Assessing the impact of verbal and visuospatial working memory load on eye-gaze cueing

Observers tend to respond more quickly to peripheral stimuli that are being gazed at by a centrally presented face, than to stimuli that are not being gazed at. While this gaze-cueing effect was initially seen as reflexive, there have also been some indications that top-down control processes may be involved. Therefore, the present investigation employed a dual-task paradigm to attempt to disrupt the putative control processes involved in gaze cueing. Two experiments examined the impact of working memory load on gaze cueing. In Experiment 1, participants were required to hold a set of digits in working memory during each gaze trial. In Experiment 2, the gaze task was combined with an auditory task that required the manipulation and maintenance of visuo-spatial information. Gaze cueing effects were observed, but they were not modulated by dual-task load in either experiment. These results are consistent with traditional accounts of gaze cueing as a highly reflexive process

Cognitive demands of face monitoring: Evidence for visuospatial overload

Young children perform difficult communication tasks better face to face than when they cannot see one another (e.g., Doherty-Sneddon & Kent, 1996). However, in recent studies, it was found that children aged 6 and 10 years, describing abstract shapes, showed evidence of face-to-face interference rather than facilitation. For some communication tasks, access to visual signals (such as facial expression and eye gaze) may hinder rather than help children’s communication. In new research we have pursued this interference effect. Five studies are described with adults and 10- and 6-year-old participants. It was found that looking at a face interfered with children’s abilities to listen to descriptions of abstract shapes. Children also performed visuospatial memory tasks worse when they looked at someone’s face prior to responding than when they looked at a visuospatial pattern or at the floor. It was concluded that performance on certain tasks was hindered by monitoring another person’s face. It is suggested that processing of visual communication signals shares certain processing resources with the processing of other visuospatial information

Quantitative evaluation of polymer gel dosimeters by broadband ultrasound attenuation

Ultrasound has been examined previously as an alternative readout method for irradiated polymer gel dosimeters, with authors reporting varying dose response to ultrasound transmission measurements. In this current work we extend previous work to measure the broadband ultrasound attenuation (BUA) response of irradiated PAGAT gel dosimeters, using a novel ultrasound computed tomography system

A role for eyebrows in regulating the visibility of eye gaze direction

The human eye is unique amongst those of primates in having white sclera against which the dark iris is clearly visible. This high-contrast structure makes the gaze direction of a human potentially easily perceptible to others. For a social creature such as a human, the ability to perceive the direction of another’s gaze may be very useful, since gaze usually signals attention. We report data showing that the accuracy of gaze deviation detection is independent of viewing distance up to a certain critical distance, beyond which it collapses. This is, of itself, surprising since most visual tasks are performed better at closer viewing distances. Our data also show that the critical distance, but not accuracy, is affected by the position of the eyebrows so that lowering the eyebrows reduces the critical distance. These findings show that mechanisms exist by which humans could expand or restrict the availability of their gaze direction to others. A way to regulate the availability of the gaze-direction signal could be an advantage. We show that an interpretation of eyebrow function in these terms provides a novel explanation for several well-known eyebrow actions, including the eyebrow flash

A Behavioural Foundation for Natural Computing and a Programmability Test

What does it mean to claim that a physical or natural system computes? One answer, endorsed here, is that computing is about programming a system to behave in different ways. This paper offers an account of what it means for a physical system to compute based on this notion. It proposes a behavioural characterisation of computing in terms of a measure of programmability, which reflects a system's ability to react to external stimuli. The proposed measure of programmability is useful for classifying computers in terms of the apparent algorithmic complexity of their evolution in time. I make some specific proposals in this connection and discuss this approach in the context of other behavioural approaches, notably Turing's test of machine intelligence. I also anticipate possible objections and consider the applicability of these proposals to the task of relating abstract computation to nature-like computation.Comment: 37 pages, 4 figures. Based on an invited Talk at the Symposium on Natural/Unconventional Computing and its Philosophical Significance, Alan Turing World Congress 2012, Birmingham, UK. http://link.springer.com/article/10.1007/s13347-012-0095-2 Ref. glitch fixed in 2nd. version; Philosophy & Technology (special issue on History and Philosophy of Computing), Springer, 201

A functorial construction of moduli of sheaves

We show how natural functors from the category of coherent sheaves on a projective scheme to categories of Kronecker modules can be used to construct moduli spaces of semistable sheaves. This construction simplifies or clarifies technical aspects of existing constructions and yields new simpler definitions of theta functions, about which more complete results can be proved.Comment: 52 pp. Dedicated to the memory of Joseph Le Potier. To appear in Inventiones Mathematicae. Slight change in the definition of the Kronecker algebra in Secs 1 (p3) and 2.2 (p6), with corresponding small alterations elsewhere, to make the constructions work for non-reduced schemes. Section 6.5 rewritten. Remark 2.6 and new references adde