German scientists recently showed what many of us suspected but
could not prove — some people just don’t learn. The German researchers
have found a genetic factor that affects our ability to learn from our errors.
The scientists demonstrated that men carrying the A1 mutation are less
successful at learning to avoid mistakes than men who do not carry this
genetic mutation. This finding has the potential to improve our
understanding of the causes of addictive and compulsive behaviors.
Some people do not give up even when they do not succeed.They refuse to
accept defeat and continue to try even when common sense tells others
there’s no use in trying.
Tilmann Klein and Dr. Markus Ullsperger at the Max Planck Institute
for Human Cognitive and Brain Sciences in Leipzig, Germany, believe
they have found the genetic cause for this "stubbornness". They
discovered that a single genetic mutation can determine whether people
repeat their mistakes. This mutation, named the A1 mutation, is found
in about one-third of the population and causes a reduction in the
amount of D2 receptors in the brain, which are the docking sites for
Dopamine is a neurotransmitter – a chemical participating in the
relay of signals between nerve cells and target cells. Among other
behavior and cognition functions, dopamine plays a key role in the
process of learning, in the feeling of pleasure, and in motivation and
reward (i.e. learning to repeat behaviors that maximize rewards).
The researchers theorized that the lower output of dopamine in
people with fewer D2 receptors leads them to repeat their mistakes,
while people with more D2 receptors comprehend that a certain action is
a mistake the first time they carry it out and do not feel any desire
to repeat it. To examine this theory, Klein and Ullsperger studied 26
healthy men, half of which carried the A1 gene variant (allele).
At first, the volunteers were shown sets of two symbols and were
asked to select one. Each choice was followed by positive or negative
feedback represented by a smiling or frowning face, respectively. The
researchers then tested whether the men had learnt to choose the symbol
that had the most positive feedback and avoid the one that led to the
most negative feedback.
The test showed that men carrying the A1 mutation responded less to
negative feedback, implying that they were less successful at learning
to avoid mistakes than the men in the other group. Brain imaging of
both groups also supported this result, revealing that during the
learning sessions the men carrying the A1 mutation had diminished
neurological activity in the posterior medial frontal cortex (pMFC), an
area in the brain involved in monitoring errors.
"Our subjects worked in an artificial laboratory setting, the reward
and punishment they received was highly abstract, whereas a real world
situation in which you could learn from feedback is normally much more
complex. More research is needed to show how our findings apply to real
world situations," Klein says.
According to the German team, the decreased sensitivity to negative
consequences of actions as a result of D2 receptor reduction may also
explain why the A1 gene variant has previously been linked to addictive
and compulsive behaviors. Even so, "It’s our strong belief that the
variant we investigated here is not the only cause for example of an
addiction – but maybe it contributes to a predisposition for developing
an addiction," Klein stresses.
TFOT previously covered a similar experiment that demonstrated the connection between high levels of brain activity and the placebo effect (reward anticipation).
Via the Max Planck Institute