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We describe a novel size illusion in which targets appear to either shrink or grow when enclosed within a narrow tube. The direction of size change is determined by the contrast step between display elements. We first noticed this effect in the context of the dynamic "rocking line" illusion (RLI), but it can also be easily seen in completely static displays. As with the RLI, the overall scale of the display seems to play an important role. We provide an online, interactive demo, enabling the reader to explore the relevant parameter space. [ABSTRACT FROM AUTHOR]

Can synchrony in stimulation guide attention and aid perceptual performance? Here, in a series of three experiments, we tested the influence of visual and auditory synchrony on attentional selection during a novel human foraging task. Human foraging tasks are a recent extension of the classic visual search paradigm in which multiple targets must be located on a given trial, making it possible to capture a wide range of performance metrics. Experiment 1 was performed online, where the task was to forage for 10 (out of 20) vertical lines among 60 randomly oriented distractor lines that changed color between yellow and blue at random intervals. The targets either changed colors in visual synchrony or not. In another condition, a non-spatial sound additionally occurred synchronously with the color change of the targets. Experiment 2 was run in the laboratory (within-subjects) with the same design. When the targets changed color in visual synchrony, foraging times were significantly shorter than when they randomly changed colors, but there was no additional benefit for the sound synchrony, in contrast to predictions from the so-called "pip-and-pop" effect (Van der Burg et al., Journal of Experimental Psychology, 1053-1065, 2008). In Experiment 3, task difficulty was increased as participants foraged for as many 45° rotated lines as possible among lines of different orientations within 10 s, with the same synchrony conditions as in Experiments 1 and 2. Again, there was a large benefit of visual synchrony but no additional benefit for sound synchronization. Our results provide strong evidence that visual synchronization can guide attention during multiple target foraging. This likely reflects the local grouping of the synchronized targets. Importantly, there was no additional benefit for sound synchrony, even when the foraging task was quite difficult (Experiment 3). [ABSTRACT FROM AUTHOR]

"No regrets" buying - using Advance Purchase Agreements (APAs) - has characterized the response to recent pandemics such as Avian flu, Zika Virus, and now COVID-19. APAs are used to reduce demand uncertainty for product developers and manufacturers; to hedge against R&D and manufacturing risks; and to secure availability of products in the face of spiking demand. Evidence on the use of APAs to buy vaccines, medicines, diagnostics, and personal protective equipment during recent pandemics illustrates how these contracts can achieve their intended objectives for buyers. But, transferring risk from suppliers to buyers - as APAs do - can have consequences, including overbuying and overpaying. Furthermore, the widespread use of APAs by high-income countries has contributed to the striking inequities that have characterized the Swine flu and COVID-19 responses, delaying access to vaccines and other supplies for low- and middle-income countries (L&MICs).We identify seven ways to address some of the risks and disadvantages of APAs, including adoption of a global framework governing how countries enter into APAs and share any resulting supplies; voluntary pooling through joint or coordinated APAs; a concessional-capital-backed facility to allow international buyers and L&MICs to place options on products as an alternative to full purchase commitments; greater collection and sharing of market information to help buyers place smarter APAs; support for a resale market; building in mechanisms for donation from the outset; and transitioning away from APAs as markets mature. While a binding global framework could in theory prevent the competitive buying and hoarding that have characterized country/state responses to pandemics, it will be very challenging to put in place. The other solutions, while less sweeping, can nonetheless mitigate both the inequities associated with the current uncoordinated use of APAs and also some of the risks to individual buyers.Analysis of recent experiences can provide useful lessons on APAs for the next pandemic. It will be important to keep in mind, however, that these contractual instruments work by transferring risk to the buyer, and that buyers must therefore accept the consequences. In the spirit of "no regrets" purchasing, having bought what hindsight suggests was too much is generally preferable to having bought not enough. [ABSTRACT FROM AUTHOR]

