Avoidance of electric shock by the cockroach Periplaneta americana

Horridge's demonstration of learning by cockroaches based on leg position, evaluated against results for animals receiving non-contingent shocks, has been confirmed. Confirmation was also obtained that animals that have received a period of non-contingent shocks are subsequently unable to learn when shocks are made contingent to responses.In a study of shock currents varying from 20 to 60 αA in 20-αA steps, it was found that learning deteriorates approximately linearly with increasing shock intensity.A prediction based on neurophysiological findings of Hoyle to the effect that animals should learn at least equally well to adopt the opposite leg position from that used in the first experiment was found to hold true.