The amplitudes of reflex and voluntary eyelid responses to a regularly recurring stimulus with varying time intervals between responses have been studied by the authors, and the following results obtained: (1) Amplitude of reflex eyelid responses increases with increase in the length of the time interval between responses from ½ to 4 and possibly to 6 seconds. (2) With voluntary reinforced eyelid responses to the same stimulus the average amplitudes of the responses are greatest at the ½ and 6 second intervals. The 1, 2, and 4 second intervals show smaller averages. These results differ from those obtained under comparable conditions except that an irregular instead of a regular time interval was used. In the former procedure the greatest amplitude of response was obtained when 2 seconds intervened between successive responses. As the interval was decreased to 1 and ½ or increased to 4 and 6 seconds the responses decreased in amplitude. (3) Reading retards, while working mental arithmetic increases the rate of the normal rhythmic eyelid responses of college students when the winking rate obtained while the subjects are carrying on their ordinary conversation is taken as normal. (PsycINFO Database Record (c) 2006 APA, all rights reserved)