Other theories, such as biological and evolutionary, will also be taken into account, as conditioning theory is criticised for a number of reasons. Psychologists have suggested phobias develop as a consequence of conditioning, and many phobics can remember a specific episode which caused the onset of their phobia (Freud, 1909; Ost and Hugdahl, 1981). However, research suggests it is not necessary for a specific episode to occur to change behaviour. Kirsch et al (2004) studied rats in a maze.
They were left to explore before food was introduced, at which point errors in the rats' route through the maze were reduced significantly. This suggests the rats learned to navigate when they were not reinforced for learning, and they formed cognitive maps without reinforcement. This evidence of latent learning suggests learning can occur without classical conditioning. Davey (1992) also found many phobics do not remember a particular aversive conditioning episode, claiming they have had their phobia since they could remember.
This suggests their phobia may have developed without conditioning. Instead there may be, for example, a biological aspect of developing phobias. There are certain phobias, such as for snakes and spiders, which are more common than others. Mineka and Ohman (2002) suggested primates and humans can quickly associate these objects with frightening events because they have evolved to do so; these objects posed a threat to their ancestors.
To support this evoluntionary theory, Cook and Mineka (1989) exposed monkeys to various objects, and found they easily acquired new fears of toy snakes and crocodiles, but did not develop fears of flowers. They suggested this is because they had no prior exposure to flowers in a frightening episode. While this research may still suggest conditioning theory is a factor in the development of phobias, as the primates still learnt to fear the object, evolution may also be a factor of phobia development.