Anxiety and defensiveness: individual differences in affective startle modulation

Anxious individuals selectively attend to threatening information, and defensiveness may influence the experience and expression of anxiety. Fifty-eight undergraduates scoring high and low on measures of anxiety and defensiveness viewed pleasant, neutral, and unpleasant pictures. Acoustic startle probes were presented 60, 240, or 2,000 ms after picture onset. At 60 ms and 240 ms, repressors (low anxiety, high defensiveness) showed weaker blinks during both pleasant and unpleasant compared to neutral pictures, suggesting enhanced early attention to affective stimuli, regardless of valence. At 2,000 ms, high-anxious but not low anxious participants showed potentiated startle responses during unpleasant compared to pleasant pictures. Although this result replicated previous research on anxiety and valence modulation of startle, exploratory analyses suggested that the valence effect was restricted to trait anxious individuals tending toward a defensive coping style. Across probe conditions, defensiveness was associated with heightened startle reactivity independent of self-reported anxiety and foreground stimulus characteristics.

Net Amount of Food Affects Autoshaped Response Rate, Response Latency, and Gape Amplitude in Pigeons

The contribution of net amount of food to conditioned response strength and topography was assessed in four pigeons under autoshaping contingencies. In each session, under one baseline phase and three replication phases, three trial types were presented sequentially: One conditioned stimulus (keylight) signaled one small pellet, another signaled one large pellet, and a third signaled seven small pellets which were weight-matched to one large pellet. Five dependent variables were response rates and latencies based on the occurrence of both keyswitch closures and gapes (beak openings) and gape amplitudes. In result, net amount of food, not pellet diameter or number, affected all dependent variables. Notably, gape amplitudes elicited by the seven-small pellet keylights were larger than the gape amplutides elicited by the one-small pellet keylights even though the gape amplitudes elicited by both unconditioned stimuli (one or seven pellets) were equally small. This mismatch between conditioned and unconditioned responses is incompatible with stimulus substitution accounts but is compatible with an associative strength account. Furthermore, the changes in the dependent variables were most likely determined by Pavlovian and not by inadvertent operant contingencies. The findings demonstrate that an analysis of classical conditioning benefits from the inclusion of topographical measures.     

The Test of Everyday Attention for Children (TEA-Ch): patterns of performance in children with ADHD and clinical controls.

The present study explores the utility of the Test of Everyday Attention for Children (TEA-Ch) as a measure of the attentional impairments displayed by children with Attention Deficit Hyperactivity Disorder (ADHD). Sixty-three children with ADHD and 23 non-ADHD Clinical Control children were compared on subtests of the TEA-Ch reflecting three attentional domains: sustained, selective, and attentional control. Results show that children with ADHD performed significantly worse than clinical controls on subtests of sustained attention and attentional control. The groups did not differ, however, on subtests of selective attention. These findings suggest that the TEA-Ch is sensitive to attentional deficits unique to ADHD and holds promise as a useful tool in the assessment of ADHD. Performance patterns and future directions are discussed.     

Processing demand modulates the effects of spatial attention on the judged duration of a brief stimulus

How does attention influence the judged duration of a brief stimulus? In the four experiments reported here, we show that the effect of spatial attention on duration judgment depends on the processing demand of the concurrent nontemporal task. When participants had to perform a speeded letter discrimination task in addition to duration rating, the judged duration was longer at a cued location than at an uncued location, regardless of whether the cue was exogenous or endogenous. However, when the same stimuli were presented but no concurrent nontemporal task was required, duration was judged to be shorter at the cued location, as compared with the uncued locations. Furthermore, although spatial attention influenced duration judgment, no object-based attentional effects were found. These findings suggest that, although spatial attention plays an important role in the judged duration of a briefly presented stimulus, its effect is mediated by the processing demand of the task.     

What do double dissociations prove?

Brain damage may doubly dissociate cognitive modules, but the practice of revealing dissociations is predicated on modularity being true (T. Shallice, 1988). This article questions the utility of assuming modularity, as it examines a paradigmatic double dissociation of reading modules. Reading modules illustrate two general problems. First, modularity fails to converge on a fixed set of exclusionary criteria that define pure cases. As a consequence, competing modular theories force perennial quests for purer cases, which simply perpetuates growth in the list of exclusionary criteria. The first problem leads, in part, to the second problem. Modularity fails to converge on a fixed set of pure cases. The second failure perpetuates unending fractionation into more modules.     

Surfing for sex: Studying involuntary celibacy using the internet

The Internet offers possibilities for sexuality research that could not have been imagined even a decade ago. Although Internet users are not representative of the general population, they are easily accessible, and the openness with which they discuss sensitive topics has created a tremendous and largely untapped pool of respondents for sex research. Moreover, the web provides access to populations that are largely hidden and difficult to reach using traditional methods. In this article, we explore such issues as sampling, research design, data collection and management, and the ethics of web-based research. In doing so, we review past research, investigate the advantages and disadvantages of using the Internet in sexuality studies, draw examples from our web-based study of involuntary celibacy, and recommend guidelines for future web based inquiries.