Biological Bases of Behaviour.
Lecture 1: Biology & Behaviour.
Learning Outcomes.
 At the end of this lecture you should be able to:
 1. Explain 3 approaches used to answer causal questions
concerning biology and behaviour.
 2. Outline the usefulness of the 'comparative approach'.
 3. Explain what is meant by the 'mind-body problem'.
 4. Describe Tinbergen's '4 why's'.
What is Biological Psychology?
 According to Kalat (2001) "Biological psychology is the study
of the physiological, evolutionary, and
mechanisms of behaviour and experience".
developmental
 The
biological
psychologist
explains
behaviour
in
physiological terms, because physiological mechanisms can
inform us about psychological processes.
 Carlson (1994) provides the following example:
 Brain damage produces language impairments, if such
damage produced exactly the same impairment this would
tell us little.
 However, damage to specific regions of the brain leads to
particular deficits in language use, the precise nature of
these impairments tells us how such abilities are organised.
Problems of Correlating Behaviour
with Physiology
 Identical behaviours may occur for different reasons.
Carlson (1994) cites the following example:
Mice build nests under 2 conditions:
1. When the temperature is low.
2. When the animal is pregnant.
A non-pregnant mouse will not build a nest if it is warm,
but a pregnant mouse will build a nest regardless of the
temperature.
 Not surprisingly, these behaviours are initiated by different
physiological mechanisms - one hormonally based, and the




other based on changes in the sensation of temperature.
The ‘Causal Approach’.
 Toates (2001): the key element of biological psychology is
that behaviour is caused by identifiable events within the
nervous system.
 This demonstrates a 'causal approach' of the form 'if X then
Y'. E.g:
 1. Does the regular use of ecstasy produce long-term
impairments in memory?
 2. Do mobile phones affect brain function?
 3. Is the hormone testosterone responsible for male
aggressive behaviours?
 4. Does alcohol impair driving performance?
 5. Is homosexuality genetic?
 6. Can the effects of brain damage be reversed?
The ‘3 Approaches’.
 According to Rosenzweig et al., (1996) to answer the
previous questions we can use 3 approaches:
 1. Somatic Intervention: The investigator can alter a
structure or function of the brain or body in order to see
how a particular change alters behaviour. Examples:
 A hormone is administered to some animals but not to
others, various behaviours are then compared.
 One region of the brain is electrically stimulated and
behavioural effects are observed.
 A group of people take ecstasy and another group take a
placebo, their subsequent cognitive performance is then
compared.
2. Behavioural Intervention.
 This is the opposite approach. Here the behaviour of an
individual is altered, and any changes in neural structure or
function are noted. Examples:
 Exposing an individual to a visual stimulus provokes
changes in electrical activity and blood flow in certain brain
regions.
 Ecstasy administration leads to observable changes in the
concentration of certain neurotransmitters.
 Learning produces alterations in the number and
connectivity of certain neurons in the brain.
3. Correlation.
 This approach consists of finding the extent to which a
given bodily measure varies with a given behavioural
measure. Examples:
 Are people with bigger brains more intelligent?
 Do regular users of ecstasy experience
cognitive/behavioural problems?
 Is the severity of schizophrenia correlated with the
magnitude of changes in brain structure?
However..
 1. We must remember that the nervous system does not
exist in isolation - it receives input from the external world
and is influenced by bodily events outside of the nervous
system (e.g. temperature). These can alter behaviour.
 2. Behaviour also has consequences for the environment,
and can thus change subsequent behaviour.
 3. There are also many methodological and ethical issues to
consider.
 4. Correlations are not proof of causality.
The Comparative Approach.
 Most of what we know about how the brain and nervous
system functions stems from animal research.
 What can the study of animals tell us about the human brain
and behaviour?
 Kalat (2001) argues that animals are studied for 4 reasons:
 1. Animal and human brains are structurally and functionally
similar.
 2. Knowledge of animal physiology and behaviour can be
used to improve animal welfare and preserve endangered
species.
 3. Understanding our near relatives (e.g. chimpanzees) can
shed light on human evolution.
 4. Some medical and psychological experiments cannot use
human participants due to ethical and legal problems.
