The familiarity effect for single-letter pairs.

A familiarity effect in these experiments is defined as a subject's ability to respond more rapidly to a familiar stimulus than to an unfamiliar stimulus. In the first experiment, responding faster to familiar letters (upright) than to unfamiliar letters (inverted) occurred only when the two stimulus types were presented in a random order. These results were interpreted in terms of the effects of processing strategy changes. The second experiment compared the responding of Japanese and American subjects to Japanese and English letters. American subjects responded faster to English letters and Japanese subjects responded faster to Japanese letters. This familiarity effect was obtained even when stimulus presentation was organized by letter type and subjects knew which letter type to expect. The final experiment compared English and Japanese letters in a memory search task. The rate of search for Japanese letters was slower than for English letters. However, no zero-intercept difference was obtained. The evidence indicates that familiarity does not affect an initial encoding process, but it can affect a comparison process.