PARENTAL BEHAVIOR 



1351 



stimulation at the same locus will induce 

 the same kind of behavior, and whether 

 stimulation by the same substances at dif- 

 ferent loci will induce different kinds of 

 behavior. A suggestive indication is found 

 in the paper by Fisher (1956) who found 

 that injection of the same testosterone salt 

 into different hypothalamic loci would re- 

 sult, in some cases, in maternal behavior, 

 in other cases in sexual behavior. Obviously, 

 we must be cautious about interpreting the 

 available data on central effects of hormones 

 as if they demonstrated the existence of 

 different "centers," each specific for a par- 

 ticular behavior pattern, and each selec- 

 tively sensitive to a particular kind of 

 humoral influence. 



Evidence from the effects of brain lesions 

 on various types of motivated behavior, and 

 on the effects of various drugs (reviewed 

 by Miller, 1957a, b; Hinde, 1959) indicate 

 that some treatments appear to have dif- 

 ferent effects upon a "motive state," de- 

 pending on how the state is measured. For 

 example, some lesions in the hypothalamus 

 increase the amount of food consumed, 

 whereas they decrease other measures of 

 "hunger," such as the rate at which the 

 animal will press a bar in order to get food. 

 As Hinde (1959) has pointed out, this sug- 

 gests the need for caution in interpreting 

 evidence that behavior is both motivated 

 and organized in centers specific for the 

 behavior patterns. 



An additional reason for reserve in in- 

 terpreting the effects of hormones upon 

 "centers" lies in the fact that the sen- 

 sitivity and activity of peripheral sense 

 organs may often be affected by centrifugal 

 influences from the central nervous system 

 (Granit, 1955) , and thus that humoral fac- 

 tors influencing the activity of central struc- 

 tures may nevertheless be influencing the 

 character of the behavior by a process 

 which includes peripheral contributions 

 (Lehrman, 1956a; Prechtl, 1956). Although 

 this does not mean that the hormones are 

 not themselves acting on a central state, 

 it does mean that the behavior resulting 

 from the change in the central state is not 

 necessarily organized within, or "emitted" 

 from, the "center." 



4. The Importance of Behavioral Analysis 



Proper definition of the behavior varia- 

 bles which are influenced by hormones re- 

 quires a careful analysis of the organization 

 of the over-all behavior pattern of the ani- 

 mal as a prerequisite to studying the be- 

 havioral effects of various hormone treat- 

 ments. For example, in some birds, such as 

 the black-headed gull (Moynihan, 1953) 

 and herring gull (Baerends, 1959) a good 

 deal of nest-building often occurs as a "dis- 

 placement activity," when the birds are 

 disturbed on the nest by extreme egg tem- 

 peratures, eggs abnormal in size, shape, or 

 number, and other disturbances at the nest. 

 Since, as I have pointed out, the endocrine 

 condition during the pre-ovulation nest- 

 building period and that during the incuba- 

 tion period are quite different, nest-building 

 during the incubation period may have a 

 very different physiologic basis from that 

 during the normal period of nest-building. 

 If analysis of the behavior had not itself 

 revealed differences in the way in which 

 building takes place at these two periods, 

 the undifferentiated statement that "nest- 

 building" takes place at both of these periods 

 would lead to confusion in the analysis of 

 the hormonal basis of the behavior. 



Courting male canaries sometimes dangle 

 a piece of string or cotton before the fe- 

 male. Behavior of this type is sometimes 

 referred to as "incipient nest-building" 

 in the ornithological literature. Shoemaker 

 (1939) found that female canaries injected 

 with testosterone propionate postured like 

 courting males, and also engaged in this 

 string-carrying behavior, reminiscent of the 

 carrying of nesting material. Such birds 

 did not, however, build nests. In this case 

 the nest-building-like behavior of court- 

 ship, and real nest-building, are quite dif- 

 ferently affected by hormones. 



These examples show that a clear under- 

 standing of the organization of the behavior, 

 based on an analysis of the over-all be- 

 havior pattern, is an important prerequisite 

 for analysis of hormonal effects upon be- 

 havior. Simple counts of "carrying nest ma- 

 terial," or "nest-building behavior," and 

 studies of the effects upon such counts of 

 hormone injections, could lead to mislead- 



