Consciousness

THE ROLE OF

CONSCIOUSNESS IN

SKILLED ACTION

The fastest serves cross the tennis court in a little over
half a second, and the ball starts its flight at well over
a hundred miles an hour. Yet these super-fast serves
can be returned with stunning accuracy. Does the
receiver have time for the mysterious double conver-
sion to consciousness and back? Is conscious percep-
tion even necessary for such skilled movements?

The answer is no. Studies of skilled motor actions
reveal a dissociation between fast visuomotor con-
trol and conscious perception. For example, in some
experiments participants are asked to point at a visual
target; then just as they begin to point, the target is
displaced. If the displacement is made during a
voluntary saccade, participants do not notice the
displacement even though they rapidly adjust their
arm movement to point correctly at the final posi-
tion (Bridgeman et al., 1979; Goodale, Pelisson, and
Prablanc, 1986). In other words, their behaviour is
accurately guided by vision even though they do
not consciously see the target move. Accurate move-
ments can also be made towards stimuli that are not
consciously perceived at all. When small visual targets
were made invisible by presenting a larger stimulus
50 ms later (this is called backward masking), par-
ticipants still responded correctly to the target they
claimed not to have seen (Taylor and McCloskey, 1990).

In the case of the tennis serve, or catching your
scrumpled paper ball, the ball is consciously per-
ceived – but when? Does the conscious perception
occur soon enough to affect the action?

One experiment (Paulignan et al., 1990) asked
participants to track by hand a moving object
that was suddenly displaced. They were able to
respond within about 100 ms, but when asked
afterwards to estimate at which point in the
movement they had seen the displacement, they
consistently reported that the object jumped just
when they were about to touch it – that is, much
later than either the actual displacement or their
own corrective movement. This finding suggested
that conscious awareness may come too late to
play a causal role in the action.

ACtIVItY 8.1

Incubation

Incubation is the process of putting a problem ‘on

the back burner’, just allowing a solution to come

by itself – if it will. Three steps are required. First,

you have to do the hard work of struggling with the

problem or acquiring the necessary skills. Second, you

have to drop the struggle and leave the problem to

itself, perhaps by engaging in some other activity, or

just sleeping on it. In this second stage, any conscious

effort is likely to be counter-productive. Third, you have

to recognise the solution when it appears.

Here are three simple brain-teasers to practise

incubation. If you are working on your own, have

a good go at trying to solve them, until you get

really frustrated. Then forget all about them and

read more of the book, or do something else for

half an hour or so. When you come back to the

problem, you may find that the solution just ‘pops

into your mind’. If you are working in a group, you

can start a lecture or discussion with five minutes

working on the problems and then return to them

at the end, making sure that those people who

solve the problems quickly don’t give the answers

away and spoil the experience for everyone else.

The solutions are given in Figures 8.17–8.19 on

p. 216.

FIGURE 8.4 • Move three

coins to turn the

triangle upside

down.

FIGURE 8.5 • Move two match

sticks to make the

cow face the other

way. You can try

this one on your

friends using real

match sticks; leave

it on the bar or the

dinner table and

let them incubate

it too.