97 research outputs found
Two (or three) is one too many : testing the flexibility of contextual cueing with multiple target locations
No full textVisual search for a target object is facilitated when the object is repeatedly presented within an invariant context of surrounding items ("contextual cueing"; Chun & Jiang, Cognitive Psychology, 36, 28-71, 1998). The present study investigated whether such invariant contexts can cue more than one target location. In a series of three experiments, we showed that contextual cueing is significantly reduced when invariant contexts are paired with two rather than one possible target location, whereas no contextual cueing occurs with three distinct target locations. Closer data inspection revealed that one "dominant" target always exhibited substantially more contextual cueing than did the other, "minor" target(s), which caused negative contextual-cueing effects. However, minor targets could benefit from the invariant context when they were spatially close to the dominant target. In sum, our experiments suggest that contextual cueing can guide visual attention to a spatially limited region of the display, only enhancing the detection of targets presented inside that region
Here today, gone tomorrow - adaptation to change in memory-guided visual search
No full textVisual search for a target object can be facilitated by the repeated presentation of an invariant configuration of nontargets ('contextual cueing'). Here, we tested adaptation of learned contextual associations after a sudden, but permanent, relocation of the target. After an initial learning phase targets were relocated within their invariant contexts and repeatedly presented at new locations, before they returned to the initial locations. Contextual cueing for relocated targets was neither observed after numerous presentations nor after insertion of an overnight break. Further experiments investigated whether learning of additional, previously unseen context-target configurations is comparable to adaptation of existing contextual associations to change. In contrast to the lack of adaptation to changed target locations, contextual cueing developed for additional invariant configurations under identical training conditions. Moreover, across all experiments, presenting relocated targets or additional contexts did not interfere with contextual cueing of initially learned invariant configurations. Overall, the adaptation of contextual memory to changed target locations was severely constrained and unsuccessful in comparison to learning of an additional set of contexts, which suggests that contextual cueing facilitates search for only one repeated target location
Right parietal rTMS induces bidirectional effects of selective attention upon object integration
No full textThe time-course of global and local attentional guidance in Kanizsa-Figure detection
No full textObject configurations can be perceptually represented at various hierarchical levels. For example, in visual search, global Kanizsa figures are detected efficiently, whereas search for local groupings is inefficient, with similarity-dependent nontarget interference arising at the hierarchical level that defines the target (Conci, Müller, & Elliott, 2007). The present study was designed to examine the electrophysiological correlates of this global-local search asymmetry. The results revealed differences between hierarchical object levels to be evident throughout a number of processing stages: Search for a global, versus a local, target elicited larger amplitudes in early sensory components (P1, N1). Moreover, the efficiency of attentional orienting towards a target was mirrored in the Posterior Contralateral Negativity (PCN), with PCN latencies being substantially delayed (by not, vert, similar70 ms) with local, versus global, targets. Finally, late components (P3 and slow wave–SW) reflected the overall search efficiency, which was determined by both the hierarchical level at which the target was defined and the similarity-based nontarget interference. Taken together, this pattern shows that multiple, sequential processes of object completion contribute to the attentional precedence of a globally bound object over a mere local element grouping
Figural Completion in Visual Search
No full textDie Integration von Teilfragmenten zu einem kohärenten und zusammenhängenden Objekt stellt einen wesentlichen Aspekt der visuellen Informationsverarbeitung dar. In der vorliegenden, kumulativen Dissertation wird diese Frage der Objektintegration untersucht indem Figurbildungsmechanismen und deren Rolle für die visuelle Suche analysiert werden. In einer Reihe von Experimenten mit virtuellen Figurkonfigurationen (‚Kanizsa’ Figuren) konnte gezeigt werden, dass die Sucheffizienz von der integrierten Formrepräsentation einzelner Objektfragmente abhängt. Die Steuerung von Suchprozessen lässt sich demnach auf Basis eines Extraktionsmechanismus verstehen, der vorhandene visuelle Informationen zu salienten Regionen gruppiert bzw. segmentiert und auf formsensitive Verarbeitungsprozesse in okzipito-parietalen Arealen zurückgreift. Komplementär zu diesen Mechanismen der figuralen Segmentation konnte zudem in einer weiteren Experimentalserie gezeigt werden, dass auch aufgabenrelevante Charakteristika auf gruppierungsspezifische Suchprozesse einwirken können. Somit sind Figurbildungsprozesse in der visuellen Suche sowohl durch die Berechnung einer salienten Region als auch durch entsprechende Anforderungen der Aufgabe modifizierbar und erklärbar
Building energy retrofit-as-a-service: a Total Value of Ownership assessment methodology to support whole life-cycle building circularity and decarbonisation: Construction Management and Economics
