Abstract
The conditioned eyelid response was developed in 45 Ss. A pure tone served as CS and a puff of air to the cornea was utilized as UCS. The magnitude of the reinforcing puff was varied in such a way that for one group of Ss the series generated an arithmetic mean intensity of 6.5 psi and a geometric mean of 4.5 psi. Control groups were stimulated at a constant value of 4.5 or 6.5 psi throughout training which consisted of 70 trials for all groups. Conditioning occurred in all groups with differences significant between the constant groups and the 6.5 psi constant group and the variable group. Failure to find a significant difference between the 4.5-psi constant group and the variable group is interpreted as support of the contention of Helson that it is the geometric mean of a series of stimuli which is its best representative value.
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