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Published on: June 29, 2016
Effects of Caffeine and Stress on Persistence and Performance in an Unsolvable Visual Search Task in Humans
Parssa Akbari1, Sabrina R Comess1, Olivia Henkoff1
1Neuroscience Program, Amherst College, Amherst, Massachusetts, USA.
Objective:
To assess the effect of caffeine and stress on behavior during unsolvable tasks in humans.
Methods:
College students were given no gum, gum or gum containing 40 mg caffeine (Experiment 1); gum or 100 mg gum (Experiment 2); or the socially evaluated cold pressor test (SECPT) or warm water followed by gum or 100 mg caffeine gum (Experiment 3). Performance was considered to be the time to finish the solvable portion of a hidden picture task with a missing picture (HPT) or an anagram task with an unsolvable anagram (ANA; Experiment 1), the HPT or a word search task with a missing word (WST; Experiment 2), or a HPT (Experiment 3). Persistence was considered to be the amount of additional time participants spent trying to solve the unsolvable portion.
Results:
Experiment 1: 40 mg caffeine did not affect performance or persistence. Experiment 2: 100 mg caffeine increased the percent of total time participants persisted in the HPT from 38.0% to 51.7%. Experiment 3: stress improved performance in the HPT and caffeine and stress produced a significant interaction effect for persistence with trends toward increased persistence in stressed participants and decreased in unstressed.
Conclusions:
Caffeine increased time spent on an unsolvable task, particularly in stressed participants.
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