Slide 1

Chapter 2

BIOLOGY AND BEHAVIOUR

BY:DR. UCHE AMAEFUNA (MD).THERE ARE MORE TO LECTURES THAN JUST SLIDES..

1. Classical conditioningClassical conditioning, also known as respondent or Pavlovian conditioning.

Ivan Petrovich Pavlov was a Russian scientist who investigated the digestive system of dogs by presenting them with meat powder and measuring the amount of saliva they produced. Pavlov found that the dogs began to salivate even before the meat powder was presented as they associated the feeder with the meat powder. This led Pavlov to conclude that the dogs were conditioned to respond to the feeder through the process of classical conditioning.

John B Watson's experimentation with 'Little Albert'; ethical issues in conditioning human behaviour.

Researchers Watson and Raynor wanted to test the idea that fear could be acquired through classical conditioning.

Their subject was Little Albert, an eleven-month-old son of a female employee at the clinic. The child's mother knew nothing about the experiment. Watson and Raynor presented Albert with a white laboratory rat while sounding a loud noise.

Little Albert soon associated the loud noise with the white rat and was conditioned to fear the rat. This fear was then generalised to other fluffy white objects such a Santa's beard and a sealskin coat.

It is not known whether this intense fear was reversed. There were many ethical issues in this experiment that were overlooked. Ethical guidelines for psychological research have certainly improved and are much different today. Key terms in classical conditioning

Some key terms in classical conditioning include: Neutral stimulus (NS) - a stimulus which, prior to conditioning, would evoke no response. This always becomes the conditioned stimulus, e.g. the bell in Pavlov's experiments. Unconditioned stimulus (UCS) - a stimulus which innately produces a response or reflex, such as the meat in Pavlov's experiments.

Unconditioned response (UCR) - an unlearned response elicited by an unconditioned stimulus, e.g. the dog involuntarily salivated at the meat (UCS). Association - a connection between two events which results in learning. Pavlov's dogs learned to associate the ringing of the bell and the presentation of the meat so that they eventually learned to salivate at the bell alone.

Conditioned stimulus (CS) - After the neutral stimulus has been paired with the unconditioned stimulus many times, the neutral stimulus becomes the conditioned stimulus. It now elicits a learned response such as the bell. Conditioned response (CR) - a learned response to a conditioned stimulus. Pavlov's dogs learned to salivate at the bell.

Remember that conditioning is another term for learning. Any stimulus or response that is unconditioned, simply means unlearned, or before learning has taken place.

The main elements involved in classical conditioning are: Extinction - when a conditioned response is no longer reinforced by the unconditioned stimulus, the conditioned response will cease to occur. For example, if the bell (CS) is continually presented without the meat (UCS), the dog will eventually stop salivating (CR) at the bell alone.

Stimulus generalisation - when an organism has been conditioned to respond to a stimulus, it will often respond to similar stimuli. For example, Pavlov's dogs responded to bells of a similar pitch to the original bell.

Stimulus discrimination - when an organism responds to a conditioned stimulus but detects a difference in other stimuli and therefore doesn't respond to them. Pavlov's dogs did not respond to bell-like stimuli that were quite different from the original bell.Spontaneous recovery - the reappearance of a conditioned response after extinction and a rest period.

Question;(1) is a stimulus which prior to conditioning, evoked no response?a. Associationb. Unconditioned stimulusc. Neutral stimulusd. Unconditioned responsee. Stimulus discriminationf. Spontaneous recoveryg. Extinctionh. Conditioned responseQuestion;

(2) is a stimulus which innately produces a response or reflex?a. Associationb. Unconditioned stimulusc. Neutral stimulusd. Unconditioned responsee. Stimulus discriminationf. Spontaneous recoveryg. Extinctionh. Conditioned response

2. Operant (Instrumental) conditioning Operant conditioning is learning where the consequence is dependent on the organism's response. The consequence then influences the likelihood of the behaviour occurring. Skinner studied hungry rats in specially designed 'skinner' boxes.

These boxes were equipped with a lever which, when pressed, dispensed food or water. Skinner would place a hungry rat in the box. Eventually the rat would accidentally press the lever and a food pellet would fall. Each time it accidentally pressed the lever, food would be dispensed.The rat then learned that each time it pressed the lever it would be rewarded with a food pellet; thus; it would constantly press the lever.

