The present experiment was devised to investigate the thesis that the behavior of any animal is the resultant of his drives to action and the opposing resistances. Observation of the behavior of the rats under these conditions showed, among other things, that in general a resistance may be overcome by increasing the strength of the drive, that a 72-hour hunger drive will overcome a 28-volt resistance; that the sex drive is weaker than the hunger drive and stronger than the maternal drive; and that a drive that is weaker than the resistance may be strengthened by other drives until it overcomes the resistance. From these observations the writer proposes the following general theses. (1) Any animal drive may be measured in terms of the resistance overcome or the resistance may be measured in terms of the drives, depending on which is known. (2) Any drive that succeeds is stronger than the resistance overcome, and any drive that fails is not as strong as the resistance. (3) Given two drives, both functioning at the same time, and so arranged that neither can succeed without neglecting or overcoming the other, the one that succeeds is the stronger drive. (4) When one drive by itself is not strong enough to overcome a resistance, it may be reinforced by other drives, until it is strong enough to overcome the resistance. (5) That drive is strongest which causes the animal to learn the problem in the shortest time and with the fewest errors. (6) Other things being equal, every time a resistance is overcome, the strength of that resistance is weakened. (7) The combined results of these experiments seem to substantiate the basic thesis that the behavior of any animal is the resultant of his drives to action and the opposing resistances. From Psych Bulletin 22:05:00533. (PsycINFO Database Record (c) 2006 APA, all rights reserved)