Forgetting from lapses of sustained attention

Abstract

When performing any task for an extended period of time, attention fluctuates between good and bad states. These fluctuations affect performance in the moment, but may also have lasting consequences for what gets encoded into memory. Experiment 1 establishes this relationship between attentional states and memory, by showing that subsequent memory for an item was predicted by a response time index of sustained attention (average response time during the three trials prior to stimulus onset). Experiment 2 strengthens the causal interpretation of this predictive relationship by treating the sustained attention index as an independent variable to trigger the appearance of an encoding trial. Subsequent memory was better when items were triggered from good versus bad attentional states. Together, these findings suggest that sustained attention can have downstream consequences for what we remember, and they highlight the inferential utility of adaptive experimental designs. By continuously monitoring attention, we can influence what will later be remembered.

Keywords: Distraction; Episodic memory; Goal-directed attention; Real time.

Figure 1

Experimental design. (a) Participants first completed a sustained attention task in which they viewed trial-unique scene images and made an indoor/outdoor judgment. Of the scenes, 90% were from one of these categories (e.g., outdoor) and 10% were from the other category (e.g., indoor). Because of this imbalance, responding correctly to the infrequent category required inhibiting the prepotent response to the frequent category. (b) Participants then completed a surprise memory test in which they reported their confidence that each scene had appeared in the first part of the experiment. Of the images, 50% were from the sustained attention task (old) and 50% were novel to the experiment (new). Among these, 50% were from the frequent category and 50% were from the infrequent category.

Figure 2

Relating sustained attention and memory. (a) RTs were slower before a correct response (blue) vs. incorrect response (pink) to an infrequent trial (all time points, ps < 0.00001). Individual participants are plotted in thinner lines and the average in thicker lines. Raw RTs are reported in the text for this analysis but normalized RTs are depicted here because they were the input to the subsequent memory analysis shown in the other panels (statistics were unaffected). (b) Illustration of approach for quantifying relationship between sustained attention and memory in one representative participant. For every item from the infrequent category, the average RT over the three preceding trials in the sustained attention task was fit to the binarized recognition judgment from the surprise memory test using logistic regression. Each dot is one item and the line is the fitted logistic function. (c) The logistic functions for all participants are plotted, revealing a reliably positive slope on average (p = 0.038). That is, slower preceding RTs correlated with better memory.

Figure 3

Online adaptive experimental design. The real-time triggering design is depicted for a period of trials from a representative participant. The dashed black line depicts the RTs to individual trials. The solid black line depicts the trailing window average RT over the 3 preceding trials. The bounds for triggering an infrequent trial, ±1 SD, are plotted in a solid gray line. Infrequent trials were triggered if the average RT was slower than the upper bound (blue dots) or faster than the lower bound (pink dots). Otherwise, frequent trials were shown.

Figure 4

The fate of triggered trials. (a) During the sustained attention task, participants made more errors on infrequent trials that were triggered by faster vs. slower RTs. (b) During the surprise memory test, participants remembered fewer images that were triggered by faster vs. slower RTs (c) Participants still remembered fewer images that were triggered by faster vs. slower RTs when the analysis was restricted to correct responses in the sustained attention task. Individual participants are depicted in gray circles. The average is the solid black circle and the error bars depict 95% CIs of the mean.