PSYC 2130 Chapter Notes - Chapter 9: Central Nervous System, Ernst Kretschmer, Somatic Nervous System
18 Dec 2016
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PSYC 2130 Personality – Textbook Notes
Chapter 9: The Biological Approach
Earliest Speculations About the Relationship Between Mind and Body
• Much of our personality is biologically influenced through genetics, inheritance, and
evolutionary processes.
o Neurochemistry – chemical actions in the nervous system – certainly has a prominent
role in the theorizing of the biologically based approach to personality.
I. Somatypes and Temperaments
• Ernst Kretschmer – Physique and Character Book
o Believed there was an apparent relationship between physique and specific types of
mental disorder among his patients.
• William Sheldon –
o Begi to t ad elate phsiue to ehaio ithi the oal age.
o Described three basic body types: endomorphic (plump), mesomorphic (muscular), and
ectomorphic (frail).
▪ Aoe ot ude these thee tpes as lassified as aeage uild.
o Described three basic temperament types: viscerontonia, somatotonia, and
cerebrotonia.
o He began the work of seeking relationships between body type and temperament.
▪ Results: Each of the body types were positively related to one and ONLY ONE of
the temperament types and negatively related to the other two.
▪ Endomorphy ~ viscerontinia
▪ Mesomorphy ~ somatontonia
▪ Ectomorphy ~ cerebrotinia
o Conclusion: Physique and temperament probably represented different expressions of
some basic underlying biological factor/genetic influence.
The Theory of Evolution and Human Behavior
• Charles Darwin – Theory of Natural Selection
o Believed that naturally occurring genetic mutations in a species could produce adaptive
advantages.
o Through increased likelihood of survival and reproductive advantage, traits become
characteristics of a species.
o The versatility of a species is enhanced by its variability.
What Has Evolved?
• According to the process of evolution through natural selection, humans are related to other
species but unique as well. Greater intelligence, linguistic ability, and neural plasticity distinguish
humans from other species.
I. The Human Nervous System
• The human nervous system regulates all bodily functions and is viewed as a complex network of
layered, interwoven, and interacting subsystems.
• Central Nervous System (CNS) – consists of brain and spinal cord
• Peripheral Nervous System (PNS) – consists of all other nerves extending throughout the body
o Further divided into autonomic and somatic divisions.
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o Autonomic nervous system – sends and receives information from the heart, intestines,
and other organs. Controls most involuntary behaviors and responses. It is composed of
two subsystems:
▪ Sympathetic nervous system – atiates the od fo fight o flight. Increases
heart and breathing rates and prepares the individual for action, while slowing
digestive system
▪ Parasympathetic nervous system – decreases heart rate and promotes the
conservation (vs. expenditure) of energy.
o Somatic nervous system – conveys information from the sense organs up to the brain
and input from the brain down to the muscles and glands of the body. Voluntary
behaviors are controlled.
• Human nervous system composed of two types of cells:
o Neurons – receive and convey information via their axons and throughout the system
releasing chemical messengers, neurotransmitters at the end points (synapses).
▪ Synapse, separates adjacent neurons.
o Glial cells – provide support, structure and insulation for neurons
• All subsystems (or networks) of the nervous system communicate within and across one
another via neurons.
o Neurotransmitters are the chemicals that work at the synapse to bring about this cross-
synaptic communication.
o These chemicals are synthesized by neurons using precursor chemicals taken from the
bloodstream, which ordinarily come from food sources.
• The postsynaptic neuron (i.e. the one receiving the message) has specific receptor sites, to
which certain neurotransmitters will bind to excite or inhibit the receiving neuron.
o Neurotransmitters may break down into component chemicals or be subject to
reuptake the presynaptic neuron that can reabsorb and store it for future use.
• Both neuromodulators and hormones can excite or inhibit synaptic transmission.
o Hormones are made by the glands and are circulated through the blood supply.
o Most important hormones for understanding the biology of personality = sex hormones
Sociobiology
• Sociobiology – the study of the evolutionary basis of social behavior.
o Much of theorizing in sociobiology has focused on how altruism might be fostered by
evolution.
• Reciprocal altruism – refers to the idea that helping others increases the likelihood that they
will help you when you need help.
o Appears that a tendency toward altruism is adaptive and may be a fundamental aspect
of human nature.
I. Mating Strategies
• Although people are usually not subject to selective breeding, multiple forces do influence their
choice of mates.
o Mating in humans and other animals is assortative (actively choosing a mate) rather
than random.
▪ Mate with others who are similar to us; genetic similarity theory.
• Two sexes use quite different selection criteria.
o Women – more selective, typically seek long-term relationships and security for
themselves and offspring.
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find more resources at oneclass.com
Document Summary
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