Neuroscientists searching for roots of empathy find
brain regions involved in learning by imitation
In a pair of pioneering studies, a
French and American team of social-cognitive
neuroscientists have identified a network of
brain regions that are involved in human
imitation and specific brain areas that
enable a person to distinguish the self
The research is part of a larger
effort to find the neurological basis
of social interaction, particularly
empathy, a basic part of human nature
that allows most, but not all, people
to care about others.
The team is headed by neuroscientist
Jean Decety of Frances Institut de
la Santé et de la Recherche Médicale and a visiting professor
at the University of Washingtons Center for Mind, Brain &
Learning, and developmental psychologist Andrew Meltzoff,
co-director of the center.
"This work is important because imitation is a natural procedure.
We dont learn to imitate. It is part of our biological nature
and we are born to imitate," said Decety.
"A 3-year-old feels empathy and will pat another child on the
shoulder or comfort his mom when shes crying," added Meltzoff.
"We believe empathy has roots early in life. It may be linked to
imitation, which we know babies do from a very early age."
In the two studies, which are being published in the January and
February issues of the journal NeuroImage, the researchers used
positron emission tomography (PET) to explore the neural mechanisms
of imitation by measuring increases in blood flow in the brain.
In the first study the researchers look at imitation from the point
of view of a teacher (the person demonstrating a task) versus the
point of view of a student (the person learning the task). Eighteen
right-handed male subjects were asked to perform five tasks
involving small, different colored objects. Their heads were held
stationary while the PET scans made images of their brains, but they
could move their right hands and watch a demonstrators hands
reflected in a mirror.
Subjects were first asked to watch the demonstrator move the objects
and then imitate the action with their hand. In the second task,
they were told to move the objects first and watch the demonstrator
copy them. The other three tasks were control experiments in which
subjects were allowed to freely manipulate the objects any way they
wanted to, just watch the demonstrator move the objects, and move
the objects and then watch the other person perform different
The researchers discovered a consistent pattern of increased brain
activity involving the superior temporal gyrus, as well as
differential activity in the two hemispheres within the inferior
parietal cortex when imitation was involved. The left inferior
parietal cortex showed increased activity when the subjects were
imitating another person. When the subjects were being imitated by
the other person, however, the right inferior parietal cortex was
Decety and Meltzoff believe the inferior parietal cortex may play
a key role in whether a person attributes an action to the self
or to another person.
"By imitation we may feel what another person felt, which is the
very definition of human empathy," said Decety.
"Imitation also is natures way of conveying culture," said
Meltzoff. "It naturally occurs in a variety of settings, such as
learning to play music and sports, or when a mother teaches her
daughter how to tie her shoelaces. The mother ties a shoelace and
the child follows, trying to imitate the action. We would expect
the same kind of lateralized brain activity in learning to tie
shoelaces as there was in our experimental task."
The second study, which involved 10 right-handed subjects, employed
a physical setup that was similar to the one used in the first
study. This time, however, subjects were shown video clips of
another person choosing, grasping and moving a Lego block into a
new position and then leaving the Lego in the new position.
In the first of six tasks, subjects had to duplicate the entire
manipulation. Next they were only shown part of a video clip that
showed the other persons hand leaving the Lego in its final
position and the subjects had to manipulate the block to achieve
that "goal." Subjects also viewed a clip that only showed "means,"
or the manipulations of a block, and had to duplicate the movements
they observed. Three control tasks also were performed. Subjects
again watched the clips showing the entire manipulation, as well as
just the goal and the means, and were asked to freely move their
Lego in any way they choose.
This paper is unique because it is believed to be the first
neuroimaging study to show that imitation can be split into two
complementary components, the goal of an action and the means to
Decety said the researchers found that not only can the components
of imitation (the goal and the means) be separated, but each
involves specific brain regions. Increased brain activity was
detected in the medial prefrontal cortex during imitation of the
means, while increased activity in the left premotor cortex was
associated with imitation of the goal.
"This supports the idea that when observing someones action, the
underlying intention is equally or perhaps more important than the
surface behavior itself," the authors write.
These findings have widespread potential applications in typical
and atypical child development, educational practice and artificial
"In child development, reading others goals or intentions from
their actions is necessary for human interaction. If you are just
literal, you will not have deep understanding of other people," said
Meltzoff. "It is also important to know what brain regions control
actions and intentions. They may not develop at the same time in
"Educators sometimes pay too much attention to the means without the
goal or to the goal without giving children the means, or the steps,
to accomplish something," Decety said.
The two studies were supported by funding from the French Ministry
of Education and the UWs Center for Mind Brain & Learning (CMBL).
Co-authors of the papers were Thierry Chaminade and Julie Grezes,
doctoral students in France.
CMBL is an interdisciplinary research center where behavioral
scientists and neuroscientists are collaborating to study the links
between behavior and the brain. The center is funded primarily by
the Talaris Research Institute, founded by a gift from the Apex
Foundation, the private family foundation created by Bruce and
"To lengthen thy life, lessen thy meals." Benjamin Franklin