Intended outcome appears longer in time

We live in a complex and dynamic world where sometimes our action yields the intended (desired) outcomes and sometimes the unintended outcomes, but does our subjective time changes as a function of outcome being intended or unintended. To find the answer, read the recent article by Mukesh Makwana and Prof. Narayanan Srinivasan, published in Scientific Reports.

In a series of five experiments involving temporal bisection task (Exp1-4) and magnitude estimation task (Exp5), they investigated whether participants perceive the duration of intended outcome differently compared to unintended outcome, and if yes then what are its underlying mechanisms.

They reasoned that when a participant intends an outcome, its representation gets activated and this prior self-activated representation would lead to earlier awareness of the intended outcome compared to unintended outcome  extending the temporal experience. Recently, pre-activation account has been used to explain temporal expansion (Press et al., 2014).

To manipulate intentional nature of the outcome they used a simple color choice question. In each trial, amongst the choice of two colors, they asked participants to indicate what color circle they want to see, by pressing the allocated key for that color. After 250ms (Exp1) of the intentional key press, they were randomly presented with circle of either intended color (50% times) or unintended color (50% times) whose duration was randomly manipulated amongst nine levels (300ms to 700ms in steps of 50ms). This was done to reduce or eliminate the sensory-motor prediction between the key press and the color of the outcome circle, so that the effect of intention on the perceived duration of the outcome is not confounded with probability-based prediction. Irrespective of the intentional nature of the outcome, participants were supposed to report whether they perceived the duration of the outcome as closer to short (300ms) or long (700ms) anchor duration that they learnt in training phase before the main experiment. Each individual data was sorted into two conditions i.e. when they get the intended outcome (i.e. Intended condition) and when they did not get the intended outcome ( i.e. unintended condition). Psychometric (Weibull) functions were fitted for this two conditions and bisection points were calculated. Bisection point or point of subjective equality is the measure of shift in temporal perception, where lower values of bisection point in a condition indicate temporal expansion relative to condition with higher bisection point. Results of Exp1 showed that participants perceived the duration of intended outcome as longer compared to unintended outcome.

They also studied whether increase in delay between the intentional action and its outcome affects the intention induced temporal expansion observed in Exp1. So further two experiments were performed with increased delay between action and outcome i.e. 500ms in Exp2 and 1000ms in Exp3. Rest stimuli, apparatus and procedure were identical to Exp1 except that in Exp2 instead red and green, yellow and blue color circles were used. Results showed that the intention induced temporal expansion was observed till 500ms delay but as the delay increased to 1000ms the temporal expansion effect vanished, suggesting that the self-activated representation fades away around 1000ms of the intentional action.

To establish that for the above-observed temporal expansion effect, intentional activation of the representation is necessary and not just priming or instruction-based action is not sufficient Exp4 was performed. In Exp4, instead of intending and selecting what color circle they wanted to see, in each trial participants  were shown color word i.e. RED or GREEN on the screen and they just pressed the corresponding key. Rest procedure, stimuli and analysis was similar to Exp1. Results showed no difference in duration perception between word congruent condition and word incongruent condition, suggesting the importance of intention in the above effect.

Lastly, Exp5 was performed using magnitude estimation paradigm to investigate whether intention affects the time perception by increasing the pacemaker speed or affecting the switch or gating component of the “internal clock model”.  The internal clock model is the most influential classical model used to explain human timing behaviour. If any factor influences the pacemaker speed then as the magnitude of the actual duration increases the difference between two conditions should also increase given a typical “slope effect”. On the other hand, if the switch or gating component is affected then no slope effect is observed. Results showed no slope effect, indicating that intention might influence the switch or gating mechanism.

In conclusion, a series of experiments in this study provides convincing evidence that intention affects temporal perception and participants perceives the intended outcome to be longer in duration compared to unintended outcome. Moreover, this intention induced temporal expansion effect depends on the temporal contiguity between the action and the outcome and it vanishes at 1000ms action-outcome delay. Furthermore, in terms of internal clock, this effect is most probably not due to increase in pacemaker speed, rather opening or closing of the switch seems more probable mechanism. As humans are intentional agents and intentions forms a critical part of daily life, more studies investigating the effects of intention on perception in general should be pursued.

