| Some of the phenomena surrounding commonplace incidents of memory blocks (temporary inability to retrieve stored target items) raise intriguing questions about memory processes. First, people who experience a memory block can judge the likelihood that continued memory search will succeed (feelings-of-knowing judgments). Second, it is not unusual for people to "stumble" onto relevant information in the midst of some unrelated activity, or to experience "flash" recall long after the question that precipitated the memory block has been removed from consciousness. Such experiences of unexpected flash recall resemble the phenomenon of incubation and illumination during problem solving.;The memory-sensitization hypothesis introduced in this dissertation states that following an unsuccessful attempt to recall a stored item related to some problem, a person's memory is sensitized to information bearing on this item, thereby leading to more efficient assimilation of relevant information and cues encountered in the environment.;Five experiments are reported to examine memory mechanisms involved in memory sensitization, the activation and metacognition of inaccessible stored information, and the encoding and assimilation of target information. The experimental procedure involved a battery of cognitive tasks. Participants first attempted to recall some rare English words cued by dictionary definitions. For the target words that could not be recalled initially, the participants rated their feelings of knowing. During subsequent tests of word perception and recognition memory, reaction time and accuracy of responses for target words and irrelevant control words were measured. In some experiments, retest on the definition questions occurred 24 hours following the first definition task.;The results revealed that the initial failure to recall target words cued by the definitions sensitized the participants to subsequent occurrences of the targets and conceptually related words. Comparison between the results for target words and control words showed faster reaction times for targets that had elicited strong feelings of knowing and also more solid encoding of targets. Feeling-of-knowing judgments correlated positively with the magnitude of these sensitization effects. The implications of these results for cognitive processes such as memory updating, acquisition of cognitive skills, decision making, and problem solving is discussed. |
