Can more coffee make us smarter?
The effect of coffee consumption and priming
with coffee on math performance
Master thesis, Msc. Marketing Management
University of Groningen - Faculty of Economics and Business
Roel Hengeveld
Introduction
› Most used psychoactive stimulant worldwide
•
Reason for many scientific articles
•
Holck (1933) – Testing on problem solving
› Relevance
•
Possible to have the benefits of coffee, without
consuming coffee
Theory
› Problem solving
(Wang & Chiew, 2010)• “One of the basic life functions of the natural intelligence of the brain”
› Cognitive performance can be enhanced by caffeine
• James (2014), Holck (1933), Warburton (1995), Hewlett & Smith (2006), Borota et al. (2014) Shukitt-Hale et al. (2013), Young & Molesworth (2011)
› Cognitive performance can be hampered by caffeine
• Trunzo et al. (2014), Rogers et al. (2013)
Theory
› Priming
(Bargh et al. 1996)• ‘incidental activation of knowledge structures, such as trait concepts
and stereotypes, by the current situational context’
› Problem solving can be influenced via priming
• Ciani & Sheldon (2010), Lang & Lang (2010)
› Priming with consumption influences problem solving
• Hicks et al. (2009), Van Koningsbruggen & Stroebe (2011)
› Interaction effect
• Will the effect of dosage on problem solving be moderated by priming • Hicks et al. (2009), Van Koningsbruggen & Stroebe (2011)
Hypotheses
› H1: A high dosage of coffee (2 cups of coffee or more) will
result in higher problem solving capabilities.
› H2: Being primed with coffee consumption will result in
higher problem solving performance, compared to not
being primed with coffee consumption.
› H3: The effect of coffee dosage on problem solving
Methodology
› 2 X 2 between-subjects factorial design
• (low dosage vs. high dosage) X 2 (primed with coffee consumption vs. control prime)
• 100 participants - (44 female, 56 male; Mage = 24.36 years, SDage = 8.02)
› Independent variables
• Low dosage: 8:30 – 11:30, High dosage: 12:00 – 17:30 • Supraliminal priming by asking 3 questions
› Dependent variable
• “Rekentest referentieniveau 2F”
› Control variables
• Need for cognition (Cacioppo et al. 1984), average consumption, gender, age, need state, impact expectancy
Results
› 2 X 2 ANOVA
•
Correctly answered questions:
•
No significant effects
• (F(1,96) = 0.23, p = 0.63) – Dosage • (F(1,96) = 0.13, p = 0.72) – Prime
• (F(1,96) = 0.01, p = 0.90) – Interaction
•
Time needed to finish the math test:
•
No significant main effects
Results
› Marginally significant cross-over interaction effect
•
(F(1,96) = 3.89, p = 0.05).
› 15:56, 4:44 versus 14:43, 4:16
› 14:41, 4:25 versus 16:59, 3:52
› Findings in line with
Borota et al. (2014) and
Rogers et al. (2013)
› ‘Psychoactive overdose’
Results
› ANCOVA
•
Correctly answered questions – no significant effects
•
Time needed to finish math test – no significant effects
• Interaction effect no longer significant
• (F(1,90) = 2.45, p = 0.12)
•
Possible explanations:
• Gender –
(F(1,90) = 7.50, p = 0.01).•
M: 14:41, 3:54 versus F: 16:49, 4:30
Conclusion
› H1 & H2 are rejected, H3 partly accepted
› Coffee & priming can make you faster, but not smarter
• Coffee is not the optimal solution to help you through exams
› Limitations & Recommendations
• Participant group
• Actual coffee consumption • Duration of interview
