Object-guided Spatial Attention in Touch: Holding the Same Object with Both Hands Delays Attentional Selection

Abstract Previous research has shown that attention to a specific location on a uniform visual object spreads throughout the entire object. Here we demonstrate that, similar to the visual system, spatial attention in touch can be object guided. We measured event-related brain potentials to tactile stimuli arising from objects held by observers' hands, when the hands were placed either near each other or far apart, holding two separate objects, or when they were far apart but holding a common object. Observers covertly oriented their attention to the left, to the right, or to both hands, following bilaterally presented tactile cues indicating likely tactile target location(s). Attentional modulations for tactile stimuli at attended compared to unattended locations were present in the time range of early somatosensory components only when the hands were far apart, but not when they were near. This was found to reflect enhanced somatosensory processing at attended locations rather than suppressed processing at unattended locations. Crucially, holding a common object with both hands delayed attentional selection, similar to when the hands were near. This shows that the proprioceptive distance effect on tactile attentional selection arises when distant event locations can be treated as separate and unconnected sources of tactile stimulation, but not when they form part of the same object. These findings suggest that, similar to visual attention, both space- and object-based attentional mechanisms can operate when we select between tactile events on our body surface.</jats:p

Visual adaptation to goal-directed hand actions

Prolonged exposure to visual stimuli, or adaptation, often results in an adaptation “aftereffect” which can profoundly distort our perception of subsequent visual stimuli. This technique has been commonly used to investigate mechanisms underlying our perception of simple visual stimuli, and more recently, of static faces. We tested whether humans would adapt to movies of hands grasping and placing different weight objects. After adapting to hands grasping light or heavy objects, subsequently perceived objects appeared relatively heavier, or lighter, respectively. The aftereffects increased logarithmically with adaptation action repetition and decayed logarithmically with time. Adaptation aftereffects also indicated that perception of actions relies predominantly on view-dependent mechanisms. Adapting to one action significantly influenced the perception of the opposite action. These aftereffects can only be explained by adaptation of mechanisms that take into account the presence/absence of the object in the hand. We tested if evidence on action processing mechanisms obtained using visual adaptation techniques confirms underlying neural processing. We recorded monkey superior temporal sulcus (STS) single-cell responses to hand actions. Cells sensitive to grasping or placing typically responded well to the opposite action; cells also responded during different phases of the actions. Cell responses were sensitive to the view of the action and were dependent upon the presence of the object in the scene. We show here that action processing mechanisms established using visual adaptation parallel the neural mechanisms revealed during recording from monkey STS. Visual adaptation techniques can thus be usefully employed to investigate brain mechanisms underlying action perception.Publisher PDFPeer reviewe

Empty hands and precious pictures: post-mortem portrait photographs of children

In an 1882 article on ‘A Grave Subject’, the photographer George Bradforde wrote: How the relatives can bear to look upon these photographs I cannot understand, unless they have a peculiar love of the horrible. For my part I cannot see the necessity of photographing the dead at all. If the departed were truly beloved, nothing that may happen in this world can ever efface the dear features from the mind’s eye: it needs not a cold, crude photograph representing the last dreary stage of humanity to recall those lineaments. Indeed, I should imagine it would in time lead to the forgetting of the pleasant smile or the lightsome laugh, and supply, in place, a ghoul-like resemblance of anything but a pleasant nature (394- 5). This sums up the reasons why photographic portraits of the dead are no longer widespread. Such images would today be viewed as ghoulish and morbid, and a photograph of a dead body now strikes us as bearable only in the form of news images in which horror is the main thrust of the story. Such pictures bear witness to the obscenity of violent death: they are a necessary record of atrocity rather than the portrait of a dead person. Victorian photographs of the dead, however, were for the most part not those of murders or victims of war; they were family members, most commonly children, who had died at home. They are not news photographs distributed widely among strangers, but portraits, commissioned by family members and kept in the home

The Prometheus Challenge

Degas, Manet, Picasso, Dali and Lipchitz produced works of art exemplifying a seeming impossibility: Not only combining incompatible attributes but doing so consistently with aesthetic strictures Horace formulated in Ars Poetica. The article explains how these artists were able to do this, achieving what some critics have called ‘a new art,’ ‘a miracle,’ and ‘a new metaphor.’ The article also argues that the author achieved the same result in sculpture by means of philosophical analysis – probably a first in the history of art

Hit Men and Midwives: Christian Witness at Work and at Worship

(Excerpt) Well, it has finally come to this: even a liturgical institute has to discuss evangelism. Almost certainly some people will look at the combination of liturgy and witness and observe from one point of view or another how this sort of thing could never have happened a generation ago

The polaroid image as photo-object

This article is part of a larger project on the cultural history of Polaroid photography and draws on research done at the Polaroid Corporate archive at Harvard and at the Polaroid company itself. It identifies two cultural practices engendered by Polaroid photography, which, at the point of its extinction, has briefly flared into visibility again. It argues that these practices are mistaken as novel but are in fact rediscoveries of practices that stretch back as many as five decades. The first section identifies Polaroid image-making as a photographic equivalent of what Tom Gunning calls the ‘cinema of attractions’. That is, the emphasis in its use is on the display of photographic technologies rather than the resultant image. Equally, the common practice, in both fine art and vernacular circles, of making composite pictures with Polaroid prints, draws attention from image content and redirects it to the photo as object