Title: Voluntary actions modulate time perception
With Eamonn Walsh and Prof. Patrick Haggard
http://www.icn.ucl.ac.uk/Research-Groups/Motor-Control-Group/index.php
Intervals of time may be perceived longer or shorter than they actually are, depending
on levels of motor activity. For example, when a voluntary action is followed by a
tone, the action is perceived to occur later and the tone earlier than in control
conditions with only actions or only tones, (Haggard, Clark and Kalogeras; 2002).
There is some evidence that the anticipatory shift of the tone towards the action
occurs because the brain can predict the tone from the motor intention. One
mechanism for this prediction may be a slowing in the rate of an ‘internal clock’, such
that action and tone are separated by fewer clock cycles than in a resting condition.
Internal clock speed can be measured by the ability to discriminate whether two
stimuli occur at the same time or not. Therefore, in order to probe these interesting
effects, the proposed experiment will deliver two mild electric shocks at various times
in the interval between an action and a tone (see Figure 1). Participants will judge
whether the shocks were successive or simultaneous. The accuracy of participants’
judgments will hopefully reveal where in the interval time is being ‘distorted’.
‘Early’ shock timing
‘Late’ shock timing
‘After’ shock timing
Tone
Action
0 ms
150 ms
450 ms
600 ms
850 ms
Time
Figure 1. It is known that time is compressed in the interval between an action and a tone. By
delivering shocks at different times during and after the interval we hope to explore where time is being
distorted the most.
Reference:
Haggard P, Clark S, Kalogeras J (2002) Voluntary action and conscious awareness.
Nature Neuroscience 5:382-385.