Human foraging tasks are beginning to provide new insights into the roles of vision, attention, and working memory during complex, multiple-target search. Here, we test the idea that "foraging tempo"—the rate of successive target selections—helps determine patterns of behaviour in these tasks. Previously, we established that the majority of target selections during unconstrained foraging happen at regular, rapid intervals, forming the "cruise phase" of a foraging trial. Furthermore, we noted that when the temporal interval between cruise phase responses was longer, the tendency to switch between target categories increased. To directly explore this relationship, we modified our standard iPad foraging task so that observers had to synchronise each response with an auditory metronome signal. Across trials, we increased the tempo and examined how this changed patterns of foraging when targets were defined either by a single feature or by a conjunction of features. The results were very clear. Increasing tempo systematically decreased the tendency for participants to switch between target categories. Although this was true for both feature and conjunction trials, there was also evidence that time constraints and target complexity interacted. As in our previous work, we also observed clear individual differences in how participants responded to changes in task difficulty. Overall, our results show that foraging tempo does influence the way participants respond, and we suggest this parameter may prove to be useful in further explorations of group and individual strategies during multiple-target search. [ABSTRACT FROM AUTHOR]

Although subjective cognitive impairment (SCI) is increasingly recognized clinically and in research as a risk factor for mild cognitive impairment and dementia (particularly Alzheimer's disease), it is etiologically heterogeneous and potentially treatable. Compared to mild cognitive impairment and Alzheimer's disease, SCI however remains poorly characterized with debate continuing regarding its clinical relevance. The primary aim of this study was to improve the characterization of SCI within the general public by investigating functions sometimes omitted clinically or in research, namely visual attention-related information processing speed (RT) and its intra-individual variability (IIVRT), general cognition, depression, anxiety, memory, quality of life (QOL), and neuroticism. Compared to individuals without SCI, those with SCI were more likely to reveal higher scores of anxiety, depression, and neuroticism and poorer perceived physical, psychological, and environmental QOL. Within-group analysis identified no significant relationships between any of the above variables for the non-SCI group whereas for the SCI group, poorer Cognitive Change Index scores were significantly correlated with slower RT, raised IIVRT, poorer memory, negative affective symptoms, higher neuroticism scores, and poorer QOL. This indicates that reports of perceived memory changes in SCI can also be associated with other characteristics, namely objectively measured detrimental change in other aspects of brain function and behavior. This outcome emphasizes the importance of a multi-function approach to characterizing and understanding SCI. Thus, although the effect of RT and IIVRT is not strong enough to differentiate SCI from non-SCI at group level, slowing and raised IIVRT do appear to characterize some people with SCI. [ABSTRACT FROM AUTHOR]

Attention is known to play an important role in shaping the behaviour of both human and animal foragers. Here, in three experiments, we built on previous interactive tasks to create an online foraging game for studying divided attention in human participants exposed to the (simulated) risk of predation. Participants used a "sheep" icon to collect items from different target categories randomly distributed across the display. Each trial also contained "wolf" objects, whose movement was inspired by classic studies of multiple object tracking. When participants needed to physically avoid the wolves, foraging patterns changed, with an increased tendency to switch between target categories and a decreased ability to prioritise high reward targets, relative to participants who could safely ignore them. However, when the wolves became dangerous by periodically changing form (briefly having big eyes) instead of by approaching the sheep, foraging patterns were unaffected. Spatial disruption caused by the need to rapidly shift position—rather the cost of reallocating attention—therefore appears to influence foraging in this context. These results thus confirm that participants can efficiently alternate between target selection and tracking moving objects, replicating earlier single-target search findings. Future studies may need to increase the perceived risk or potential costs associated with simulated danger, in order to elicit the extended run behaviour predicted by animal models of foraging, but absent in the current data. [ABSTRACT FROM AUTHOR]

Several lines of evidence point to the existence of a visual processing advantage for horizontal over vertical orientations. We investigated whether such a horizontal advantage exists in the context of top-down visual search. Inspired by change detection studies, we created displays where a dynamic target -- a horizontal or a vertical group of five dots that changed contrast synchronously -- was embedded within a randomly flickering grid of dots. The display size (total dots) varied across trials, and the orientation of the target was constant within interleaved blocks. As expected, search was slow and inefficient. Importantly, participants were almost a second faster finding horizontal compared to vertical targets. They were also more efficient and more accurate during horizontal search. Such findings establish that the attentional templates thought to guide search for known targets can exhibit strong orientation anisotropies. We discuss possible underlying mechanisms and how these might be explored in future studies. [ABSTRACT FROM AUTHOR]

