Robert B Zajonc has combined neuropsychological interests with a leaning towards experimental social psychology. In the 1960s he revived interest in the everyday observation that people or objects you come across on a regular basis can "grow on you". His experiments were dubbed “mere exposure” effects. With stimuli completely new to his subjects, he varied the amount of repetition. He confirmed that, as the number of previous exposures to a particular stimulus increases from zero, so reported liking for the stimulus also increases. This setup makes it look as though the repetition causes the liking. A large literature followed upon this report. Reviewing it more than thirty years later Zajonc claimed “mere exposure” is a robust effect "across cultures, across species and across diverse stimulus domains". Alarm and caution at something new may, as nothing aversive happens, give way to a “settling of nerves” that is experienced as pleasurable. But with more and more repetitions the liking reaches a peak and then turns downward.
This was first observed with stimulus domains like names and snatches of music. Though at first they manifest an "exposure effect", beyond a certain degree of familiarity that turns into an overexposure effect of decreased liking. Though this early work was correlational rather than experimental, some work of my own confirmed the basic results. Current Psychology 6 was experimental (using synthetic speech as the stimulus) and though Journal of Environmental Management 21 was correlational it used a different stimulus - landscapes. It is possible that liking increases only until the subject has “learned” the stimulus - there have been some suggestions that the exposure effect is easier to demonstrate with complex stimuli (and see Social and Behavioral Sciences Documents 16). The advantages conferred by microprocessors offering "do-loops" for the Zajonc-type experiment have transformed the ease of investigation. The machines do not tire or vary and repetition can be carried on far beyond the maximum frequency used by Zajonc.
Undergraduate
projects that I have supervised found that
brain
damage from stroke reduces the exposure effects. Furthermore,
amnesia is likely to influence exposure effects (Neuropsychology
4).