiguous

RVF target words following semantically divergent multiple

primes should be facilitated, but, perhaps, to a lesser extent

than in the case of three dominant primes. In contrast, when

ambiguous target words are presented to the left visual field

(LVF)/RH, all types of priming word triads should facilitate

target word recognition, although according to Beemans

theory greater priming is still predicted in the two conver-

gent conditions than in the two divergent conditions [6,9].

2. Experiment 1

2.1. Methods

2.1.1. Participants

The participants were 20 Bar-Ilan University students,

native Hebrew speakers, aged 2025 years and strongly righthanded (laterality quotient of at least +90 on the Edinburgh

Inventory) [28]. All had normal or corrected to normal vision

and volunteered to participate in the experiment.

2.1.2. Materials

The stimulus pool consisted of priming words and target

word and nonword items, all in Hebrew. The target stimuli

were two-to-four letter words and nonwords. The 75 target

words were ambiguous, having at least two different, unre-

lated dictionary meanings (e.g. shniya in Hebrew means

secondboth as a unit of time and as an ordinal number). Ten

students, who did not participate in the experiment, were pre-

sented with 150 ambiguous words and asked to provide themeaning of each word when presented in isolation. The first

meaning given by each judge was designated as the domi-

nant meaning. Only words with a clear distinction between

their dominant (first choice of at least 75% of the judges)

and subordinate (first choice of no more than 25% of the

judges) meanings were chosen for the experiment. The 75

nonword targets were constructed by changing one letter of

each word target stimulus.

The priming stimuli were three-to-six letter words that

were related to either the dominant or subordinate meanings

of the ambiguous target words, or were completely unre-

lated. Related targets were generated in a word associationpretest in which 10 students were given each ambiguous

word and asked to write all related words that came to mind.

In a second pretest, the three related words most frequently

mentioned for each meaning of each ambiguous target word

were presented as a group to 20 different students and they

were asked to generate the corresponding ambiguous word

(the target). Only targets that were generated within 3 min by

at least 14 judges were selected for the experiments. Thus,

the final pool of priming stimuli consisted of 225 words

related to the dominant meanings of the ambiguous target

words and 225 words related to the subordinate meanings

of the ambiguous target words. The 225 unrelated priming

words were from the same list, randomly paired with unre-

lated target words.

Five kinds of word triads were constructed from these

priming words. Examples of priming word triads for the

target second (shniya in Hebrew) are provided following

the description of each type of prime:

1. A convergent (three dominant) prime: all three words

were related to the dominant meaning of the ambiguous

target word (minute, watch, time).

2. A divergent (two dominant + one subordinate) prime:

two words were related to the dominant meaning and


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one word was related to the subordinate meaning of the

ambiguous target word. The subordinate priming word

was always presented as the second stimulus, i.e. between

the two dominant priming words (minute, first, time).

3. A divergent (one dominant + two subordinate) prime:

two words were related to the subordinate meaning and

one word was related to the dominant meaning of theambiguous target word. The dominant priming word was

always presented as the second stimulus, i.e. between the

two subordinate priming words (first, watch, line).

4. A convergent (three subordinate) prime: all three words

were related to the subordinate meaning of the ambiguous

target word (first, last, line).

5. An unrelated prime: all three words were completely un-

related to the ambiguous target word (bomb, apple, joy).

As can be seen from the example given above, in the two

convergent priming conditions (1, 4) all three primes were

related both to the ambiguous target words and to each other,

while in the two divergent priming conditions (2, 3), oneprime was related only to the target word while the other two

primes were related both to the target word and to each other,

but not to the third prime [5]. However, the divergent primes

could also be related to each other via mediated priming,

with the target being the mediator [29]. In the unrelated

priming condition (5), all three primes were related neither

to the target word nor to each other.