The accurate perception of human crowds is integral to social understanding and interaction. Previous studies have shown that observers are sensitive to several crowd characteristics such as average facial expression, gender, identity, joint attention, and heading direction. In two experiments, we examined ensemble perception of crowd speed using standard point-light walkers (PLW). Participants were asked to estimate the average speed of a crowd consisting of 12 figures moving at different speeds. In Experiment 1, trials of intact PLWs alternated with trials of scrambled PLWs with a viewing duration of 3 seconds. We found that ensemble processing of crowd speed could rely on local motion alone, although a globally intact configuration enhanced performance. In Experiment 2, observers estimated the average speed of intact-PLW crowds that were displayed at reduced viewing durations across five blocks of trials (between 2500 ms and 500 ms). Estimation of fast crowds was precise and accurate regardless of viewing duration, and we estimated that three to four walkers could still be integrated at 500 ms. For slow crowds, we found a systematic deterioration in performance as viewing time reduced, and performance at 500 ms could not be distinguished from a single-walker response strategy. Overall, our results suggest that rapid and accurate ensemble perception of crowd speed is possible, although sensitive to the precise speed range examined. [ABSTRACT FROM AUTHOR]

We used the Multi-Item Localisation (MILO) task to examine search through two sequences. In Sequential blocks of trials, six letters and six digits were touched in order. In Mixed blocks, participants alternated between letters and digits. These conditions mimic the A and B variants of the Trail Making Test (TMT). In both block types, targets either vanished or remained visible after being touched. There were two key findings. First, in Mixed blocks, reaction times exhibited a saw-tooth pattern, suggesting search for successive pairs of targets. Second, reaction time patterns for vanish and remain conditions were identical in Sequential blocks—indicating that participants could ignore past targets—but diverged in Mixed blocks. This suggests a breakdown of inhibitory tagging. These findings may help explain the elevated completion times observed in TMT-B, relative to TMT-A. [ABSTRACT FROM AUTHOR]

We used the Multi-Item Localisation (MILO) task to examine search through two sequences. In Sequential blocks of trials, six letters and six digits were touched in order. In Mixed blocks, participants alternated between letters and digits. These conditions mimic the A and B variants of the Trail Making Test (TMT). In both block types, targets either vanished or remained visible after being touched. There were two key findings. First, in Mixed blocks, reaction times exhibited a sawtooth pattern, suggesting search for successive pairs of targets. Second, reaction time patterns for vanish and remain conditions were identical in Sequential blocks--indicating that participants could ignore past targets--but diverged in Mixed blocks. This suggests a breakdown of inhibitory tagging. These findings may help explain the elevated completion times observed in TMT-B, relative to TMT-A. [ABSTRACT FROM AUTHOR]

This article introduces a mobile app version of the Multi-Item Localization (MILO) task. The MILO task was designed to explore the temporal context of search through a sequence and has proven useful in both basic and applied research settings. Here, we describe the basic features of the app and how it can be obtained, installed, and modified. We also provide example data files and present two new sets of empirical data to verify that previous findings concerning prospective planning and retrospective memory (i.e., inhibitory tagging) are reproducible with the app. We conclude by discussing ongoing studies and future modifications that illustrate the flexibility and potential of the MILO Mobile app. [ABSTRACT FROM AUTHOR]

This article introduces a mobile app version of the Multi-Item Localization (MILO) task. The MILO task was designed to explore the temporal context of search through a sequence and has proven useful in both basic and applied research settings. Here, we describe the basic features of the app and how it can be obtained, installed, and modified. We also provide example data files and present two new sets of empirical data to verify that previous findings concerning prospective planning and retrospective memory (i.e., inhibitory tagging) are reproducible with the app. We conclude by discussing ongoing studies and future modifications that illustrate the flexibility and potential of the MILO Mobile app. [ABSTRACT FROM AUTHOR]

In a previous series of studies, we have shown that search for human targets in the context of natural scenes is more efficient than search for mechanical targets. Here we asked whether this search advantage extends to other categories of biological objects. We used videos of natural scenes to directly contrast search efficiency for animal and human targets among biological or nonbiological distractors. In visual search arrays consisting of two, four, six, or eight videos, observers searched for animal targets among machine distractors, and vice versa (Exp. 1). Another group searched for animal targets among human distractors, and vice versa (Exp. 2). We measured search slope as a proxy for search efficiency, and complemented the slope with eye movement measurements (fixation duration on the target, as well as the proportion of first fixations landing on the target). In both experiments, we observed no differences in search slopes or proportions of first fixations between any of the target–distractor category pairs. With respect to fixation durations, we found shorter on-target fixations only for animal targets as compared to machine targets (Exp. 1). In summary, we did not find that the search advantage for human targets over mechanical targets extends to other biological objects. We also found no search advantage for detecting humans as compared to other biological objects. Overall, our pattern of findings suggests that search efficiency in natural scenes, as elsewhere, depends crucially on the specific target–distractor categories. [ABSTRACT FROM AUTHOR]

