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Empathy, and especially empathy
for other people’s pain, is a universal human trait. Being able to understand
that a situation that one of our peers is going through may also be painful for
us, without our having to experience it ourselves, may have provided a significant
adaptive advantage. But what happens to people whose jobs require them
to witness other people’s pain every day, or even to inflict pain in order
to cure their illnesses? Do doctors, for example, feel the distress of all the
patients whom they see every day? Luckily not, because doctors who were constantly
affected emotionally by their patients’ suffering could never make all the
informed decisions that a doctor’s work requires. Professional
caregivers thus manage to keep their initial impulse of empathy at a distance.
How? A brain-imaging study by Yawei Chang and Jean Decety compared acupuncturists
with a control group of people who were not in the health professions. This study
showed major differences between these two groups in the ways that their brains
were activated when they observed people having needles inserted into their skin.
In the control group, watching needles being inserted activated several
parts of the brain that are responsible for processing pain, including the anterior
insula, the anterior cingulate cortex, the somatosensory cortex, and the periaqueductal
grey matter. Among the acupuncturists, these areas were not activated
at all. Instead, the researchers observed extensive activation of the brain areas
associated with higher functions, such as the regulation of emotions—structures
such as the medial prefrontal cortex, the medial frontal gyrus, the parahippocampal
gyrus, and the inferior parietal lobe. Moreover, when asked to rate, on
a scale of 1 to 10, the unpleasantness of the needle insertions that they watched
someone else receive, the acupuncturists assigned scores of only 3 or 4, while
the subjects in the control group assigned much higher scores, around 6.5 on average.
(Note that the members of the two groups had shown similar results in psychological
tests for general empathy and for sensitivity to pain, thus eliminating differences
along these lines that might have explained the results of the overall experiment.)
Thus, the most plausible explanation for the mechanisms underlying health
professionals’ ability to control their empathy seems to be that they use
areas of their brain associated with cognitive control functions to literally
silence the circuits associated with pain. These cognitive areas might include,
for example, those involved in the memory processes on which their professional
experience depends (structures such as the parahippocampal gyrus) or those involved
in making the distinction between self and others (structures such as the temporoparietal
junction). |
The human predisposition toward
empathy may foster mutual understanding, but this sensitivity to other people’s
distress can also sometimes be a burden. For example, some people feel burdened
by all the suffering of large numbers of human beings throughout the world, to
which they are exposed every day through the mass
media. The Romantic poets of the 19th century provided detailed accounts
of this state of melancholy, sadness, or pessimism to explain their inability
or refusal to adjust to the realities of what they considered a destructive world.
The German writer Jean Paul coined the term Weltschmerz
(literally, “world-pain”) to describe what French writers of the early
19th century called le mal du siècle(the illness
of the age). Other authors have equated this resignation before the cruelty of
the world, which can lead to depression,
with the state
of anomie described by French sociologist Émile Durkheim. |
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SHARING OTHER PEOPLE’S
PAIN | | Many hypotheses have been
offered about the evolutionary origins of empathy in human beings. One such hypothesis
is that this ability to place ourselves “in
someone else’s skin” enabled our ancestors to make better predictions
about other people’s intentions and needs, thereby also encouraging the
behaviours of co-operation
and mutual assistance among the highly interdependent individuals of our species.
This ability to feel other individual’s affective states would also have
played a crucial role in communication.
More specifically, understanding other people’s
pain often lets us avoid dangerous situations without having to experience them
ourselves. Sharing other people’s distress also leads us to inhibit behaviours
of aggression and self-gratification. This
inhibition has been observed in many species of mammals, for example, laboratory
rats who stop pressing on a lever that dispenses food to them, when they see that
when they press this lever, it also gives an electric shock to a fellow rat. Human
empathy for other people’s suffering may also have evolved from brain circuits
that inform us about pain in our own bodies. Numerous brain-imaging studies have
shown that when we experience empathy for someone else’s pain, structures
are activated in our own brains that also become activated when we experience
pain ourselves (for example, the anterior
cingulate cortex and the insula).
| | But
this raises a very fundamental question: how do we distinguish other people’s
pain from our own? It certainly wouldn’t have been adaptive if we were overwhelmed
with pain whenever we saw someone else experiencing it, and indeed, that is not
what happens (see, however the sidebar on Weltschmerz and mal du
siècle). Although we may feel other people’s pain, most of the
time we manage to maintain a certain detachment from it. In any case, we know
that it is not our own body that is in pain, even if we are experiencing its negative
affective component ourselves. | So what
are the mechanisms that let us make this distinction? To answer this question,
let’s begin by reviewing what we know about some other, related phenomena.