There were 1500 experimental permutations [375 priming

stimuli (75 triads consisting of three unrelated words, 75 tri-

ads consisting of three dominant words, 75 triads of consist-

ing of two dominant words+one subordinate word, 75 triads

consisting of two subordinate words and one dominant word,75 triads consisting of three subordinate words) visual

field (left/right) lexicality (word/nonword)]. Five stimu-

lus lists, each containing 300 target stimuli (150 words, 150

nonwords) were needed to completely rotate items over ex-

perimental conditions in the full experimental design. Thus,

each participant viewed each target item twice, but in a

different experimental condition and visual field. Analysis

of the first versus second presentation of each target item

indicated that repetition did not affect the results, neither

as a main effect nor in interaction with any of the other

variables. Consequently, responses to both first and second

presentation of stimuli were included in all of the analy-

ses. Cell means were based on 15 trials per condition per

participant.

2.1.3. Apparatus and procedure

Each participant completed one experimental session, dur-

ing which he/she was exposed to a single list. Stimulus pre-

sentation and responses were controlled and recorded by a

Pentium PC 586 computer. The priming word triads were

presented simultaneously in normal horizontal orientation,

at, above and below the center of the screen, followed by the

target stimulus displayed 2 to the left or right of the cen-

trally presented +. Targets subtended, on average, 1.90

of horizontal visual angle (0.7 vertical) at a viewing dis-

tance of 50 cm.

The participant placed his/her right index finger on the

middle key of the computer mouse and waited for a focus-

ing signal (500 ms duration) which appeared on the cen-

ter of the screen and indicated the onset of a trial. Imme-

diately following the disappearance of the focusing signal,the priming word triad appeared for 500ms (pilot testing

indicated that the three words could be read and under-

stood within 500 ms). Participants were instructed to read

the words silently. Next, the focusing signal reappeared and

remained on the screen for 400 ms, until the end of the target

stimulus presentation, to ensure full fixation. The participant

was instructed at the beginning of the session to focus on

the central + and not to move his/her eyes while it was

present. Three hundred ms after the appearance of the fo-

cusing signal (total SOA800 ms), the target stimulus was

presented randomly to the RVF of LVF for 100 ms. Par-

ticipants were tested individually in a quiet, dim lit room.

They were instructed to indicate as rapidly and accuratelyas possible whether the target stimulus was a word or a non-

word by moving their finger from the middle mouse key

to the right or left mouse keys. Assignment of the keys to

word/nonword responses was counterbalanced over partici-

pants. The next trial began when a response was made or, in

the case of no response, after 3 s from the target onset. The

session began with a practice list, consisting of 30 priming

word triads and target stimuli not used in the experimental

lists.

2.2. Results

A 25 repeated measures analysis of variance with visual

field (left/right) and type of prime (dominant, dominant +subordinate, subordinate+dominant, subordinate, unrelated)

was performed on accuracy and correct RTs for target words.

Accuracy and RT for target nonwords presented to the RVF

and LVF were 68% and 1001 ms, and 63% and 999 ms,

respectively.

Means and S.D.s for response times and percent of correct

responses for ambiguous target words presented to the RVF

and LVF following the five types of primes are given in

Table 1. All correct RTs ranging from 300 to 1600 ms were

included in the analyses, 96% of all of the responses.

The main effect of visual field was significant for RT

and accuracy. Participants responded more quickly and ac-

curately to RVF (801 ms, 88%) than to LVF (845 ms, 81%)

target words, RT F (1, 19) = 13.9, P < 0.01; accuracy

F (1, 19) = 7.3, P < 0.01. In addition, a main effect of type

of prime was obtained for RT, F (4, 76) = 10.1, P < 0.001,

and accuracy, F (4, 76) = 15.9, P < 0.001. Post-hoc anal-

yses (Neuman Keuls, P < 0.05) revealed that this was due

to faster and more accurate responses to dominant (801 ms,

89%), dominant + subordinate (786 ms, 85%) and subordi-

nate + dominant (812 ms, 88%) primes than to either sub-

ordinate (847 ms, 84%) or unrelated (868 ms, 73%) primes.


