Research Strategies in Psychology

Descriptive Research Strategies: The Case Study

“Given a thimbleful of [dramatic] facts we rush to make generalizations as large as a tub” - Psychologist Gordon Allport »Fears after school shootings or kidnappings »The contradictory case: e.g. “My grandfather smoked until he was 102” »Unreliability of anecdotal evidence

Descriptive Research Strategies: The Survey Used in both descriptive and correlational studies Asks people to report on behaviour and opinions.

The Survey: Wording Effects Should cigarette ads or pornography be allowed on television? People prefer “not allowing” to “forbidding” or “censoring” Only 27% of Americans approved of “government censorship” of media sex and violence, while 66% approved of “more restrictions on what is shown on television” People prefer “aid the needy” to “welfare” EI instead of UI

The Survey: Sampling False consensus affect A “sample” is a small group selected randomly to represent the larger population The larger the sample the more accurately it represents the larger population - Top of pg26

Descriptive Research Strategies: Naturalistic Observations Not just about chimpanzees in nature.

Correlational Research Strategies: Correlation The Correlation coefficient is a statistical measure of relationship. Is there a relationship between stress and illness? Is there a relationship between test scores and school success? Scatter plots: pg 28

Correlational Research Strategies: Correlation and Causation Correlation is not causation For example: –Low self esteem and depression have a positive correlation Low self-esteem could cause depression Depression could cause low self esteem Distressing events or biological disposition could cause both depression and low self esteem.

Correlational Research Strategies: Illusory Correlation When we believe there is a relationship between two things, we are likely to notice and recall instances that confirm our belief. –Full moon correlations –Getting cold and wet makes one catch a cold –Sugar makes kids hyperactive

Correlational Research Strategies: Perceiving Order in Random Events Shown random data, scientists and psychics alike can often “see” an interesting pattern. If I flip a coin 9 times and ‘heads’ comes up each time, is it more likely that the tenth time will be ‘tails’? When no ones wins a given lottery draw, the prize of the subsequent draw increases and more people buy tickets. How does this affect the chances of a single ticket winning? Do professional athletes go on “streaks” or develop “hot hands” – pg 32

Experimental Research Strategies: Experiments enable a researcher to focus on the possible effects of one or more factors by: 1.Manipulating the factors of interest 2.Holding constant (“controlling”) other factors E.g. There is a strong positive correlation between breast feeding and later intelligence. Is the later intelligence caused by breast feeding? Pg 33

Experimental Research Strategies: Evaluating Therapies If we get better 3 days after taking a certain pill we tend to think that pill is the reason we got better. 1700’s bloodletting seemed to be very effective. To find if something is actually effective we need to experiment

Experimental Research Strategies: Evaluating Therapies The Placebo Effect …fake pills often work because people believe they do. Double-blind procedure creates an experimental condition in which people receive the treatment and a contrasting control condition without the treatment. By randomly assigning people to these conditions the two groups should otherwise be identical.

Experimental Research Strategies: Evaluating Therapies The independent variable: the experimental factor that is manipulated; the variable whose effects are being studied The dependent variable: the variable that may change in response to manipulations of the independent variable (e.g. behaviour or mental process) “Experiments aim to manipulate an independent variable, measure the dependent variable, and control all other variables” –pg35 Can Subliminal Tapes Improve Your Life? –pg 35

Statistical Reasoning: Bombarded by numbers Harper’s Index

Statistical Reasoning: Measures of Central Tendency Mode – the most frequently occuring score in distribution Mean – the average Median – the middle score in a distribution; half the scores above and half are below it.

Statistical Reasoning: Measures of Variation Averages based on scores with low variability are more reliable than averages based on scores with high variability Range: the difference between the highest and lowest scores in a distribution Standard Deviation: a computed measure of how much scores vary around the mean score

Statistical Reasoning: Making Inferences When is an observed difference reliable? 1.Representative samples are better than biased samples 2.Less-variable observations are more reliable than those that are more variable. 3.More cases are better than fewer

Statistical Reasoning: Making Inferences When is a difference significant? –Statistical significance: a statistical statement of how likely it is that an obtained result occurred by chance. –Occurs when the sample averages are reliable and the difference between them is relatively large.