According to the spreading hypothesis of object-based attention, a subliminal cue that can successfully capture attention to a location within an object should also cause attention to spread throughout the whole cued object and lead to the same-object advantage. Instead, we propose that a subliminal cue favors shifts of attention between objects and strengthens the between-object link, which is coded primarily within the dorsal pathway that governs the visual guidance of action. By adopting the two-rectangle method and using an effective (...) subliminal cue to compare with the classic suprathreshold cue, we found a different result pattern with suprathreshold cues than with subliminal cues. The suprathreshold cue replicated the conventional location and object effects, whereas a subliminal cue led to a different-object advantage with a facilitatory location effect and a same-object advantage with an inhibitory location effect. These results support our consciousness-dependent shifting hypothesis but not the spreading hypothesis. (shrink)

Intercellular signaling plays an important role in spatially regulated developmental processes. Myxococcus xanthus C signal transmission during fruiting body formation requires motile, densely packed, well aligned cells. tThe fruiting body consists of two domains: an outer domain which has densely packed, well aligned, motile cells: and an inner domain of more loosely packed, non‐motile, sporulating cells. The two domains are characterized by different patterns of C‐dependent gene expression, which begins in the outer domain where C‐signaling is most efficient, and reaches (...) its maximum in the inner domain. These domains may be maintained by a dynamic mechanism which relies on passive transport of the sporulating cells from the outer domain, where sporulation is initiated, to the inner domain by the motile cells in the outer domain. (shrink)

Planar cell polarity, the polarization of cells within the plane of the epithelium, orthogonal to the apical‐basal axis, is essential for a growing list of developmental events, and – over the last 15 years – has evolved from a little‐studied curiosity in Drosophila to the subject of a substantial research enterprise. In that time, it has been recognized that two molecular systems are responsible for polarization of most tissues: Both the “core” Frizzled system and the “global” Fat/Dachsous/Four‐jointed system produce molecular (...) asymmetry within cells, and contribute to morphological polarization. In this review, we discuss recent findings on the molecular mechanism that links “global” directional signals with local coordinated polarity. (shrink)

ABSTRACTSpatial cueing paradigms are popular tools to assess human attention to emotional stimuli, but different variants of these paradigms differ in what participants’ primary task is. In one variant, participants indicate the location of the target, whereas in the other they indicate the shape of the target. In the present paper we test the idea that although these two variants produce seemingly comparable cue validity effects on response times, they rest on different underlying processes. Across four studies using both (...) variants and manipulating the motivational relevance of cue content, diffusion model analyses revealed that cue validity effects in location tasks are primarily driven by response biases, whereas the same effect rests on delay due to attention to the cue in identification tasks. Based on this, we predict and empirically support that a symmetrical distribution of valid and invalid cues would reduce cue validity... (shrink)

Participants maneuvered a rat image through a circular region on the computer screen to find a hidden target platform, blending aspects of two well-known spatial tasks. Like the Morris water maze task, participants first experienced a series of learning trials before having to navigate to the hidden target platform from different locations and orientations. Like the dot-location task, they determined the location of a position within a two-dimensional circular region. This procedure provided a way to examine how the number (...) of surrounding cues (1, 2, or 3) affects the memory for spatial location in navigation. Memory performance was better when there were more cues and when targets were close to cues, consistent with the idea that cues bolster fine-grain memory, especially in proximal regions. Early and late measures of bias in memory reflected biases in a direction toward the nearest cue, implicating a cue-based category structure of the navigational space. Collectively, results suggest cue-based spatial memory representations that have been inferred from the dot-location task generalize to a navigation task within a simple, computer-based environment, as demonstrated by the good fits of the spatial model developed for the dot-location task (Fitting, Wedell, & Allen, 2005, 2007). (shrink)