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896 M. Faust, A. Kahana/ Neuropsychologia 40 (2002) 892901

Table 1

Means and S.D.s for RT and percent correct for target words presented to the RVF and LVF following five different types of primes at 800ms SOA

Prime type RVF LVF

RT (ms) Percent correct RT (ms) Percent correct

Three dominant primes 743 (93) 92 (12) 853 (134) 85 (11)

Two dominant and one subordinate prime 759 (125) 87 (9) 813 (113) 83 (13)

One dominant and two subordinate primes 803 (101) 93 (6) 823 (112) 84 (11)Three subordinate primes 833 (130) 89 (13) 861 (102) 79 (13)

Unrelated primes 861 (107) 75 (13) 875 (141) 70 (21)

Responses to subordinate primes were more accurate than

to unrelated primes.

Of greatest importance, the predicted two-way interaction

between visual field and type of prime was obtained for RT,

F (4, 76) = 4.5, P < 0.01. The critical priming predictions

are represented by contrasting each type of prime to the

unrelated prime in the two visual fields.

Fig. 1 presents the overall priming in RT for target wordspresented to the RVF and the LVF following five types of

primes. As can be clearly seen in Fig. 1, for the RVF/LH

presented targets, differences between the unrelated con-

dition and the prime conditions were largest for dominant

[118 ms, F (1, 19) = 108.9, P < 0.0001] and dominant

+ subordinate [102 ms, F (1, 19) = 55.4, P < 0.0001]

primes. The facilitation from three and two dominant re-

lated primes was larger than from one dominant prime

(F (1, 19) = 3.5, P < 0.001). Thus, priming effects were

relatively smaller, although statistically reliable, for the

subordinate + dominant condition [58 ms, F (1, 19) = 17.1,

P < 0.001]. No priming was found for the subordinate

primes [28 ms, F (1, 19) = 2.2, P < 0.2]. However, forLVF/RH presented targets, differences between the unre-

lated condition and the prime condition were largest for the

dominant+subordinate [61 ms, F (1, 19) = 9.9, P < 0.005]

and the subordinate +dominant [52 ms, F (1, 19) = 4.3,

P < 0.05] priming conditions. No priming was found for

either the dominant [22 ms, F (1, 19) = 1.5, P < 0.3] or

subordinate primes [14 ms, F (1, 19) = 0.4, P < 0.6]. Re-

sponse latency was not correlated with response accuracy

Fig. 1. RT priming for target words presented to the RVF and LVF following four types of primes (800 ms SOA).

in either the RVF/LH, r(20) = 0.06 or the LVF/RH,

r(20) = 0.08. Thus, in accordance with previous research

[4] participants were not sacrificing accuracy for speed

when responding to either RVF/LH or LVF/RH targets

following the different prime combinations.

2.3. Discussion

The overall pattern of priming reported in experiment 1

indicates that the combinatorial influence of multiple re-

lated primes is different within each hemisphere. Results

for RVF/LH presented target suggest that at an SOA of

800 ms, the LH had no more access to subordinate meanings

of ambiguous words and could not benefit from the pres-

ence of primes that are related to the subordinate meaning

of the ambiguous target word. In the LH no facilitation was

uncovered for multiple primes that converged on a single

subordinate representation. Thus, the results for RVF tar-

get words presented after three subordinate primes are more

similar to that of single word primes than to that of sen-

tence primes [1,14,23]. Furthermore, facilitation from mul-tiple primes that diverged on both the dominant and sub-

ordinate representations seemed to be entirely dependent

on the presence of dominant primes. The facilitation from

two and three dominant related primes was larger than from

one dominant prime. Thus, priming in the LH tended to in-

crease with the number of dominant primes. In contrast, for

LVF/RH presented targets, only semantically divergent mul-

tiple primes facilitated target recognition significantly. Prim-


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ing from combinations of either two dominant related and

one subordinate related primes or two subordinate related

and one dominant related primes was significant whereas

three dominant or three subordinate primes did not have a

significant facilitation effect.

