Food-deprivation effects on punished schedule-induced drinking in rats.

Food-deprived rats (at 80% of their free-feeding weights) were exposed to a fixed-time 60-s schedule of food-pellet presentation and developed schedule-induced drinking. Lick-dependent signaled delays (10 s) to food presentation led to decreased drinking, which recovered when the signaled delays were discontinued. A major effect of this punishment contingency was to increase the proportion of interpellet intervals without any licks. The drinking of yoked control rats, which received food at the same times as those exposed to the signaled delay contingency (masters), was not consistently reduced. When food-deprivation level was changed to 90%, all master and yoked control rats showed decreases in punished or unpunished schedule-induced drinking. When the body weights were reduced to 70%, most master rats increased punished behavior to levels similar to those of unpunished drinking. This effect was not observed for yoked controls. Therefore, body-weight loss increased the resistance of schedule-induced drinking to reductions by punishment. Food-deprivation effects on punished schedule-induced drinking are similar to their effects on food-maintained lever pressing. This dependency of punishment on food-deprivation level supports the view that schedule-induced drinking can be modified by the same variables that affect operant behavior in general.     

Persistent crying and parenting: Search for a butterfly in a dynamic system

The risks and causes of persistent crying in early infancy are discussed on the basis of a study of 61 infants referred to the Munich Interdisciplinary Research and Intervention Program for Fussy Babies for persistent crying between 1 and 6 months of age, and of a community sample of 51 infants of the same age. Particular attention was paid to pre-verbal parent-infant communication, the development of which was interpreted in terms of a dynamic interactional system including both regulatory and communicative predispositions in infants and intuitive competence for supporting infant predispositions in parents. Neither a gut problem nor any other single causal factor was identified for persistent crying in the majority of cases. In contrast, persistent crying was significantly associated with multiple biological and psychosocial risk factors for both parents and infants. Neurological immaturity, difficult temperament and sleep problems in infants, and impaired psychological conditions, limited resources and failures of intuitive competences in mothers were found to threaten the developmental process in infants and give rise to ‘vicious circles’ which were destabilizing the interactional systems. Increased attention to intuitive parental competences is recommended as one effective model for therapeutic interventions.     

Infants' sensitivity to arbitrary object-odor pairings

The ability of 4-month-old infants to learn the arbitrary relationship between an object and a distinctive odor was assessed. Infants were familiarized with two objects while one of them was paired with a cherry odor. Results indicated that only female subjects showed evidence of matching. They increased their looking to the target object in the presence of the odor but not in the absence of the odor, relative to baseline levels.     

Communication in preterm infants: Why is it different?

The present paper selectively reviews the literature which compares full-term and preterm infants' communication with their mothers in the first year of life. The review is focused not only on what differences are found between full-term and preterm infants, but also why such differences exist. Particular emphasis is placed on the importance of interpreting the findings in the light of the developmental phase of the infants, the heterogeneity of the preterm population and the situation in which communication is studied. Most studies were not designed to consider these issues in any detail. Differences with respect to these factors can be found between studies, however, which may have contributed to the often contradictory findings. Consequently, comparisons between these studies provide clues about the effects of these factors on communicative development. The ultimate goal of this review is to point to important directions for future research on early communication in preterm infants.     

Beyond the relational principle of reinforcement

Behavior under baseline conditions in which the contingency is absent can shed some light on the individual's performance under a schedule, but is insufficient as a basis for prediction of performance. This insufficiency of the baseline data runs counter to a recent formalization of the relational principle of reinforcement (Donahoe, 1977). A more satisfactory predictive model must incorporate not only the baseline level of the instrumental response and that of the contingent response, but also the schedule requirements, the character of each response in relation to the other, and the behavior required in simply switching from each to the other.     

Food deprivation induces conspecific pup-killing in mice

Periods of 24 to 48 hours of food deprivation reliably induced pup-killing in 30–50% of non-killer male mice. The behavior was prevented by previous experience with young and did not perseverate to non-deprived states. Castrated males and intact females also exhibited pup-killing following food deprivation, suggesting that the behavior is neither sexdependent nor related to the presence of testosterone. The findings are discussed in terms of their relationship to predatory behaviors and population dynamics.     

城镇化进程中离乡农民心理健康特点调查及心理素质、相对剥夺感的影响机制

为探讨城镇化进程中离乡农民的心理健康特点以及心理素质、相对剥夺感对其的影响,通过量表对1339名城乡居民进行调查。结果发现:离乡与留乡农民在幸福感、拥有生命意义感、感知控制感、心理素质方面显著低于城镇居民,在状态焦虑方面显著高于城镇居民; 离乡农民在抑郁上显著高于城镇居民,在感知控制感上显著高于留乡农民,在心理素质上显著低于留乡农民; 留乡农民在相对剥夺感上显著高于城镇居民; 离乡农民的幸福感、拥有生命意义感、感知控制感态与相对剥夺感呈显著负相关,与心理素质呈显著正相关; 离乡农民的抑郁、状态焦虑与相对剥夺感呈显著正相关,与心理素质呈显著负相关; 离乡农民的相对剥夺感与心理素质之间呈显著负相关。心理素质除了可以直接预测心理健康各项指标,还可以通过相对剥夺感的中介作用,间接预测幸福感、抑郁及状态焦虑。提升心理素质和降低相对剥夺感是离乡农民心理健康服务的重要切入点。     

婴儿面孔偏好理论模型述评

在婴儿早期的视觉经验中,面孔是最特殊的一类刺激,小婴儿从出生开始就喜欢看面孔,这种现象称为面孔偏好。面孔偏好的发展反映了婴儿知觉能力的发展规律,具有重要的社会化意义。该文系统介绍了线性系统模型、右脑优势模型、CONSPEC理论、视觉模块理论和非特异化识别理论5种最主要的婴儿面孔偏好理论,并对这些理论的区别和联系进行了探讨。最后,对面孔偏好研究的新趋势和未来方向进行了评价和展望