Recency order judgments in short term memory: Replication and extension of Hacker (1980)

Abstract

The classic finding from short-term relative JOR tasks is that correct response time (RT) depends on the lag to the more recent item but not to the less recent item (Hacker, 1980). For decades, researchers have argued that this finding is consistent with a self-terminating backward scanning model (Muter, 1979;Hacker, 1980;Hockley, 1984;McElree & Dosher, 1993). This finding has taken on new importance in light of recent proposal that many forms of memory depend on a compressed representation of the past (Howard, Shankar, Aue, & Criss, 2015). This paper replicates and extends the results of the classic papers. A Bayesian t-test showed substantial evidence for the null e↵ect of lag to the less recent item on correct RT. In addition, this paper reports that correct RT is a sub-linear function of lag to the more recent probe and replicates the classic finding that error RT depends on lag to the less recent probe. These findings place new constraints on models of short-term memory scanning.In a relative judgment of recency (JOR) task participants choose which of two probes from a list was presented more recently. Recency in this task is traditionally measured in units of lag, which is the number of time steps in the past at which the probe was presented. That is, if the last item in the list was presented as a probe, it would be associated with a lag of one. The classic finding from short-term relative JOR tasks is that correct response time (RT) depends on the lag to the more recent item but not to the less recent item (see Fig. 1, Muter, 1979;Hacker, 1980;Hockley, 1984). For decades, researchers have argued that this finding is consistent with a self-terminating backward scan (Muter, 1979;Hacker, 1980;Hockley, 1984;McElree & Dosher, 1993). Because the scan starts at the present and proceeds backwards in time, RTs show a recency e↵ect. Because the scan is self-terminating this naturally accounts for the finding that correct RTs do not depend on the lag of the less-

Is working memory stored along a logarithmic timeline? Converging evidence from neuroscience, behavior and models

“…This pattern of results suggests a backward self-terminating search model. We review recent neural evidence from the macaque lateral prefrontal cortex (lPFC) (Tiganj, Cromer, Roy, Miller, & Howard, in press) and behavioral evidence from human JOR task (Singh & Howard, 2017) bearing on this question. Notably, both lines of evidence suggest that the timeline is logarithmically compressed as predicted by Weber-Fechner scaling.…”

Constructing neural-level models of behavior in working memory tasks

“…letters or words) one at a time, and then probed with two stimuli from the list and asked which of the two stimuli was presented more recently. The classical finding is that the time it takes subjects to respond (reaction time) depends on the recency of the more recent probe, but not the recency of the less recent probe ( Figure 3A) (Hacker, 1980;Singh & Howard, 2017). This result provides an important insight into how working memory is maintained, suggesting that the subjects maintain working memory as a a temporally organized, scannable representation.…”

“…Shade of the line denotes lag of the more recent item, with the most recent item shown in black and the most distant item shown in the lightest shade of gray. (From Singh and Howard (2017).) B.…”

“…In other words, the result of the JOR experiment is consistent with a self-terminating backward scan along a temporally organized memory representation. Moreover, the reaction time is a sublinear function of the lag ( Figure 3B) (Singh & Howard, 2017), suggesting that the working memory representation is compressed.…”

“…First, we evaluate the ability of the proposed architecture in modeling behavior using human data from the JOR task (Singh & Howard, 2017). To model the JOR task, the first step of the model was to wait for the probe item to appear.…”