Delay discounting as impaired valuation: Delayed rewards in an animal obesity model

Obesity is a major public health problem, which, like many forms of addiction, is associated with an elevated tendency to choose smaller immediate rather than larger delayed rewards, a response pattern often referred to as excessive delay discounting. Although some accounts of delay discounting conceptualize this process as impulsivity (placing the emphasis on overvaluing the smaller immediate reward), others have conceptualized delay discounting as an executive function (placing the emphasis on delayed rewards failing to retain their value). The present experiments used a popular animal model of obesity that has been shown to discount delayed rewards at elevated rates (i.e., obese Zucker rats) to test two predictions that conceptualize delay discounting as executive function. In the first experiment, acquisition of lever pressing with delayed rewards was compared in obese versus lean Zucker rats. Contrary to predictions based on delay discounting as executive function, obese Zucker rats learned to press the lever more quickly than controls. In the second experiment, progressive ratio breakpoints (a measure of reward efficacy) with delayed rewards were compared in obese versus lean Zucker rats. Contrary to the notion that obese rats fail to value delayed rewards, the obese Zucker rats' breakpoints were (at least) as high as those of the lean Zucker rats.     

Reactivity to Stress: When Does a History of Medical Adversity Foster Resilience Versus Vulnerability?

Young adults with (or without) a history of medical or physical disorders (MPDs) were exposed to repeated laboratory stress. The effects of MPD status on habituation (as measured by changing levels of cortisol) were found to be moderated by the extent to which respondents reported “attachment feelings” in their relationships (as measured by the Social Provisions Scale). Students in the MPD group who reported attachment feelings showed (a) cortisol increases during their first exposure to a laboratory stressor; and (b) cortisol decreases during a second exposure to the same stressor 1 week later. No equivalent benefit was found for students who lacked this medical history. Findings suggest the extent to which medical adversity—under the right interpersonal circumstances—promotes resilience.     

Mothers’ and Fathers’ Responsive Problem Solving with Early Adolescents: Do Gender,Shyness, and Social Acceptance Make a Difference?

We assessed the extent to which youths’ (n = 231) shyness and social acceptance in preadolescence were associated with parents’ responsive problem solving 1 year later after controlling for initial levels of parents’ problem solving. Teachers (n = 176) completed assessments of youths’ shyness and social acceptance, and parents (n = 231 married pairs) completed assessments of their responsive problem solving with the child. For shy daughters, higher levels of social acceptance from peers predicted more responsive problem solving from fathers. Greater social acceptance predicted marginally less maternal problem solving for sons, but greater social acceptance predicted marginally more maternal problem solving with daughters. Results suggest the salience of child gender, shyness, and social acceptance when considering typical levels of parental involvement with youth. Implications for parents include the importance of successful problem solving discussions with emerging adolescents, especially youth who are shy or excluded by peers.     

A Confirmatory Comparison of the Factor Structure of the Children's Depression Inventory between European American and African American Youth

We examined the factor structure of the Children's Depression Inventory (CDI) among a sample of 523 African American children (m age = 12.76) and a sample of 564 European American youth (m age = 12.43). Previous investigations have produced discrepant factor structures among samples of predominantly majority-culture children, but fewer investigations of the factor structure of the CDI have been conducted among non-European American samples. Confirmatory factor analyses of the original 5 factors identified by Kovacs (1983, 1991) revealed that the items had invariant measurement properties across the samples. The latent factor structure, however, revealed telling differences between the two samples. For European American youth, only one of the original five factors was meaningfully differentiated from the others, whereas for the African American youth, two of the factors clearly emerged as unique facets of depression. Consistent with other reports, between-group mean differences on the CDI and its factors were noted. We argue that further validation of the CDI among traditionally underserved populations is warranted. Predictive validation investigations, in particular, are needed to examine the relationship between CDI factor scores and clinical outcomes.     

