Effect of different parameters of shock on tonic immobility

Four separate experiments were conducted with chickens to explore the effects of various parameters of electric shock on tonic immobility. Immobilizing subjects at varying times after the receipt of shock affected the duration of immobility only after delays of over 15 min. Duration of shock affected immobility differently, depending upon whether alternating current or continuous direct current was used. The effects of continuous dc, pulsating dc. and ac shock were also examined. The results were discussed in terms of shock onset-offset characteristics being an important consideration.