Most obsessions revolve aroud washing and checking- historically people died from living unhygenically- it became adaptive to wash several times a day. Checking may stem from living in environments with little protection from animals/climate.
Abed and de Pauw (1998)- obsessions are uncontrollable thoughts that produce strong aversive states. These thoughts are the product of the 'involuntary risk scenario generating system' which allows individuals to avoid harm without having to confront real life dangers. OCD involves over activation of warning signals.
Szetchman and Woody (2004)- most obsessions and compulsions revolve around the theme of safety/ security. We have a security motivation system designed to prevent dangers from turning into emergencies- eays…