Dissociating sub-processes of aftereffects of completed intentions and costs to the ongoing task in prospective memory: A mouse-tracking approach

Abstract

In the present study, we used mouse tracking to investigate two processes underlying prospective memory (PM) retrieval: First, we aimed to explore to what extent spontaneous retrieval of already completed PM intentions is supported by reflexive-associative and discrepancy-plus-search processes. Second, we aimed to disentangle whether costs to an ongoing task during the pursuit of a PM intention are associated with presumably resource-demanding monitoring processes or with a presumably resource-sparing strategic delay of ongoing-task responses. Our third aim was to explore the interaction of processes underlying costs to the ongoing task and processes of spontaneous retrieval. Our analyses replicated response-time patterns from previous studies indicating aftereffects of completed intentions and costs to ongoing-task performance, as well as increased aftereffects while pursuing a PM intention. Notably, based on our mouse-tracking analyses, we argue that aftereffects of completed intentions are best explained by a reflexive initiation of an already completed intention. If the completed intention is not performed in its entirety (i.e., no commission error), the reflexive initiation of the completed intention is followed by a subsequent movement correction that most likely represents a time-consuming response-verification process. Regarding performance costs in the ongoing task, our analyses suggest that actively pursuing a PM intention most likely leads to a strategic delay of ongoing activities. Lastly, we found that pursuing a novel PM task after intention completion exacerbated orienting responses to all deviant stimuli, exacerbated the readiness to initiate the completed intention reflexively, and substantially prolonged the response-verification process following this reflexive intention retrieval.

Keywords: Commission errors; Costs; Delay theory; Intention deactivation; Monitoring; Mouse tracking; Prospective memory; Spontaneous retrieval.

Fig. 1

Procedure. a Example trials of the active phase with a prospective memory (PM) task and the finished phases with or without a PM task are shown. In all trials except for PM trials, participants had to categorize digits according to parity by moving the mouse cursor from the lower edge of the screen into the corresponding response boxes at the upper-left of the screen (i.e., the lower response box for odd numbers and the upper one for even numbers). In the active phase, participants had to respond to specific symbols (e.g., triangle), which served as PM cues, by moving the mouse cursor into the response box at the upper-right of the screen. In finished phases, participants either performed a PM-task-repetition condition or an ongoing-task-only condition. In the PM-task-repetition condition, they performed another PM task in which they had to give a PM response to a different symbol than the PM cue from the active phase. In the ongoing-task-only condition, they had to perform only the ongoing task in all trials. Aftereffects of completed intentions were assessed during finished phases by comparing ongoing-task-performance and commission error rates in PM_REPEATED trials and oddball trials. Standard trials were trials without an additional symbol surrounding the target digit and required only an ongoing-task response. Note that the framing of trial types was not present in the experiment but serves exclusively to illustrate different trial types in this figure. b Schematic representation of the procedure. The experiment started with Instructions and practice of the mouse-tracking procedure, followed by a brief practice of the PM task. After that, participants performed 12 experimental cycles that each consisted of an active phase and a finished phase. Participants alternated between cycles with a finished phase in the PM-task-repetition condition and cycles with a finished phase in the ongoing-task-only condition. One half of the participants started the experiment with a cycle in the PM-task-repetition condition, while the other half started with a cycle in the ongoing-task-only condition

Fig. 2

a Mean response times (RT) and b mouse trajectories (x and y coordinates) as a function of trial type in the active phase and as a function of finished phase condition (PM-task-repetition and ongoing-task only) and trial type in the finished phase. In panel (a) error bars represent standard errors. In panel (b), confidence areas indicate the standard error in the respective time step. PM = prospective memory

Fig. 3

Results of continuous regression analyses on mouse movement in PM_REPEATED vs. oddball trials in the (a) PM-task-repetition condition and (b) ongoing-task-only condition of the finished phase. Dashed lines indicate the angle of the mouse movement. Grey, solid lines indicate the speed of mouse movement. For the movement angle, positive beta weights indicate a stronger orientation of movements toward the PM-response box in PM_REPEATED than in oddball trials; negative values indicate a stronger movement orientation toward the ongoing-task response boxes in PM_REPEATED than in oddball trials. For movement speed, positive beta weights indicate faster movements in PM_REPEATED than in oddball trials. Negative beta weights indicate slower movements in PM_REPEATED than in oddball trials. Lines above the graphs indicate segments of beta weights that were significantly different from zero (consecutive t-test; only segments with a minimum of ten consecutive significant time steps are shown). Confidence areas indicate standard errors of beta weights

Fig. 4

Results of continuous regression analyses on mouse movement in PM_REPEATED vs. oddball trials (dash-dotted line) and in PM-task-repetition condition vs. ongoing-task only condition (solid line) with the dashed line showing the interaction of condition and trial type. Continuous regression analyses were performed on speed (a) and angle (b) of mouse movement. Lines above the graphs indicate segments of beta weights that differ significantly from zero (t-test, a minimum of ten consecutive significant time steps). Confidence areas indicate standard errors of beta weights. The positive/negative characteristics describe the direction of effects. Positive beta weights signify larger values in PM_REPEATED than in oddball trials (dash-dotted line), respectively, in the PM-task-repetition condition than in the ongoing-task-only condition (solid line). Negative beta weights signify smaller values in PM_REPEATED than in oddball trials (dash-dotted line), respectively, in the PM-task-repetition condition than in the ongoing-task-only condition (solid line). The positive interaction (dashed line) in the analysis of speed in the second third of a trial suggests inverse aftereffects in this segment. However, note, this interaction does not result in a significant main effect of the factor trial type in this segment. The negative interaction in the last third indicates increased aftereffects in the corresponding segment

Fig. 5

Correlation of the peak deviation of movement deflection in the second third of a trial and subsequent speed of mouse movement in the ongoing-task only condition (dashed) and the PM-task-repetition condition (solid) for each participant. PM = prospective memory

Fig. 6

Results of continuous regression analyses on mouse movement in standard trials of the finished phase in the ongoing-task-only condition compared to the PM-task-repetition condition. The dashed line indicates the angle of the mouse movement. The solid line indicates the speed of the mouse movement. Positive beta-weights represent a stronger deflection of mouse movement in the direction of the PM-task response box (dashed line) or, respectively, a greater speed of mouse movement (solid line) in the PM-task-repetition condition than in the ongoing-task-only condition. Lines above the graphs indicate that segments of beta weights differ significantly from zero (t-test, a minimum of ten consecutive significant time steps). Confidence areas mark standard errors of beta weights