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Animal Behaviour: Candidates should be able to:
(a) explain the advantages to organisms of innate behaviour;
(b) describe escape reflexes, taxes and kineses as examples
of genetically-determined innate behaviours;
(c) explain the meaning of the term learned behaviour;
(d) describe habituation, imprinting, classical and operant
conditioning, latent and insight learning as examples of
learned behaviours;
(e) describe, using one example, the advantages of social
behaviour in primates;
(f) discuss how the links between a range of human
behaviours and the dopamine receptor DRD4 may contribute
to the understanding of human behaviour
Innate Behaviour is a pattern of inherited, pre-set behaviour that does not
require learning or practice. An animal is capable of innate behaviour from birth.
Such behaviours appear to be very inflexible in their operation. The responses are
stereotypical and always performed in the same way to the same stimulus.
Truly
innate
behaviour
must be
‘hard
wired’
into an
organism’s
nervous
system.
Therefore
if a
behaviour
is innate,
it is
largely
determine
d by an
animal’s
genes.
A reflex action is a fast, automatic
response to a stimulus. Reflex
actions are involuntary responses
that are used to avoid predators
or remove an organism from
danger.
Earthworms have highly touch sensitive
receptors on their heads. If these
receptors sense vibrations, the
longitudinal body muscles to contract.
The worm’s body shortens so that it
rapidly withdraws into its burrow, to
escape from predators such as birds.
Taxis is a directional locamotory response. The direction of the movement is
described in relation to the stimulus which triggers the behavioural response.
Positive chemotaxis: towards chemicals
Fly Maggots move
away from bright light
Negative chemotaxis: away from chemicals
sources – this is
Positive phototaxis: towards light
negative phototaxis.
Negative phototaxis: away from light
Kinesis is a response involving a changed
level of activity. The level of activity
increases when an organism is in
unfavourable conditions.
This behaviour is non-directional.
If woodlice are placed in dry,
bright conditions, they will move
around rapidly and randomly
until they are in more suitable
damp and dark conditions.
Learned behaviour refers to animal responses that
can be changed or modified with experience.
Habituation: gradual decline of a response to a stimulus resulting from
repeated exposure to the stimulus. Habituation is important in filtering the
large amounts of information received from the surrounding environment. By
habituating to less important stimuli, an animal can focus its attention on the
most important features of its environment. Habituation allows animals to
screen out non-dangerous environmental stimuli such as wind and waves.
Birds learn
to ignore
scarecrows
Imprinting is a modification of behaviour that happens during a relatively short
window of time (‘receptive period’) early in an organism’s life. An organism comes
to treat a particular object or organism as something to which it should remain near
as though it were its mother. It is significant in helping the young to learn skills from
their parents such as flight in birds. Konrad Lorenz proved this withy his gosling
experiment: the goslings behaved as if he were their mother.
Insight Learning: using thinking and reasoning
skills to solve a new problem. A type of
learning in which an animal appears to
integrate memories arising from 2 or more
pieces of behaviour in order to produce a new
response that achieves a reward.
Wolfgang Kohler’s experiment:
chimpanzees were presented
with bananas hung out of
reach and a set of boxes. The
chimps were able to stack the
boxes on top of each other to
reach the bananas.
Classical conditioning is a form of learning in which two unrelated stimuli are
applied to an animal. The first will be an ‘unconditioned stimulus’, which elicits a
reflex response without conditioning, and the second being an unrelated ‘neutral
stimulus’. After repeated exposure to both stimuli together, the animal will
eventually respond with the normal reflex response to the unrelated stimulus.
The ‘neutral stimulus’ therefore becomes a ‘conditioned stimulus’ and the
response elicited is a ‘conditioned response’.
This diagram
shows
Pavlov’s
experiment
using dogs as
a way to
show
classical
conditioning.
Operant Conditioning
Operant conditioning is trial and error
learning. This type of learning takes
place in animals given punishment or
reward to reinforce the performance
of a particular operation.
Reinforcers are responses
from the environment which
act to increase the probability
of a behaviour being
repeated.
Positive reinforcers
strengthen a behaviour by
providing a consequence that
an individual finds rewarding –
like food pellets.
Negative reinforcers involves
the removal of an unpleasant
stimulus – like removing an
electric current from beneath
an animal’s feet.
This diagram shows a rat in a Skinner Box. The
operation of a lever rewards the rat with a food
pellet (positive reinforcement). The operation of
the lever can also stop the electric grid from
initiating an electric shock (negative
reinforcement)
Punishments are designed to decrease the
frequency of a behaviour. Positive punishment
involves administering an unpleasant stimulus
after a behaviour has been performed – like giving
an electric shock.
Negative punishment involves withdrawing a
potentially rewarding stimulus – like taking away a
child’s toy.
Learning that occurs in the absence of obvious reward, which is only
manifested later in different circumstances. The knowledge remains
dormant and may not be available to consciousness until specific events or
experiences may need this knowledge to be demonstrated for survival.
Latent
Learning
Social Behaviour in Primates
Mountain gorillas live in troops of about 10 individuals. This consists of
one mature dominant male – a silverback – and adult females and their
offspring. The dominant male protects the troop, mates with females and
leads them in their search for food.
Advantages of Social Behaviour:
 Females give birth to one or very few infants
at a time. The maternal care and group
protection enhances survival rate of young.
Important Social behaviours:
 Grooming – one individual will pick parasites form  Young learn through observation and play –
learned behaviour is vital to their survival
another
 Care of young offspring: during first 5 months,
 Final relatively large brain size slows
infant remains in constant contact with mother,
maturation of primates. The security of a
suckling at hourly intervals.
group enhances the survival and learning of
 Communication systems exist: calls, displays and
immature young.
grunts are used to signal danger, issue threats to
 Knowledge and protection of food sources
predators or other groups and in play fighting as
shared with group
juveniles learn how to behave as adults.
 Facial expressions are important – in particular for  Greater ability to detect and deter predators
is achieved by groups working together.
recognising other members of the group.
Human Behaviour, Dopamine and DNA
Dopamine acts as a neurotransmitter
and a hormone. It is a precursor
molecule to adrenaline and
noradrenaline. Dopamine increases
arousal and decreases inhibition.
Low levels of dopamine are associated with
Parkinson’s Disease. Parkinson’s can be
treated by administering a drug called
levodopa (L-Dopa). L-Dopa is a precursor to
dopamine and is transformed into dopamine
in the dopaminergic synapses of the patient.
There are 5 different dopamine receptors –
DRD1 to DRD5. Each of these receptors is
coded for by a separate gene. Binding of
dopamine to its receptor is involved in a
number of processes, like control of
motivation and leaning and regulation of
the release of other neurotransmitters.
High levels of dopamine are associated with
schizophrenia. Excess dopamine is also
associated with psychotic behaviour: psychosis is
a mental health condition characterised by an
impaired grasp on reality, impaired impulse
control and hallucinations.
There are over 50 known variants of the DRD4
gene. The variants differ in a specific sequence
known as a variable tandem repeat. A short
section of nucleotides shows a different number
of repeats in each variant. Some of these
variants are involved in certain human
behavioural conditions: the inheritance of
particular variants of the DRD4 gene affects the
levels and action of dopamine in the brain.
Some variants of the DRD4 receptor gene have
been found to increase the likelihood of
addictive behaviours like drinking and smoking.
A particular dopamine receptor variant of DRD4
has been shown to be more frequent in
individuals suffering from ADHD. Ritalin is a
drug used to treat ADH by affecting dopamine
levels in the brain.