In experiment 2, the same primes and targets were again

presented to each hemisphere. The experiment was designedto determine how the availability of different combinations

of multiple primes changes over time in each hemisphere.

Therefore, in experiment 2 we used an even longer SOA, of

2500 ms, that is much longer than that used in most priming

studies of simple word recognition.

Previous research suggests that the differences between

the two hemispheres with respect to the availability of word

meanings may be more pronounced for long SOAs. Specifi-

cally, unique RH priming of more distant semantic relations

is found later in processing [17]. Furthermore, when very

long SOAs (several seconds) were used in the context of

insight problem solving, that requires the sustained avail-

ability of remote meanings, the RH tended to show not onlylarger priming effects than the LH, but even an advantage in

raw response times [7,10] and a tendency for an advantage

in response accuracy [26], an unusual result in normal, right

handed participants. Thus, results of experiment 2 were ex-

pected to replicate those observed in experiment 1 and to be

even more robust, showing greater priming for divergent and

for subordinate primes in the RH as compared to the LH.

3. Experiment 2

3.1. Methods

3.1.1. Participants

The 30 participants were Bar-Ilan University students,

native Hebrew speakers, aged 2025 years and strongly right

handed (laterality quotient of at least +90 on the Edinburgh

Inventory) [28]. All had normal or corrected to normal vision

and volunteered to participate in the experiment. None of

them had participated in experiment 1.

3.1.2. Materials

The stimulus pool consisted of priming words and target

word and nonword items, all in Hebrew, that were identicalto those used in experiment 1.

Table 2

Means and S.D.s for RT and percent correct for target words presented to the RVF and LVF following five different types of primes at 2500ms SOA

Prime type RVF LVF

RT (ms) Percent correct RT (ms) Percent correct

Three dominant primes 686 (152) 88 (9) 695 (130) 88 (9)

Two dominant and one subordinate prime 715 (157) 83 (12) 666 (111) 87 (14)

One dominant and two subordinate primes 707 (172) 82 (12) 673 (131) 86 (13)

Three subordinate primes 740 (184) 80 (14) 676 (127) 85 (10)

Unrelated primes 747 (179) 66 (16) 725 (152) 73 (17)

3.1.3. Apparatus and procedure

Apparatus and procedure were identical to those used in

experiment 1, except for the difference in SOAs. In experi-

ment 2, the priming words were presented for 2200 ms, so

that the total SOA was 2500 ms (2200 ms prime duration +300 ms focusing signal duration) as compared to 800 ms in

experiment 1 (500 ms prime duration+ 300 ms focusing sig-nal duration).

3.2. Results

A 25 repeated measures analysis of variance with visual

field (left/right) and type of prime (dominant, dominant +

subordinate, subordinate+dominant, subordinate, unrelated)

was performed on accuracy and correct RTs for target words.

Accuracy and RT for target nonwords presented to the RVF

and LVF were 72% and 803 ms, and 68% and 811 ms, re-

spectively.

Means and S.D.s for response times and percent of correct

responses for ambiguous target words presented to the RVF

and the LVF following the five types of primes are given in

Table 2. All correct RTs ranging from 300 to 1600 ms were

included in the analyses, 95% of all of the responses.

The main effect of visual field was significant for RT

and marginally significant for accuracy. However, the effect

was opposite to that expected. Participants responded more

quickly and accurately to LVF (687 ms, 84%) than to RVF

(720 ms, 80%) target words, RT F (1, 29) = 5.8, P < 0.05;

accuracy F (1, 29) = 2.4, P < 0.15. In addition, a main

effect of type of prime was obtained for RT, F (4, 116) =6.8, P < 0.001, and accuracy F (4, 116) = 30.4, P

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kahana faust 2002