Caffeine expectancy, explicit and implicit memory performance among female nursing students: a placebo-controlled quasi-experimental study.

backgroundFor nursing students, memory performance is important for medication learning, clinical reasoning, patient safety, and skill acquisition. This study examined whether caffeine expectancy was associated with explicit and implicit memory performance during morning and afternoon testing sessions.

methodsA convenience sample of 74 female nursing students participated. Participants were classified into high- and low-expectancy groups based on CaffEQ scores and were tested either in the morning (8 AM) or afternoon (4 PM). Explicit and implicit memory were assessed using standardized memory tasks. Data were analyzed using a 2 × 2 factorial ANOVA.

resultsParticipants had a mean age of 21.05 ± 0.97 years. Explicit and implicit memory scores showed only minor descriptive differences across expectancy groups and testing sessions. Two-way factorial ANOVA revealed no significant main effects of caffeine expectancy or time of day on explicit or implicit memory performance, and no significant interaction between caffeine expectancy and time of day was found. Overall, memory performance did not differ significantly across study conditions, and all effects remained nonsignificant under the Bonferroni-adjusted threshold of p < .025.

conclusionCaffeine expectancy was not significantly associated with explicit or implicit memory performance under the present study conditions. Given the limited sample size, absence of chronotype assessment, and relatively weak expectancy manipulation, these null findings should be interpreted cautiously.