Parallel experiments with rats and pigeons examined whether the size of a pre-trial ratio requirement would affect choices in a self-control situation. In different conditions, either 1 response or 40 responses were required before each trial. In the first half of each experiment, an adjusting-ratio schedule was used, in which subjects could…

In comments addressed to the Annual Convention of the American Psychological Association, Miami Beach, 1970, the author proposes that two levels of communication exist between the experimenter and his subjects: (1) the overt or the expected response and (2) the covert level or the guessed intent of the experimenter. (BY)