Withdrawing attention at little or no cost: Detection and discrimination tasks

We used a concurrent-task paradigm to investigate the attentional cost of simple visual tasks. As in earlier studies, we found that detecting a unique orientation in an array of oriented elements (“pop-out”) carries little or no attentional cost. Surprisingly, this is true at all levels of performance and holds even when pop-out is barely discriminable. We discuss this finding in the context of our previous report that the attentional cost of stimulus detection is strongly influenced by the presence and nature of other stimuli in the display (Braun, 1994b). For discrimination tasks, we obtained a similarly mixed outcome: Discrimination of letter shape carried a high attentional cost whereas discrimination of color and orientation did not. Taken together, these findings lead us to modify our earlier position on the attentional costs of detection and discrimination tasks (Sagi & Julesz, 1985). We now believe that observers enjoy a significant degree of “ambient” visual awareness outside the focus of attention, permitting them to both detect and discriminate certain visual information. We hypothesize that the information in question is selected by a competition for saliency at the level of early vision.     

Mission and People with Disabilities

This article begins with a few thoughts and some historical and canonical encounters about how lay and ordained people with disabilities have been involved in Orthodox mission work in the past. It then presents two concrete contemporary situations in which people with disabilities are involved in Orthodox ordained ministry work despite the persisting tradition that disabled people not be ordained. The first example is taken from the Eritrean Orthodox Tewahedo Church, where the involvement of people with disabilities in both ordained and lay ministry provides significant support for a church that lives in a delicate situation. The second example is taken from the Romanian Orthodox Church and presents the case of Father Theophilus P?r?ian, one of the most prominent contemporary Romanian Orthodox monastic figures, who served as an ordained priest despite his disability. This article pleads for a deeper involvement of disabled people in both ordained and lay ministry in Orthodox churches.     

An inexpensive automated system for the measurement of rotational behavior in small animals

A reliable, low-cost automated system for the quantification of rotational behavior from up to 10 subjects simultaneously is described. The system resolves quarter and full turns to the left and right, and can relay data to another computer for statistical analysis. The system is easily constructed from simple and inexpensive components, including the computer, that total less than $1,000 and can be used with a variety of different test chambers.     

The existence and role of retinotopic and spatiotopic forms of visual persistence

Current theoretical conceptualizations of visual persistence fail to address the issue of its functional role. Based on extant experimental data we tentatively identify two general types of visual persistence: one resides in activity along the afferent visual pathway and is retinotopically organized; the other resides at central levels and is spatiotopically organized. Moreover, whereas the former afferent persistence is eliminated via saccadic suppression mechanisms in order to separate successive, retinotopic frames of pattern information, the latter, central one, in contrast, is generated and enhanced via extraretinal signals accompanying saccades in order to preserve phenomenal continuity of a stable spatiotopic representation of the environment from one fixation to the next.     

The effect of light intensity when onset or termination of illumination is used as reinforcing stimulus

The Psychological Record - Two experiments were performed to examine the reinforcing effects of onset and termination of non-aversive illumination, made conterminous with lever contacting, as a...