Animal Behaviour: Candidates should be able to:

1. 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

2. Innate Behaviouris 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 inflexiblein their operation. The responses are stereotypical and always performed in the same way to the same stimulus. 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. Truly innate behaviour must be ‘hard wired’ into an organism’s nervous system. Therefore if a behaviour is innate, it is largely determined 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. 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 Negative chemotaxis: away from chemicals Positive phototaxis: towards light Negative phototaxis: away from light Fly Maggots move away from bright light sources – this is negative phototaxis. 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.

3. Learned behaviour refers to animal responses that can be changed or modified with experience. Birds learn to ignore scarecrows 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. 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.

4. 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.

5. 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. 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) 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. 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.

6. 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. • Young learn through observation and play – learned behaviour is vital to their survival • Final relatively large brain size slows maturation of primates. The security of a group enhances the survival and learning of immature young. • Knowledge and protection of food sources shared with group • Greater ability to detect and deter predators is achieved by groups working together. • Important Social behaviours: • Grooming – one individual will pick parasites form another • Care of young offspring: during first 5 months, infant remains in constant contact with mother, suckling at hourly intervals. • Communication systems exist: calls, displays and grunts are used to signal danger, issue threats to predators or other groups and in play fighting as juveniles learn how to behave as adults. • Facial expressions are important – in particular for recognising other members of the group.

7. Human Behaviour, Dopamine and DNA 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. 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 calledlevodopa (L-Dopa). L-Dopa is a precursor to dopamine and is transformed into dopamine in the dopaminergic synapses of the patient. 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.