Thursday, 31 March 2011

People who are more aware of their own heart-beat have superior time perception skills

What underlies our sense of time? A popular account claims an internal pacemaker emits regular pulses, which are detected by an accumulator. The amount of accumulated pulses represents the amount of time that's passed.

Trouble is, this is all very theoretical and no-one really knows how or where in the brain these functions are enacted. One suggestion is that the pulses are based on bodily feedback and in particular the heart-beat. Consistent with this is a recent brain imaging study that showed activity in the insular (a brain region associated with representing internal bodily states) rose linearly as people paid attention to time intervals (pdf). Now a behavioural study by Karin Meissner and Marc Wittmann has built on these findings by showing that people who are more sensitive to their own heart-beat are also better at judging time intervals.

Thirty-one participants listened to auditory tones of either 8, 14, or 20 seconds duration. After each one, they heard a second tone and had to press a button when they thought its duration matched the first. Counting was forbidden during the task and a secondary, number-based memory task helped enforce this rule. Heart-beat perception accuracy was measured separately and simply involved participants counting silently their own heart-beats over periods of 25, 35, 45 and 60 seconds.

The take away message is that the participants who were more in tune with their heart-beats also tended to perform better at the time estimation task. A further detail is that physiological measures taken during the encoding part of the task showed that as time went on, the participants' heart-rate slowed progressively, and their skin conductance (i.e. amount of sweat on the skin) reduced. Moreover, the rate of change in a participant's heart-rate (but not skin conductance) was linked with the accuracy of their subsequent time estimates.

'These results suggest that the processing of interoceptive signals [i.e. of internal bodily states] in the brain might contribute to our sense of time,' Meissner and Wittmann concluded.

The new findings add to past research showing that patients with cardiac arrhythmia are poorer than controls at time estimation tasks, and that drug-induced speeding or slowing of the autonomic nervous system (including heart-rate) affects people's under- or over-estimation of time intervals.

ResearchBlogging.orgMeissner, K., and Wittmann, M. (2011). Body signals, cardiac awareness, and the perception of time. Biological Psychology, 86 (3), 289-297 DOI: 10.1016/j.biopsycho.2011.01.001

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.


Neuroskeptic said...

I remember hearing a cautionary tale about the early days of LSD research. They gave this guy LSD and asked him to estimate the passage of time. Meanwhile they were taking his heart rate, in case that was changed by the drug, and they were reading that outloud.

So he counted his heartbeats and divided that by the heart rate to tell the time. He did amazingly well! But not because of the LSD.

It may have been in The Electric Kool-Aid Acid Test... maybe not, though...

Anonymous said...

It was Ken Kesey.

Anonymous said...

Hmm, but if you're someone whose heart rate doesn't budge from resting, except under significant exercise load, demonstrating awareness of your pulse is very easy.

I wonder if you'd get just as solid a correlation if you compared time sense to "how consistent is the pulse rate between measurements."

(The person I know with a pronounced respiratory sinus arrhythmia also seems to have an awful sense of time...)

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