The brain is an extraordinarily complex organ that we are
struggling to understand scientifically. To help us understand the way the
brain works, we often use the most complex machines of an era to give us
insight into what the brain is doing.
And starting in the 1950’s, the most complex machine we had was the
computer.
One influence of this computer metaphor for the mind is that
it has emphasized the information that is processed in the brain over the
relationship between mind and body.
After all, computers have poor bodies.
They have a keyboard and mouse as a sensory system and a display and
internet connection as ways of acting on the world around it. As a result, most research in psychology
focuses on how the brain processes particular kinds of information without much
focus on how the body influences that thought.
There are some streams of research that buck this
trend. In research on adults, there is
work on situated cognition that
explores how the environment affects the way people think. There are also studies in embodied cognition that examine how body
and mind interact.
Over the years, there has also been work on how the body
influences learning in infants and children.
In my last
blog entry, for example, I talked
about how experience moving influences children’s curiosity about heights.
A fascinating paper in the February, 2014 issue of Child Development by Sarah Gerson and Amanda
Woodward examines how 3-month-olds learn about other people’s goals from their
own actions.
If you have ever spent any time with a 3-month-old, then you
know that they are not particularly coordinated. Jessica Sommerville, Amanda Woodward, and Amy
Needham developed an ingenious method for looking at actions in 3-month-olds
(reported in a paper in the journal Cognition in 2005). They attached
mittens with Velcro on them to infants’ hands.
Then, the infants could reach out and move toys that also had Velcro on
them.
In Gerson and Woodward’s study, all of the infants had a
chance to sit with the toys for a few minutes without the mittens. Then, some infants had the mittens put on, and
they reached out and played with the toys for a few minutes. For these infants, playing with the toy
generally meant moving it back-and forth across the table. A second group of infants was matched with
the infants from the first group. For
each infant in the second group, the experimenter mimicked the actions of the
infant using Velcro gloves, so that this infant got to watch something similar
to what the first infant did. That
provides a control condition in which the infants are exposed to the actions
without actually performing the actions themselves.
After this initial exposure, infants were tested. It is hard to test 3-month-olds, because they
cannot speak or understand much language.
Instead, researchers typically use a looking procedure.
In this study, the two toys that were used in the first part
of the study were placed on a stage. A
gloved hand reached out and picked up one of the toys. This event was presented several times until
the infants stopped looking at it. This
decrease in looking time is called habituation
and is used as a measure that the children can predict what is going to happen.
Then, the positions of the two toys were switched. So, the one on the left is now on the right
and vice versa. Now, two types of test
trials were given. In one type of test
trial, the hand reached out and grabbed the toy that was now on the left. In this case, the hand performed the same
action, but the outcome was different.
In the other type of test trial, the hand picked the same object that it
selected before. In this case, the
movement was different (because the hand had to reach all the way to the
right), but the outcome was the same (because the same object that was touched
earlier was selected again).
The experimenters measured how long infants looked at each
type of test. The longer infants look,
the more interested they are in that outcome, generally because that outcome is
different from what they expected.
The infants who watched someone else acting on the toys did
not look reliably longer at either type of event. Those infants who acted on
the toys themselves looked for a longer time at the event with a different
outcome than at the event with the same outcome. That is, by playing with the toys, infants
seemed to learn that other people often direct their actions at particular
outcomes rather than just making particular movements.
The infants learned something very specific from this
experience, though. A third group of
infants played with the toys using the mittens, but then the test trials
involved a different set of toys than the ones they played with. This group also did not look reliably longer
at either type of test event. That is,
the infants learned only about outcomes involving the specific toys they played
with.
What does all of this mean?
One way that infants learn about what other people want to
do is by learning about how they perform actions in the world. As they learn that their actions can be
directed toward particular outcomes, they also learn that other people may act
to bring about particular outcomes.
However, it also appears that this learning is very conservative. That is, infants start by learning about
their interactions with particular objects.
It is valuable to keep from generalizing too far from early experience,
because there are likely to be many exceptions to the early rules that infants
learn.
More broadly, this research demonstrates the importance of
acting on the world when learning. Too
often, even adults try to learn passively by listening to others and reading
superficially. It is important to engage
with the world when learning rather than just treating the process of learning
as if we were computers that were being fed information.
