Citation

Barmack JE. J. Exp. Psychol. 1940; 27(6): 690-698.

Copyright

(Copyright © 1940, American Psychological Association)

DOI

10.1037/h0056657

PMID

unavailable

Abstract

Subjects added pairs of numbers for eight 15-min. periods, after which they filled out a rating sheet with 4 nine-point scales of bored-interested, peppy-fatigued, sleepy-wide-awake, and attentive-inattentive. This was done under the following conditions: (1) control, (2) 2 grs. of alkaloid caffeine one hour before adding, (3) 2 grs. 2 hours before adding, and (4) 2 grs. 3 hours before adding. The following results were obtained: (1) 2 grs. administered one hour before adding allayed: (a) loss in rate of adding, (b) development of unfavorable reports on all subjective rating scales. (2) Caffeine given 2 or 3 hours before adding had a similar, though lesser effect. (3) The effect of caffeine on the initial rate of addition, or on initial subjective reports, was negligible, regardless of time of administration. In a second experiment to determine whether caffeine is actually without initial effect subjects added for one 15 minutes period only and filled out rating scales under 3 conditions: (1) control, (2) 2 grs. of caffeine 2 hours before adding, and (3) 2 grs. 3 hours before adding. Under these conditions: (1) caffeine had no effect on rate of addition; (2) caffeine affected subjective reports in the favorable direction, particularly those given immediately after adding. (PsycINFO Database Record (c) 2012 APA, all rights reserved)