Biological Basis of Behaviour
Chapter 1: The Major Issues
1.1 The Mind-Brian Relationship
- Biological psyc is the study of psychological, evolutionary and development
mechanisms of behaviour and experience
- BP is a way to understand behaviour in terms of how it evolved and how the
functioning of the brain and other organs control behaviour.
- Comsology: the branch of physics that asks why the universe exists at all
2 types of cells
1. Neurons: convey msgs to one another and to muscles and glands. ( large in
size,fn, and shape)
2. Glia: smaller than the neurons and have many functions but do convey info
over great distances.
Biological Explanations of Behaviour
- Biological explanations of behaviour go into four categories: physiological,
ontogenetic, evolutionary, and functional explanation.
1. Physiological explanation: relates a behaviour to the activity of the brain
and other organs, deals with the machinery of the body.
2. Ontogenetic explanation: describes a structure or behaviour develops,
including the influence of genes, nutrition, experiences and their
3. Evolutionary explanation : reconstructs the evolutionary history of a
structure or behaviour, states what evolved from what.
4. Functional explanation: describes ‘why’ a structure/behaviour evolved
the way it did.
The Brain and the Conscious Mind
- Biological explanations of behaviour raise the ‘mind-body’ or ‘mind-brain’
- Dualism: the belief that mind and body are different kinds of substance that
- French Philosopher Rene Descrates defended dualism. He proposed that
mind and brain interact at a single point in space, which he suggested was
the pineal gland.
- Monism: the belief that the universe consists of only one kind of substance,
such as materalism, mentalism, and identity position.
1. Materalism : the view that everything that exists is material or physical.\
2. Mentalism: The view that only the mind exists and that the physical world
could not exist unless the mind was aware of it. 3. Identity position: the view that mental process and certain kinds of brain
processes are the same thing, described in different words.
1.1 in Closing
- Biological psychologist try to answer 4 types of questions about any given
1. Physiological: how does it relate to the physiology of the brain and other
2. Ontogenetic: how does it develop w/I the individual?
3. Evolutionary: how did the capacity for the behaviour evolve ?
4. Functional: Why did the capacity for the behaviour evolve?
- Biological explanations of behaviour do not necessarily assume that the
individual understands the purpose or function of the behaviour.
- Philosophers and scientists continue to address the mind-brain relationship.
Dualism, the view that the mind exists separately from the brain is opposed
by the principle that only matter and energy can affect other matter and
- Nearly all philosophers and scientists who have addressed the mind-brain
problem favor some version of monism, the belief that the universe consists
of only one kind of substance.
1.2 The Genetics of Behaviour
- Gregor Mendel explains inheritance through the process of genes.
- Know the basics of words such as chromosomes and DNA (deoxyribonucleic
acid), homogeneous (identical chromosome), heterogeneous( different
chromosomes), dominant and recessive genes.
- A strand of a DNA acts as a template for RNA ( ribonucleic acid) which is
single stranded. RNA can serve for protein synthesis and enzymes.
Sex Linked and Sex Limited Genes
- The genes located on the sex chromosome are known as sex linked gene.
There is X and Y, Females have 2 X and males have X and Y.
- Sex-limited genes which are present in both sexes, generally on autosomal
but actively mainly in one sex.
- A sex-linked gene is on a sex chromosome (usually X chromosome). A sex-
limited gene could be on any chromosome, but it is activated by sex
hormones and therefore shows its effects only in one sex or the other.
Heredity and Environment - To determine the contribution of heredity and environment, researchers rely
on 2 kinds of evidence: 1. Monozygotic (from one egg) twins or Dizygotic
(from 2 eggs twin) 2. Adopted children study.
- In some cases. They identity specific genes that are more common in people
w/ one type of behaviour than another.
- Humans are difficult research animals because researchers cannot ppl’s
heredity or environment.
- It is difficult to distinguish b/w heredity and parental influences.
- Multiplier effect: If genet