What contributions have different perspectives in psychology?

There are many approaches in psychology. An approach is a perspective that is not as clearly outlined as a theory and 'provides a general orientation to a view of humankind (coolican et al., 1996 as cited in Alberry et al., 2008:15).
The three major approaches chosen in this essay are the behaviourist, the humanistic and the cognitive approach.
Behaviourism changed the subject of psychology from mind to behaviour and emphasised the importance of the environment in shaping behaviour. Behaviourism explained behaviour in terms of associations made by stimuli (S) and responses (R) through interaction with the environment.
There are two main theories of learning: classical conditioning and operant conditioning. The theory of classical conditioning is based on the work of Pavlov. Pavlov noted that dogs salivate (Unconditioned response/UCR) when they see food (unconditioned stimulus/UCS). Before conditioning, the taste of food will naturally and automatically make the dog salivate, but the sound of the bell wont. He attempted to provoke salivation (UCR) with an alternative stimulus. To achieve this, Pavlov sounded a bell whenever food was presented. If the bell and food were paired often enough, the dog started to salivate as soon as it hears the bell and before the food is present. The salivation is now referred to as a conditioned response (CR), because it is produced by the bell which is a conditioned stimulus (CS). Over time the bell became a trigger for salivation, even when no food was present. (continued on chapter 8, (Alberry et al., 2008).
In 1920, Watson and Rayner succeeded in deliberately producing a phobia of rats to a boy called Albert, in the case of little Albert. Watson striked a hammer on a four foot piece of steel behind Albert's head as he was stroking a rat. This occurred several times in total over the seven weeks. The rat which was the CS frightened Albert and the fear was now a CR. (GROSS book). This study has benefited people with phobias by modifying behaviour from behaviour therapies including desensitization. It is unclear whether Watson and Rayner intended to remove Albert's phobia; what's certain is that his mother removed him before this could happen. They might have attempted to remove it through the method of 'direct unconditioning', as used by Jones (1924), (Gross, R.,2010).
The theory of operant conditioning (or instrumental conditioning) is about the organism operating in the environment to produce an outcome. If someone or somebody was to do something and the outcome was positive then there is a greater chance they will do it again. Skinner was instrumental in shaping behaviourism and put forward the view that behaviour followed laws. Skinner investigated this by training rats to press a lever in exchange for food and found that rewarding an action increased the likelihood of that action being performed; called positive reinforcement. The opposite of positive reinforcement is negative reinforcement whereby a punishment, such as an electric shock,reduces the likelihood of an action occurring, (Alberry et al., 2008).
Operant conditioning has proven an effective way of modifying behaviour amongst people who may be difficult to teach in another way such as children who have autism.
Thorndike (1898), put a cat in a cage with a latch on the door. Cat food was placed outside the cage. The task was to operate a latch that would automatically cause the door to spring open, freeing them. As the cat was attempting to get the food he accidentally knocked on the latch which opened the cage door. After the cat had eaten the food the process was repeated where it took them less time to open the latch to gain access to the food. The behaviour exhibited by the cat was strengthened by its relationship with reward. Thorndike referred to this as 'the law of effect.' This is a crucially important way of distinguishing classical and operant