Theoretical implications of quantitative properties of interval timing and probability estimation in mouse and rat

Although theoretical discussions typically assume that positive and negative reinforcement differ, the literature contains little unambiguous evidence that they produce differential behavioral effects. To test whether the two types of consequences control behavior differently, we pitted money‐gain positive reinforcement and money‐loss‐avoidance negative reinforcement, scheduled through identically programmed variable‐cycle schedules, against each other in concurrent schedules. Contingencies of response‐produced feedback, normally different in positive and negative reinforcement, were made symmetrical. Steeper matching slopes were produced compared to a baseline consisting of all positive reinforcement. This free‐operant differential outcomes effect supports the notion that that stimulus‐presentation positive reinforcement and stimulus‐elimination negative reinforcement are functionally “different.” However, a control experiment showed that the feedback asymmetry of more traditional positive and negative reinforcement schedules also is sufficient to create a “difference” when the type of consequence is held constant. We offer these findings as a small step in meeting the very large challenge of moving negative reinforcement theory beyond decades of relative quiescence.     

Successful Aging Across Adulthood: Hassles,Uplifts, and Self-Assessed Health in Daily Context

To examine the ways in which age, sex, daily uplifts, and daily hassles influence fluctuations in self-assessed health (SAH). A 14-day experience sampling study was conducted among community-dwelling adults (N?=?87). The distribution-free method of generalized estimating equations was used to examine whether changes in the intensity of daily hassles and changes in intensities of daily uplifts predicted subsequent changes in SAH. Both hassles and uplifts influenced SAH, although neither age nor sex influenced these associations. Findings are discussed in terms of the benefits of examining the daily context as an influence on successful aging.     

Behavioral analysis of NR2C knockout mouse reveals deficit in acquisition of conditioned fear and working memory

N-methyl-D-aspartate (NMDA) receptors play an important role in excitatory neurotransmission and mediate synaptic plasticity associated with learning and memory. NMDA receptors are composed of two NR1 and two NR2 subunits and the identity of the NR2 subunit confers unique electrophysiologic and pharmacologic properties to the receptor. The precise role of NR2C-containing receptors in vivo is poorly understood. We have performed a battery of behavioral tests on NR2C knockout/nβ-galactosidase knock-in mice and found no difference in spontaneous activity, basal anxiety, forced-swim immobility, novel object recognition, pain sensitivity and reference memory in comparison to wildtype counterparts. However, NR2C knockout mice were found to exhibit deficits in fear acquisition and working memory compared to wildtype mice. Deficit in fear acquisition correlated with lack of fear conditioning-induced plasticity at the thalamo-amygdala synapse. These findings suggest a unique role of NR2C-containing receptors in associative and executive learning representing a novel therapeutic target for deficits in cognition.     

Peers increase adolescent risk taking by enhancing activity in the brain's reward circuitry

The presence of peers increases risk taking among adolescents but not adults. We posited that the presence of peers may promote adolescent risk taking by sensitizing brain regions associated with the anticipation of potential rewards. Using fMRI, we measured brain activity in adolescents, young adults, and adults as they made decisions in a simulated driving task. Participants completed one task block while alone, and one block while their performance was observed by peers in an adjacent room. During peer observation blocks, adolescents selectively demonstrated greater activation in reward-related brain regions, including the ventral striatum and orbitofrontal cortex, and activity in these regions predicted subsequent risk taking. Brain areas associated with cognitive control were less strongly recruited by adolescents than adults, but activity in the cognitive control system did not vary with social context. Results suggest that the presence of peers increases adolescent risk taking by heightening sensitivity to the potential reward value of risky decisions.     

