The early work of Richard Solomon and his colleagues provides
an elegant, yet often overlooked, animal behavioural
model of OCD (6), Solomon and others worked with dogs in
shuttle boxes (which were small rooms divided in 2 by a hurdle
over which the animal could jump). Each half of the shuttle
box was separately furnished with an electric grate that could
be independently electrified to give the dog an electric shock
through its paws. In addition, a light served as a conditioned
stimulus. The procedure for producing the compulsive rituallike
behaviour was to pair the light with an electric shock (the
shock occurred 10 seconds after the light was turned on). The
dog soon learned to jump into the other compartment of the
shuttle box, which was not electrified, once he had received
the shock. After several trials, the dog learned to successfully
avoid the shock by jumping to the nonelectrified compartment
in response to the light (that is, within 10 seconds). In other
words, the experimenter produced a conditioned response to
the light, namely, jumping from one compartment ofthe box
to the other.