The Rough Guide to Psychology An Introduction to Human Behaviour and the Mind (Rough Guides)

THE ROUGH GUIDE TO PSYCHOLOGY

spinal cord – also needs to know the current position of all your limbs.
This is achieved via feedback from special receptors known as muscle
spindles. Finally, all your muscles needs to be coordinated. Bending
your arm, for example, means simultaneously relaxing the muscle
used to straighten it. Simply twisting your torso will have massive
ramifications for any manual movements you’re currently engaged in.
In fact, any movement you make will probably have implications for
the control of any other part of your body. It’s not entirely clear how
the brain manages this degree of complexity, but it seems likely that
movements are launched according to best estimates and then they’re
monitored and corrected “online”.
It’s because of the predictive processes that the brain uses to over-
come transmission delays that we’re unable to tickle ourselves. One
such predictive process is to anticipate in advance what the conse-
quences will be of our own actions. So when we perform a movement,
any expected consequences are predicted and cancelled out. When it
comes to tickling yourself, this means the sensory consequences of
your own tickling are predicted and removed. Supporting this account,
psychologist Sarah Jayne-Blakemore found she could reinstate people’s
ability to tickle themselves by providing them with control of a foam-
covered robotic interface with a built-in delay. The effect of the delay
was to make it seem as if someone else was performing the tickling.

Posterior parietal cortex

Premotor cortex

Supplementary

motor cortex

Primary motor cortex