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Getting Things Under Control: The Case of Clever Hans

Chapter 6

Snow and Cholera

• John snow: search for the cause of cholera

• Compared two groups in the same neighborhood supplied by different water companies.

• Results

Basis of Scientific Thinking

• Comparison: Observing similarities and differences between two or more groups.

• Control: Regulation of variables. Eliminating some and isolating others.

• Manipulation: • Independent Variable: variable observed or

manipulated and believed to affect dependent variable.

• Dependent Variable: what is measured. Out come variable, theorized to be caused by independent variable.

What Defines a True Experiment

• Random Assignment: Unbiased randomization

• Replication: repeating an experiment with all the essential features to see if the same results are obtained.

• Confounding Variables: Extraneous variables that could affect the dependent variable and therefore must be controlled for.

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Importance in Control Groups

• Essential for comparison of information.

• Verifies validity

• Ensures accurate conclusion.

Goal of Experimental Design

• Controlled isolation of variables

• Along with manipulation of these variables

• Allows scientists to compare each scenario in order to find the most highly supported, strongest explanations and discard the weaker less supported explanations.

Getting Things Under Control

• Clever Hans case: (1990):

• Autistic children being able to express themselves through typing, with help of facilitators. (FC: Facilitated communication) • Different controlled experiments were set up. Found

that facilitators had much more of an impact than expected on responses.

• “It is evident that some assistants through the use either of tactile/visual cues or through the actual imposition of movement, manipulate their clients’ responses.” (p. 240)

Exploring Experiments

• Reasons that caused further experimentation.

• Very profound things written

• Sexual abuse claims.

� Situations needed to be controlled and different factors manipulated.

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Prying Variables Apart

• The occurrence of any event in the world is often correlated with many other factors.

• In order to pry/separate apart the causal influence of many simultaneously occurring events, we must create situations that will never occur in the ordinary world.

• Scientific experimentation breaks apart the natural correlations in the world to isolate the influence of a single variable.

Prying Variables Apart

• Many classic experiments in psychology involve this logic of prying apart the natural relationships that exist in the world so it can be determined which variable is the dominant cause.

• In short it is necessary for scientists to create special conditions that will test a particular theory about a phenomenon. Merely observing the event in its natural state is rarely sufficient.

• Creating special conditions to test for actual causal relationships is a key tool we can use to prevent pseudoscientific beliefs from attacking us like a virus.

Summary

• The many inadequacies in people’s intuitive theories of behavior illustrate why we need

the controlled experimentation of psychology; so that we can progress beyond our flat earth

conceptions of human behavior to a more accurate scientific conceptualization.