McCord, F. (1939). The delayed reaction and memory in rats. I. Length of delay. Journal of Comparative Psychology, 27(1), 1-37.
http://dx.doi.org/10.1037/h0055212
The animals were first trained to jump from a square platform to each of four boxes, one of which appeared opposite each side of the platform. The door of each box was hinged from above so that when the rat jumped against it he had access to the food within. Incorrect doors were locked. Each door contained a different black and white figure. The stimulus used to elicit jumping was presentation of a small pan of food through the correct door. After an animal had learned to jump toward the door in which it had seen food, an enclosure like a bird cage was used to prevent jumping prior to delay periods. The periods were 7, 15, and 30 seconds and 1, 2, 4, 6, and 8 minutes. The percentages of correct responses at these delays were, respectively, 68, 67, 81, 82, 64, 78, 67, and 32. The mean times taken to respond after release were, respectively, 34.0, 32.3, 6.0, 9.5, 10.7, 19.7, and 40.1 seconds. Behavior during delay did not involve fixed orientation. Response to the absent differential cues is believed to be centrally controlled. Bibliography. (PsycINFO Database Record (c) 2016 APA, all rights reserved)