A Conceptual Framework

• Scientific worldview• Scientific inquiry • Scientific enterprise

•Scientific Worldview• The world is understandable

– “Science presumes that the things and events in the universe occur in consistent patterns that are comprehensible through careful, systematic study.”

• Ideas are subject to change– “Change in knowledge is inevitable because new

observations may challenge prevailing theories.”

• Knowledge is durable– “Although scientists reject the notion of attaining

absolute truth and accept some uncertainty as part of nature, most scientific knowledge is durable.”

• Science Cannot Provide Complete Answers to All Questions– “There are many matters that cannot usefully be

examined in a scientific way “

Scientific Inquiry• Sound empirical evidence

– “Sooner or later, the validity of scientific claims is settled by referring to observations of phenomena.”

• Logic plus imagination– “Scientists do not work only with data and well-developed theories.”

• Science Explains and Predicts– “Scientists strive to make sense of observations of phenomena by

constructing explanations for them that use, or are consistent with, currently accepted scientific principles.”

– “Theories should also fit additional observations that were not used in formulating the theories in the first place; that is, theories should have predictive power.”

• Scientists Try to Identify and Avoid Bias– “But scientific evidence can be biased in how the data

are interpreted, in the recording or reporting of the data, or even in the choice of what data to consider in the first place.”

• Not authoritarian– “In the long run, no scientist, however famous or highly

placed, is empowered to decide for other scientists what is true, for none are believed by other scientists to have special access to the truth.”

Scientific Inquiry

The Scientific Enterprise• Complex social activity

– “Men and women of all ethnic and national backgrounds participate in science and its applications. “

• Science Is Organized Into Content Disciplines– “Organizationally, science can be thought of as the

collection of all of the different scientific fields, or content disciplines.”

• Ethical principles– “Most scientists conduct themselves according to the

ethical norms of science.”

• Scientist-as-citizen– “Scientists can bring information, insights, and analytical

skills to bear on matters of public concern.”

Overview of Scientific method

PsychologyPsychology QuestionsQuestions• We need to do research because we don’t always know how people will behave

or what they think.

• For example, answer “True” or “False” to these statements:

• Mothers talk to their younger children differently than they talk to their older children.

• False

• Very few students will confess to ruining a computer program if they didn’t do it.

• False

• Writing about adjusting to college improves students’ grades.

• True

The Scientific Method

The scientific method is the way that scientific psychologists gain knowledge about behavior and mental processes.– The scientific method is not a particular technique or tool.– Instead, it is a general approach to gaining knowledge.

We can compare the scientific method to our “everyday,” nonscientific ways of gaining knowledge on several dimensions:

general approach instrumentsobservation measurementreporting hypothesesconcepts attitude

NonscientificIntuitive

Uncritical, accepting

Casual, uncontrolled

Biased, subjective

Ambiguous

Inaccurate, imprecise

Not valid or reliable

Untestable

ScientificEmpirical

Critical, skeptical

Systematic, controlled

Unbiased, objective

Clear definitions

Accurate, precise

Valid and reliable

Testable

Table 2.1

General approach

Attitude

Observation

Reporting

Concepts

Instruments

Measurement

Hypothesis

General Approach

Nonscientific

• Intuitive– judgments and decisions are

based on what “feels right.”

What is an advantage of intuitive thinking?

Scientific

• Empirical– judgments and decisions are

based on direct observation and experimentation.

– What is an advantage of an empirical approach

Observation

Nonscientific

• Casual, uncontrolled– personal biases and other

factors influence observation.

Scientific

• Systematic, controlled– control is the essential

ingredient of science.– Scientists gain the greatest

control when they conduct an experiment.

Observation (continued)

• Control: Scientists investigate the effect of various factors one at a time in an experiment.

• An experiment has at least one independent variable and at least one dependent variable.– Independent Variable (IV): A factor that researchers control or

manipulate in order to determine the effect on behavior.• A minimum of two levels: The treatment (experimental) condition

and the control condition– Example: In the Pennebaker and Francis (1996) study, the independent variable was whether

students wrote about adjusting to college (experimental condition) or about superficial topics (control condition).

