Conditioned taste aversions accompanied by geophagia: evidence for the occurrence of "psychological" factors in the etiology of pica.

A conditioned taste aversion procedure was used to produce an avoidance of saccharin by rats. In the first experiment, saccharin consumption was paired with cyclophosphamide in two conditioning trials during which the animals were permitted to engage in pica. In the second experiment, saccharin consumption was paired with lithium chloride in four conditioning trials during which the animals were not allowed to engage in pica. Conditioned animals in both experiments subsequently engaged in geophagia when presented with saccharin alone. The absence of geophagia in noncontingently poisoned and "sham" injected control groups indicates that the pica was due to the acquisition of a conditioned illness during the conditioning trials. In addition to providing a demonstration of "psychological" involvement in the etiology of pica, these results indicate that visceral conditioning may accompany the formation of conditioned taste aversions. It is suggested that if there is a relationship between infantile pica and adult drug addiction, a plausible mediational mechanism is that pica-prone and addiction-prone individuals are similar in possessing a high susceptibility to visceral conditioning.