Deficits of duration estimation in individuals aged 10-20 years old with idiopathic mild intellectual disability: The role of updating working memory

Duration estimation is a conceptual ability that plays a crucial role in human behaviour. Impairments in duration estimation ability have a significant impact on daily autonomy and social and cognitive capacities, even more so in psychological disorders. It has been recently shown that the ability to estimate durations develops at a slower pace in individuals with mild intellectual disability (MID) compared with typically developing (TD) individuals. More generally, it has been also demonstrated that duration estimation requires working memory updating. In this study, we compared the duration estimation and updating performances of individuals aged 10-20 years with idiopathic MID without associated disorders to those of typical individuals of the same ages (N = 160). Our results highlight a developmental lag not only in the capacity to estimate short durations (<1 s) in individuals with idiopathic MID, both in a bisection task and in a reproduction task, but also in working memory updating capacity. The findings also emphasise-for the first time-the importance of updating for both the age-related increase in duration estimation capacities and the deficits of these capacities in idiopathic MID. This is consistent with the hypothesis that duration estimation deficits in idiopathic MID may be due, to a large extent, to lower updating abilities.

An Illusory Motion in Stationary Stimuli Alters Their Perceived Duration

Despite having equal duration, stimuli in physical motion are perceived to last longer than static ones. Here, we investigate whether illusory motion stimuli produce a time-dilation effect similar to physical motion. Participants performed a duration discrimination task that compared the perceived duration of static stimuli with and without illusory motion to a reference stimulus. In the first experiment, we observed a 4% increase in the number of "longer" responses for the illusory motion images than static stimuli with equal duration. The time-dilation effect, quantified as a shift in the Point of Subjective Equality (PSE), was approximately 55 ms for a 2-second stimulus. Although small, the effect was replicated in a second experiment in which the total number of standard-duration repetitions was reduced from 73 to 19. In the third experiment, we found a positive linear trend between the strength of the illusory motion and the magnitude of the time-dilation effect. These results demonstrate that, similar to physical motion stimuli, illusory motion stimuli are perceived to last longer than static stimuli. Furthermore, the strength of the illusion influences the extent of the lengthening of perceived duration.

Post-interval potentials in temporal judgements

Research suggests that post-stimulus positive deflections could be associated with timing. We compared offset-locked potentials N1, P2, N1P2, and late positive component (LPC) in temporal generalization and temporal bisection-with visual probe intervals. In both tasks, the LPC amplitude decreased with the duration of the current probe interval. A larger LPC was found after shorter intervals, whereas other ERP amplitudes did not change between tasks or across durations. We also found that the LPC for different responses indicates subjective time. We discussed our findings in relation to theories of human timing.

The effect of pain on reference memory for duration

Previous research has consistently reported that pain related stimuli are perceived as lasting longer than non-pain related ones, suggesting that pain lengthens subjective time. However, to date, the investigation has been limited to the immediate effects of pain on time perception. The current study aims to investigate whether pain affects how a duration is recalled after a period of delay. In two experiments, participants were asked to complete four temporal generalisation tasks, where they were required first to remember the duration of a standard tone (learning phase) and then to compare the standard duration to a series of comparison durations (testing phase). Using a 2 × 2 design, the four tasks differed in terms of whether participants were exposed to a painful or non-painful stimulus during the learning phase, and whether the testing phase started immediately or 15 min after the learning phase. Participants were exposed to low pain in Experiment 1 and high pain in Experiment 2. Two possible results were expected: pain could decrease temporal accuracy, because pain disrupts cognitive processes required for accurate timing, or pain could increase temporal accuracy, because pain facilitates memory consolidation. Contrary to expectations, results from both Experiments indicated that participants’ temporal performances were similar in the pain and no-pain conditions when testing occurred 15 min after the learning phase. Findings, therefore, suggest that pain neither disrupts nor enhances long-term memory representations of duration.