Chapter 2- How Psychologists do Research

Chapter 2- How Psychologists Do Research What Makes Psychological Research Scientific? 1. Precision  Theory/Hunch→ Hypothesis→ Predictions with Operational Definitions→ Evidence  Theory- an organized system of assumptions and principles that purports to explain a specified set of phenomena and their interrelations  Hypothesis- a statement that attempts to predict or to account for a set of phenomena; scientific hypotheses specify relations among events or variables and are empirically tested  Operational definition- a precise definition of a term is a hypothesis, which specifies the operations for observing and measuring the process of phenomenon being defined. 2. Skepticism- don’t accept ideas on faith/authority- show me! 3. Reliance on empirical evidence 4. Willingness to make “risky predictions”  Principle of Falsifiability- the principle that a scientific theory must make predictions that are specific enough to expose the theory to the possibility of disconfirmation; that is, the theory must predict now only what will happen but what will not happen  Confirmation bias- the tendency to look for or pay attention only to information that confirms one’s own belief 5. Openness- no secrecy, free flow of ideas, disclosure  Other scientists must be able to replicate and verify the results  These principles correspond to critical thinking guidelines  Peer review, where scientists submit their results to professional journals, which send findings to experts in the field before deciding to publish them, ensures that the work lives up to accepted scientific standards Descriptive Statistics: Establishing the Facts Representative sample- a group of individuals, selected from a population for study, which matches the population on important characteristics such as age and sex Descriptive methods- methods that yield descriptions of behaviour but not necessarily casual explanations. Case Studies  A detailed description of a particular individual based on careful observation or formal psychological testing.  Commonly used by clinicians, also academic researchers  Most detailed picture of an individual  Drawbacks- information often missing or hard to interpret  Bias affects what is noticed vs. what is overlooked  Limited usefulness for deriving general behaviour principles  Used as sources of hypotheses, rather than tests Observational Studies  A study in which the researcher carefully and systematically observes and records behaviour without interfering with the behaviour; may involve either naturalistic or laboratory observation  Frist step in a program of research  Many participants  Count, rate or measure behaviour systematically  Naturalistic observation  Make sure not to be obvious- don’t want to be noticed  Find out how people/animals act in their normal social environment  Laboratory observation-  more control over situation  Bad in that it may cause people to behave differently  Observational studies more useful for describing than explaining Tests Psychological tests (assessment instruments) - procedures used to measure and evaluate personality traits, emotional states, aptitudes, interests, abilities, and values  Objective tests/inventories measure beliefs, feelings or behaviours and individual is aware of  Projective tests are designed to tap unconscious feelings or motives Standardize- in test construction, to develop uniform procedures for giving and scoring a test Norms- in test construction, established standards of performance Reliability- in test construction, the consistency of scores derived from a test, from one time and place to another  Test-retest reliability- given twice for same results  Alternate-forms reliability- given in two forms same results Validity- the ability of a test to measure what it was designed to measure  Content validity- items broadly represent trait in question  Criterion validity- able to predict independent measures/criteria of the trait in question Surveys  Questionnaires/ interviews that ask people directly about their experiences, attitudes, opinions Volunteer bias- a shortcoming of findings derived from a sample of volunteers instead of a representative sample; the volunteers may differ from those who did not volunteer.  Sampling problems an issue, people can lie  Technology can help with this- computer surveys  Risk because they don’t know if participants understand questions and take them seriously Correlational Studies: Looking for Relations Correlational study- a descriptive study that looks for a consistent relation between two phenomena Correlation- a measure of how strongly two variables are related to one another Variables- characteristics of behaviour or experience that can be measured or described by a numeric scale Positive correlation- an association between increases in one variable and increases in another, or between decreases in one and in another Negative correlation- an association between increases in one variable and decreases in another Coefficient of correlation- a measure of correlation that ranges in value from -1.00 to +1.00 Illusory correlations- apparent associations between two things that are not really related  Correlation does not equal causation- just because two things are correlated, doesn’t mean that one is causing the other or vice-versa  Ex. More churches in an area is correlated with more crime, doesn’t mean they cause each other Experiments: Hunting for Causes Experiment- a controlled test of a hypothesis in which the researcher manipulates one variable to discover its effect on another Independent variable- a variable that an experimenter manipulates Dependent variable- a variable that an experimenter predicts will be affected by manipulations of the independent variable  Assigned to control group (no change in independent variable) or experimental group (change independen