In a series of four experiments, standard visual search was used to explore whether the onset of illusory motion pre-attentively guides vision in the same way that the onset of real-motion is known to do. Participants searched for target stimuli based on Akiyoshi Kitaoka's classic illusions, configured so that they either did or did not give the subjective impression of illusory motion. Distractor items always contained the same elements as target items, but did not convey a sense of illusory motion. When target items contained illusory motion, they popped-out, with flat search slopes that were independent of set size. Search for control items without illusory motion – but with identical structural differences to distractors – was slow and serial in nature (> 200 ms/item). Using a nulling task, we estimated the speed of illusory rotation in our displays to be approximately 2 °/s. Direct comparison of illusory and real-motion targets moving with matched velocity showed that illusory motion targets were detected more quickly. Blurred target items that conveyed a weak subjective impression of illusory motion gave rise to serial but faster (< 100 ms/item) search than control items. Our behavioral findings of parallel detection across the visual field, together with previous imaging and neurophysiological studies, suggests that relatively early cortical areas play a causal role in the perception of illusory motion. Furthermore, we hope to re-emphasize the way in which visual search can be used as a flexible, objective measure of illusion strength. [ABSTRACT FROM AUTHOR]

Traditional search tasks have taught us much about vision and attention. Recently, several groups have begun to use multiple-target search to explore more complex and temporally extended “foraging” behaviour. Many of these new foraging tasks, however, maintain the simplified 2D displays and response demands associated with traditional, single-target visual search. In this respect, they may fail to capture important aspects of real-world search or foraging behaviour. In the current paper, we present a serious game for mobile platforms, developed in Unity3D, in which human participants play the role of an animal foraging for food in a simulated 3D environment. Game settings can be adjusted, so that, for example, custom target and distractor items can be uploaded, and task parameters, such as the number of target categories or target/distractor ratio are all easy to modify. We are also making the Unity3D project available, so that further modifications can also be made. We demonstrate how the app can be used to address specific research questions by conducting two human foraging experiments. Our results indicate that in this 3D environment, a standard feature/conjunction manipulation does not lead to a reduction in foraging runs, as it is known to do in simple, 2D foraging tasks. [ABSTRACT FROM AUTHOR]

In previous studies, we have used an iPad task to explore how humans "forage" through static displays containing multiple targets from two categories. When demands on attention were increased, foraging patterns tended to shift from random category selection to exhaustive category selection. Here, we used the same task on a vertically oriented touch-screen. In separate blocks, static or dynamic target items were selected using different modalities, specifically: (a) mouse (b) touchscreen or (c) infrared hand tracker. Although the different selection modalities varied considerably in terms of familiarity and difficulty of use, there was a minimal effect on the patterns of foraging. While there was a consistent reduction in the number of category switches with increased attentional load, the tendency to use exhaustive runs was much reduced, particularly with dynamic displays. We suggest that this pattern is a consequence of generally slowed response times. These findings indicate that in addition to capacity limits, temporal constraints are likely to be an important determinant of foraging patterns in humans. We introduce the term "foraging tempo" to capture this latter notion and to emphasize the probable role played by the overall pace of the regular, repetitive selections required during multi-target search tasks. [ABSTRACT FROM AUTHOR]

Person recognition is an important human ability. The main source of information we use to recognize people is the face. However, there is a variety of other information that contributes to person recognition, and the face is almost exclusively perceived in the presence of a moving body. Here, we used recent motion capture and computer animation techniques to quantitatively explore the impact of body motion on person recognition. Participants were familiarized with two animated avatars each performing the same basic sequence of karate actions with slight idiosyncratic differences in the body movements. The body of both avatars was the same, but they differed in their facial identity and body movements. In a subsequent recognition task, participants saw avatars whose facial identity consisted of morphs between the learned individuals. Across trials, each avatar was seen animated with sequences taken from both of the learned movement patterns. Participants were asked to judge the identity of the avatars. The avatars that contained the two original heads were predominantly identified by their facial identity regardless of body motion. More importantly however, participants identified the ambiguous avatar primarily based on its body motion. This clearly shows that body motion can affect the perception of identity. Our results also highlight the importance of taking into account the face in the context of a body rather than solely concentrating on facial information for person recognition. [ABSTRACT FROM PUBLISHER]