Observation (continued)

– Dependent Variable (DV): The measure of behavior that is used to assess the effect of the independent variable.

• Example: In the Pennebaker and Francis (1996) study on the effects of emotional writing compared to superficial writing, one dependent variable was students’ Grade Point Average (GPA).

• In most psychology research, several dependent variables are measured to assess the effects of the independent variable.

– For example, Pennebaker and Francis also measured students’ health.

Concepts

• Nonscientific– Ambiguous– We use words even when not clear in their meaning

(e.g., “intelligence”).

• Scientific– Clear, specific definitions– Construct = concept

Constructs

• There are many psychological constructs.Examples: aggression, depression, emotion, intelligence, memory, personality, stress, well-being.

• An operational definition is the specific procedure used to produce and measure a construct.

• Advantages of operational definitions:– Allow scientists to define specifically what they mean by their

construct– Allow clear communication among scientists.

• Disadvantages:– A potentially limitless number of operational definitions exists for any

particular construct.

– Some operational definitions may be meaningless.

Constructs (continued)

Match each construct with an operational definition:

Construct Operational DefinitionA. score on the Minnesota Multiphasic

Aggression Personality Inventory

Depression B. score on the final exam of this course

Intelligence C. number of times person hits another person

Memory D. number of depression symptoms from the

Knowledge of Diagnostic and Statistical Manual

research methods E. score on the Wechsler Adult Intelligence

Personality Scale (WAIS)

F. score on the Digit-Span Test of memory

Measurements

• Physical measurement involves dimensions that have agreed-upon standards and instruments.– Examples: length, weight, time

• Psychological measurement is used to measure constructs for which there is no agreed upon standard or instrument.– Are there agreed upon standards for what is considered beauty,

intelligence, or aggression?

• Psychologists develop measures to assess these and other psychological constructs.

Measurements

• Measures must be valid and reliable.– Validity refers to truthfulness; a valid measure is one that measures

what it claims to measure.• Example: Do exams in your courses test the material covered in

course lectures and texts?

– Reliability refers to the consistency of a measure.• For example, a measure is considered reliable when different

observers consistently agree about an observation.

– Note that a measure may be reliable but not valid.• For example, a scale that consistently underreports someone’s

weight is reliable but not valid.

Hypotheses

• Hypotheses are not testable if they have any of these three characteristics:– Constructs are not adequately defined.

• Example: People become aggressive following exposure to media violence because the violence is “disturbing.”

– The hypothesis is circular — the event itself is used as an explanation of the event.

• Example: People become aggressive following exposure to media violence because they become verbally or physically abusive.

– The hypothesis appeals to ideas or forces that are not recognized by science.

• Example: People become aggressive following exposure to media violence because they are overcome by the Devil.

Goals of the Scientific Method

• Description - Researchers define, classify, catalogue, or categorize events and their relationships to describe mental processes and behavior.

• Prediction – Use relationships among variables to predict mental processes and behavior.

• Explanation - Researchers understand and can explain a phenomenon when they can identify its cause(s).

• Application - Psychologists apply their knowledge and research methods to improve people’s lives.

Description

• Researchers define, classify, catalogue, or categorize events and their relationships to describe mental processes and behavior.

– Example: Psychologists describe symptoms of depression. One operational definition of depression comes from the list of symptoms in the Diagnostic and Statistical Manual.

Description

• Most psychology research is nomothetic rather than idiographic.– Nomothetic: large sample sizes, “average”

performance of a group– Idiographic: individual case studies

• Most psychology research is quantitative rather than qualitative– Quantitative: statistical summaries of performance– Qualitative: verbal summaries of research findings

Prediction• When researchers identify correlations (relationships) among

variables, they are able to predict mental processes and behavior.– Example: As level of depression increases, individuals exhibit more

helplessness (failure to initiate activities and pessimism regarding the future).

