Characteristics of Psychological Science

Characteristics of Psychological Science
(Summary of Stanovitch)

1. Psychology progresses by investigating empirical problems.

2. Psychologists propose testable hypothesis.

Falsifiability and Folk Wisdom

Folk Wisdom & the Benefits of Work Experience for Youth

Psychological Studies on the Effects of Work Experience for Youth

Characteristics of Psychological Science
(Summary of Stanovitch)

1. Psychology progresses by investigating empirical problems.

2. Psychologists propose testable hypothesis.

3. The concepts in these hypothesis are operationally defined.

4. Psychologists use many different empirical methods.

5. Most conclusions are arrived at only after slowly accumulating data from many experiments.

6. The behavioral principals eventually uncovered at are almost always probabilistic.

7. Psychological data and theories are only acceptable after publication in peer reviewed scientific journals.

Stanovich

While many scientists sincerely wish to make scientific knowledge accessible to the general public, it is intellectually irresponsible to suggest that a deep understanding of a particular subject can be obtained by the layperson when that understanding is crucially dependent on certain technical information that is only available through formal study.

Such is the case with statistics and psychology.

Characteristics of a Scientific Experiment

Manipulation (of the independent variable)

Control (of extraneous variables - potential confounds)

Measurement [of the dependent variable(s)]

Comparison (of the measurements with appropriate statistics)

Hypothesis Testing

Hypothesis Testing

Hypothesis Testing

Inferential Statistics

A key aspect of science is that it deals with testable hypotheses

The key tool for testing these hypotheses are inferential statistics

Inferential Statistics can be either parametric or non-parametric

Inferential Statistics

Factors Contributing to Group Mean Differences

Factors Contributing to Within-Group Differences

Accept or Reject H₀?

Accept or Reject H₀?

Ways of Increasing Power

Ways of Increasing Power

Ways of Increasing Power

Power

Peer Ethics Review

Types of Inferential Statistics

Nonparametric Statistics

Bivalent Between Subjects Memory Experiment
20 intro psychology subjects, 10 randomly assigned to each group

Experimental group

Male experimenter

written instructions

10 min travel film

1 o’clock testing

group testing

15 s final scene version ‘a’ - mutilated body seated in chair (operational def. of emotional shock) - I.V.

Measure # items (of 10) correctly remembered - D.V.

Control group

Male experimenter

written instructions

10 min travel film

1 o’clock testing

group testing

15 s final scene version ‘b’ - craftsperson weaving a basket - I.V.

Measure # items (of 10) correctly remembered - D.V.

Hypothetical Results of Bivalent Between Subjects Memory Experiment

Mann-Whitney U-Test

Hypothetical Results of Bivalent Between Subjects Memory Experiment

Mann-Whitney U-test

Mann-Whitney U-test

Analogous to dealing 5 black cards in a row from a randomly shuffled deck of 10 cards, 5 of which are black & 5 red.

p= (5/10)*(4/9)*(3/8)*(2/7)*(1/6)= 0.00396

Hypothetical Results of Bivalent Between Subjects Memory Experiment

Mann-Whitney U-test

Hypothetical Results of Bivalent Between Subjects Memory Experiment

Mann-Whitney U-test