Sylvie Droit-Volet

How emotions colour our perception of time

Our sense of time is altered by our emotions to such an extent that time seems to fly when we are having fun and drags when we are bored. Recent studies using standardized emotional material provide a unique opportunity for understanding the neurocognitive mechanisms that underlie the effects of emotion on timing and time perception in the milliseconds-to-hours range. We outline how these new findings can be explained within the framework of internal-clock models and describe how emotional arousal and valence interact to produce both increases and decreases in attentional time sharing and clock speed. The study of time and emotion is at a crossroads, and we outline possible examples for future directions.

BRIEF REPORT Perception of the duration of emotional events

Participants were trained on a temporal bisection task in which visual stimuli (a pink oval) of 400 ms and 1600 ms served as short and long standards, respectively. They were then presented comparison durations between 400 ms and 1600 ms, represented by faces expressing three emotions (anger, happiness, and sadness) and a neutral‐baseline facial expression. Relative to the neutral face, the proportion of long responses was higher, the psychophysical functions shifted to the left, and the bisection point values were lower for faces expressing any of the three emotions. These findings indicate that the duration of emotional faces was systematically overestimated compared to neural ones. Furthermore, consistent with arousal‐based models of time perception, temporal overestimation for the emotional faces increased with the duration values. It appears, therefore, that emotional faces increased the speed of the pacemaker of the internal clock.

Speeding up an Internal Clock in Children? Effects of Visual Flicker on Subjective Duration:

Children of 3, 5, and 8 years of age were trained on a temporal bisection task where visual stimuli in the form of blue circles of 200 and 800 ms or 400 and 1600 ms duration, preceded by a 5-s white circle, served as the short and long standards. Following discrimination training between the standards, stimuli in the ranges 200-800 ms or 400-1600 ms were presented with the white circle either constant or flickering. Relative to the constant white circle, the flicker (1) increased the proportion of “long” responses (responses appropriate to the long standard), (2) shifted the psychophysical functions to the left, (3) decreased bisection point values, at all ages, and (4) did not systematically affect measures of temporal sensitivity, such as difference limen and Weber ratio. The results were consistent with the idea that the repetitive flicker had increased the speed of the pacemaker of an internal clock in children as young as 3 years. The “pacemaker speed” interpretation of the results was further strengthened by a greater effect of flicker in the 400/1600-ms condition than in the 200/800-ms condition.

Embodied Temporal Perception of Emotion

The role of embodiment in the perception of the duration of emotional stimuli was investigated with a temporal bisection task. Previous research has shown that individuals overestimate the duration of emotional, compared with neutral, faces (S. Droit-Volet, S. Brunot, & P. M. Niedenthal, 2004). The authors tested a role for embodiment in this effect. Participants estimated the duration of angry, happy, and neutral faces by comparing them to 2 durations learned during a training phase. Experimental participants held a pen in their mouths so as to inhibit imitation of the faces, whereas control participants could imitate freely. Results revealed that participants overestimated the duration of emotional faces relative to the neutral faces only when imitation was possible. Implications for the role of embodiment in emotional perception are discussed.

Time flies in the presence of angry faces… depending on the temporal task used!

A number of studies have reported that the perception of an arousing emotional stimulus, such as an angry face, results in temporal overestimations which are probably due to the speeding up of a clock-like system. The aim of the present study was to examine whether this emotional effect can be generalized to all temporal tasks irrespective of the underlying cognitive processes involved in each task. Five different temporal tasks involving the presentation of neutral and angry faces were therefore tested: bisection, generalization, verbal estimation, production and reproduction. Our results showed an overestimation of time for the angry compared to the neutral faces in the temporal bisection, verbal estimation and production tasks but not in the temporal generalization and reproduction tasks. Moreover, the results obtained in the temporal verbal estimation and production tasks suggest that this temporal overestimation of the angry faces was associated with relatively more accurate estimates. The involvement of both arousal and attention mechanisms in the effect of emotional facial expressions on time perception is discussed in the light of the differences in the impact of the same emotional stimulus as a function of the temporal task considered.

