Scientific Thinking &

Scientific Thinking &
Psychological Science
Scientific Approach is preferred if interested in causality

Historical Examples:

Benjamin Rush (1793)

Yellow fever and bloodletting

Joseph Goldberg

Pellagra

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)

Scientific Observations

Two rules:

1. Operational Definitions

2. No Distortion

Why operational definitions?

avoid confusion

makes study reproducible

makes measurements reliable
But

trade off between precision of an operational definition and it’s construct validity

Sources of Distortion?

instruments

sampling

observer bias

Observer Bias

Two historical examples

Rene Blondlot’s N’Rays

Clever Hans

Current examples

Female mate choice in wolves

Alex - talking parrot

Koko - the talking chimp

What, me biased?

What is this?

What you all saw

Flotsam and Jetsam Assignment
(stuff to watch for when surfing)

challenge the Scientific basis for claims, not the truthfulness of the claim

proper attribution of causal relations (control for placebo effects?)