• A correlation occurs when two measures of the same people, events, or things vary together or go together.

• Correlation does not imply causation. We don’t know why the variables are correlated.– For example, there’s a correlation between the amount of hair in one’s

ear and the presence of heart disease. (true)– Does this mean that having hair in one’s ears causes heart disease?

• Correlation does not imply causation. We don’t know why the variables are correlated

Prediction (continued)

• When two variables are correlated, if we know people’s scores for one variable, we can statistically compute (predict) their scores for the second variable.– For example, if we know the extent to which someone

has experienced life stress, we can compute their likelihood of experiencing physical illness (and predict stress based on illness).

– Because test scores (SAT, GRE) are correlated with grades, we can predict students’ grades based on knowing their test scores (and predict test scores from grades).

Explanation

• Researchers understand and can explain a phenomenon when they can identify its cause(s).

– Example: Research participants exposed to unsolvable problems become more pessimistic and less willing to do new tasks (i.e., they become helpless) than participants who are asked to do solvable problems.

Explanation (continued)• Researchers conduct controlled experiments to

identify the causes of a phenomenon.• Control requires that researchers manipulate

factors, one at a time, to determine their effect on the event of interest — these are independent variables.

• Researchers observe the effect of the independent variable by measuring dependent variables.

• Remember: The word “experiment” is often used in everyday language to mean the same thing as “research,” but the word experiment refers to a very specific type of research study.

Explanation (continued)• Three conditions for making a causal inference:

1. Covariation of events: If one event causes the other, the two events must vary together (when one changes, the other must change also).

2. Time-order relationship: The presumed cause must occur before the presumed effect.

3. Elimination of plausible alternative causes: We accept a causal explanation only when other possible causes of the effect have been ruled out.

Causal Inferences

– Scientific control requires that the effects of independent variables are isolated.

– A confounding occurs when two potentially effective independent variables are allowed to vary together simultaneously — we cannot determine which variable caused the effect on the dependent variable.

– When an experiment is free of confoundings, we can make a causal inference regarding the effect of the independent variable on the dependent variable.

Generalization• Researchers are not interested just in the one

sample of people or the one set of circumstances they tested.

• They wish to generalize a study’s findings to different populations, settings, and conditions beyond those used in the specific study.– Can we generalize or apply the findings from psychology

studies with college students samples to other people?– Can we generalize the findings of highly controlled

laboratory studies to real-world settings?– For example, can a study that examines conditions of

aggression in the lab with college students be used to understand real-life conditions of aggression?

Application• Applied Psychologists apply their knowledge and

research methods to improve people’s lives.

– Applied Research: Psychologists conduct research to change people’s lives for the better.

• Applied research is often conducted in “real world” or natural settings.

– Basic Research: Psychologists conduct research to understand behavior and mental processes — “seeking knowledge for its own sake.”

• Basic research is often carried out in laboratory settings with the goal of testing theories.

Scientific Theory Construction and Testing

• Theories are proposed explanations for the causes of phenomena. – A theory is a logically organized set of statements that

• define events (concepts), • describe relationships among these events, and • explain the occurrence of these events.

• Vary in their scope and complexity• Successful theories

– organize what we know about a behavior or mental process (empirical knowledge),

– guide future research by suggesting testable hypotheses, and

– survive rigorous testing (such as falsification).

Psychological Theories

– Theories vary in their scope and complexity.– Successful theories

• organize what we know about a behavior or mental process (empirical knowledge),

• guide future research by suggesting testable hypotheses, and

• survive rigorous testing (such as falsification).

– Good theories are logical and internally consistent, precise, and parsimonious.

Psychological Theories

• Intervening Variables – To explain the relationship between an I.V. and a D.V.– “hidden” processes that are represented by psychological

constructs• Example: Pennebaker and Francis (1996) found that

emotional writing about adjusting to college, compared to superficial writing, caused students to have higher GPAs.

• They proposed an intervening variable: Emotional writing causes cognitive change (e.g. how people think about college), which causes higher GPAs.