178 



HORMONAL REGULATION 



1956, 1958), Soulairac (1952a-c), and 

 Baerends, Brouwer and Waterbolk (1955). 

 Not unrelated is the organic separation of 

 activities associated with courtship and 

 spawning which Clark, Aronson and Gor- 

 don (1954) felt may exist in the fishes they 

 studied. 



Nissen, obviously influenced by Moll 

 (1897) and Gerhardt (1924), divided sexual 

 "drive" into two behavior sequences, a con- 

 trectation drive which brings animals into 

 the proximity of the sex object and, in rats, 

 leads to nosing of the genitalia, gentle bit- 

 ing, and other sex play, and a detumescence 

 drive which culminates in coitus. 



Beach postulated that one of the two 

 mechanisms is "erotic sensitivity" or the 

 "susceptibility to sexual arousal." He 

 thought of the arousal mechanism as being 

 organized and functional in sexually inex- 

 perienced animals. It can be "conditioned" 

 to a variety of nonsexual cues. "In male 

 rats, cats, and dogs," he writes, "sexual 

 arousal can be conditioned to new cues, but 

 there is no evidence that females are simi- 

 larly affected by experience." The sexual 

 responsiveness of male primates is more 

 labile and modifiable than that of male 

 rodents and carnivores, and female primates 

 differ from the females of lower species in 

 that the arousal mechanism can be affected. 



The other function is that of "potency" 

 or the "capacity for sexual performance" 

 ("mating responses" in Beach, 1947). It in- 

 cludes "the promptness with which mating 

 is initiated, the frequency of copulation, and 

 the rapidity with which ejaculation occurs." 

 The function is mediated by what he calls 

 the "executive" or "consummatory mecha- 

 nism." It is thrown into action when sexual 

 arousal reaches a threshold level. He con- 

 tinues: "The functional organization of the 

 CM (consummatory mechanisms) is proba- 

 bly complete in inexperienced male and fe- 

 male rats, rabbits, dogs, and cats. The 

 motor pattern of copulation is stereotyped 

 and invariable, and is not materially altered 

 by experience." 



Development of the concept seems to have 

 followed observations on the copulatory 

 behavior of partially decorticate rats 

 (Beach, 1940, 1944b, 1956). There was a 

 proportional decrease in the percentage of 



tests in which copulatory behavior occurred, 

 but the number of copulations during each 

 positive test was not affected, even in the 

 lesion group in which the percentage of 

 postoperative copulators was lowest. As 

 Beach interpreted the results, there had 

 been a decrease in the ease of arousal to the 

 point of the practical abolition of copula- 

 tory behavior, but without an effect on the 

 actual copulatory pattern. 



Experiments on the guinea pig (Valen- 

 stein, Riss and Young, 1955) have also pro- 

 vided evidence for dual functions, excita- 

 bility, corresponding to susceptibility to 

 sexual arousal, and the capacity for re- 

 sponse corresponding to the capacity for 

 sexual performance and depending on the 

 existence of an organized neural pattern. 

 The suggestion originated from the observa- 

 tion that an occasional male will achieve 

 a complete copulation in only 1 or 2 of 10 

 tests with an estrous female, whereas in the 

 other tests he will give the appearance of 

 being generally indifferent. The capacity for 

 the sexual response exists, but the level of 

 excitability or arousal is so low that copula- 

 tion usually does not occur. Under other 

 conditions, excitability is shown, but no 

 organized pattern is present and the male 

 does not know how to copulate. Certain 

 males brought up under conditions of iso- 

 lation (see Table 19.3, groups II and IV) 

 display excitability, but they lack an or- 

 ganized pattern and copulation is not 

 achieved. In this respect the male guinea pig 

 resembles the ringdove (Craig. 1914) and 

 chimpanzee (Nissen, 1956) rather than the 

 rat (Beach, 1958). 



The place of the concept of duality of 

 function in the present context is especially 

 well indicated by Baerends, Brouwer and 

 Waterbolk (1955) in their discussion of the 

 structure of courting behavior of the male 

 guppy, Lebistes reticulatus. The terms "ap- 

 petitive behavior" and the "consummatory 

 act" introduced by Craig (1918) are used. 

 The former is variable in form and leads 

 the animal toward the external situation 

 necessary for evoking the consummatory 

 act which is rigid and stereotyped. Craig 

 reserved the term consummatory act for 

 the final activity of definitive behavioral 

 complexes and emphasized that after its 



