Neuroscientist
Marco Iacoboni discusses mirror neurons, autism and the
potentially damaging effects of violent movies.
Marco Iacoboni,
a neuroscientist at the University of California at Los Angeles,
is best known for his work on mirror neurons, a small circuit of
cells in the premotor cortex and inferior parietal cortex. What
makes these cells so interesting is that they are activated both
when we perform a certain action—such as smiling or reaching for
a cup—and when we observe someone else performing that same
action. In other words, they collapse the distinction between
seeing and doing. In recent years, Iacoboni has shown that
mirror neurons may be an important element of social cognition
and that defects in the mirror
neuron system may underlie a variety of mental disorders, such
as autism. His new book,
Mirroring People: The Science of How We Connect to Others,
explores these possibilities at length.
Mind Matters
editor
Jonah Lehrer
chats with Iacoboni about
his research.
LEHRER: What first got you interested in
mirror neurons? Did you
immediately grasp their explanatory potential?
IACOBONI: I actually became interested in mirror neurons
gradually. Neuroscientist
Giacomo Rizzolatti and his
group at the University of Parma in Italy approached us at the
UCLA Brain Mapping Center because they wanted to expand the
research on mirror neurons
using brain imaging in humans. I thought that mirror neurons
were interesting, but I have to confess I was also a bit
incredulous. We were at the beginnings of the science on mirror
neurons. The properties of these neurons are so amazing that I
seriously considered the possibility that they were experimental
artifacts. In 1998 I visited Rizzolatti’s lab in Parma, I
observed their experiments and findings, talked to the
anatomists that were studying the anatomy of the system and I
realized that the empirical findings were really solid. At that
point I had the intuition that the discovery of mirror neurons
was going to revolutionize the way we think about the brain and
ourselves. However, it took me some years of experimentation to
fully grasp the explanatory potential of mirror neurons in
imitation, empathy, language, and so on—in other words in our
social life.
LEHRER: Take us inside a social interaction. How might mirror
neurons help us understand what someone else is thinking or
feeling?
IACOBONI: What do we do when we
interact? We use our body to
communicate our intentions and our feelings. The
gestures,
facial expressions, body
postures we make are social signals, ways of communicating with
one another. Mirror neurons are the only brain cells we know of
that seem specialized to code the actions of other people and
also our own
actions. They are obviously
essential brain cells for social interactions. Without them, we
would likely be blind to the actions, intentions and emotions of
other people. The way mirror neurons likely let us understand
others is by providing some kind of inner imitation of the
actions of other people, which in turn leads us to “simulate”
the intentions and emotions associated with those actions. When
I see you smiling, my mirror neurons for smiling fire up, too,
initiating a cascade of neural activity that evokes the feeling
we typically associate with a smile. I don’t need to make any
inference on what you are feeling, I experience immediately and
effortlessly (in a milder form, of course) what you are
experiencing.
LEHRER: In 2006 your lab published a
paper in
Nature
Neuroscience linking a mirror neuron dysfunction to
autism. How might reduced
mirror neuron activity explain the symptoms of autism? And has
there been any progress on this front since 2006?
IACOBONI: Patients with autism have hard time understanding the
mental states of other people; this is why social interactions
are not easy for these patients. Reduced mirror neuron activity
obviously weakens the ability of these patients to experience
immediately and effortlessly what other people are experiencing,
thus making social interactions particularly difficult for these
patients. Patients with autism have also often motor problems
and language problems. It turns out that a deficit in mirror
neurons can in principle
explain also these other major
symptoms. The motor deficits in autism can be easily explained
because mirror neurons are just special types of pre-motor
neurons, brain cells essential for planning and selecting
actions. It has been also hypothesized that mirror neurons may
be important in language
evolution and language
acquisition. Indeed, a human brain area that likely contains
mirror neurons overlaps with a major language area, the
so-called
Broca’s area. Thus, a deficit
in mirror neurons can in principle account for three major
symptoms of autism, the social, motor and language problems.
LEHRER: If we're wired to automatically internalize the
movements and mental states of others, then what does this
suggest about violent movies, television programs, video games,
etcetera? Should we be more careful about what we watch?
IACOBONI: I believe we should be more careful about what we
watch. This is a tricky argument, of course, because it forces
us to reconsider our long cherished ideas about free will and
may potentially have repercussions on free speech. There is
convincing behavioral evidence linking media violence with
imitative violence. Mirror
neurons provide a plausible neurobiological mechanism that
explains why being exposed to media violence leads to imitative
violence. What should we do about it? Although it is obviously
hard to have a clear and definitive answer, it is important to
openly discuss this issue and hopefully reach some kind of
“societal agreement” on how to limit media violence without
limiting (too much) free speech.
LEHRER: Are you worried about mirror neurons getting over-sold
or
over-hyped?
IACOBONI: I am a bit concerned
about that. The good news is, the excitement about
mirror neurons reveals that people have an intuitive
understanding of how neural mechanism for mirroring
work. When told about this research, they can finally
articulate what they already “knew” at some sort of
pre-reflective level. However, the hype can backfire and
mirror neurons may lose their specificity. I think there
are two key points to keep in mind. The first one is the
one we started with: mirror neurons are brain cells
specialized for actions. They are obviously critical
cells for social interactions but they can’t explain
non-social cognition. The second point to keep in mind
is that every brain cell and every neural system does
not operate in a vacuum. Everything in the brain is
interconnected, so that the activity of each cell
reflects the dynamic interactions with other brain cells
and other neural systems.
Mirror Neurons are a direct response
to input information, so if you lack the ability to
interpret input -- then you are at a disadvantage.
Some of the questions put to Dr. Iacoboni on his blog
I am interested in group dynamics, and am wondering if any readers have ideas about how mutual "mirroring" in a group might combine to account for group dynamics such as conformity, scapegoating,
etc
Has any research looked into different responses of mirror neurons in males and females?
People often anecdotally say women are more socially aware, or empathetic than men (in general) - perhaps females have more active mirror neurons ?
People talk of 'bonding' with a new born child - again reported more in the mothers.
Perhaps a real physical change in the brain occurs for this bonding to take place - say, mirror neurons somehow tune in to the new-born's face...?
