Investigated the relative efficiency of reward and punishment as methods of training. Six albino and black and white female rats were required to discriminate between 2 lights of different intensity. Some of the animals were punished with an electric shock for incorrect choices, and others were given milk-soaked bread as reward for correct choices. Results show that a combination of punishment and reward motives was more effective in bringing about visual discrimination in the rat than was either punishment or reward used alone. Punishment was more effective than reward in the rate of learning. (PsycINFO Database Record (c) 2006 APA, all rights reserved)