Discrimination of polymorphous stimulus sets by pigeons

Pigeons were trained to perform a visual discrimination between stimulus sets in which the presence of any two of three positive features made a stimulus positive, while any two of three negative features made it negative (there were thus three different positive and three different negative stimuli). After training, the birds were exposed to test stimuli that contained either all three positive or all three negative features. In Experiment I three pigeons were successfully trained by a successive method, and subsequently responded to the test stimuli as though they were positive or negative respectively. In Experiment II four pigeons were trained by a simultaneous method. Three learned the discrimination and generalized appropriately to the test stimuli, but they showed no preference between positive test and positive training stimuli, nor any consistent difference in speed of response to them; and similar results were found for negative stimuli. It is argued from this that the pigeons learned to respond to the stimuli as patterns (configurations of features) rather than to the constituent features, but that they generalized to the test stimuli by using the common features. The experiments show that pigeons could in principle learn to discriminate natural polymorphous classes (such as “pigeon” or “person”) without using any single feature, but neither the present experiments nor earlier ones demonstrating discriminations of such natural classes establish that pigeons make use of polymorphous concepts in the same way as people.     

Postpartum feeding attitudes, maternal depression, and breastfeeding in Barbados

Maternal feeding attitudes, maternal moods and infant feeding practices during the first 6 months postpartum were assessed in 226 healthy, well-nourished Barbadian mother-infant dyads. Factor analysis of the feeding attitudes questionnaire resulted in six independent factors. The belief that breastfeeding was better than bottle-feeding was associated with higher family income, more information seeking behavior and older maternal age at the time of her first pregnancy. Women who believed that breastfeeding was better at 7 weeks postpartum were also more likely to breastfeed at concurrent and later ages, up to 6 months postpartum. This belief was also associated with less maternal depression at 7 weeks and 6 months. The association between feeding attitudes and actual feeding practices was significant even after correcting for maternal moods and other background variables. Conversely, after controlling for feeding attitudes, maternal mood at 7 weeks was still significantly associated with infant feeding practices at 6 months. Thus, feeding attitudes and maternal moods were closely linked, but each contributed independently and uniquely to different aspects of breastfeeding, especially at 6 months. These findings suggest that early intervention addressing maternal feeding attitudes, may improve the extent of breastfeeding and the health of children in this setting.     

Bed-sharing, breastfeeding and maternal moods in Barbados

Bed-sharing among Barbadian mothers and infants was studied in relationship to maternal and infant characteristics. This prospective study followed 226 healthy, well-nourished mother–infant dyads at birth, 7 weeks, 3 months, and 6 months postpartum. At each age, approximately half of the infants shared the same beds as their mothers. Bed-sharing was associated with demographic characteristics, especially fewer home conveniences, and also maternal characteristics, including less information seeking by the mother and younger maternal age at first pregnancy. Bed-sharing was also associated with lower infant birth weights. Maternal moods were significantly correlated with bed-sharing, such that mothers who reported having more despair and anxiety were also more likely to sleep with their infants. Bed-sharing was also significantly associated with increased breastfeeding at all infant ages, but this relationship was no longer significant once the effects of maternal moods were controlled. This study emphasizes the importance of assessing maternal moods in studies evaluating the risk and benefits of bed-sharing.     

Proactive personality and the successful job search: a field investigation with college graduates

The current article tests a model of proactive personality and job search success with a sample of 180 graduating college students. Using structural equation modeling, the authors tested a theoretical model that specified the relations among proactive personality, job search self-efficacy, job search behaviors, job search effort, and job search outcomes. Job seekers were surveyed at 2 separate points in time, once 3-4 months prior to graduation and once 2-3 months following graduation. The results suggest that proactive personality (a) significantly influenced the success of college graduates' job search, (b) was partially mediated through job search self-efficacy and job search behavior, and (c) was independent of self-esteem and conscientiousness. The findings are discussed in terms of their general implications for understanding the nature of the process through which distal personality factors, such as proactive personality, affect the nature and success of an individual's job search.     

You can take it with you: individual differences and expatriate effectiveness

The authors report the collaborative efforts of 2 research teams that independently investigated the effects of stable personality traits (the Big Five) and specific behavioral competencies (cultural flexibility, task and people orientations, and ethnocentrism) on key dimensions of expatriate effectiveness: psychological adjustment, assignment withdrawal cognitions, and job performance. Analyses of multiple-source and longitudinal data from 3 studies, including a diverse sample of expatriates in Hong Kong and separate samples of Korean and Japanese expatriates posted around the world, indicate several direct effects of individual differences. Further data show reliable distinctions between the traits and competencies as well as incremental prediction by either set of predictors in the presence of the others.     

Working memory span tasks: A methodological review and user’s guide

Working memory (WM) span tasks—and in particular, counting span, operation span, and reading span tasks—are widely used measures of WM capacity. Despite their popularity, however, there has never been a comprehensive analysis of the merits of WM span tasks as measurement tools. Here, we review the genesis of these tasks and discuss how and why they came to be so influential. In so doing, we address the reliability and validity of the tasks, and we consider more technical aspects of the tasks, such as optimal administration and scoring procedures. Finally, we discuss statistical and methodological techniques that have commonly been used in conjunction with WM span tasks, such as latent variable analysis and extreme-groups designs.     

Putnam's internal realism and von Balthasar's religious epistemology

International Journal for Philosophy of Religion -