The Blursday Database: Individuals’ Temporalities in Covid Times

The Covid-19 pandemic and associated lockdowns triggered worldwide changes in the daily routines of human experience. The Blursday database provides measures of subjective time and related processes from more than 2,800 participants (over 9 countries) tested on 14 questionnaires and 15 behavioral tasks during the Covid-19 pandemic. The easy-to-process database and all data collection tools are made fully accessible to researchers interested in studying the effects of social isolation on temporal information processing, time perspective, decision-making, sleep, metacognition, attention, memory, self-perception, and mindfulness. Blursday also includes vital quantitative statistics such as sleep patterns, personality traits, psychological well-being, and lockdown indices. Herein, we exemplify the use of the database with novel quantitative insights on the effects of lockdown (stringency, mobility) and subjective confinement on time perception (duration, passage of time, temporal distances). We show that new discoveries are possible as illustrated by an inter-individual central tendency effect in retrospective duration estimation.

Working Memory in Aphasia: The Role of Temporal Information Processing

Aphasia is an acquired impairment of language functions resulting from a brain lesion. It is usually accompanied by deficits in non-linguistic cognitive processes. This study aimed to investigate in patients with aphasia the complex interrelationships between selected cognitive functions: auditory speech comprehension, working memory (WM), and temporal information processing (TIP) in the millisecond time range. Thirty right-handed subjects (20 males) aged from 27 to 82 years suffering from post-stroke aphasia participated in the study. Verbal working memory (VWM) and spatial working memory (SWM) were assessed with: (1) a receptive verbal test and (2) the Corsi Block-Tapping Test, respectively. Both these WM tests used the forward tasks (mainly engaging maintenance processes, i.e., storing, monitoring, and matching information) and backward tasks (engaging both maintenance and manipulation processes, i.e., reordering and updating information). Auditory comprehension was assessed by receptive language tests, and TIP efficiency was assessed by auditory perception of temporal order in the millisecond time range. We observed better performance of forward WM tasks than backward ones, independently of the type of material used. Furthermore, the severity of auditory comprehension impairment correlated with the efficiency on both forward and backward VWM tasks and the backward SWM task. Further analysis revealed that TIP plays a crucial role only in the latter task. These results indicate the divergent pattern of interactions between WM and TIP depending on the type of WM tasks. Level of verbal competency appeared to play an important role in both VWM tasks, whereas TIP (which is associated with manipulation processes) appeared to be important for SWM, but only on the backward task.

One second is not a special time

The Distinct Timing Hypothesis (DTH) proposes that two different neuronal computations underlie temporal information processing below and above one second. We tested DTH predictions by varying the interval between two visual events (S and C) from 400 to 2000 ms. To verify whether attentive encoding processes play a role, we deployed three durations for S (120, 160, and 200 ms), which map to attentive sampling frequencies of 8.33, 6.25, and 5 Hz. The one-second divide does not modulate sensory precision in duration discrimination, while it determines whether participants will dilate/compress perceived S duration. However, all distortion effects disappear when S is extended to 200 ms, suggesting that a sampling rate of 5 Hz optimizes subjective decisions. Since the effects of the one-second divide on perceived duration are not hardwired, a single computational mechanism may underlie both sub-second and supra-second temporal scales for behavior, in flexible interaction with attentive encoding processes.

Bayesian estimation on logarithmic scales as an explanation for spatiotemporal interferences with a tendency of deceleration

Spatial and temporal information processing interfere with each other. Kappa effect is a famous spatiotemporal interference, in which the estimated time between two lights increases as an increase of distance between the lights, showing a tendency of deceleration. A classical model attributes the interference to constant speeds and predicts a linear relation, whereas a slowness model attributes the interference to slow speeds and proposes the tendency is the result of the variance of stimuli locations. The present study developed a logarithmic version of the classical model and asserts that the tendency is the result of the Web-Fechner law. These hypotheses were tested in two time discrimination tasks by manipulating the variance of stimuli locations and distance between stimuli. The results demonstrate that estimated time was not modulated by the variance of stimuli locations, and increased as an increase of distance with a tendency of deceleration. The Bayesian model on logarithmic scales made more accurate behavioral predictions than the linear model; the estimated constant speed of the logarithmic Bayesian model was equal to the absolute threshold of speed; the strength of the Kappa effect positively correlated with the variability of time perception. Findings suggest that the interference in the Kappa effect is driven by slow speeds, the strength of the interference is influenced by the variability of time perception, and the tendency of deceleration is the result of the Weber-Fechner law. This Bayesian framework may be useful when applied in the field of time perception and other types of cross-dimensional interferences.