Taste aversions to mother's milk: the age-related role of nursing in acquisition and expression of a learned association.

The development of taste aversion learning to novel cues contained in mother's milk was examined in rat pups. Pups receiving distinctive mild by experimenter-delivered oral infusions followed by toxicosis formed an aversion to the dam's diet. Robust aversions were learned as early as Day 10 and were retained for at least 11 days. When the same distinctive milk was obtained directly from a foster mother through nursing, however, only weanling-age pups (over 20 days) formed an aversion. X-ray analysis of nipple location in the mouths of suckling pups suggested that pups between the ages of 10 and 21 days receive milk at a similar tongue locus. Flavored milk was then delivered at specific time intervals in controlled quantities through tongue cannulas implanted at loci corresponding to the nipple position shown by the X-rays. Cannulated preweanling pups that were attached to a nipple during milk delivery failed to associate the taste cue with illness, whereas both preweanlings off the nipple and weanlings on the nipple acquired aversions to the taste cue in the milk. The evidence obtained in these experiments suggests that pups of all ages are incapable of expressing a taste aversion in a nursing situation and that preweanling pups in particular are also dificient in acquiring aversions within a suckling context. The inability of preweanling pups to acquire taste aversions in a nursing situation appears to result from a failure to associate taste cues with illness rather than a failure to detect taste cues obtained from a nipple.     

Generalized and specific expectancies: Sequential mediators of interpersonal behavior1

Two experiments confirmed sequential mediation of social interaction by investigating the effects of generalized expectancies on specific expectancies and the effects of specific expectancies on performance. Both experiments used a simulated tutoring task in which the subject took the role of tutor while a confederate took the role of student. In Experiment 1 subjects combined generalized expectancies about the effectiveness of certain tutoring responses with specific situational information to produce specific expectancies about the results of the tutoring responses under the experimental circumstances. Experiment 2 replicated this finding and showed that specific expectancies of the relative effectiveness of different responses influenced which response was performed more. Results were discussed in terms of cognitive motivation theory and social learning theory.     

An adolescent symptom checklist for juvenile deliquents

A rating instrument was developed to assess the personality functioning of problem adolescents who have a brief history of official delinquency. Subjects were 186 residents at a short-term diagnostic detention facility. The instrument that emerged from a factor analysis was tested for reliability, validity, and cross-situational generality. Two major orthogonal factors emerged, Apathy-Withdrawal (I) and Anger-Defiance (II). Each factor was found to be congruent with the corresponding dimension on behavior rating instruments that had previously yielded two orthogonal factors and that had been shown to be relevant to a large number of psychological and educational issues. Significant correlations between the factors and a series of global ratings measuring behavior and measures indicative of the frequency and seriousness of official delinquency provided further evidence of construct and discriminant validity as well as evidence of cross-setting consistency of personality functioning.     

The generality of learned helplessness in the rat

Two experiments were simultaneously conducted in which two different groups of 40 rats each were exposed to one of two different stressors. In both experiments half the subjects were pretreated with shock, half with underwater exposure. For each pretreatment stressor, half the subjects were allowed to escape, the other half were not. The experiments differed in the test task used. Approximately 24 hr after pretreatment, one-half the subjects from each pretreatment group received 20 water-escape trials in an underwater maze, the other half received 20 shock-escape trials in a two-way shuttle box. The subjects in each of the inescapable pretreatment conditions were slower to escape in the subsequent shock-escape and water-escape tasks when compared with subjects in the corresponding escapable pretreatment condition. The “learned helplessness” effect appeared to be no smaller when aversive stimuli were changed between pretreatment and test than when they remained the same.     

INCREASING EXTENDED CARE FACILITY RESIDENTS' ATTENDANCE AT RECREATIONAL ACTIVITIES WITH CONVENIENT LOCATIONS AND PERSONAL INVITATIONS1

Residents of extended care facilities generally exhibit a low level of attendance at recreational and therapeutic activities. Spatial arrangement of rooms, prompting, snacks, and small prizes have been suggested as factors that affect attendance. The present study examined the effects of an extensive system of prompts and the location of activity areas on the attendance of residents at a variety of activities. Twenty-six subjects were randomly selected from the ambulatory population of the facility. The first time each subject entered the activity room during the first 6 min of an activity session their name was recorded. Reliability measures were taken at 10 sessions, with a 95% mean agreement between observers. The variables examined were the amount of individualization of subjects (experimental group I: names announced versus experimental group 2: names not announced), room location (central or peripheral), use of names in announcements (activity only versus activity and group I names), and mode of announcement (PA system only versus PA system and in-person). A counter-balanced group design with repeated measures was used, with a randomly determined order of application of experimental treatments. An analysis of variance split plot 2.222 (Kirk, R. E. Experimental Design: Procedures for the Behavioral Science. Belmont, Ca.: Brooks-Cole, 1968.) of the level of subject attendance yielded significant main effects for room location, F(1, 24) = 5.47, p < 0.05, and type of announcement, F(1, 24) = 9.10, p < 0.01, and significant interactions for Individualization × Use of Names in Announcements, F(1, 24) = 5.57, p < 0.05, and Room Location × Mode of Announcement, F(1, 24) = 7.90, p < 0.01. The results indicate that using a centrally located room and announcement of resident names increases attendance at a variety of activities. The increased social and environmental interaction generated by activity attendance has potential therapeutic benefits for the residents involved. Furthermore, the kind of information reported here and by others should be taken into consideration by planners of a variety of group living facilities, ranging from nursing homes to residential treatment cottages.     

Anorexia and conditioned taste aversions in the rat

The present study examined whether or not certain anorexic agents produced flavor aversions. Rats showed comparable anorexia when injected with lithium chloride, ammonium sulfate, arginine·HCl, and d-glucose. Only lithium chloride produced a flavor aversion to either a novel liquid or food. Only arginine was found to interfere with the formation or recall of an association. The effects of the other chemicals were discussed in terms of the relationship between anorexia and induced sickness.     

Group participation and intergroup relations: An experimental study of negotiation groups

Negotiations were conducted to investigate the effects on settlement-points andon the attitudes and perceptions of participants of (i) group participation and (ii)belief in own group's point of view, in a 2 × 2 factorial design. Ninety-six school children prepared cases in groups of four before representing their group's position against an individual of a similarly prepared opposed group. Group participation was manipulated by groups either participating in preparatory discussions or observing video films of another group's discussions. Belief was manipulated by systematically varying the composition of groups according to scores on a pre-test of attitudes towards the raising of the school-leaving age. In general the belief manipulation operated as expected, ‘believers’ exhibiting less variability, more tit-for-tat agreements and less opinion change than the ‘disbelievers’. Group participation did not influence the measures as predicted, and measures of interpersonal perception did not conform to the pattern of findings in recent experiments on intergroup discrimination. The results are discussed in terms of (i) their relevance to the issue of the appropriate relationship of the representative to his group in a negotiation and (ii) their implications for intergroup relations theory.     

A comfortable attachment for a thermistor respiration transducer

The construction of a simple thermistor respiration-transducer support assembly, which allows the monitoring of respiration in human subjects without the discomfort often associated with more traditional attachment methods, is described.