This article was published on Psychology Today. by Warren W Tryon Ph.D, a Professor of Psychology in Fordham Univeristy Click here for link to the original article.
The distinction between mind and body was
unfortunately made centuries ago and remains with us today. We label illnesses
caused by germs or viruses as “physical”. We label other illnesses such as
depression and anxiety as “mental”. Yet the distinction between mental and
physical is often unclear. For example, placebos are substances, such as sugar
pills, that are thought to be physically inactive but can produce medical
benefits in patients who believe they will work.
In my book Cognitive
Neuroscience and Psychotherapy: Network Principles for a Unified Theory, I
point out that “Kirsch et al. (2008) reported that placebos are about 80% as
effective as antidepressant medications are and 50% as effective as analgesic
medications are. Kirsch and Sapirstein (1998) estimated that placebos were 75%
as effective as antidepressive medications” (p. 252).
The field of psychobiology studies placebo
responses and other instances of mind-brain links. The field of biopsychology
involves the reverse case; it is concerned with ways that the physical body
effects mental states. For example, it studies how legal and illegal
psychoactive drugs alter the ways that we think, feel, and act.
Most people probably think of transitional
fossils or species when they hear the term “missing link” but another just as
important missing link is the one between psychology and biology, between our
physical and mental states. The terms psychobiology and biopsychology imply
that psychology and biology are connected and interact. The problem with both
psychobiology and biopsychology is that there is a missing causal explanatory
link between mind and brain.
A very well accepted theoretical orientation in
psychological science is the BioPsychoSocial (BPS) model. You might think that
this model explains how psychology and biology interact, but you would be
wrong. The BPS model is actually just a list of ingredients. It lists important
biological, psychological, and social variables and claims that they mutually
interact but does not provide any natural science mechanism information that
can explain how they interact.
Some authors place these terms in boxes and draw
arrows among them to impute causality but never provide any natural science
mechanism information that actually explains how they physically interact. In
short, the BPS model explains nothing more about how psychology and biology
interact than explaining how a car works by listing that it is made of glass,
metal, and petroleum. Listing is not explaining. Instead, the missing
explanatory link is glossed over in hopes that you will either not notice or
ask about it.
The most important task facing psychobiologists
and biopsychologists is to provide a natural science explanation that links
psychology and biology. This task requires identifying principles that provide
mechanism information because mature sciences are organized around principles;
psychology is currently not. Those of you who have taken an introductory
psychology course or who have read about psychology will recognize that
psychology is currently organized around famous people, such as Freud and
Skinner, or around “isms” such as behaviorism and cognitivism. This
organization differs from all other natural sciences. They are organized around
physical entities such as the cell in biology and molecules in chemistry. This
allows biologists and chemists to explain more about how things work than
psychologists can. Imagine how much better our therapies will become once we
understand how and why they work.
I provide some of the missing explanatory details
in my book entitled Cognitive
Neuroscience and Psychotherapy: Network Principles for a Unified Theory.
The remainder of this blog briefly presents the general conceptual framework
for understanding how psychology and biology interact that my book is based on.
I refer to this explanatory approach as a Bio«Psychology Network (BPN)
explanatory system because it consists of four core and now nine corollary
principles that together can explain a wide variety of well replicated
psychological phenomena in ways that are fully consistent with neuroscience.
The first thing to understand is that our brains
are made up of neurons that form neural networks. Hence, some form of network
theory is required to explain how psychology and biology interact. How can
these neural network models explain psychology? To answer that, we must first
recognize that learning and memory form the basis of all psychology. Carlson,
Miller, Heth, Donahoe, and Martin (2010) stated that “Learning refers to the
process by which experiences change our nervous system and hence our behavior.
We refer to these changes as memories” (p. 440; italics in the original).
Learning is crucial to human survival. If we could not form memories as
infants, we could not learn to do anything. We would not develop language nor
could we benefit from experience. In short, we would never develop into the
children, adolescents, and adults that we are familiar with.
Rumelhart and McClelland (1986) and McClelland
and Rumelhart (1986) provided demonstration proofs that artificial neural
networks, called connectionist models, can form memories, can learn, and
therefore can do psychology. Connectionist models of many psychological
phenomena have been developed. The Psychological Review is a journal that
specializes in psychological theory. It has published numerous long articles
featuring connectionist neural network models. Many other demonstration proofs
have been published in a wide variety of journals and books. Connectionist
neural network models now rival traditional cognitive psychology models.
