Interaction of Separation Discomfort with kontact Comfort and Discomfort in the Dog

JOHN C . GURSKI Department of Psychology Fort Hays State University

Hays, Kunsas

KENNETH DAVIS J . P. SCOTT

Department of Psychology Bowling Green State University

Bowling Green, OIzio

This experiment concerns 2 issues: the time of onset of the process of social attachment in the dog, and the nature of the interaction between the emotion of separation distress and that caused by discomfort. The subjects were 48 puppies from 4 genetic backgrounds: beagles, Telomians, and their reciprocal F, hybrids. Puppies were divided into 4 groups and isolated for short periods under comfortable and uncomfortable conditions beginning at 3, 11, 17, and 25 days from birth. The dependent variable was distress vocalization during a 10-min period. Separation distress did not occur before 11 days and remained at a low level until 21 days, when it rose rapidly. The process of attachment is thus initiated in the transition period but does not reach a high level until some 2 weeks later. Interaction between the 2 kinds of affect is compatible and additive.

This paper forms part of a series of experiments designed to determine the nature of affective arousal caused by separation from familiar areas and individuals, and the nature of its interaction with other major sorts of affect. Within a framework of systems theory, emotions can be studied on 3 levels: (1) the subjective reports of internal sensations by human subjects; (2) the expressions of emotions as communicative interactions between members of a social system; and (3) the changes in physiological systems which accompany the above. In studying separation distress in the dog, we are limited to the latter 2 possibilities.

Separation distress responses in the dog, as elicited by the absence of familiar objects and/or places, are emotional responses that are not alleviated by most classes of psychotropic drugs (Scott, 1974), but are alleviated by contacts with humans and

Reprint requests should be sent to Dr. John C. Gurski, Department of Psychology, Fort Hays State University, Fort Hays, Kansas 67601, U.S.A.

Received for publication 21 January 1979 Revised for publication 9 April 1979 Developmental Psy chobiologv, 13(5):463-467 ( 198 0) @ 1980 by John Wiley & Sons, Inc. 00 12-1630/80/00 13-0463$01 .OO

464 GURSKI, DAVIS, AND SCOTT

conspecifics (Pettijohn, Wong, Ebert, & Scott, 1977). In studies where 2 affect-arousing conditions were varied independently, for example, hunger and separation (Scott & Bronson, 1964) and fear and separation (Davis, Gurski, & Scott, 1977), separation suppressed hunger-motivated behaviors, but fear of loud noises varied independently of separation distress. Fear of the strange follows an independent developmental sequence from that of separation distress (Freedman, King, & Elliot, 1961; Scott, Stewart, & De Ghett, 1974).

The response to separation, and the attachments to conspecifics and homesites which presumably underlie i t , develops within the 1st 4 weeks after birth (Elliot & Scott, 1961 ; Scott, Stewart, & DeGhett, 1973). In our attempts to determine the precise ontogeny of the response to separation we realized that several factors interact with it. One of these is physical discomfort in the testing situation: discomfort gives rise to vocalizations that could suppress or interact with a similar response to separation. Neonatal puppies spontaneously make contact with warm, soft objects, and prefer contact with such a surrogate over an uncomfortable wire one (Igel & Calvin, 1960). In our preliminary work on the present study we found that we could completely eliminate distress vocalization in puppies in the Neonatal Period by using a soft horizontal and vertical surface with which the subject could make contact, and a controlled temperature setting (approximately 30°C).

Method

The following conditions were used to determine the onset of the separation distress reaction when discomfort was not a confounding factor. The comfortable condition (C) was one in which the puppies were placed in a short vertical section of stovepipe, lined with disposable diapers which were discarded after each test in order to keep the area free from odors, and situated in a ventilated incubator with partially soundproofed walls and a thermostat set at 30°C. The incubator contained a microphone so that vocalizations within it could be clearly heard through earphones by the experimenter. The diameter of the pipe was slightly larger than the body length of the puppies and was increased as they grew. The uncomfortable situation (U) was a modification of a standard 60-cm cubical box used for testing separation responses of older puppies and was used at room temperature (approximately 21°C). In this case, the floor was a sheet of aluminum and the walls were bare plywood. The apparatus was washed with a weak soap solution between each use to eliminate familiar odors. Minute-by-minute vocalizations during a 10-min trial were counted in both situations.