 

Reference:

 

  1. Press, C., Berlot, E., Bird, G., Ivry, R., & Cook, R. (2014). Moving time: The influence of action on duration perception. Journal of Experimental Psychology: General, 143(5), 1787.

 

Source article:  Makwana, M., & Srinivasan, N. (2017). Intended outcome expands in time. Scientific Reports, 7(6305) doi:  10.1038/s41598-017-05803-1

 

—Mukesh Makwana (mukesh@cbcs.ac.in),

Doctoral student,

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

 

Summer 2017 Conference Season

Finally back in London, ON, after a slightly extreme summer conference tour: The Neurosciences and Music IV in Boston; preceded by our homegrown satellite, Neural Entrainment and Rhythm Dynamics (NERD, credit Ed Large for name/acronym combo); cuttingEEG in Glasgow; and the Rhythm Perception and Production Workshop (RPPW) in Birmingham [had a little break in between those last two to drive around Scotland with my dad and brother]. All of it was extremely inspiring, but of course too much info for any one human to retain, so I’ll try to summarize what I felt were some of the highlights.

I’m of course extremely biased, but I loved every minute of NERD. It was full-on day of fantastic 7-min talks on rhythm and entrainment punctuated by thought-provoking discussion periods. There were two major things I took away from NERD (I’ll only talk about one in any detail). First, we’re not all speaking the same language a lot of the time. That’s of course a problem that has been and will be around forever to some extent, and it’s also OK. For example, when I talk about “rhythm” or “beat”, that’s not quite the same thing someone else is talking about when they use the same words. A particularly sticky word at the moment is “entrainment”, which seems to mean a lot of things to a lot of different people, despite being very well defined in the math/physics domains. Even things like “beat salience” or “beat strength” are contested terms, making them hard things to study and talk about. The important thing, I think, is that we make sure we’re operationally defining terms in the papers we’re publishing and the talks we’re giving, so that even if we’re using terms differently, we can talk about the same phenomena. It sounds obvious, but this is done surprisingly infrequently, including by myself I’m sure. The second thing I took away, which I won’t discuss here and which very well may be the subject of a future blog, is that rhythmic/temporal expectation effects on behavior are harder to observe than one might think. More on that later.

There were a million interesting talks and posters at both NeuroMusic and RPPW, but here I’ll focus on timing-related issues. Even though I’ve heard various bits of the data before, I was struck (again) by the idea and accumulating evidence that synchrony is social. We need to be synchronized with each other to successfully navigate conversational turn-taking. Toddlers are more likely to exhibit pro-social helping behaviors towards adults that they have moved in synchrony with compared to someone they have moved out-of-sync with. Babies synchronize eye contact with a singer to the beat of the song the singer is producing.

A relatively new focus was on synchronization between brains. New ways to analyze electrophysiological data (using “intersubject synchronization” or “intersubject correlation”) allow us to assess interpersonal neural synchrony. Traditionally, measures of intersubject synchronization don’t necessarily focus on social situations, but nonetheless show that individual brains are more synchronized with each other (i.e., respond more similarly to the same stimulus) when individuals are more engaged with whatever they are watching or listening to. We presented EEG data that we collected from 60 EEG participants, 20 at a time, in slightly different social situations while viewing/listening to a concert. But I’m not here to self-promote. One really interesting twist on this idea was to use noninvasive brain stimulation to force pairs of brains to be either in sync or out of sync with each other. Despite the situation not actual being social (the individuals making up each pair were not able to see or interact with each other, but did have auditory information about the other person’s behavior), pairs of participants synchronized tapping better with each other when their brains were in sync compared to when their brains were out of sync. The moral of the story is that better neural synchronization leads to better behavioral synchronization, which could in turn lead to stronger affiliation in the social domain.

In general, rhythm and timing were very present topics at the conferences I attended this summer. And it seems like the more we know about how brains are actually involved in behavioral synchrony, the better we stand to understand how synchrony is involved in social situations. I look very much forward to seeing how this research evolved over the next years, and in hopefully being a part of it myself.