Individual patterns of attentional exploration predict the extent of fear generalization in humans

Generalization of fear is an important mechanism contributing to the etiology and maintenance of anxiety disorders. Although previous studies have identified perceptual aspects and evaluation processes as determinants of fear generalization, it is currently unclear, to what degree overt attention might mediate its magnitude. To test the prediction that attentional preferences for diagnostic stimulus aspects reduce fear generalization, we developed a set of facial stimuli that was meticulously manipulated such that pairs of faces could be distinguished by looking into predefined diagnostic areas. These pairs were then employed as CS+ and CS− in a differential fear conditioning paradigm followed by a generalization test. Results indicated a typical quadratic fear generalization gradient in shock expectancy ratings but its shape was altered depending on individual attentional deployment. Subjects who dwelled on the distinguishing stimulus regions faster and for longer periods of time exhibited less fear generalization. Although heart rate responses also showed a generalization gradient with heart rate deceleration increasing as a function of threat, these responses were not significantly related to patterns of attentional exploration. Altogether the current results indicate that the extent of fear generalization depends on individual patterns of attentional exploration. This implies that overgeneralization of fear, as observed in patients with anxiety disorders, might be treated by perceptual trainings that aim to augment discriminability between threatening and safe situations.

Olfactory Generalization in Detector Dogs

Generalizing to target odor variations while retaining specificity against non-targets is crucial to the success of detector dogs under working conditions. As such, the importance of generalization should be considered in the formulation of effective training strategies. Research investigating olfactory generalization from pure singular compounds to more complex odor mixtures helps to elucidate animals’ olfactory generalization tendencies and inform ways to alter the generalization gradient by broadening or narrowing the range of stimuli to which dogs will respond. Olfactory generalization depends upon both intrinsic factors of the odors, such as concentration, as well as behavioral and cognitive factors related to training and previous experience. Based on the current research, some training factors may influence generalization. For example, using multiple target exemplars appears to be the most effective way to promote elemental processing and broaden the generalization gradient, whereas increasing the number of training instances with fewer exemplars can narrow the gradient, thereby increasing discrimination. Overall, this research area requires further attention and study to increase our understanding of olfactory generalization in dogs, particularly detector dogs, to improve training and detection outcomes.

More is Still not Better: Testing the Perturbation Model of Temporal Reference Memory across Different Modalities and Tasks

The ability of the perturbation model (Jones & Wearden, 2003) to account for reference memory function in a visual temporal generalization task and auditory and visual reproduction tasks was examined. In all tasks the number of presentations of the standard was manipulated (1, 3, or 5), and its effect on performance was compared. In visual temporal generalization the number of presentations of the standard did not affect the number of times the standard was correctly identified, nor did it affect the overall temporal generalization gradient. In auditory reproduction there was no effect of the number of times the standard was presented on mean reproductions. In visual reproduction mean reproductions were shorter when the standard was only presented once; however, this effect was reduced when a visual cue was provided before the first presentation of the standard. Whilst the results of all experiments are best accounted for by the perturbation model there appears to be some attentional benefit to multiple presentations of the standard in visual reproduction.

Generalization Gradients for Acquisition and Extinction in Human Contingency Learning

Two experiments investigated the perceptual generalization of acquisition and extinction in human contingency learning. In Experiment 1, the degree of perceptual similarity between the acquisition stimulus and the generalization stimulus was manipulated over five groups. This successfully generated a generalization gradient of acquisition. In the subsequent phase, the response to the generalization stimulus was extinguished in each group. Finally, the acquisition stimulus was presented again. The response recovered differently over groups, thereby establishing the generalization gradient of extinction. In Experiment 2, the acquisition stimulus itself was extinguished before the set of generalization stimuli was tested between groups. One group evidenced a response recovery at test, which suggests that the gradient of acquisition is somewhat broader than the gradient of extinction.

The Effect of Feedback on Timing in Children and Adults: The Temporal Generalization Task

Children aged 5 and 8 years and adults were tested on a temporal generalization task with a standard duration of 600 ms in a condition with or without corrective feedback. In all conditions, the participants produced orderly temporal generalization gradients, although these were flatter in the younger children, especially in the no-feedback condition. Nevertheless, the results show that the feedback increased the steepness of the generalization gradient in all age groups and in a greater extent in the younger children. Our clock-based model suggested that feedback reduces the variability of the memory representation of the standard duration but also the probability of random responses in the 5-year-olds.