Investigating the Dual Processes Underlying Human Recognition Memory

This thesis examines two aspects of human recognition memory by using two separate behavioral paradigms. Given the dual process hypothesis of recognition memory, the first chapter investigates the correlation between encoding and retrieval of recognition and source memory for images by using a cued retrieval paradigm. Participants were shown images in a particular judgment task (source context) and later asked to retrieve them in a cued retrieval task. Recording from the human brain, I found separate cell populations to be responsive to the source context during the encoding and recognition stages of the task, suggesting a lack of single-cell level reactivation during source retrieval. In the second chapter, I examined how recognition memory signals change over time using repeated longitudinal behavioral testing in an fMRI study. Through repetitive presentation and memory tests over a period of three months, face stimuli were introduced to three participants. The behavioral outcome of the task showed that as frequency of exposure to specific faces increases, the memory performance and judged confidence increases correspondingly, supporting the hypothesis of a continuous familiarity signal