In a paper recently published in Scientific Reports, Sven Thönes, Christoph von Castell, Julia Iflinger, and Daniel Oberfeld investigated whether duration judgments depend on the color (hue) of stimuli to be judged.

As color represents a basic feature of visual stimuli in lab experiments as well as in every-day environments, potential effects of hue on our perception of time are important to be considered. In particular, the well-known effects of arousal on time perception suggest that arousing hues, such as red, induce an overestimation of duration.

In a two-interval duration-discrimination task, the authors investigated whether participants indeed overestimate the duration of red stimuli in comparison to blue stimuli, while controlling for differences in brightness (individual adjustments by means of flicker photometry) and saturation (colorimetric adjustment in terms of the CIELAB color space). The mean duration of the stimuli was 500 ms. Moreover, the participants’ affective reaction (arousal, valence, dominance) towards the color stimuli were measured by means of the Self Assessment Manikin Scales.

Interestingly, the results showed a significant overestimation of the duration of blue compared to red stimuli, even though the red stimuli were rated as being more arousing. The estimated point of subjective equality showed that blue and red stimuli were perceived to be of equal duration when the blue stimulus was in fact 60 ms (12%) shorter than the red stimulus.

These surprising results (high arousal related to temporal underestimation) question arousal to be the main driving factor in the context of color and time perception. Moreover, the precision (variability) of duration judgments, i.e., the duration difference limen, did not differ between red and blue stimuli, questioning also an explanation in terms of attentional processes. The authors propose that specific neurophysiological mechanisms of color processing might be the basis of the effect, which need to be investigated in more detail in future studies.

Importantly, in timing-related visual experiments, it needs to be considered that the hue of the stimuli can affect time perception.

Source article:

Thönes, S., von Castell, C., Iflinger, J., & Oberfeld, D. (2018). Color and time perception: Evidence for temporal overestimation of blue stimuli. Scientific Reports, 8(1688) doi: 10.1038/s41598-018-19892-z

–Dr. Sven Thones (thoenes@ifado.de)

Sense of agency (SoA) is an important feeling associated with voluntary actions, enabling one to experience that he/she is controlling the actions and through them the events in the external environment. Until now, only the distortion of time interval between the action and its consequence (i.e. intentional binding effect) was associated with SoA, but a recent study by Shu Imaizumi and Tomohisa Asai, published in Consciousness and Cognition showed that even perceived duration of consequence is linked with SoA.

To investigate this association, they measured the perceived duration (measure of subjective time) of visual display and the rating for amount of control (explicit measure of agency) as a function of temporal contiguity (between action and visual display) and identity of visual display (being participants own hand vs. someone else’s hand). In each trial, participant performed a complex hand gesture as depicted by the image on the screen. This hand gesture was recorded by the overhead camera and projected on the screen after variable delay. While participants performed this task, their hands were covered so the only visual feedback of their action was the one that they saw on the screen. Participants reported whether they perceived the duration of the displayed video feedback (3000ms) as “short” or “long”. They also reported whether they felt that they controlled the displayed hand, by providing a binary response as “totally agree” or “totally disagree”.

The agency was manipulated in two ways, one by changing the visual display (self vs. others) and second, by manipulating the action consequence delay (50ms, 250ms, 500ms, 1000ms or 1500ms). In half trials, participants saw recording of their own hand (self-condition) and in other half trials, they saw the prerecorded clips of other person hand movements performing similar action (other-condition). Orthogonally, the temporal contiguity between action and visual feedback (50ms, 250ms, 500ms, 1000ms or 1500ms) was also manipulated. Based on prior studies on SoA, it was expected that seeing visual feedback of one’s own hand should elicit stronger SoA compared to seeing someone else hand. Similarly, one should experience a stronger SoA for visual feedback displayed with short delay (50ms, 250ms, or 500ms) compared to longer delay (1000ms or 1500ms). They hypothesized that if SoA influences perceived duration then participants should report “long” judgment more often for conditions that are known to boost SoA.

Results revealed that when the visual feedback display consisted of participant’s own hand, they reported stronger SoA and perceived the duration as longer, for short action outcome delay (50ms, 250ms, or 500ms) and this effect become weaker as the delay become longer (1000ms and 1500ms). Furthermore, the above effect was not observed when display consisted of someone else hand, suggesting the possibility that SoA and perceived outcome duration might be linked. Another similar experiment, investigated the effect of participants own hand projected from first person perspective (upright) vs. second person perspective (inverted). Authors expected that inverted perspective would be treated as non-self and will not influence perceived duration, but surprisingly both inverted as well as upright perspective showed similar effect on perceived duration and agency, suggesting that independent of orientation the visual information regarding one’s own hand is processed in a similar manner.

In conclusion, this study provides evidence that SoA also affects perceived duration and participants perceives the outcome duration to be longer when they feel stronger SoA. However, this study is unclear about the exact mechanism that would explain the observed temporal expansion associated with SoA. Moreover, only single duration was used to evaluate changes in temporal perception. Another recent study published in Scientific Reports by Makwana and Srinivasan, also demonstrated similar temporal expansion associated with intentional action, which was sensitive to temporal contiguity and source of action (intention-based vs. stimulus-based). They demonstrated the intention induced temporal expansion, using multiple durations and paradigms (temporal bisection and magnitude estimation), In addition, they also investigated its underlying mechanism in terms of internal clock (most influential model of time perception), suggesting the role of switch dynamics and not the pacemaker speed, to be involved in such temporal expansion. Thus, these studies overall suggest that intention and intentional action, not only influence the time between the action and the outcome but may also influence other aspects of the outcome events such as its duration, and more studies are required to fully understand in what all ways our perception is distorted  by intentional action.

Reference:

1. Moore, J. W., & Obhi, S. S. (2012). Intentional binding and the sense of agency: a review. Consciousness and cognition, 21(1), 546-561.
2. Makwana, M., & Srinivasan, N. (2017). Intended outcome expands in time. Scientific Reports, 7(6305) doi: 1038/s41598-017-05803-1

Source article:  Imaizumi, S., & Asai, T. (2017). My action lasts longer: Potential link between subjective time and agency during voluntary action. Consciousness and cognition, 51, 243-257.

—Mukesh Makwana (mukesh@cbcs.ac.in),

Doctoral student,

Centre of Behavioural and Cognitive Sciences (CBCS), India.