The subjects were 4 8 puppies (Canis familiaris) reared with mother and littermates under standard conditions, 12 each from 4 different genetic backgrounds: beagle, Telomian, and their 2 reciprocal F 1 hybrids. In each litter 1 puppy was assigned at random to each of 4 age groups. The age groups consisted of puppies whose testing began at approximately weekly intervals, as follows: 3 , 11, 17, and 25 days from birth. These starting points were selected to lie respectively in the early and late parts of the Neonatal Period, middle of Transition Period, and 4 days beyond the assumed onset of the Period of Socialization a t 21 days, and tested the possible cumulative effects of experience as opposed to maturation.

Pups were tested every other day in order to allow recovery from fatigue and other

SEPARATION DISTRESS AND CONTACT COMFORT 465

110-

100

80 90: 70-

60-

50-

40-

30-

20-

10-

possible physiological effects due to testing. On test days, each puppy was tested in both conditions, the 2nd test never being run closer than 1 hr after the 1st test. The order of testing was reversed in each day and balanced between subjects.

N E o N A T A SOCIAL I Z A T l O N PERIOD PERIOD PERIOD

E Y E S F I R S T OPEN S T A R T L E

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Results

Vocalization in the uncomfortable condition started at a high level and rose steadily until approximately 21 days, when it reached a plateau. Vocalization in the comfortable situation remained at zero until 11 days; then it rose curvilinearly until Day 31 to approximately the same level as the uncomfortable situation (Fig. 1).

The data were analyzed in detail with an overall analysis of variance with repeated measures between conditions and over trials. Testing condition, age of testing, and age at which testing was begun were each overwhelmingly significant (p7s< .001), with various significant interactions reflecting changes with age in the 2 testing conditions. Also, breed differences in the U condition were significant, reflecting the fact that the hybrids vocalized at a higher rate than the purebred strains. A slight but nonsignificant difference appeared between the reciprocal hybrids, those with beagle mothers showing the higher rates. In general, genetic differences in the separation response tended to be minor compared with differences reported in other traits (Scott & Fuller, 1965).

From the viewpoint of the relationship between arousal due to discomfort and that due to separation distress, the experiment clearly indicates that these 2 phenomena are developmentally discriminable, in confirmation of previous evidence that the separation reaction forms an arousal or motivational system separate from all others (Davis et al., 1977).

AGE IN DAYS

Fig. 1. Mean vocalization rates over 2 test periods for the 4 experimental groups under 2 test conditions. -, uncomfortable. - - -, comfortable. 0 , 3 day; 0, 11 day; 0, 17 day; 0, 25 day.

466 CURSKI, DAVIS, AND SCOTT

100-

90 -

80 -

70 - W

C

- 6 0 -

(0

0

2 m

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5 0 - ._ - 8

30 -

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Age-Weeks

Fig. 2. Comparison of distress vocalization in all possible combinations of separation distress (S) and distress due to discomfort (U). When neither situation is present, vocaliation is zero. Ln the U - S condition (puppies weighed in home room in a different experiment), vocalization steadily declines toward zero as the puppies are able to stand and walk, thus making the situation less uncomfortable. In the U + S situation (mean data from present experiment) vocalizations increase from a base point a t 1 week to a near maximum at 3 weeks, presumably because of a combination (possibly facilitating) of separation distress and discomfort distress. The - U + S curve begins a t zero at 1 week, rises slowly through 3 weeks, and rapidly thereafter, conforming to previous data regarding the onset of the attachment process. 0 = U f S; = U - S; A = - U + S. Baseline = - U - S.

