The Biological Approach
Physiological
Foundations of Behavior
Studying
Mind and Brain: The Use of Case Studies
Drugs and
Behavior
Genetics
and Behavior
On-line
Publications Related to the Biological Approach
Understanding the Physical
Basis of Behavior
One of the most perplexing
issues in psychology is understanding the relationship between the mind
and the brain. We all recognize that we have conscious awareness of our
surroundings, and also of ourselves (self-awareness). It is this
experience which has normally been described as the mind. But what
is the basis of the mind? Is it the expression of a non-physical soul, or
is it a product of physical processes within our body? Philosophers and
scientists have been pondering this question for centuries. Explaining the
nature of consciousness (that is, the mind) was regarded by William James
(one of the great pioneers of psychology) as the most challenging question
for psychology to answer. Today, a hundred years after James made that
comment, the challenge still exists.
Underlying questions about
mind and brain are a number of basic assumptions. Most physiological
researchers today are materialists, who see both behavior and
consciousness as simply the product of physiological processes. In
essence, the brain is the mind. Thus, the task is to identify the
structures and processes which produce conscious awareness. Among those
who take this approach are James Watson (co-discoverer of DNA) and Dominic
Domasio. Both are engaged in research aimed at supporting this view, and
their work has drawn public attention. (See references below.)
Arrayed against this stance
are a number of opponents, who argue the issue on various grounds. Some
physiological researchers have adopted a neo-Cartesian position, arguing
that consciousness (and therefore the mind) is not localized in any brain
structure, and can therefore not be unequivocally proven to be purely
physical in nature. Among these are John Eccles, an eminent British
researcher, and the late Wilder Penfield, a pioneering Canadian
neurosurgeon. Another approach to the issue comes from those who connect
mind to the sense of self. This idea also has Cartesian overtones, since
the self is closely associated with the notion of a soul in traditional
thought. While many variants exist, the basic argument is that the self
is a phenomenological construction, which is both in continual flux, and
yet experienced as an on-going identity. In this view, the mind/self may
well be a product of physiological processes, but it is no more
synonymous with the underlying structures than a building is synonymous
with its builder. Roger Sperry, a pioneer in the study of hemispheric
specialization, has described consciousness as an emergent process
of the brain--a product of the whole, whose properties cannot be explained
simply by studying the underlying structures.
At present, of course, the
debate cannot be resolved--the answer to William James' century-old
question continues to elude us.
Resources
Descartes
and Dualism--essay on the continuing impact of Descartes' concept of
dualism; appears in Serendip, an on-line journal from Bryn Mawr
Univ. which includes topics related to the Biological Approach in many of
its essays
Time
Magazine, July 17, '95--Cover story, "Glimpses of the Mind"
Digital
Anatomist--An on-line interactive anatomy atlas at the Univ. of
Washington
Neuropsychology
Central--A website of resources related to the biology of behavior
Neuroscience
Laboratory and Classroom Activities--extensive set of activities for
teachers and students, maintained by National Association of Biology
Teachers and the Society for
Neuroscience. (Note: activities are in Adobe PDF format; link on site
for plug-in if needed.)
One of the earliest methods
used to explore the workings of the brain was the detailed analysis of
clinical patients--typically individuals who had suffered some type of
physical trauma. Such case studies have often led to remarkable
insights. For example, Pierra Broca in 1861 was able to identify an area
of the brain involved with speech production (now called "Broca's
area") based on studying an individual who for more than thirty years
had suffered a fundamental language defect: he could understand spoken
language, and could make various sounds, but could not produce coherent
speech. Based on his behavioral observations and an anatomic analysis
after the patient died, Broca concluded that speech capacity is located in
the third convolution of the frontal lobe of the left hemisphere. This
represented a dramatic advance in physiological understanding--forming a
direct connection between the structure of the brain and behavior. In
addition, Broca saw the broader implications of his analysis, asserting
that all behavior can be associated to some specific mechanism/structure
in the brain--a concept called localization of function. Over time,
researchers have used case studies to gather further support for this
principle. Today, other techniques have provided new ways to study the
functions of the brain, but case studies still provide insights, as well
as fascinating reading.
The Case of Phineas Gage
One of the best-known clinical
cases involved a dramatic injury to an unfortunate railroad worker,
Phineas Gage. One day in 1848, he was working on track construction near
Cavendish, Vermont. While Gage was placing an explosive charge, a spark of
metal against rock set off the charge, sending a long metal tamping rod
flying upwards. The rod entered Gage's head just below the left eye, and
exited from the tob of his skull, somewhat forward of left center.