Other Skinner boxes were equipped with electric shocks to punish the animal for certain responses. In this way, Skinner developed his theory of operant conditioning where he believed that our behaviour operates on the environment and that our behaviour is instrumental in producing the consequences (rewards and punishments).Operant response - a response or behaviour of an organism that is voluntary and not associated with a particular stimulus. This response acts on or modifies the environment. For example, a person picking up a book to read.

Reinforcer - the reward given for a response in order to strengthen it and increase the likelihood of the response occurring again. Positive reinforcer - a reward which strengthens a response by providing a pleasurable consequence such as praise or a chocolate bar. Negative reinforcer - a reward which strengthens a response by removing or reducing an unpleasant stimulus such as taking away a house chore or homework.

Schedules of reinforcement

This refers to the frequency in which a response is reinforced in operant conditioning.

There are different schedules of reinforcement within this type of learning.Continuous reinforcement - when a satisfying response is reinforced every time.Partial reinforcement - reinforcement which does not occur continuously. The reinforcement may be administered in the following ways:

Fixed ratio schedule - a satisfying response is reinforced after a set number of responses have been made, e.g. every fifth response. Fixed interval schedule - a satisfying response is reinforced at regular time intervals e.g. every five minutes. Variable ratio schedule - a satisfying response is reinforced at irregular intervals, but the average number of responses is fixed, e.g. poker machines.

Variable interval schedule - a satisfying response is reinforced at random intervals within a fixed length of time e.g. catching four fish within a two-hour period.

Punishment (including negative effects of punishment) and ways to maximise effectiveness

The side effects of punishment include:- Aggression- Frustration- Avoidance learning

- Escaped learning- Learned helplessness- not decreasing the behaviour but teaching the child to be aggressive or to avoid the punisher- Sometimes being positive reinforcement or serving to satisfy the frustration of the punisher.

Punishment differs from negative reinforcement in that it aims to decrease the likelihood of the response occurring. It is the introduction of an unpleasant stimuli such as a hit or yell, whereas negative reinforcement is taking away the unpleasant stimulus to increase the probability of the response occurring.

Potential punishers are any consequences which might lead to a decrease in the response. Some consequences may be punishers for some people but not others. Side-effects of punishment include aggression, frustration, avoidance learning, escape learning and learned helplessness. The punishment may not decrease the behaviour at all but teach the child to be aggressive or avoid the punisher. Sometimes the punishment ends up being positive reinforcement or only serves to satisfy the frustration of the punisher.

Effective punishment should address the person's actions not the person's character. It should be related to the undesirable behaviour and it should consist of penalties or response cost (the removal of a reinforcer) rather than psychological or physical pain.

Elements in operant conditioning

Extinction - if the reinforcement ceases, the operantly conditioned response will disappear over time.Stimulus generalisation - when the organism responds to stimuli which is similar to the original stimulus. For example, if a pigeon has been operantly conditioned to peck a blue light by receiving food pellets whenever it does so, the pigeon may also generalise to other similar coloured lights. However, if other lights are increasingly different from the original light stimulus, the pigeon is less likely to peck at them.

Stimulus discrimination - when the organism learns which responses will be reinforced and which will not.Spontaneous recovery - when the extinguished response reappears after a rest period.Shaping - when the organism is reinforced for any response which moves towards the desired behaviour, e.g. rewarding your cat for any behaviour that relates to it using the kitty litter.Operant conditioning in practice

Animal training - The principles of shaping are used to teach animals certain behaviour. The animal is reinforced for any behaviour which moves toward the desired goal, as in animal training or training guide dogs.

Behaviour modification - Positive reinforcement and the withdrawal of reinforcement is administered to eliminate inappropriate behaviour and to teach new responses, i.e. modify behaviour. Token economies - A technique which rewards people for appropriate behaviour with tokens which can then be traded for privileges. For example, primary school children could be given gold stars as a reward for good behaviour which could then be traded in for certain privileges at the end of the week. These privileges could range from time on the class computer or extra play time.ELEMENTSCLASSICAL CONDITIONINGOPERANT CONDITIONINGRole of learnerPassiveActiveTiming of stimulus and responseReinforcement occurs before the responseReinforcement occurs after the responseNature of responseAutomatic; Involuntary Response (salivation)Depends on reinforcement (meat powder) being presentedVoluntary and Involuntary Reinforcement (food pellet) depends on response (press lever) being made