The research process Psych 231: Research Methods in Psychology

Announcements This is the final lecture Wednesday (optional) – Review Q&A, help with posters, etc. Labs this week Poster presentations Turn in group ratings sheets Turn in results and reference section for group project

Longitudinal design Developmental designs Follow the same individual or group over time Age is treated as a within-subjects variable Age 11 time Age 20Age 15 Cross-sectional design Study groups of individuals of different ages at the same time Age is subject variable treated as a between-subjects variable Age 4 Age 7 Age 11

Developmental designs Measure groups of participants as they age Example: measure a group of 5 year olds, then the same group 10 years later, as well as another group of 5 year olds Age is both between and within subjects variable Combines elements of cross-sectional and longitudinal designs Addresses some of the concerns raised by other designs For example, allows to evaluate the contribution of cohort effects Cohort-sequential design

Developmental designs Cohort-sequential design Time of measurement Cohort A Cohort B Cohort C Cross-sectional component 1970s 1980s 1990s Age 5 Age 15Age 25 Age 5 Age 15 Age 5 Longitudinal component

Developmental designs Advantages: Get more information Can track developmental changes to individuals Can compare different ages at a single time Can measure generation effect Less time-consuming than longitudinal (sort of) Can examine age comparisons along the way Disadvantages: Still time-consuming Need lots of groups of participants Still cannot make causal claims (about the age variable) Cohort-sequential design

Course Review: The Research Process Get an idea Presenting your work  A set of skills leading to knowledge & understanding  A way of thinking (beware small samples, correlation is not causation, etc.)  A way of life? Stats.orgStats.org: Stats in the news

The Research Process  Get an idea – Often the hardest part – No firm rules for how to do this – Observations – Past research – Review the literature

The Research Process Review the literature What has already been done? What variables have people looked at What hasn’t been looked at How are other experiments in the area done? What methods are used? To measure the dependent variable To manipulate the independent variable To control extraneous variables

 Formulate a testable hypothesis – What is a hypothesis? – A predicted relationship between variables – What does it mean to be testable? – Must be falsifiable – Can it be replicated – Must be able to observe/measure (and manipulate for experiments) the variables – Directly – Indirectly – Operational definitions The Research Process

Design the research – What method? – Experiment, Survey, Developmental designs, … – What kind of comparisons are used –Control groups –Baseline conditions – What are your variables? –How many levels of your Independent variable(s) –How do you measure your dependent variable(s) – What can be done to control for biases and confounds? The Research Process

Collect Data Importance of pilot research Who do you test? What is your population? Your sample? Your sampling method? The Research Process

Analyze the data Design drives the statistics Understanding Variables and variability Descriptive statistics (summarizing) Means, standard deviations Graphs, tables Correlation Inferential statistics (drawing conclusions) What kind of analysis is appropriate for your design T-tests ANOVA Between or within versions The Research Process

Interpret the results Correlation versus causation Reject or fail to reject null hypotheses Statistical vs. theoretical significance Support or refute the theory (or revise) Generalizability of the results The Research Process

Present the results Getting the research “out there” Conference presentations Posters Talks Written reports APA style Supports clarity The Research Process

Repeat Each set of results leads to more research questions Refine the theory Test a refined theory Test alternative explanations The Research Process

Reviewing for the final exam Wed Dec. 14 1:00-2:50 It is cumulative, covers the entire course. The majority is on new material (roughly 65%), the rest is material covered on Exams 1 & 2. All multiple choice/scantron for the final

Reviewing for the final exam Non experimental methods Survey, correlational, & developmental Statistics Descriptive Inferential Presentations Papers, Posters, & Talks Final 1/3 of the course

Reviewing for the final exam  Scientific method  Getting ideas  Developing (good) theories  Reviewing the literature  Psychological Science  Ethics  Basic methodologies  APA style  Underlying reasons for the organization  Parts of a manuscript Variables Sampling Control Experimental Designs Vocabulary Single factor designs Between & Within Factorial designs First 2/3 of the course