For example, we know that the difference between the brain areas activated when
we make a certain movement and those activated when we simply imagine ourselves
making it can be subtle. Except for the actual motor-control circuits, mentally
visualizing a movement activates practically the same neural circuits as when
we actually carry this movement out. We also know
that even when no pain stimulus is present, anticipating a painful experience
can activate the parts of the cortex that are associated with pain. Moreover,
the intensity of this anticipatory neural activity is proportional to the intensity
of the anticipated pain. Another finding that scientists
have confirmed repeatedly is that when one person experiences empathy while observing
another person expressing an emotion, the activation of the first person’s
brain is less intense than when that person is actually experiencing this emotion
himself or herself. Thus intensity of activation seems
to play a role in preventing us from confusing ourselves with other people when
we are sharing affect with them. But there are other mechanisms that may also
help us to make this distinction. To identify them, we will now look at three
other components of empathy: affective response, emotional regulation, and cognitive
influences. The affective response that
is triggered automatically when we observe other people’s emotions can be
seen as the resonance
of neural networks that we share with them. But this resonance is only partial:
a number of studies have shown that the brain areas activated when we observe
an emotion and those activated when we experience it ourselves do not overlap
perfectly. For example, some areas, such as the right
temporoparietal junction, the precuneus,
and the posterior
cingulate cortex, are more activated when we adopt someone else’s perspective,
rather than our own, in assessing emotion or pain. (This is the same role that
these structures are already known to play in other mental tasks.) In
contrast, in other studies, when the subjects imagined themselves in pain, their
pain
matrix was more widely activated (awakening structures such as the secondary
somatosensory cortex and the posterior part of the anterior cingulate cortex)
than when they observed someone else in pain. This difference in activation was
seen even at the level of individual cortical structures. Within the insula, for
example, the sub-groups of neurons that fired under the former condition were
different from those that fired under the latter. These
findings thus suggest a possible mechanism behind the difference between the sensation
aroused by our own pain and that aroused by pain that we observe in other people.
Researchers have also noted a continuum of activation between these two situations,
with an increasingly posterior activation in structures such as the insula and
the anterior cingulate cortex the more that the painful situation being considered
relates to ourselves.
Painting by Paul Walsh | | Thus,
though it is useful for us to be able to share other people’s suffering
to a certain extent, our brains also have mechanisms that they can apply to let
us maintain a certain degree of autonomy and a certain amount of control over
this empathic response. (This response is also subject to a number of external
factors, discussed in the box below.) For example, doctors and nurses, who are
in contact with other people’s suffering every day, must maintain some control
over their empathic response to maintain the distance they need to make good decisions
for their patients (see sidebar). | One
of the most effective psychological strategies for achieving this regulation
of your emotional response to other people’s pain is to adopt a
detached position with respect to them. Forming a mental image of yourself as
an observer who is not very affected by what he or she sees can reduce the anxiogenic
experience associated with observing pain. Brain-imaging experiments have identified
specific areas in the medial and anterolateral prefrontal cortex that appear to
inhibit this automatic component of the empathic response. There
are other, cognitive mechanisms that you can use to control this
automatic aspect of empathy and thus maintain a boundary between yourself and
others (these mechanisms probably remain idle when you get caught up in phenomena
such as emotional
contagion, for example). These mechanisms involve, for example, your theory
of mind, in other words, your ability to make a conscious effort to imagine
things from someone else’s point of view, to try to see the world through
their system of beliefs and way of thinking. In this
regard, there is a large amount of data indicating that the medial prefrontal
cortex is involved in such tasks that require you to make inferences about other
people’s mental states to achieve a more nuanced understanding of them.
For instance, imagining yourself going through the precise kind of pain felt by
someone who has just lost a family member is a more complex cognitive process
than simply recognizing the emotion of sadness expressed on his or her face. Brain-imaging
data also show that although these processes generally occur together, they recruit
different neural networks. These networks are interconnected, however (for instance,
the connections between the medial
prefrontal cortex and both the insular
cortex and the anterior cingulate cortex are well known).
