Motivation is seen as an internal state of an organism that drives it to behave in a certain way. The behaviour is seen to be goal directed. The clearest examples of this can be derived from the studies made by Cannon. Cannon (1932) developed a primary or physiological drive theory. This theory is associated with the concept of homeostasis, a term used to describe the stable equilibrium of body systems. Claude Bernard (1956) was the first to emphasis the importance of a constant internal environment to survival.
The internal environment of the body consists of such systems as the oxygen content of the blood, the concentration of nutrients such as glucose, the water balance and temperature. All of these systems can only fluctuate within narrow limits if health or even survival is to be maintained. As a system fluctuates from its stable state for reasons such as if we go out in the cold or use up a lot of energy, the body tries to restore homeostatic equilibrium through physiological and behavioural mechanisms.
For instance if we have not eaten for a while, we develop a body tissue need for food.
This leads to a drive to eat, and eating reduces the drive and restores homeostasis. This sequence is a simple example of behaviour motivated by a primary physiological drive aroused by a tissue need, and the whole class of motivated behaviours is represented by these homeostatic primary drives. Cannon’s drive theory has been developed to explain more complicated behaviours. In these models the behaviour is driven by an internal state of need. For example we go to work to earn money, which in turn buys us food, which satisfies our tissue need.
The simple picture of a tissue deficiency leading to a specific need, which in turn arouses appropriate behaviour, is very appealing and many experiments have been carried out to see if this is the case. However, most of these studies have been carried out on non-human animals. Therefore this area of study could be criticised for being unrepresentative and ridged. Some behaviours such as why rats eat saccharin cannot be explained by this model, as saccharin is a not a nutritious, but sweet tasting substance, which does not satisfy a primary tissue need.
Humans lead full and complex lives; some researches believe that our motivated behaviour cannot be compared to that of a non-human animal. In the past motivation has been divided up into extrinsic and intrinsic motives. With extrinsic motives you can identify a clear reward or incentive or reinforcement for the behaviour. Behaviourists have shown that almost any behaviour can be learnt on the basis of a reward. Other behaviours seem to have no obvious external reward and these are referred to as intrinsic motives. Humans have many behaviours without a strong link to physiology such as curiosity and manipulation.
However these drives are simply descriptions of the behaviour so in theory anyone could make up there own set of motives. Murray (1938) used his Thematic Apperception Test (TAT) to provide a more reliable set of motives. TAT consists of 20 pictures of people in various situations. The participant is asked to use their imagination to write a story about each picture. The stories are then analysed in terms of the types of motivation represented. From these analyses, Murray produces a set of 20 social motives, or psychogenic needs. These include achievement, affiliation, aggression, deference, nurturance, play, and understanding.
Murray’s list sounds convincing and is based on the TAT. However this itself is a projective test and relies on Murray’s own analysis. McClelland (1961) supported Murray’s motives. By using a rating scale, he measured achievement imagery in the stories that children write. McClelland’s work has given achievement more validity as one of the central human motives. However, McClelland’s work is not representative of the whole as it only takes into account children. Other motives in Murray’s list have not been studied in great detail and so lack a degree of validity.