Remarkably, Gage survived (though he was blinded in his left eye). Even
more remarkably, his behavior changed dramatically. Whereas Gage had
previously been likeable and responsible, he became erratic, and given to
terrible fits of temper. Sadly, he spent his remaining years wandering
around the United States, displaying the hole in his skull and the iron
rod which had brought him such grief.
Gage's story has been a source
of endless fascination ever since. (His skull, and the iron rod, are still
on display in the Harvard Medical School museum.) Given the pathway of the
rod through his head, it would seem that the injury extensively damaged
the association areas of the left frontal lobe. The behavioral changes,
especially in emotionality, have been used as evidence that this region is
involved in the expression of emotion. (A view seconded by advocates of frontal
lobotomies in the 1940's and '50's.)
Resources
Discover, May, '95--A discussion of a case of agnosia, where the
individual is unable to recognize something, despite intact senses .(The
text refers to a case of visual agnosia; this example concerns anosagnosia,
the inability to recognize part of one's own body).
As discussed in the text,
psychoactive drugs affect behavior by affecting neural activity. Drugs may
do this in various ways (for example, mimicing a natural neurotransmitter,
or altering its normal function and metabolism), and many drugs affect a
variety of different types of neurons in various parts of the brain.
Consequently, it can be difficult to pinpoint precisely how a drug works.
This is one reason new drugs must go through extensive laboratory and
clinical testing before they are approved for public use.
The difficulties are further
compounded when dealing with illicit drugs, sold on the street. Because
there is no mechanism for quality control, users may receive drugs of
varying potency and purity--and in some cases, what is sold is not even
what it is claimed to be. (For example, a combination of strychnine and
milk powder has been sold as "heroin", and various substances
have been sold as MDMA or "ecstasy".) Consequently, street drugs
pose two concerns: the effects of the drug (including long-term effects)
may not be well understood, and the risks associated with taking something
whose true content is uncertain. Note that these concerns have nothing to
do with moral attitudes towards drug use: they represent practical
concerns about the use of illicit psychoactive drugs.
Resources
Ecstasy...The Science--Time Magazine article describing the origins of
the drug MDMA (called "ecstasy" on the street), and what is
currently known about how it affects the nervous system and behavior.
Earlier this year, researchers
announced that the mapping of the human genome, is nearing
completion, at least in preliminary form. In many ways, this represents
one of the greatest feats in the history of science: for one thing, our
genetic makeup is extraordinarily complex, being composed of some 100,000
genes made up of millions of individual amino acids. At an even deeper
level, identifying our genes poses the possibility of understanding what
role genetics plays in our behavior.
The debate between nativists,
who believe that behavior is fundamentally innate, and environmentalists,
who believe our behavior is shaped by our experiences, goes back to
ancient times. (As Approaches to Psychology notes, it has been
argued that the first known "psychology experiment", in ancient
Babylon, was concerned with whether language was innate or learned.)
Today, a wide variety of techniques are used to explore the issues of
heredity; one of the most recent has been the application of evolutionary
theory to try to understand how inherited behaviors may have originated,
called evolutionary psychology. (Of course, this assumes that
behavior is inherited to begin with!)
Resources
The DNA Files--Website for a PBS Radio series dealing with genetics;
includes both original material and many relevant links.
Institute
for the Study of Academic Racism--Site funded in part by NIH Human
Genome Project; explores ways in which behavior genetics has sometimes
been associated with racism, both in the past and today.
Center
for Evolutionary Psychology--Site maintained at Univ. of Calif., Santa
Barbara by Leda Cosmides & John Tooby, two of the founders of
evolutionary psychology.
Psychology,
Culture, & Evolution--Site maintained by Al Cheyne of the Univ. of
Waterloo, containing material on evolutionary psychology as well as
various related issues.
Sociobiology
Sanitized--A somewhat critical essay from Science as Culture,
providing an extensive review of the history and recent debates about
evolutionary psychology and its "cousin", sociobiology: includes
extensive reference list.
Behavioral
and Brain Sciences--Current articles, but no on-line archive.
The
Harvard Brain--on-line journal edited by Harvard undergraduates in
neurosciences
Journal
of Cognitive Neuroscience--journal site which has on-line archive of
contents and abstracts, with some sample articles
Society
for Neuroscience--as of Jan. 1, 1999, the Society began publishing
brief papers in an on-line format; site also provides good links to other
related Web resources
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