These are excerpts and elaborations from my book "The Nature of Consciousness"
Somatic markers According to Damasio, the only thing that truly matters for an individual’s emotional life
is what goes on in the brain. The brain
maintains a representation of what is going on in the body. A change in the environment may result in a
change in the body. This is immediately
reflected in the brain's representation of the body state. The brain also creates associations between
body states and emotions. Finally, the
brain makes decisions by using these associations, whether in conjunction or
not with reasoning. The brain evolved over
millions of years for a purpose: it was advantageous to have an organ that
could monitor, integrate and regulate all the other organs of the
organism. The brain's original purpose
was, therefore, to manage the wealth of signals that represent the state of the
body (the "soma"), signals that come mainly from the inner organs and
from muscles and skin. That function is
still there, although the brain has evolved many other functions (in
particular, for reasoning). Damasio identified a region of the
brain (in the right, "non-dominant" hemisphere) that could be the
place where the representation of the body state is maintained. Damasio's
experiments showed how, when that region is severely damaged (usually after a
stroke), the person loses awareness of the left side of the body. The German
neurologist Kurt Goldstein had already noticed in the
1930s that the consequence of right-hemisphere lesions is indifference. The brain links a body
change with the emotion that accompanies it.
For example, the image of a tiger with the emotion of fear. By using both inputs, the brain constructs
new representations that encode perceptual information and the body state that
occurred soon afterwards. Eventually,
the image of a tiger and the emotion of fear, as they keep occurring together,
get linked in one brain event. The
brain stores the association between the body state and the emotional reaction.
That association is a "somatic marker". Somatic markers are the
repertory of emotions that we have acquired throughout our lives and that we
use for our daily decisions. The
somatic marker records emotional reactions to situations. Former emotional reactions to similar past
situations is what the brain uses to
reduce the number of possible choices and rapidly select one course of
action. There is an internal preference
system in the brain that is inherently biased to seek pleasure and avoid
pain. When a similar situation occurs
again, an "automatic reaction" is triggered by the associated
emotion: if the emotion is positive, like pleasure, then the reaction is to
favor the situation; if the emotion is negative, like pain or fear, then the
reaction is to avoid the situation. The
somatic marker works as an alarm bell, either steering us away from choices
that experience warns us against or steering us towards choices that experience
makes us long for. When the decision is
made, we do not necessarily recall the specific experiences that contributed to
form the positive or negative feeling. In philosophical terms, a
somatic marker plays the role of both belief and desire. In biological terms, somatic markers help
rank "qualitatively" a perception. In other words, the brain is
subject to a sort of "emotional conditioning". Once the brain has "learned" the
emotion associated to a situation, that emotion will influence any future
decision related to that situation. The
brain areas that monitor body changes begin to respond automatically whenever a
similar situation arises. It is a popular belief that
emotion must be constrained because it is irrational: too much emotion leads to
"irrational" behavior.
Instead, Damasio found that a number of brain-damage cases in which a reduction in
emotionality was the cause for "irrational" behavior. Somatic markers help to make
"rational" decisions, and help to make them quickly. Emotion, far from being a biological oddity,
is actually an integral part of cognition.
Reasoning and emotions are not separate: in fact, they cooperate. Back to the beginning of the chapter "Emotion" | Back to the index of all chapters |