Vertebrate Brains.
cerebrum
cerebrum
cerebellum
Brain stem
cerebellum
Brain stem
cerebrum
cerebrum
cerebellum
Brain stem
cerebellum
Brain stem
Kalat, 2001, p21
Brain, Mind, and Behaviour.
 Most people have no difficulty in explaining animal
behaviours in terms of genes, hormones, neural activity etc.
 Many are uncomfortable using such explanations for
complex human behaviours such as love, religious
experience, morality, aggression, consciousness etc.
 Biological psychologists tend to be 'deterministic' i.e. they
believe than we can identify physical causes for all
observed behaviours.
 The extreme form of this is known as 'reductionism' in that
very complex processes (e.g. consciousness) can be
reduced to events at a lower level (i.e. the actions in
specific neurons).
Problems with Reductionism.
 It may not always be possible to employ this approach,
Toates (2001) points out that the assumption that the mind
needs a physical body does not necessarily mean that the
laws applicable to mental states can be reduced to those of
biological structure.
 He uses the argument of liquid water (the product of
combining oxygen with hydrogen).
 The final product does not resemble either of the original
components, and cannot be reduced to the sum of the
properties of each.
 The property of liquid water only emerges from their
combination.
Mind/Body Problem
 Many philosophers have addressed the 'mind-body
problem’ by asking 'How are the mind and brain related'?
 Some argued that the mind and brain are separate entities
- this is called ‘dualism’, the most famous exponent being
Descartes who stated “cogito ergo sum” - ‘I think therefore
I am’
 He argued that while animals were simply 'machines'
lacking a higher form of consciousness, humans possessed
souls that controlled the body via the pineal gland in the
brain.
 BUT, if the mind is not part of the material world then how
can it exert a force that can influence physical matter?
 Many people still hold dualist views - e.g. the survival of the
mind after the physical death of the body.
Monism.
 Most philosophers and neuroscientists now reject dualism
in favour of 'monism'.
 This argues for the singularity of mind and brain; that
human thoughts, feelings, experiences, etc are simply the
product of complex neurological / neurochemical /
neuroelectrical / neurohormonal activity.
 Many human behaviours can be explained in such terms,
but others remain mysterious.
 The fundamental question of why humans possess selfconsciousness and what kinds of physical activity is
necessary to produce a conscious being remain
unanswered.
Can We Explain Consciousness?
 Chalmers (1995) proposed that consciousness is a
fundamental property of living matter which cannot be
reduced to specific physiological events.
 Dennett (1991) argued that one day we will be able to
explain consciousness at a physiological level.
 Are animals conscious? If so should they be treated the same
as humans?
 Are brain-damaged humans conscious? If not, then are they
human?
 Sperry (1987) developed the notion of 'emergent
interactionism' :
 1. Consciousness is an emergent property of millions of
neurons.
 2. The activity of individual neurons can only be understood
in terms of their participation in the whole system.
Biological Explanations of Behaviour.
 These fall into 4 categories originally prposed by Tinbergen
(1951) and are thus referred to as 'Tinbergen's 4 whys':
 1. Physiological.
 This explanation relates a specific behaviour to the activity of
certain regions or structures of the brain, or other organs. It
covers cellular, chemical, and hormonal influences.
 E.g the ability to learn information, memorise it, and then
recall it appears to be governed by the hippocampus and its
connections to other brain regions.
 Damage to this area of the brain severely impairs the ability
to transfer short-term memories into long-term ones.
 Individuals with hippocampal damage can only retain
information over a short delay.
Biological Explanations of Behaviour.
 2. Ontogenetic (developmental): ‘Ontogeny’ is the process
whereby an individual changes and develops through their
life span.
 This type of explanation tries to explain how a certain
behaviour develops throughout life.
 It covers genetic and environmental (nature versus
nurture) influences and their interactions.
 E.g intelligence is a complex set of skills that are partially
determined be genetic factors, but the expression of these
genes is also determined by the environment i.e. nutrition,
stimulation etc.
Biological Explanations of Behaviour.
 3. Evolutionary: This examines a structure or behaviour in
terms of the evolutionary history of the species
('phylogeny').