How Psychology Changes Biology
Here I sketch a general explanation that derives
from parallel-distributed-processing (PDP) connectionist-neural-network (CNN)
models that I collectively refer to as Computational Neuropsychology (CNP). Two
major features characterize these models. The first major feature of these
models is that they simulate neural architecture by using layers of simulated
neurons. The second major feature of these models is that these simulated
neurons are connected by simulated synapses. Artificial neural networks learn through
training that modifies these synapses. Some synapses become more excitatory
while others become more inhibitory of received activations. The difference
between what the neural network computes as simulated behavior and the desired
response is considered to be an error. These errors are used to modify the
simulated synapses. These changes simulate the way that experience-dependent
plasticity mechanisms modify real synapses in biological neural networks while
they learn by forming memories. And then another learning trial begins. The
network’s performance gradually improves through additional synaptic
modification. Here we can see that learning is mostly about modifying synaptic
connections.
But more brain changes are involved in
psychological development. Infants are born with far more synapses than they
will need as adults. Neural network pathways that are active while learning
language, music, reading, writing, and playing sports, among other skills, are
biologically reinforced by modifying synapses. Unused synapses are cannibalized
to save precious metabolic energy. Psychological development literally,
physically, sculpts the brain in addition to modifying synapses and thereby
changes biology! Our brains physically specialize as we develop psychologically.
This explains why it is more difficult for older people to learn a new
language.
How Biology Changes Psychology
Our neural network understanding of how
psychology changes biology prepares us to understand how biology modifies
psychology. Understanding that the synapses that connect neurons contain our
memories of who we are, the people that we know, the experiences we have had,
and our attitudes about everyone and everything along with how we feel enables
us to see that directly modifying them with legal or illegal psychoactive
substances will change our psychology. Psychology normally changes our synapses
by activating internal experience-dependent plasticity mechanisms. Drugs
directly modify these same synapses pharmacologically and consequently alters
our psychology. Pharmacological psychiatry is a relatively young field. The
clinical practice of selecting the right medication to make therapeutic
synaptic modifications is, by and large, a trial and error business. It can
take several weeks for therapeutic effects to be noticed. Therapeutic effects
are often dose dependent which means that dosage may need to be systematically
increased.
Conclusion
Neural network models enable us to see how
psychology changes biology because the memory formation process that drives
learning and all psychological development modifies synapses through
experience-dependent plasticity neuroscience mechanisms. This knowledge enables
to understand that modifying synapses pharmacologically will also change our
psychology. The causal role of synapses in learning and memory make them the
missing link in psychobiology and biopsychology. I predict that psychology will
organize around the synapse when it becomes a mature natural science just as
biology organized around the cell when it became a mature natural
science.
References
Carlson,
N. R., Miller, H., Heth, C. D., Donahoe, J. W., & Martin, G. N. (2010).
Psychology: The science of behavior (7th ed.) (p. 196); Boston: Allyn &
Bacon.
Kirsch,
I., Deacon, B. J., Huedo-Medina, T. B. H., Scoboria, A., Moore, T. J., &
Johnson, B. T. (2008). Initial severity and antidepressant benefits: A
meta-analysis of data submitted to the Food and Drug Administration. PLoS
Medicine, 5, 260-268.
Kirsch,
I., & Sapirstein, G. (1998) Listening to Prozac but hearing placebo: a
meta-analysis of antidepressant medication. Prevention and treatment, Vol. I,
article 0002a, posted June 26, 1998, available athttp://journals.apa.org/prevention/volume1/pre0010002a.html.
McClelland,
J. L., Rumelhart, D. E., & the PDP Research Group (1986). Parallel
distributed processing: Explorations in the microstructure of cognition,
Vol. 2: Psychological and biological models. Cambridge, MA: MIT Press.
Rumelhart,
D. E., McClelland, J. L., & the PDP Research Group (1986). Parallel
distributed processing: Explorations in the microstructure of cognition, Vol.
1: Foundations. Cambridge, MA: MIT Press.
Tryon,
W. W. (2014). Cognitive neuroscience and psychotherapy: Network Principles for
a Unified Theory. New York: Academic Press. http://store.elsevier.com/9780124200715
Source:Psychology Today
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