Running speed as a function of deprivation period and reward magnitude.

It has been recognized for a considerable period of time that one of the critical experimental variables in determining response strength in instrumental reward conditioning is magnitude of the reward object (WK). Several investigators (Crespi, 1942; Czeh, 1954; Zeaman, 1949) have found that, within limits, response strength increases as magnitude of the goal object increases. Most of the theoretical interest in this particular independent variable has been generated by its use as one of the defining operations for the incentive motivation factor (K) employed by such theorists as Hull (19S2) and Spence (1956). Another variable which has been found to exert significant systematic effects in such conditioning situations is time of deprivation (TC|). A number of studies (Horenstein, 1951; Kimble, 1951; Strassburger, 1950; Yamaguchi, 1951) have reported that, in general, response strength increases as deprivation interval is lengthened up to some maximal point, beyond which response strength declines. Again, Hull and Spence, in particular, have employed the deprivation operation as one of the conditions defining the theoretical construct of generalized drive (D). The present, study was undertaken in an attempt to determine the manner in which the D and K factors combine or interact in determining performance. In particular, the present research, employing running speed in a straight alley as the response measure, studied the effects of varying jointly three levels of incentive magnitude, 0.1, 1.0, and 2.0 gin. of food with three periods of food privation, 3, 22, and 44 hr.