Responsiveness to Threat and Incentive in Bipolar Disorder: Relations of the BIS/BAS Scales with Symptoms

Over the past 10 years, theorists have suggested that bipolar disorder symptoms result from increases and decreases in the activity of the Behavioral Activation or Facilitation System (BAS or BFS) and the Behavioral Inhibition System (BIS). These neurobehavioral systems are thought to determine the intensity of affective and behavioral responses to incentives and threats. This study examined cross-sectional and prospective associations of self-reported BIS and BAS with mania and depression in a sample of 59 individuals diagnosed with Bipolar I disorder. Depression was tied to BIS, pointing to the importance of sensitivity to threats in depression. However, links between BIS and depression appeared state-dependent. BAS subscales did not correlate with manic symptoms in a state-dependent manner; however, BAS (total scale and reward responsiveness subscale) predicted relative intensification of manic symptoms over time. Thus, evidence suggests that BAS sensitivity may constitute a vulnerability to mania among persons diagnosed with bipolar disorder. Discussion focuses on the integrative potential of the BIS/BAS constructs for linking psychosocial and biological research on bipolar disorder.     

Place learning in virtual space III: Investigation of spatial navigation training procedures and their application to fMRI and clinical neuropsychology

This paper describes the utilization of a desktop virtual environment task, the Computer-Generated (C-G) Arena, in the study of human spatial navigation. First, four experiments examined the efficacy of various training procedures in the C-G Arena. In Experiment 1, participants efficiently located a hidden target after only observing the virtual environment from a fixed position (placement learning). In Experiment 2, participants efficiently located a hidden target after only observing an experimenter search the virtual environment (observational learning). In Experiment 3, participants failed to display alatent learning effect in the virtual environment. In Experiment 4, all training procedures effectively taught participants the layout of the virtual environment, but the observational learning procedure most effectivelytaught participants the location of a hidden target within the environment. Finally, two experiments demonstrated the application of C-G Arena procedures to neuroimaging (Experiment 5) and neuropsychological (Experiment 6) investigations of human spatial navigation.     

Divine Omnipotence and Divine Omniscience: A Reply to Michael Martin

In Atheism: A Philosophical Justification, Michael Martin argues that to posit a God that is both omnipotent and omniscient is philosophically incoherent. I challenge this argument by proposing that a God who is necessarily omniscient is more powerful than a God who is contingently omniscient. I then argue that being omnipotent entails being omniscient by showing that for an all-powerful being to be all-powerful in any meaningful way, it must possess complete knowledge about all states of affairs and thus must be understood to be omniscient.

Tacit and accessible understanding of language

The empirical nature of our understanding of language is explored. I first show that there are several important and different distinctions between tacit and accessible awareness. I then present empirical evidence concerning our understanding of language. The data suggests that our awareness of sentence-meanings is sometimes merely tacit according to one of these distinctions, but is accessible according to another. I present and defend an interpretation of this mixed view. The present project is shown to impact on several diverse areas, including inferential role semantics and holism, the nature of learning, and the role of linguistics in the law. I am indebted to a number of people for their useful feedback, especially Peter Ludlow, Paul Pietroski, and two anonymous reviewers. Earlier versions of this paper were presented at an Eastern meeting of the APA, a meeting of the Society for Exact Philosophy at Simon Fraser University, and at a semantics workshop in Ottawa, Canada. I greatly appreciate the comments from those audiences.     

Retracted: When nothing compares to me: how defensive motivations and similarity shape social comparison effects

While similarity typically breeds social comparison, all information gained from social comparisons is not equally influential. Three studies illustrate the situations in which individuals defensively interpret social comparison information such that they incorporate information that reflects positively on the self and disregard negative information. Study 1 extends previous research to show that self‐threat broadens the conditions under which defensive interpretations occur to include those in which similarity is ambiguous. Studies 2 and 3 demonstrate that defensive interpretations are less likely to occur when individuals are affirmed or when the comparison information is unimportant. These findings suggest that the impact of social comparisons on self‐views is determined by both similarity of comparison targets and the motives of the perceiver. Copyright © 2006 John Wiley & Sons, Ltd.     