The lived experiences of Qatari adolescents attending international secondary school

Many Qatari families are opting to have their children educated at international schools with curricula based upon western thought and educational standards. Exploring the perceptions of Qatari adolescents as they are engaged in this experience provided an opportunity to uncover the phenomenon of Qatari ways of being as related to Western educational thought. A hermeneutic phenomenological approach was used to investigate the lived experience of Qatari adolescents attending gender integrated, international, secondary schools in Qatar. Nineteen participants took part in five gender segregated focus groups. Qatari Culture and Islamic faith were the primary themes that emerged and these interconnected with the sub-themes of family, identity, and respect. The participants shared common traits with Third Culture Kids. At times, school expectations, norms and values conflicted with traditional family values, practices and culture, but participants saw the cross-cultural value in attending international schools.     

Gender Differences in Narcissism and Courtship Violence in Dating Couples

The current study explored the relationship between courtship violence and the exploitativeness/entitlement factor of overt narcissism, covert narcissism, and sexual narcissism. Data were analyzed from 63 currently dating couples on their own and partner’s aggression using the CTS2. All were white, heterosexual students from a small US college in Central Pennsylvania. An interdependence analysis showed that correlations were entirely explained at the individual-level, thus demonstrating that gender is a key element in understanding narcissism and courtship violence. For women, exploitativeness/ entitlement was significantly correlated with sexual coercion in both dating partners. For men, covert narcissism was correlated with physical assault and sexual narcissism was correlated with their partner’s sexual coercion. Narcissism also influenced some discrepancies in self- and partner-rated aggression.     

An inexpensive infrared detector to verify the delivery of food pellets

The reproducibility of experimental outcomes depends on consistent control of independent variables. In food-maintained operant performance, it is of utmost importance that the quantity of food delivered is reliable. To that end, some commercial food pellet dispensers have add-on attachments to sense the delivery of pellets. Not all companies, however, offer such add-ons. Aside from availability, cost and temporary reduction in throughput may be a problem for smaller labs. The present paper outlines our recent development of a simple, inexpensive infrared device to detect and confirm the delivery of pellets. The in-line construction of the detector routes the falling pellet through a barrel so that it passes between an infrared emitter and receiver. The circuitry was designed to be compatible with all commercially available behavioral measurement systems, and so may be retrofit to any existing system. Our tests with the detector so far have shown that it is 100% accurate in detecting pellet delivery. The individual unit cost is approximately 25 dollars. The low cost and versatility of the device offer an easy method to ensure the integrity of food delivery in operant settings.     

Dupré's Anti–Essentialist Objection to Reductionism

In his 'The Disorder of Things' John Dupré presents an objection to reductionism which I call the 'anti–essentialist objection': it is that reductionism requires essentialism, and essentialism is false. I unpack the objection and assess its cogency. Once the objection is clearly in view, it is likely to appeal to those who think conceptual analysis a bankrupt project. I offer on behalf of the reductionist two strategies for responding, one which seeks to rehabilitate conceptual analysis and one (more concessive) which avoids commitment to any such analysis.     

A critical examination of the spectral contrast account of compensation for coarticulation

Vocal tract gestures for adjacent phones overlap temporally, rendering the acoustic speech signal highly context dependent. For example, following a segment with an anterior place of articulation, a posterior segment’s place of articulation is pulled frontward, and listeners’ category boundaries shift appropriately. Some theories assume that listeners perceptually attune or compensate for coarticulatory context. An alternative is that shifts result from spectral contrast. Indeed, shifts occur when speech precursors are replaced by pure tones, frequency matched to the formant offset at the assumed locus of contrast (Lotto & Kluender, 1998). However, tone analogues differ from natural formants in several ways, raising the possibility that conditions for contrast may not exist in natural speech. When we matched tones to natural formant intensities and trajectories, boundary shifts diminished. When we presented only the critical spectral region of natural speech tokens, no compensation was observed. These results suggest that conditions for spectral contrast do not exist in typical speech.