Computerized assessment of syntactic complexity in Alzheimer’s disease: a case study of Iris Murdoch’s writing

Currently, the majority of investigations of linguistic manifestations of neurodegenerative disorders such as Alzheimer’s disease are conducted based on manual linguistic analysis. Grammatical complexity is one of the language use characteristics sensitive to the effects of Alzheimer’s disease and is difficult to operationalize and measure using manual approaches. In the current study, we demonstrate the application of computational linguistic methods to automate the analysis of grammatical complexity. We implemented the Computerized Linguistic Analysis System (CLAS) based on the Stanford syntactic parser (Klein and Manning, Pattern Recognition, 38(9), 1407–1419, 2005) for longitudinal analysis of changes in syntactic complexity in language affected by neurodegenerative disorders. We manually validated CLAS scoring and used it to analyze writings of Iris Murdoch, a renowned Irish author diagnosed with Alzheimer’s disease. We found clear patterns of decline in grammatical complexity consistent with previous analyses of Murdoch’s writing conducted by Garrard, Maloney, Hodges, and Patterson (Brain, 128(250–260, 2005). CLAS is a fully automated system that may be used to derive objective and reproducible measures of syntactic complexity in language production and can be particularly useful in longitudinal studies with large volumes of language samples.     

The big, the rich, and the powerful: physical, financial, and social dimensions of dominance in mating and attraction

Dominance is a key feature on which romantic partners are evaluated, yet there is no clear consensus on its definition. In Study 1 (N=305), the authors developed scales to measure three putatively distinct dimensions of dominance: social, financial, and physical. In Study 2 (N=308), the authors used their scales in a mate-selection paradigm and found that women perceived physical dominance to be related to both attractiveness and social dominance. For both sexes, attractiveness predicted desirability for a one-night stand, whereas attractiveness and agreeableness were predictors of desirability for a serious relationship. In Study 3 (N=124), the authors surveyed romantic partners in monogamous relationships and found that although aspects of a partner's dominance-financial for women and social for men-played a bivariate role in relationship satisfaction, agreeableness was the strongest predictor of current and future relationship satisfaction and the only significant predictor of relationship dissolution.     

Behavioral and self‐reported aggression as a function of domain‐specific self‐esteem

On the basis of a domain‐specific theory of self‐esteem, it was hypothesized that functionally distinct domains of self‐esteem would predict aggression differentially. Participants completed self‐report measures of self‐perceived superiority, mate value, social inclusion, and global self‐esteem, as well as of aggression. Self‐assessed mate value emerged as a reliable, positive predictor, and social inclusion as a reliable inverse predictor, of self‐reported hostility and aggression. In a subsequent laboratory experiment, in which participants had an opportunity to aggress against the source of positive or negative feedback about a personal essay that they had written, mate value again predicted increased aggression, whereas global self‐esteem predicted decreased aggression. These main effects were moderated by the feedback manipulation, such that their respective simple effects were only present among participants that received negative feedback. Aggr. Behav. 00:1–11, 2005. © 2005 Wiley‐Liss, Inc.     

Expression and Indication in Ethics and Political Philosophy

We sometimes have reasons to perform actions due to what they would communicate. Those who have discussed such reasons have understood what an action ‘communicates’ as what it conventionally expresses. Brennan and Jaworski argue that when a convention ensures that expressing the appropriate thing would be costly, we should change or flout the convention. I argue that what really matters is often what attitudes we indicate rather than conventionally express, using social science to show that indicating our attitudes is often unavoidably costly, and sometimes worth the cost. I use this account to defend communicative arguments for egalitarian distributive policies.

     

A Case of Mind/Brain Identity: One Small Bridge for the Explanatory Gap

Based on the technique ofpressure blinding of the eye, two types of after-image (AI) were identified. A physicalist or mind/brain identity explanation was established for a negative a AI produced by moderately intense stimuli. These AI's were shown to be located in the neurons of the retina. An illusory AI of double a grating's spatial frequency was also produced in the same structure and was both prevented from being established and abolished after establishment by pressure blinding, thus showing that the location was not more central. The illusory AI was predicted from the knownnon-linearity in the retina and this is the first case of a clear cut type-type identity of a sensation and a neural process. Some implications for the concepts of the explanatory gap between neurology and consciousness and multiple neural realizations of conscious states and topic neutrality are discussed.