Motivation in Brain and in Mind
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Motivation
is not just one more set of psychological processes. If animals
evolved with a motile strategy to go after the substances and
conditions they need, the most basic requirement for their survival is
successful goal striving. In that case, all animal evolution, right up
to humans, must have centered on natural selection of whatever
facilitated attaining goals. This must mean that everything about
humans evolved in the service of successful goal striving—including
human anatomy, physiology, cognition, and emotion. These other
features of being human must therefore be understood in terms of their
relationship to goal striving and the motivational systems that make
it possible.
In
recent decades, neuroscientists have turned up dramatic evidence of
the close connections between virtually all psychological processes
and those associated with emotion and goal-striving. Ledoux (e.g.,
1995) showed that, in the brain sensory systems, pathways
bifurcate—some leading from sense organs to the cerebral cortex, and
others from sense organs to the limbic system, which is heavily
implicated in emotion. This suggests that sensory signals begin to
trigger emotional reactions at least as quickly as they trigger
cognitive processes that analyze the signals in order to make more
detailed sense of them. There are also pathways from the limbic system
to the cortex and from the cortex to the limbic system, which provides
a system for mutual alerting, refinement, and correction between
emotional and cognitive responses to the signal. Neurons in the
anterior cingulate, a part of the limbic system, fire according to
expectancy of reward (Shidara & Richmond, 2002). Thus, brain
anatomy indicates that emotional response and closely related
motivational processes are a central part of responding to something.
The
centrality of emotional and motivational processes is also apparent in
the work of Antonio and Hanna Damasio and their colleagues. They have,
for example, shown that destruction of specific brain areas, such as
the medial prefrontal cortex, leaves people unable to stay on course
toward their goals, substantially crippling their ability to lead
normal, satisfying lives (Damasio, 1994). The ventromedial prefrontal
cortex appears to integrate emotion-related signals from the limbic
system with signals from various cortical areas, including some that
are necessary for planning and volition.Without this integration,
people become impulsive, make unrealistic plans, and are easily
distracted from their goals. Along similar lines, a controlled
experiment showed that, unlike normal individuals, patients with
ventromedial prefrontal damage were unable to learn to avoid risky or
nonoptimal strategies in a laboratory game (Bechara, Tranel,&Damasio,
2000; Bechara et al., 1997). In the first of these two studies, the
brain-damaged participants, in contrast to others, manifested no skin
conductance responses when they chose risky strategies. Here skin
conductance responses presumably reflect fear of taking a risk that
would be inappropriate relative to the individual’s goal in the
task. Thus, the particular brain damage of these patients interfered
with input from their emotional responses and correspondingly
compromised their ability to make appropriate, goal-related decisions. Mounting evidence such as this confirms the centrality of motivational and emotional processes in the organization of the brain. Correspondingly, it supports the parallel, older evidence of their centrality to psychological organization, and it underlines the importance for counselors and psychotherapists of understanding the interconnections with motivational processes and integrating applicable methods into treatment procedures.
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