928). Experimental tests of preparedness theory supports this notion with studies comparing fear conditioning with pictures of snakes and flowers serving as Conditioned stimuli's (CSs) (Öhman, Fredrikson, Hugdahl and Rimmo, 1976). It was reported that different stimuli affected CSs differently with a group conditioned to fear-relevant stimuli, snakes and spiders, showed greater resistance to extinction than a group conditioned to fear-irrelevant stimuli, that is, flowers and mushrooms (p.313). According to McNally and Reiss (1982) fear conditioning with fear-relevant stimuli such as snakes differs in three different ways than for fear conditioning with fear-irrelevant stimuli such as flowers. Fear of the snake should be acquired more rapidly, the fear should be more resistant to extinction and as well as more resistant to cognitive influences such as instructions that the CS no longer will follow the US (McNally, 1989, p. 283). .
Rachmen (1977) and Seligman (1971) have noted important differences between phobias and fear responses conducted in laboratory settings by conditioning. Thus, phobias are assumed to be capable of rapid, one-trial acquisition compared to laboratory Conditioned Responses (CRs) which develop across a number of trials (Siddle, Power, Bond and Lovibond, 1988, p. 179). Seligman (1971) proposed that the unequal dispersion of human fear can be understood in terms of biological predispositions so that (CSs) are either prepared, unprepared, or contra prepared for fear conditioning. The relative preparedness of an organism varies considerably on a continuum for classical conditioning. If an organism acquires a fear response consistently from the first pairing of the CS, this represents a clear instinctive response, indicative of the extreme end of the preparedness continuum. If a fear response after only a few pairings is established, the organism is somewhat prepared and if the fear response emerges after many pairings the organism is unprepared.