We examined how social cues and representational ones jointly shape people's spatial memory representations and their subsequent descriptions. In 24 pairs, Directors studied an array with a symmetrical structure while either knowing their Matcher's subsequent viewpoint or not. During the subsequent description of the array, the array's intrinsic structure was aligned with the Director, the Matcher, or neither partner. According to memory tests preceding descriptions, Directors who had studied the array while aligned with its structure were more likely to (...) use its orientation as an organizing direction. Directors who had studied the array while misaligned with its structure used its orientation more frequently as an organizing orientation when knowing that the Matcher would be aligned with it, but used their own viewpoint more frequently as an organizing direction when not knowing the Matcher's viewpoint. Directors also adapted their descriptions strategically, using more egocentric expressions when aligned with the intrinsic structure and more partner-centered expressions when their Matchers were the ones aligned with the structure, even when this information wasn't available in advance. These findings suggest that speakers are guided by converging social and representational cues to adapt flexibly the organization of their memories and the perspectives of their descriptions. (shrink)

We are highly tuned to each other's visual attention. Perceiving the eye or hand movements of another person can influence the timing of a saccade or the reach of our own. However, the explanation for such spatial orienting in interpersonal contexts remains disputed. Is it due to the social appearance of the cue—a hand or an eye—or due to its social relevance—a cue that is connected to another person with attentional and intentional states? We developed an interpersonal version of (...) the Posner spatial cueing paradigm. Participants saw a cue and detected a target at the same or a different location, while interacting with an unseen partner. Participants were led to believe that the cue was either connected to the gaze location of their partner or was generated randomly by a computer (Experiment 1), and that their partner had higher or lower social rank while engaged in the same or a different task (Experiment 2). We found that spatial cue‐target compatibility effects were greater when the cue related to a partner's gaze. This effect was amplified by the partner's social rank, but only when participants believed their partner was engaged in the same task. Taken together, this is strong evidence in support of the idea that spatial orienting is interpersonally attuned to the social relevance of the cue—whether the cue is connected to another person, who this person is, and what this person is doing—and does not exclusively rely on the social appearance of the cue. Visual attention is not only guided by the physical salience of one's environment but also by the mental representation of its social relevance. (shrink)

In contrast to Constructivist Views, which construe perceptual cognition as an essentially reconstructive process, this article recommends the Deictic View, which grounds perception in perceptual-demonstrative reference and the use of deictic tracking strategies for acquiring and updating knowledge about individuals. The view raises the problem of how sensory-motor tracking connects to epistemic and integrated forms of tracking. To study the strategies used to solve this problem, we report a study of the ability to track distal individuals when only their directions (...) can be perceived and not their locations. We introduce a new experimental paradigm named the 'Modified Traveling Salesman Problem' (MTSP), which requires subjects to visit n invisible targets in a 2D display once each. Surprisingly, subjects are competent at this task for up to 10 targets. We consider two types of tracking strategies that subjects might use: 'location-based' strategies and 'deictic direction-based' strategies. A number of observations suggest that subjects used the latter, at least for larger numbers of targets. We hypothesize that subjects used perceptual-demonstrative reference and deictic strategies (i) to perform the sensory-motor tracking of directional segments, (ii) to bind the segments with their updated status in the task, and (iii) to perform the epistemic tracking of invisible targets by means of perception-based inferences. (shrink)

Last year at VSS, Bullot, Droulez & Pylyshyn reported studies using a Modified Traveling Salesman Paradigm in which a virtual vehicle had to visit up to 10 targets once and only once, and in which the invisible targets were identified only by line segments pointing from the vehicle toward each target. We hypothesized that subjects used two distinct strategies: A “location-based strategy”, which kept track of where targets were located in screen coordinates, and a “segment-based strategy” that kept track of (...) which segments corresponded to visited targets. We report new studies that further explore these two strategies. Subjects passively observed a computer-controlled virtual vehicle that visited a number of targets. Two forms of display were used: an “Allocentric” display, in which the vehicle moved and the targets remained fixed in screen coordinates, and an “Egocentric” display, in which the vehicle's position on the screen remained fixed while the targets moved -- as if the environment were being viewed by an observer on the vehicle. At the end of each trial, the directional segments were extended to the edge of the screen and subjects were asked to perform two tasks by referring to these segments. In the “status task” observers had to indicate for each segment whether the corresponding target had been visited or not. In the “locating task” they had to locate each target along its directional segment. Performance on these two tasks measures the use of the two hypothesized strategies. Results showed that observers do well on the status task with 4 or 6 targets in both display conditions, but do poorly on the locating task, especially in the egocentric condition when there are more targets. These results are consistent with the hypothesis that in the egocentric condition the MTSP task is carried out primarily by segment-tracking, which can be viewed as a deictic strategy. (shrink)

