Priming effect. Covert recognition and implicit memory.

    This paper describes recent developments of priming research in cognitive psychology. There are two lines of studies on priming, semantic priming and repetition priming. Semantic priming refers to the phenomenon that the processing of a target stimulus is facilitated by a previously presented prime stimulus that is semantically related or associated with the target. This phenomenon has been investigated to elucidate the organization of semantic memory and the process of word recognition. Recent studies demonstrate that associative priming occurs even when subjects don't identify prime, indicating that semantic processing occurs covertly without subject's awareness. However, there are some controversies over the procedure of covert semantic priming experiment. On the other hand, repetition priming refers to the phenomenon that the processing of a target stimulus is facilitated when the identical stimulus has been previously presented. Word fragment completion task is often used in repetition priming studies, in which subjects are required to fill missing letters to make a word (e. g., ps_ch_lo_y to psychology). The performance of this task is higher for a previously presented word than for a new word. The characteristic of the task is that conscious remembering of previous events is not necessary, while typical memory tests such as recognition and recall test require subjects to recollect past events consciously. The former type of memory test is called implicit memory test, and the latter is explicit memory test. There are many discrepancies between these tests, such that repetition priming found in implicit memory test lasts over a week or a month, though explicit memory test performance declines to a chance level in shorter period. The levels of processing and the modality change influence implicit memory and explicit memory tests differently. These observations suggests the different systems or processes underlie the explicit memory and the implicit memory test performance.