In a 2019 study published in the journal
Neuroscience, Andrés Molero-Chamizo of the University of
Huelva, Spain acted as the lead researcher examining the effects of anodal
transcranial direct current stimulation (tDCS) on self-reported aggressiveness
in prisoners with violent offenses. tDCS is a non-invasive, painless form of
neurostimulation in which electrodes placed on the head deliver a low-intensity
electrical current to a specific part of the brain. Anodal tDCS refers to the excitation
of neuronal activity, whereas cathodal tDCS inhibits neuronal activity. In this
particular study, Molero-Chamizo and his team of researchers applied anodal tDCS
stimulation bilaterally to the prefrontal cortex. They chose to activate this area
of the brain because reduced activity in the prefrontal cortex has been
associated with aggression and violence. The researchers split their 41 male participants
into two groups: 15 murderers and 26 non-murderers. The researchers had the
participants fill out the Buss-Perry Aggression Questionnaire (BAQ) before and
after their tDCS treatments. The questionnaire asks participants how much they
agree with statements such as, “Sometimes I fly off the handle for no good
reason.” The tDCS was applied for 15 minutes per day for three consecutive
days. After the treatment, both inmate groups displayed a reduction in their
self-perceived aggression. The BAQ evaluates four dimensions of aggression: anger,
hostility, verbal aggression, and physical aggression. Aside from the
non-murderer group failing to show a significant reduction in hostility, both
groups displayed significant reductions in all dimensions of aggression.
Molero-Chamizo plans to follow up
this study with one that includes a few improvements to the procedure in order
to address some of the limitations from the first study. The initial study was
only single-blinded and the control group consisted of prisoners that received no
tDCS. For the following study, Molero Chamizo plans to include the university’s
psychology students in the participant pool as well as acquiring saliva samples
to measure cortisol levels before and after the tDCS treatment. Cortisol is an
indicator of stress and could possibly suggest some aspect of aggressiveness. He
also aims to examine the long-term effects of this particular type of tDCS
treatment.
Both Andrés Molero-Chamizo and Joe
Vukov’s work present two different aspects of neuromodulation. The article by Molly J. Crockett that the
class read in preparation for Joe Vukov’s talk deals with the question of how
brain chemistry affects morality. Throughout her essay, she presents evidence
indicating that our moral judgements are not fixed, but malleable. Although we
typically view our moral judgements as inherently personal, distinctive, and
indicative of who we are as people, they are often affected by neuromodulator
levels, stress, hunger, and so forth. Joe Vukov’s presentation dealt with very
similar questions. Although we see our moral intuitions as intrinsic, inborn
elements of ourselves, they are undoubtedly shaped and cultivated by our
particular upbringing. It’s easy to imagine that you’d have very different
political or religious beliefs depending on what part of the world you were
born in or to what type of parents you were brought up with, even though we see
our political and religious beliefs as a reflection of our moral character.
Following the same path, Molero-Chamizo’s work provides a more concrete example
that morality is not fixed. Reducing aggressiveness certainly does not entail
moral goodness, but this study does have an underlying goal of finding a
possible avenue for reducing instances of violent crime, which is embedded in
morality.
This type of work can have major
implications. Societies are structured around a shared moral code, but we are
now finding evidence that our moral intuitions can be tinkered with. Research
such as this brings with it a collection of ethical questions regarding neuromodulators’
effect on moral judgments and whether it should be permissible to dabble with
another’s moral inclinations.
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