Delayed detection of tonal targets in background noise in dyslexia

Individuals with developmental dyslexia are often impaired in their ability to process certain linguistic and even basic non-linguistic auditory signals. Recent investigations report conflicting findings regarding impaired low-level binaural detection mechanisms associated with dyslexia. Binaural impairment has been hypothesized to stem from a general low-level processing disorder for temporally fine sensory stimuli. Here we use a new behavioral paradigm to address this issue. We compared the response times of dyslexic listeners and their matched controls in a tone-in-noise detection task. The tonal signals were either Huggins Pitch (HP), a stimulus requiring binaural processing to elicit a pitch percept, or a pure tone-perceptually similar but physically very different signals. The results showed no difference between the two groups specific to the processing of HP and thus no evidence for a binaural impairment in dyslexia. However, dyslexic subjects exhibited a general difficulty in extracting tonal objects from background noise, manifested by a globally delayed detection speed.     

Effect of prefrontal cortex damage on resolving lexical ambiguity in text

The function of suppression of context-inappropriate meanings during lexical ambiguity resolution was examined in 25 adults with prefrontal cortex damage (PFCD) localized to the left (N=8), right (N=6), or bilaterally (N=11); and 21 matched Controls. Results revealed unexpected inverse patterns of suppression between PFCD and Control groups, with measures suggesting decreased interference across time in the PFCD group and increased interference in the Control group. The PFCD group, however, had significantly lower accuracy rates for the context-inappropriate condition. Results suggest a loss of the control aspects of inhibitory processes in lexical ambiguity resolution following PFCD. An aging effect on suppression function is also suggested.     

Tone sequences with conflicting fundamental pitch and timbre changes are heard differently by musicians and nonmusicians

An Auditory Ambiguity Test (AAT) was taken twice by nonmusicians, musical amateurs, and professional musicians. The AAT comprised different tone pairs, presented in both within-pair orders, in which overtone spectra rising in pitch were associated with missing fundamental frequencies (F0) falling in pitch, and vice versa. The F0 interval ranged from 2 to 9 semitones. The participants were instructed to decide whether the perceived pitch went up or down; no information was provided on the ambiguity of the stimuli. The majority of professionals classified the pitch changes according to F0, even at the smallest interval. By contrast, most nonmusicians classified according to the overtone spectra, except in the case of the largest interval. Amateurs ranged in between. A plausible explanation for the systematic group differences is that musical practice systematically shifted the perceptual focus from spectral toward missing-F0 pitch, although alternative explanations such as different genetic dispositions of musicians and nonmusicians cannot be ruled out. ((c) 2007 APA, all rights reserved).     

Reconciling reinforcement learning models with behavioral extinction and renewal: implications for addiction, relapse, and problem gambling

Because learned associations are quickly renewed following extinction, the extinction process must include processes other than unlearning. However, reinforcement learning models, such as the temporal difference reinforcement learning (TDRL) model, treat extinction as an unlearning of associated value and are thus unable to capture renewal. TDRL models are based on the hypothesis that dopamine carries a reward prediction error signal; these models predict reward by driving that reward error to zero. The authors construct a TDRL model that can accommodate extinction and renewal through two simple processes: (a) a TDRL process that learns the value of situation-action pairs and (b) a situation recognition process that categorizes the observed cues into situations. This model has implications for dysfunctional states, including relapse after addiction and problem gambling.     

Genetic and environmental influences on behavior: capturing all the interplay

Basic quantitative genetic models of human behavioral variation have made clear that individual differences in behavior cannot be understood without acknowledging the importance of genetic influences. Yet these basic models estimate average, population-level genetic and environmental influences, obscuring differences that might exist within the population and masking systematic transactions between specific genetic and environmental influences. This article discusses a newer, more sophisticated and powerful quantitative genetic model that articulates these transactions. Results from this model highlight the ways in which the gene- environment interaction and correlation are intertwined. They can be used to integrate findings from quantitative and molecular genetic studies and to understand the roles of genetic influences and social forces in manifested behaviors, even when DNA sequence variation is not relevant.