Perception of the duration of auditory and visual stimuli in children and adults

This experiment investigated the effect of modality on temporal discrimination in children aged 5 and 8 years and adults using a bisection task with visual and auditory stimuli ranging from 200 to 800 ms. In the first session, participants were required to compare stimulus durations with standard durations presented in the same modality (within–modality session), and in the second session in different modalities (cross–modal session). Psychophysical functions were orderly in all age groups, with the proportion of long responses (judgement that a duration was more similar to the long than to the short standard) increasing with the stimulus duration, although functions were flatter in the 5–year–olds than in the 8–year–olds and adults. Auditory stimuli were judged to be longer than visual stimuli in all age groups. The statistical results and a theoretical model suggested that this modality effect was due to differences in the pacemaker speed of the internal clock. The 5–year–olds also judged visual stimuli as more variable than auditory ones, indicating that their temporal sensitivity was lower in the visual than in the auditory modality.

Emotional time distortions: The fundamental role of arousal

An emotion-based lengthening effect on the perception of durations of emotional pictures has been assumed to result from an arousal-based mechanism, involving the activation of an internal clock system. The aim of this study was to systematically examine the arousal effect on time perception when different discrete emotions were considered. The participants were asked to verbally estimate the duration of emotional pictures from the International Affective Picture System (IAPS). The pictures varied either in arousal level, i.e., high/low-arousal, for the same discrete emotion (disgust or sadness) or in the depicted emotion, e.g., disgust/fear for pictures matched for arousal (high-arousal). The results systematically revealed a lengthening effect on the perception of the duration of the emotional compared to the neutral pictures and indicated that the magnitude of this effect increased with arousal level. Nevertheless, variations in time perception were observed for one and the same arousal level, with the duration of disgust-inducing pictures (e.g., body mutilation) being judged longer than that of fear-inducing pictures (e.g., snake). These results suggest that arousal is a fundamental mechanism mediating the effect of emotion on time perception. However, the effect cannot be reduced to arousal, since the impact of the content of pictures also plays a critical role.

Time perception, depression and sadness

This study examined changes in time perception as a function of depressive symptoms, assessed for each participant with the Beck Depression Inventory (BDI). The participants performed a temporal bisection task in which they had to categorize a signal duration of between 400 and 1600 ms as either as short or long. The data showed that the bisection function was shifted toward the right, and that the point of subjective equality was higher in the depressive than in the non-depressive participants. Furthermore, the higher the depression score was, the shorter the signal duration was judged to be. In contrast, the sensitivity to time was similar in these two groups of participants. These results thus indicate that the probe durations were underestimated by the depressive participants. The sadness scores assessed by the Brief Mood Inventory Scale (BMIS) also suggest that the emotional state of sadness in the depressive participants goes some way to explaining their temporal performance. Statistical analyses and modeling of data support the idea according to which these results may be explained by a slowing down of the internal clock in the depressive participants.

Anger and time perception in children.

The present study investigated age-related variations in judgments of the duration of angry facial expressions compared with neutral facial expressions. Children aged 3, 5, and 8 years were tested on a temporal bisection task using angry and neutral female faces. Results revealed that, in all age groups, children judged the duration of angry faces to be longer than that of neutral faces. Findings are discussed in the framework of internal clock models and the adaptive function of emotion.

Time Estimation of Fear Cues in Human Observers

Previous research suggests that time judgments are a function of the affective properties of to-be-timed stimuli and that time judgments are longer for stimuli that are fear-inducing (e.g., Hare, 1963; Watts and Sharrock, 1984). The goals of the present study were twofold: to replicate the effect of a fear cue on time estimation, and to evaluate the mechanism underlying the effect. Seven stimulus durations in two different duration ranges (short: 250-1000 ms; long: 400-1600 ms) were employed in the bisection procedure. Adult human participants were exposed to two successive sessions, one each with the short and long range. Images from the International Affective Picture System (IAPS; Lang et al., 2008) that were rated on three scales including arousal and fear were presented as temporal stimuli. Three images that were rated high on fear and three rated low served as fear cues and neutral control images, respectively. Results indicated that for both ranges, judgments were longer for fear cues than for neutral images, and that the magnitude of the effect did not differ between ranges as measured by the bisection point. Application of scalar expectancy theory (SET; Gibbon, 1977; Church, 1984) to these results suggests that the fear effects were mediated by switch latency of an internal clock, rather than by clock speed.