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consilience
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Cognitive neuroscience
This is another relatively new discipline, which took off in the 1980s, and it essentially
forms the nexus of evolutionary biology and evolutionary psychology. Cognitive
neuroscience seeks to relate neural states in the brain to mental states, and to events
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in the world external to the organism under study. In many ways thus, cognitive
neuroscience studies behavior, and decision-making in particular, in ways that are
relevant for the attempts of economists to understand the material basis of decision-
making. This led to the formation of the new fi eld of neuroeconomics, which refers to
the use of empirical evidence relating to brain activity in order to come to conclusions
relating to economic behavior.
Cognitive neuroscience has seen signifi cant empirical advances made possible by a
number of recent technological developments, particularly in terms of brain scanning
and imaging techniques like PET (positron emission tomography), fMRI (functional
magnetic resonance imaging), EEG (electroencephalography), rCBF (regional cerebral
blood fl ow) and TMS (transcranial magnetic stimulation). These methods detect (or in
the case of TMS, block) brain activity in particular areas in terms of electrical activity or
increased blood fl ow, and this has been used to shed light on various topics of interest
in behavioral economics. Relevant results have been infl uential in the area of decision-
making heuristics, learning processes and the role of the emotions.
Perhaps the most fundamental discovery in neuroscience has been the concept of
brain modularity
. This means that different types of thinking or mental process are
performed in different parts of the brain, indicating the importance of brain structure or
anatomy, and it is attributed to evolutionary processes, whereby new parts of the brain
have been successively added to older more primitive parts, and have become more
developed over time. One of the most profound consequences of modularity, certainly
as far as behavioral economics is concerned, is that humans have different decision-
making systems that operate in different circumstances. The most obvious illustration
of this is that we have a ‘cold’ rational system for reasoning through some problems,
like doing a crossword puzzle, and a ‘hot’ system involving emotions, that tends to
operate, for example, when somebody cuts in front of us in a traffi c jam. We also fi nd
that we tend to perform some processes automatically, like a skilled musician playing
the piano, without conscious thought about what keys to play, whereas other actions
require conscious decisions, for example, where a beginner is attempting to play the
same piece. The reason why this aspect of brain modularity is signifi cant for behavioral
economics is that there are often confl icts between different systems, and these can
cause phenomena such as preference reversals and time-inconsistent preferences, that
are frequently observed anomalies in the standard model. There are executive control
systems that mediate these different systems, and these are necessary in order to bring
into effect some action when there are internal confl icts. However, it is important
that we do not think of these control systems as being the ‘self’, or the ‘I’, that decides.
This would amount to Cartesian Dualism, or a belief in what the philosopher Gilbert
Ryle has termed ‘the ghost in the machine’ (Ryle, 1949). Executive control systems
may indeed operate subconsciously, for example, when we run from a wasp fl ying
toward us.
Another important discovery in neuroeconomics is that different chemicals and
hormones have a signifi cant infl uence on behavior. Given these developments, various
examples of neuroeconomic studies will be given throughout the book. It is important
to realize, though, that relevance and application of neuroeconomics has remained a
controversial issue in the discipline.
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