Dimensional weighting of primary and secondary target-defining dimensions in visual search for singleton conjunction targets

Two experiments investigated dimension-based attentional processing in a complex singleton conjunction search task. In Experiment 1, observers had to discern the presence of a singleton target defined by a conjunction of size (fixed primary dimension) with either color or motion direction (secondary dimension). Similar to findings in singleton feature search, changes (vs. repetitions) of the secondary dimension across trials resulted in reaction time (RT) costs—which were, however, increased by a factor of 3–5 compared to singleton feature search. In Experiment 2, the coding of search-critical, dimensional saliency signals was investigated by additionally presenting targets redundantly defined in both secondary dimensions, with redundant-target signals being either spatially coincident or separate (i.e., one vs. two target items). Redundant-target RTs significantly violated Miller’s (Cognit Psychol 14:247–279, 1982) race model inequality only when redundant signals were spatially coincident (i.e., bound to a single object), indicating coactive processing of target information in the two secondary dimensions. These findings suggest that the coding and combining of signals from different visual dimensions operates in parallel. Increased change costs in singleton conjunction search are likely to reflect a reduced amount of weight available for processing the secondary target-defining dimensions, due to a large amount of weight being bound by the primary dimension.

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Inhibitory and facilitatory location priming in patients with left-sided visual hemi-neglect

In visual search for pop-out targets, reaction times are facilitated when the target on the current trial appears at a previous target location, and inhibited when it appears at a previous distractor location, relative to when it appears at a previously empty (neutral) location (Maljkovic and Nakayama, Perception and Psychophysics 58:977–991, 1996). However, while normal subjects are able to positively/negatively tag selected target/rejected distractor locations to guide search on the next trial, patients with visual hemi-neglect may have a (uni- or bilateral) deficit in these functions that may contribute to their disturbed visual scanning behavior. To examine this, using a pop-out search task, the present study assessed cross-trial facilitatory and inhibitory priming in 14 patients with left-sided visual hemi-neglect and in 14 age-, education-, and IQ-matched control subjects. The group of neglect patients did show significant facilitatory and inhibitory priming. However, while control subjects exhibited balanced effects of facilitation and inhibition, inhibition was relatively reduced in magnitude in neglect patients. In particular, inhibition was virtually absent in two patients with lesions affecting superior regions of the frontal cortex, putatively encroaching on the frontal eye field of the right hemisphere. These findings provide neuropsychological evidence that facilitatory and inhibitory priming effects are based on dissociable mechanisms, consistent with Geyer et al. (Journal of Experimental Psychology: Human Perception and Performance 33:788–797, 2007).     

Object-based selection operating on a spatial representation made salient by dimensional segmentation mechanisms: a re-investigation of Egly and Homa (1984)

Three experiments re-investigated selective attention in the ‘ring-cueing’ paradigm of Egly and Homa (J Exp Psychol: Human Percept Perform 10:778–793, 1984). Observers were cued to attend to one of three concentric rings of radius 1°, 2°, or 3°, and their signal detection accuracy for cued and uncued rings was measured. Experiment 1, which used a central color cue to indicate a like-colored ring, replicated ring-cueing effects along the lines of Egly and Homa. Experiments 2 and 3 examined whether these effects were produced by observers exploiting secondary-depth cues possibly inherent in the display layout. With color cues, the availability of secondary-depth information had no influence on the ring-cueing effects. However, making the rings monochrome and using central size cues significantly reduced the ring-cueing effects when the depth information was disrupted. The results suggest that selection was object-based, operating on a spatial ‘grouped-array’ representation of the cued ring made salient by color- or depth-based segmentation mechanisms.

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Closure of salient regions determines search for a collinear target configuration

Grouping operations offer an effective mechanism by which to structure complex visual scenes. Among the various principles that support element integration, closure may be regarded as a main factor in shape extraction. In five experiments, we investigated the impact of grouping by closure on search for target configurations made up of collinearly arranged corner junctions. Systematic variations in the configuration of distractor elements were explored to investigate how the figural information of distractors interferes with target detection. The results showed no search interference for distractor configurations that were open forms. By contrast, distractors making up closed forms reduced the efficiency of search performance, indicating closure as a major contributor to form detection in multielement configurations. In conclusion, the effects reported may be considered to arise from mechanisms of unit formation that support the rapid extraction of salient regions to guide search.     