In contextual cueing, previously encountered context tends to facilitate the detection of the target embedded in it than when the target appears in a novel context. In this study, we investigated whether the contextual cueing could develop at early time when the search display was presented briefly. In four experiments, participants searched for a target T in an array of distractor Ls. The results showed that with a rather short presentation time of the search display, participants were able (...) to learn the spatial context and speeded up their response time overall, with the learning effect lasting for a long period. Specifically, the contextual cueing effect was observed either with or without a mask after a duration of 300-ms presentation of the search display. Such a context learning under rapid presentation could not operate only with the local context information repeated, thus suggesting that a global context was required to guide spatial attention when the viewing time of the search display was limited. Overall, these findings indicate that contextual cueing might arise at an “early,” target selection stage and that the global context is necessary for the context learning under rapid presentation to function. (shrink)

Neuropsychological studies suggest the existence of lateralized networks that represent categorical and coordinate types of spatial information. In addition, studies with neural networks have shown that they encode more effectively categorical spatial judgments or coordinate spatial judgments, if their input is based, respectively, on units with relatively small, nonoverlapping receptive fields, as opposed to units with relatively large, overlapping receptive fields. These findings leave open the question of whether interactive processes between spatial detectors and types of (...) spatial relations can be modulated by spatial attention. We hypothesized that spreading the attention window to encompass an area that includes two objects promotes coordinate spatial relations, based on coarse coding by large, overlapping, receptive fields. In contrast, narrowing attention to encompass an area that includes only one of the objects benefits categorical spatial relations, by effectively parsing space. By use of a cueing procedure, the spatial attention window was manipulated to select regions of differing areas. As predicted, when the attention window was large, coordinate spatial transformations were noticed faster than categorical transformations; in contrast, when the attention window was relatively smaller, categorical spatial transformations were noticed faster than coordinate transformations. Another novel finding was that coordinate changes were noticed faster when cueing an area that included both objects as well as the empty space between them than when simultaneously cueing both areas including the objects while leaving the gap between them uncued. (shrink)

The thresholds of human observers detecting line targets improve significantly when the targets are presented in a spatial context of collinear inducing stimuli. This phenomenon is referred to as spatial facilitation, and may reflect the output of long-range interactions between cortical feature detectors. Spatial facilitation has thus far been observed with luminance-defined, achromatic stimuli on achromatic backgrounds. This study compares spatial facilitation with line targets and collinear, edge-like inducers defined by luminance contrast to spatial facilitation (...) with targets and inducers defined by color contrast. The results of a first experiment show that achromatic inducers facilitate the detection of achromatic targets on gray and colored backgrounds, but tend to suppress the detection of chromatic targets. Chromatic inducers facilitate the detection of chromatic targets on gray and colored backgrounds, but tend to suppress the detection of achromatic targets. Chromatic spatial facilitation appears to be strongest when inducers and background are isoluminant. The results of a second experiment show that spatial facilitation with chromatic targets and inducers requires a longer exposure duration of the inducers than spatial facilitation with achromatic targets and inducers, which is already fully effective at an inducer exposure of 30 ms only. The findings point towards two separate mechanisms for spatial facilitation with collinear form stimuli: one that operates in the domain of luminance, and one that operates in the domain of color contrast. These results are consistent with neural models of boundary and surface formation which suggest that achromatic and chromatic visual cues are represented on different cortical surface representations that are capable of selectively attracting attention. Multiple copies of these achromatic and chromatic surface representations exist corresponding to different ranges of perceived depth from an observer, and each can attract attention to itself. Color and contrast differences between inducing and test stimuli, and transient responses to inducing stimuli, can cause attention to shift across these surface representations in ways that sometimes enhance and sometimes interfere with target detection. (shrink)

