3 conditions of electric shocks of different intensities and frequencies administered during the imprinting experience were tested for their effects on chicks at 14, 18, 32, or 48 hr. after hatching. Experimental Ss followed significantly more than controls at 14 and 18 hr. if the shocks were either strong but infrequent, or relatively weak but much more frequent. Older chicks, however, followed significantly less under these 2 shock conditions. Strong and frequent shocks did not affect the amount of following in Ss at 14 hr., but seriously interfered with it at all later ages. The data, in light of the maturational state of the Ss, indicate that the performance of following is approximately an inverted U shaped function of the intensity of the neural activity associated with the administration of painful stimulation. (PsycINFO Database Record (c) 2006 APA, all rights reserved)