No full textThe regulatory drive to accelerate the clean energy and circular economy transitions in the European building stock is currently failing to overcome systemic implementation barriers. These barriers include high initial investment costs, misaligned financial incentives among stakeholders, and the relatively low cost of less sustainable energy and materials. A Product-Service Systems (PSS) approach could successfully overcome many of these barriers by (1) outsourcing capital investment, as well as financial and technical risks, (2) providing shared economic incentives to collaborating stakeholders, and (3) retaining extended producer responsibility and ownership over materials and products. However, PSS is still not seen as a viable business model when compared to both a standard “ownership” contract and a “no-retrofit” scenario. This paper proposes a Total Value of Ownership (TVO) method to evaluate the financial performance of a building energy retrofit in terms of Net Present Value, comparing a matrix of scenarios. Results show that – when accounting for capital and opportunity costs tied to alternative investments, internalising externalities, and monetising soft values such as user productivity and property value – a PSS model can deliver the highest NPV. Furthermore, results show that a PSS alternative can act as a positive future-proofing strategy to safeguard the building owner’s position in the face of uncertain future market indicators and carbon taxation. Recommendations for policymakers, investors, financiers, building owners, and end-users are presented to identify the economic value of PSS contracts, leading to better-informed decisions which can accelerate deep energy retrofit of the building stock.Building Product Innovatio
A Zero Energy terminal building for Amsterdam Airport Schiphol
No full textA methodology to reach energy neutrality, applicable to any commercial building, presented with the case-study of the project for a new terminal building for Schiphol.Building TechnologyArchitecture and The Built Environmen
The role of unique color changes and singletons in attention capture
No full textPrevious studies have shown that a sudden color change is typically less salient in capturing attention than the onset of a new object. Von Mühlenen, Rempel, and Enns (Psychological Science 16: 979-986, 2005) showed that a color change can capture attention as effectively as the onset of a new object given that it occurs during a period of temporal calm, where no other display changes happen. The current study presents a series of experiments that further investigate the conditions under which a change in color captures attention, by disentangling the change signal from the onset of a singleton. The results show that the item changing color receives attentional priority irrespective of whether this change goes along with the appearance of a singleton or not
The effect of task-irrelevant objects in spatial contextual cueing
No full textDuring visual search, the spatial configuration of the stimuli can be learned when the same displays are presented repeatedly, thereby guiding attention more efficiently to the target location (contextual cueing effect). This study investigated how the presence of a task-irrelevant object influences the contextual cueing effect. Experiment 1 used a standard T/L search task with “old” display configurations presented repeatedly among “new” displays. A green-filled square appeared at unoccupied locations within the search display. The results showed that the typical contextual cueing effect was strongly reduced when a square was added to the display. In Experiment 2, the contextual cueing effect was reinstated by simply including trials where the square could appear at an occupied location (i.e., underneath the search stimuli). Experiment 3 replicated the previous experiment, showing that the restored contextual cueing effect did not depend on whether the square was actually overlapping with a stimulus or not. The final two experiments introduced a display change in the last epoch. The results showed that the square does not only hinder the acquisition of contextual information but also its manifestation. These findings are discussed in terms of an account where effective contextual learning depends on whether the square is perceived as part of the search display or as part of the display background
Limitations of perceptual segmentation on contextual cueing in visual search
No full textIn visual search, detection of a target in a repeated layout is faster than search within a novel arrangement, demonstrating that contextual invariances can implicitly guide attention to the target location (“contextual cueing”; Chun & Jiang, 1998). Here, we investigated how display segmentation processes influence contextual cueing. Seven experiments showed that grouping by colour and by size can considerably reduce contextual cueing. However, selectively attending to a relevant subgroup of items (that contains the target) preserved context-based learning effects. Finally, the reduction of contextual cueing by means of grouping affected both the latent learning and the recall of display layouts. In sum, all experiments show an influence of grouping on contextual cueing. This influence is larger for variations of spatial (as compared to surface) features and is consistent with the view that learning of contextual relations critically interferes with processes that segment a display into segregated groups of items
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