Photic Stimulation of Young Rats

Zajonc, Harrison, and their colleagues have recently conducted a series of studies demonstrating a positive, monotonic relation between frequency of “mere” exposure and liking for stimuli. Other studies have found either the inverted-U relation or a decrease in liking. It was proposed that an emphasis upon mere exposure may be somewhat misleading, and that a concern with degree of stimulus familiarity might be more fruitful. Conflicting forms of the exposure-liking relation seem to be potentially reconcilable if consideration is given to factors that influence the rate at which stimuli become familiar, or capable of being anticipated and represented in memory.

Two experiments using stimuli and procedures taken from Zajonc (23) yielded a positive, monotonic relation between frequency and liking. A third experiment, designed to produce greater attention to the stimuli and thus hasten familiarization, yielded an inverted-U relation. A fourth experiment used simpler verbal stimuli than the first three. This was designed to result in even faster familiarization. As expected, there was a negative relation between liking and exposure frequency.

The “frequency group” of investigators has explained the monotonic exposure effect in terms of the response competition hypothesis. However, the latter is incapable of handling a nonmonotonic relation. A reasonable alternative seems to be the expectancy arousal hypothesis (5): viz., that liking is maximum for stimuli that arouse moderately strong expectancies of either a “molar” or a “molecular” nature. Previous research (5, 6, 7, 8) has supported this hypothesis, although some of the studies are also amenable to the response competition hypothesis. A further experiment was designed to distinguish between predictions from the response competition and the expectancy arousal hypotheses. The results supported the latter.