Elevated anxiety vulnerability is associated with a tendency to interpret ambiguous stimuli as threatening, but the causal basis of this relationship has not been established. Recently, procedures have been developed to systematically manipulate interpretive bias, but the impact of such manipulation on anxiety reactivity to a subsequent stressor has not yet been examined. In the present study, training procedures were used to induce interpretive biases favoring the threatening or nonthreatening meanings of ambiguous information in a sample of 48 undergraduate students. Following this interpretive training, participants' emotional reactions to a stressful video were assessed. The finding that the manipulation of interpretive bias modified emotional reactivity supports the hypothesis that interpretive bias can indeed play a causal role in anxiety vulnerability.

Previous research has established that clinical anxiety patients and nonclinical populations with high levels of anxiety vulnerability characteristically orient attention toward moderately threatening stimuli. In contrast, populations with low levels of anxiety vulnerability typically orient attention away from such stimuli. The differing experimental predictions generated by 2 classes of hypothetical explanation for this anxiety-linked attentional discrepancy were tested, using attentional probe methodology to compare the attentional responses of high and low trait anxious individuals to facial stimuli of differing threat intensities. The results support the view that all individuals orient attention away from mildly threatening stimuli and toward strongly threatening stimuli, with differences in anxiety vulnerability reflecting the intensity of stimulus threat required to elicit the attentional vigilance response.

No abstract

The effects of dietary nickel (0, 25, 50, 75, 100, and 150 mg/kg) on the bone strength characteristics and performance parameters of male broilers were investigated. Broilers were housed in either cages or floor pens. At 6 wk of age, the shear fracture energy of the tibia from the caged birds increased when the basal diet was supplemented with 25 mg of dietary nickel per kilogram of feed. The shear force, stress, and fracture energy of the radius from the caged birds also increased at 25 mg/kg nickel. Dietary nickel had no effect on bird body weight, but the caged broilers (2,161 g) were heavier than the floor birds (2,005 g). Nickel had no effect on the strength characteristics of the tibia from the floor birds. Percent tibia bone ash, a measure of bone density, was not influenced by dietary nickel, but the tibia ash of the floor birds was greater than that of the caged birds. Overall, the data indicates that adding 25 mg/kg of dietary nickel to a poultry diet will have a positive influence on bone strength characteristics and performance.

The breadth of work dedicated to defining and accounting for variation in emotional experience amply indicates that emotions are complex constructs that involve an interactive relationship between behavioral, somatic, and cognitive factors (see Lambie & Marcel, 2002). The cognitive aspects of the emotions, which are the focus of this chapter, may be studied from at least two perspectives. The focus of study may be either the subjective cognitive contents associated with different emotions or the individual differences in styles of selective information processing, which may plausibly give rise to such cognitive content. In modern psychological science, cognitive explanations of emotions extend as far back as the work of Arnold (1960) and are underpinned by the premise that the manner in which any situation is subjectively represented will determine the nature and intensity of the resulting emotional response (e.g., Lazarus, 1968Lazarus, , 1991. Cognitive accounts of affective psychopathology similarly suggest that idiosyncratic styles of attribution and inference may underlie proneness to such psychopathology. For example, Beck and his colleagues (e.g., Beck, 1976Beck, , 1985 argued that clinical depression and anxiety disorders result, at least in part, from an inflated tendency to construe life experiences as having negative meanings and implications.