Discussion

These data give a more precise definition of the onset of the critical period for primary socialization in the dog than was previously possible. They reinforce the conclusion that no hgh degree of attachment occurs before 3 weeks of age and confirm the similar results obtained by Stewart and DeChett with less precisely controlled environmental conditlons (Scott et al., 1974). No evidence exists that attachment takes place in the Neonatal Period. Slight amounts of separation distress appear in the Transition Period, indicating that attachment is proceeding at a low level. The maximum degree of separation distress appears only in the 5th week, which other experiments (e.g., Cairns & Werboff, 1967) indicate is a time when very rapid attachment takes place.

The chief limitation on this experiment is that it makes no distinction between site attachment and social attachment, processes that appear to take place simultaneously in the dog. Presumably the separation distress reaction that appears at approximately 2

SEPARATION DISTRESS AND CONTACT COMFORT 467

weeks of age is the result of a combination of separation from familiar places and familiar individuals, as had been previously demonstrated as early as 3 weeks (Elliot & Scott, 1961).

With respect to the interaction of social and site attachment in the dog, the next step in this series of experiments would be to subject the pup to similar discomfort without separating it from the familiar environment. Some earlier, less well-controlled observations (Scott & Fuller, 1965), on pups weighed weekly resting on a cool metal surface of a platform balance in its home room, when superimposed on data gathered in the present study (Fig. 2), indicate that vocalizations due to discomfort decline as those due to separation increase, producing the combined curve seen in U condition of this study. We conclude that the interaction between the 2 kinds of affect is compatible and roughly additive. These results again confirm separation distress as a distinct and important form of affective arousal.

Notes

Research reported in this paper was supported by Grant HD-03778 from the National Institute of Child Health and Human Development, National Institutes of Health.

References

Cairns, R. B., and Werboff, J. A. (1967). Behavior development in the dog: An interspecific analysis. Science, 158: 1070-1 072.

Davis, K. L., Gurski, J. C., and Scott, J. P. (1977). Interaction of separation distress with fear in infant dogs. Dev. Psychobiol., 10: 203-212,

Elliot, O., and Scott, J. P. (1961). The development of emotional distress reactions to separation in puppies. J. Genet. Psychol., 99: 3-22.

Freedman, D. G., King, J . A. , and Elliot, 0. (1961). Critical period in the social development of dogs. Science, 133: 1016-1017.

Igel, C . J . , and Calvin, A. D. (1960). The development of affectional responses in infant dogs. J. Comp. Physiol. Psychol., 53: 302-305.

Pettijohn, T. F., Wong, T. W., Ebert, P. D., and Scott, J . P. (1977). Alleviation of separation distress in three breeds of young dogs. Dev. Psychobiol., 10: 373-381.

Scott, J. P. (1974). Effects of psychotropic drugs on separation distress in dogs. Excerpta Med. Inr. Congr. Ser. No. 359, 1974, 735-745.

Scott, J. P., and Bronson, F. H. (1964). Experimental exploration of the et-epimeletic or care-soliciting behavioral system. In P. H. Leiderman and D. Shapiro (eds.), Psychobiolugieal Approaches ro Social Behavior. Stanford, California: Stanford University Press. Pp. 174-193.

Scott, J. P., and Fuller, J. L. (1965). Genetics and the Social Behavior of rhe Dog. Chicago: University of Chicago Press.

Scott, J. P., Stewart, J , M., and DeGhett, V. J. (1973). Separation in infant dogs: Emotional and motivational aspects. In E. Senay and J. P. Scott (eds.), Separation and Depression. Washington, D.C.: American Association for the Advancement of Science. Pp. 3-32.

Scott, J. P., Stewart, J. M., and DeGhett, V. J. (1974). Critical periods in the organization of systems. Dev. Psychobiol., 7: 489-51 3.