Theories of autobiographical memory emphasise effortful, generative search processes in memory retrieval. However recent research suggests that memories are often retrieved directly, without effortful search. We investigated whether direct and generative retrieval differed in the characteristics of memories recalled, or only in terms of retrieval latency. Participants recalled autobiographical memories in response to cue words. For each memory, they reported whether it was retrieved directly or generatively, rated its visuo-spatial perspective, and judged its accompanying recollective experience. Our results indicated (...) that direct retrieval was commonly reported and was faster than generative retrieval, replicating recent findings. The characteristics of directly retrieved memories differed from generatively retrieved memories: directly retrieved memories had higher field perspective ratings and lower observer perspective ratings. However, retrieval mode did not influence recollective experience. We discuss our findings in terms of cue generation and content construction, and the implication for reconstructive models of autobiographical memory. (shrink)

The valence–arousal conflict theory assumes that both valence and arousal will trigger approaching or withdrawing tendencies. It also predicts that the speed of processing emotional stimuli will depend on whether valence and arousal trigger conflicting or congruent motivational tendencies. However, most previous studies have provided evidence of the interaction between valence and arousal only, and have not provided direct proof of the interactive links between valence, arousal and motivational tendencies. The present study provides direct evidence for the relationship between approach–withdrawal (...) tendencies and the valence–arousal conflict. In an empirical test, participants were instructed to judge the valence of emotional words after visual–spatial cues that appeared to be either approaching or withdrawing from participants. A three-way interaction was observed such that the response time was shorter if participants responded to a negative high-arousal stimulus after a withdrawing cue, or to a positive low-arousal stimulus after an approaching cue. These findings suggest that the approach–withdrawal tendency indeed plays a crucial role in valence–arousal conflict, and that the effect depends on the congruency of valence, arousal and tendency at an early stage of processing. (shrink)

Cue labels are useful during multimedia learning. According to spatial contiguity principle, people learn more when related words and pictures are displayed spatially near one another. Well-arranged labels of multimedia material can greatly facilitate learning. This study used eye tracking to examine the joint influence of label size and color on multimedia learning. The results revealed that larger labels led to better retention test performance and a higher AOI glance count, but no cueing effect was found for color. (...) Cues have a certain attention-leading function that promotes the learner remembering the content. These findings suggest that salient labels that provide explanatory information can guide learners’ attention and facilitate learning, though a combination of label size and color salience did not demonstrate a superior cueing effect. (shrink)

Visual attentional processes have been an important topic in psychological research for years. Over the last few decades, new methods have been developed, aiming to explore the characteristics of the focus of attention in more detail. Studies that applied the “Attention-Window Task” quantified the maximum extent of the “Attention Window” along its horizontal, vertical, and diagonal meridians, when subjects were required to perceive two peripheral stimuli simultaneously. In three experiments using the AWT, we investigated the effects of cue validity, stimulus-onset (...) asynchrony, and target stimuli complexity on the size and shape of the AW. Results showed that the AW was greater under valid cue conditions compared to invalid conditions, when the locations of cue and target stimuli differed. Furthermore, the AW decreased when the SOA between the cue and targets was reduced and also when the task complexity was higher and more objects within the target stimuli had to be classified. Overall, it can be stated that the AWT with its possible task changes and adjustments can be considered as a potential standard tool to measure the maximum spread and shape of the spatial AW. (shrink)

Visual, somatosensory, and perspectival cues normally provide congruent information about where the self is experienced. Separating those cues by virtual reality techniques, recent studies found that self-location was systematically biased to where a visual–tactile event was seen. Here we developed a novel, repeatable and implicit measure of self-location to compare and extend previous protocols. We investigated illusory self-location and associated phenomenological aspects in a lying body position that facilitates clinically observed abnormal self-location . The results confirm that the self is (...) located to where touch is seen. This leads to either predictable lowering or elevation of self-localization, and the latter was accompanied by sensations of floating, as during out-of-body experiences. Using a novel measurement we show that the unitary and localized character of the self can be experimentally separated from both the origin of the visual perspective and the location of the seen body, which is compatible with clinical data. (shrink)