Aetiology of spider phobia: classificatory differences between two origins instruments

The origins of fear of spiders was investigated in 33 spider phobic Ss entering a treatment study. All Ss completed Menzies and Clarke's (1993a) Origins Questionnaire (OQ) (Behaviour Research and Therapy, 31, 355-365) and Ost and Hugdahl's (1981) Phobic Origins Questionnaire (POQ) (Behaviour Research and Therapy, 19, 439-447). The results for the individual questionnaires were similar to those reported in previous studies. However a comparison of assignments of origin category for the two questionnaires showed widely discrepant results. The POQ returned 17 positive responses for classical conditioning, the OQ only 2. By contrast the OQ returned 10 origins as 'non-conditioning traumatic event', 9 of which returned positive responses for classical conditioning on the POQ. A further 15 Ss on the OQ were categorised as 'always been this way', the preponderance of these being classified as vicarious or informational in origin on the POQ. The POQ does not have a specific question or category for non-associative acquisition of phobias. The results of the origins assignments are detailed and their relation to the structure and questions of the questionnaires is outlined. Past studies using the POQ have produced results supporting acquisition of a substantial proportion of phobias by classical conditioning. The findings of this study suggest that such results mainly reflect inherent bias in that instrument.