Zur Beendigung von Lehranalysen

An attempt is made to give an open account about the goals, problems and results concerning the ending of eight training analyses. The connection of trauma, individual defence structure and mental disturbances as well as the need for their therapeutic change is emphasized. Three problems are offered for further discussion: 1. to transform acting outs of training analysts standing under the pressure of the projections by training analysands onto the institute, into interpretation; 2. the difficulty to understand the varieties of the depressive position within the mental patterns of foreign civilisations; 3. the hypothetical effect of the analysis of character neuroses on the abstinence of training analysts and on the decision for lower frequency by former training analysands.     

Independence of long-term contextual memory and short-term perceptual hypotheses: Evidence from contextual cueing of interrupted search

Observers are able to resume an interrupted search trial faster relative to responding to a new, unseen display. This finding of rapid resumption is attributed to short-term perceptual hypotheses generated on the current look and confirmed upon subsequent looks at the same display. It has been suggested that the contents of perceptual hypotheses are similar to those of other forms of memory acquired long-term through repeated exposure to the same search displays over the course of several trials, that is, the memory supporting “contextual cueing.” In three experiments, we investigated the relationship between short-term perceptual hypotheses and long-term contextual memory. The results indicated that long-term, contextual memory of repeated displays neither affected the generation nor the confirmation of short-term perceptual hypotheses for these displays. Furthermore, the analysis of eye movements suggests that long-term memory provides an initial benefit in guiding attention to the target, whereas in subsequent looks guidance is entirely based on short-term perceptual hypotheses. Overall, the results reveal a picture of both long- and short-term memory contributing to reliable performance gains in interrupted search, while exerting their effects in an independent manner.     

Are abilities dispositions?

Synthese - Abilities are in many ways central to what being an agent means, and they are appealed to in philosophical accounts of a great many different phenomena. It is often assumed that...     

Body Experience After Liver Transplantation: A Body Grid Examination

Living with a donated organ raises not only clinical aspects, such as surgery risks and possible graft rejection, but also questions regarding the psychological integration of the donor organ and the recipient's body experience. Organ recipients need to cope with the transplantation and its impact on their bodies and lives. This study presents findings concerning the psychological outcome of liver recipients and their body experience after transplantation. The focus lies on the psychological integration of the liver by the recipients and on differences in the body experience between recipients of a living liver donation (LDLT) and a deceased donor donation (LTx). To study the subjective body experience and the donor-organ integration, we used the body grid, a modification of the repertory grid technique pioneered by Kelly (1955 Kelly, G.A. (1955). The psychology of personal constructs. New York, NY: Norton. [Google Scholar]). This technique allows both a quantitative and a qualitative research approach. We examined 22 liver recipients (12 LDLT; 10 LTx), matched for age, gender, years since transplantation, and type of liver disease. Additionally, quality of life data were collected using the Short Form-8 health survey (SF-8), along with sociodemographic data, including the current living situation, changes after transplantation, living donor data, and the donor-recipient relationship for the LDLT cases. Correlations between the SF-8 scores and the element distances were calculated. The results depict the recipients’ body experiences after liver transplantation, the psychological integration of the transplanted organ, and correlations between quality of life and organ integration. Differences between the LDLT and LTx group are discussed, as well as implications for improving the treatment and psychological support of the recipients.     

Electrophysiological markers of visual dimension changes and response changes

In cross-dimensional visual search tasks, target discrimination is faster when the previous trial contained a target defined in the same visual dimension as the current trial. The dimension-weighting account (DWA; A. Found & H. J. Müller, 1996) explains this intertrial facilitation by assuming that visual dimensions are weighted at an early perceptual stage of processing. Recently, this view has been challenged by models claiming that intertrial facilitation effects are generated at later stages that follow attentional target selection (K. Mortier, J. Theeuwes, & P. A. Starreveld, 2005). To determine whether intertrial facilitation is generated at a perceptual stage, at the response selection stage, or both, the authors focused on specific event-related brain potential components (directly linkable to perceptual and response-related processing) during a compound search task. Visual dimension repetitions were mirrored by shorter latencies and enhanced amplitudes of the N2-posterior- contralateral, suggesting a facilitated allocation of attentional resources to the target. Response repetitions and changes systematically modulated the lateralized readiness potential amplitude, suggesting a benefit from residual activations of the previous trial biasing the correct response. Overall, the present findings strengthen the DWA by indicating a perceptual origin of dimension change costs in visual search.