Building and accessing a compressed internal timeline of the future
Inder Singh1,2, Marc Howard2; 1Northeastern University, 2Boston University
Prior neurophysiological and modeling work seems to suggest a symmetry between the mechanisms that allow us to access the past and the future. However, there is a derth of behavioral paradigms that directly compare the symmetry between the mechanisms used to access the past and the future events. In this study we use temporal order judgment paradigms to test retrospective and prospective access under carefully controlled experimental conditions that ideally mirror the search through representations of the past and future. The Judgement of Recency (JOR) task measures order judgments for the past. Hacker (1980) found that the response time varies as a function of the distance to the more recent item and does not depend on the distance to the less recent item. This finding suggests a serial self-terminating search along a temporally ordered representation. Further, the response times vary as a sub-linear function of the lag to the target item. This suggests that the representations are compressed. We propose a novel Judgement of Imminence (JOI) task that closely parallels the design of the JOR task. We find that the response times in the JOI task reflect the search mechanics observed in the JOR task. This supports the hypothesis that ordered representations for the future are symmetrical to the ordered representations of the past and can be accessed using a serial search process. Further, the response times show evidence for sub-linearity thereby suggesting a compressed future timeline.
Topic Area: LONG-TERM MEMORY: Episodic