It is currently not known whether caffeine has an enhancing effect on long-term memory in humans. We used post-study caffeine administration to test its effect on memory consolidation using a behavioral discrimination task. Caffeine enhanced performance 24 h after administration according to an inverted U-shaped dose-response curve; this effect was specific to consolidation and not retrieval. We conclude that caffeine enhanced consolidation of long-term memories in humans.
M.A.Y. is supported by US National Institute on Aging P50 AG05146 and R01 AG034613. J.P.T. is supported by US National Science Foundation CHE-1213438. D.B. is supported by a Johns Hopkins University Provost Undergraduate Research Award. We thank A. Newman and C. Townsend for the use of their high-performance liquid chromatography instrument, D. Spira, A. Ward and J. Kim for help with participant testing, Z. Reagh for help with data analysis, and J. Knierim for helpful discussions regarding this manuscript.
Integrated supplementary information
Supplementary Figures 1–2 and Supplementary Table 1