 Certain physical and behavioural features have emerged
over evolutionary time because they have solved certain
problems in a way that have improved the reproductive
capability of the individual showing that feature (they are
'adaptive').
 E.g when certain species of animals are threatened, they
respond by erecting their body hairs making them look
bigger and more intimidating (piloerection).
 When humans are frightened they also erect their body
hairs, but as humans have lost most of their body hair this
results in the sensation known as goose bumps.
Biological Explanations of Behaviour.
 4. Functional: This tries to answer how a particular
behaviour has evolved - i.e. what is its purpose, what
genetic/survival advantage might a particular behaviour
have for an individual?
 Darwin's theory of 'natural selection' emphasised that all of
the physical and behavioural characteristics of an organism
have (or had) a functional significance.
 E.g some species can change the colour of their skin to
match their surroundings, the functional significance of this
ability to hide from predators is obvious.
 We thus need to understand the natural history of a
species, so that the behaviours can be seen in the correct
context.
 The evolutionary and functional explanations are often
difficult to separate and are often discussed together.
Example: Birdsong
 Catchpole & Slater (1995) illustrated these different types
of explanations by considering birdsong:
 Physiological explanation: Birdsong depends upon 2 areas
of the brain - the caudal nucleus of the hyperstriatum
ventrale and the robust nucleus of the archistriatum.
 These areas are larger in songbirds than in non-singing
species, in males than females, and in breeding males than
immature males.
 The size of these regions depends upon the hormone
testosterone, which is secreted in higher levels in males of
a breeding age, at certain times of the year.
Testosterone Level and Size of the
Song Production Areas.
Testosterone
level
Size of
songproduction
area
song
Spring
Autumn
Ontogenetic Explanation.
 In certain bird species, a young male learns a song by
listening to and copying adult males.
 Development of his singing ability requires the genetic
program that prepares him to learn the song and the actual
experience of hearing a song during a sensitive period in
early life.
 Interestingly, although the song is learnt at a young age
the individual will not get a chance to practice it until later
in life.
 Birds that do not sing (e.g. pigeons) do not have a sensitive
period; they make the noises throughout their
development.
Sensitive Periods and Singing.
Birth
Sensitive
period
Time of first
vocalisation
Time
Bird must
hear song here
Evolutionary Explananation.
 Closely-related bird species have similar vocalisations,
suggesting that they share a common ancestor.
 We can investigate this by analysing changes between the
evolutionary relationships ('taxonomy') of different bird
species.
 E.g although Baird's sandpiper looks physically like other
sandpipers (and was originally named as one), its song is
more like that of the Dunlin.
 Genetic analysis revealed that it is indeed more closely
related to the Dunlin.
Functional Explanation.
 We have already seen that:
 Genes + appropriate environment = song.
 This combination must have some adaptive benefit to the
individual. The following have been proposed:
 1. Singing songs is a feature of mate value - males sing
during the breeding season to attract females.
 Only males with the best singing voices, or who can sing
the most complex songs, will be selected as mates and pass
their singing ability to their offspring.
 2. Singing a song helps to establish a territory, it also gives
honest signals about the age and size of the singer.
References and Bibliography.
 Carlson, N.R. (1994). Physiology of Behaviour. Allyn & Bacon.
 Catchpole, C.K., & Slater, P.J.B. (1995). Bird Song: Biological
Themes and Variations. Cambridge University Press.
 Chalmers, D.J. (1995). Facing up to the problem of consciousness.
Journal of Consciousness Studies, 2: 200-219.
 Dennett, D.C. (1991). Consciousness Explained. Little Brown & Co.
 Kalat, J.W. (2001). Biological Psychology, 7th edition, Wadsworth.
 Rosenzweig, M.R., Leiman, A.L., & Breedlove, S.M. (1996).
Biological Psychology. Sinauer Associates.
 Sperry, R.W. (1987). Structure and significance of the
consciousness revolution. Journal of Mind and Behaviour, 8: 3766.
 Tinbergen, N. (1951). The Study of Instinct, Oxford University
Press.
 Toates, F. (2001). Biological Psychology: An Integrative Approach.
Prentice Hall.