Essay

Describe the key details of Kathy Gilliland's classic study on caffeine and personality. In your description, identify the independent variables (including the specific dosage of caffeine used), the dependent variable, and the specific pattern of results that illustrated a cross-over interaction.

Question: Describe the key details of Kathy Gilliland's classic study on caffeine and personality. In your description, identify the independent variables (including the specific dosage of caffeine used), the dependent variable, and the specific pattern of results that illustrated a cross-over interaction.

Sample answer: In Kathy Gilliland's study, the independent variables were personality type (introverts vs. extraverts) and caffeine consumption (no caffeine vs. 44 mg of caffeine per kilogram of body weight). The dependent variable was verbal test scores. The results showed that when no caffeine was consumed, introverts performed better than extraverts. In contrast, after ingesting 44 mg of caffeine per kilogram of body weight, extraverts outperformed introverts. This complete reversal of the performance effect of caffeine based on personality type serves as a classic illustration of a cross-over interaction.

Key points:

  • Identifies personality type (introverts vs. extraverts) as an independent variable.
  • Identifies caffeine consumption (no caffeine vs. 44 mg/kg) as an independent variable.
  • Identifies verbal test scores as the dependent variable.
  • Specifies that introverts performed better in the no-caffeine condition.
  • Specifies that extraverts performed better after ingesting 44 mg/kg of caffeine.
  • Explains that the complete reversal of effects defines the cross-over interaction.

Rubric: To receive full credit, the student must recall and state: 1) The independent variables: personality type (introverts vs. extraverts) and caffeine consumption (no caffeine vs. 44 mg/kg). 2) The dependent variable: verbal test scores. 3) The pattern of results: introverts scored higher than extraverts with no caffeine, but extraverts scored higher than introverts after ingesting 44 mg/kg of caffeine. 4) That this complete reversal of effects constitutes a cross-over interaction.

0

1

Updated 2026-05-27

Contributors are:

Who are from:

Tags

KPU

Research Methods in Psychology - 4th American Edition @ KPU

Related