Thus, the affective and cognitive mechanisms of empathy are somewhat like two
sides of the same coin, the former acting more “from
the bottom up” and the latter “from the top down”, depending
on what information you have access to about a given situation. This
mental effort of imagining what someone else is feeling thus goes well beyond
an automatic
mimicry based on mirror neurons. For example, French neurologist Nicolas Danziger
has shown that people
who (as the result of genetic mutations) were born without the ability to feel
pain could nevertheless tell how much pain someone else was in, by judging
from the expression on his or her face. Because these people necessarily accomplished
this task without recalling painful sensations that they themselves had experienced
in the past, they must have had to perform a cognitive task to imagine the other
person’s pain. When these subjects looked at
images evocative of pain, such as a picture of a hammer striking someone’s
finger, their ventromedial prefrontal cortexes became activated. This suggests
that they were applying an elaborate reasoning process to understand what other
people must feel in such situations. Thus, in normal
human subjects, empathy—not just superficially recognizing someone else’s
subjective experience but actually understanding it—most likely requires
this significant cognitive contribution by the prefrontal cortex as well. In other
words, the mirror neurons are only part of the story.
Though we humans are predisposed
to have empathy for other people, this response can vary greatly, depending on
the circumstances. Several factors can alter the degree of empathy that we feel
for someone else. The intensity of the emotion shown by
the person whom we are observing is one such factor: in general, the more intense
this emotion, the greater the empathy that we will feel. Seeing a needle penetrating
deeply into someone’s skin, we will respond with more empathy than if the
needle only scratches the surface. Similarly, seeing someone in acute pain activates
our pain
matrix more than when we see someone who is suffering from chronic pain.
The context of the situation can also influence our perception
of someone else’s pain. For example, in experiments where the subjects are
told that the person whom they are watching is in pain because he or she is receiving
a treatment that will be beneficial, their empathic responses are more limited.
Another factor that can modulate empathy is attention.
When subjects are simply asked to look at pictures of hands in painful situations,
the parts of their brain associated with pain are activated more than when the
subjects are distracted because they have been asked to count the number of injured
hands in the pictures. Certain characteristics of the person experiencing
the empathy can also modulate the intensity of the emotions that they
share from someone else. Hospital caregiving staff who are exposed to other people’s
pain every day manage to control their empathic responses more effectively than
the general public (see sidebar). Another factor that can be decisive for
the amount of empathy experienced is the relationship between the subject
and the person observed. We all know that seeing a loved one suffer arouses
more empathy than seeing an enemy in pain. An experiment by German social neuroscientist
Tania Singer has also shown that, in male subjects but not in female subjects,
the empathic response to an observed person’s pain is more limited if the
subject has just formed an opinion of that person as being unfair for having cheated
at a game. In the second part of this study, published in 2006, functional
magnetic resonance imaging (fMRI) revealed less activity in the pain circuits
of the brains of these men who were less empathic toward cheaters. Moreover, fMRI
images also revealed concomitantly greater neural activity in these men’s
pleasure
circuits, betraying their enjoyment at seeing the cheaters punished. From
an evolutionary standpoint, this reaction seems consistent with the value
placed on co-operation, which has fostered cohesiveness in human groups since
time immemorial. Other studies have shown that observers’ relationships
with the person whom they are observing can also modify their perception of their
own pain when they receive nociceptive stimuli. Subjects who receive burning stimuli
at the same time as they observe someone whom they like receiving such stimuli
will experience them as more painful than when they observe someone whom they
do not like receiving the same stimuli. And the more they like the person whom
they are observing, the more unpleasant they will find the stimuli that they are
receiving themselves. This same increased perception of pain also occurs when
the subjects observe people whom they like receiving non-nociceptive stimuli.
The authors of the study in question therefore conclude that the origins of this
phenomenon seem to lie in the empathy that the subjects inherently feel toward
the people whom they are observing, and not in the specific situation in which
these people are experiencing pain. Another somewhat counterintuitive study,
on the influence of family situation on perception of pain, showed that this perception
was positively correlated with the degree of concern that women showed for their
husbands who suffered from chronic
back pain. When a pain stimulus was applied to the backs of a group of such
men, those husbands whose wives tended to show a great deal of caring
or concern about their pain experienced more pain than those husbands
whose wives tended to distract them from their pain by calling their attention
to something else. Thus chronic
pain, contrary to acute pain, seems to be eased more by distractions than
by displays of concern. |
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