Mobile technologies, such as tablet devices, open up new possibilities for health-related diagnosis, monitoring, and intervention for older adults and healthcare practitioners. Current evaluations of cognitive integrity typically occur within clinical settings, such as memory clinics, using pen and paper or computer-based tests. In the present study, we investigate the challenges associated with transferring such tests to touch-based, mobile technology platforms from an older adult perspective. Problems may include individual variability in technical familiarity and acceptance; various factors influencing usability; acceptability; response characteristics and thus validity per se of a given test. For the results of mobile technologybased tests of reaction time to be valid and related to disease status rather than extraneous variables, it is imperative the whole test process is investigated in order to determine potential effects before the test is fully developed. Researchers have emphasized the importance of including the 'user' in the evaluation of such devices; thus we performed a focus group-based qualitative assessment of the processes involved in the administration and performance of a tablet-based version of a typical test of attention and information processing speed (a multi-item localization task), to younger and older adults.We report that although the test was regarded positively, indicating that using a tablet for the delivery of such tests is feasible, it is important for developers to consider factors surrounding user expectations, performance feedback, and physical response requirements and to use this information to inform further research into such applications. [ABSTRACT FROM AUTHOR]

A popular model of the function of selective visual attention involves search where a single target is to be found among distractors. For many scenarios, a more realistic model involves search for multiple targets of various types, since natural tasks typically do not involve a single target. Here we present results from a novel multiple-target foraging paradigm. We compare finger foraging where observers cancel a set of predesignated targets by tapping them, to gaze foraging where observers cancel items by fixating them for 100 ms. During finger foraging, for most observers, there was a large difference between foraging based on a single feature, where observers switch easily between target types, and foraging based on a conjunction of features where observers tended to stick to one target type. The pattern was notably different during gaze foraging where these condition differences were smaller. Two conclusions follow: (a) The fact that a sizeable number of observers (in particular during gaze foraging) had little trouble switching between different target types raises challenges for many prominent theoretical accounts of visual attention and working memory. (b) While caveats must be noted for the comparison of gaze and finger foraging, the results suggest that selection mechanisms for gaze and pointing have different operational constraints. [ABSTRACT FROM AUTHOR]

The article focuses on the topic of processing biological motion (BM) and its genetic aspects. It discusses on the understanding, complexities, and interrelated skills of biological motion in the social world. The understanding is based on the social cognition, perception, and perceptual levels in the neural networks. The local motion is designed on genetic techniques of behavior and individual performance.

The human body is a highly familiar and socially very important object. Does this mean that the human body has a special status with respect to visual attention? In the current paper we tested whether people in natural scenes attract attention and “pop out” or, alternatively, are at least searched for more efficiently than targets of another category (machines). Observers in our study searched a visual array for dynamic or static scenes containing humans amidst scenes containing machines and vice versa. The arrays consisted of 2, 4, 6 or 8 scenes arranged in a circular array, with targets being present or absent. Search times increased with set size for dynamic and static human and machine targets, arguing against pop out. However, search for human targets was more efficient than for machine targets as indicated by shallower search slopes for human targets. Eye tracking further revealed that observers made more first fixations to human than to machine targets and that their on-target fixation durations were shorter for human compared to machine targets. In summary, our results suggest that searching for people in natural scenes is more efficient than searching for other categories even though people do not pop out. [ABSTRACT FROM AUTHOR]

Local motion is known to produce strong illusory displacement in the perceived position of globally static objects. For example, if a dot-cloud or grating drifts to the left within a stationary aperture, the perceived position of the whole aperture will also be shifted to the left. Previously, we used a simple tracking task to demonstrate that active control over the global position of an object did not eliminate this form of illusion. Here, we used a new iPad task to directly compare the magnitude of illusory displacement under active and passive conditions. In the active condition, participants guided a drifting Gabor patch along a virtual slalom course by using the tilt control of an iPad. The task was to position the patch so that it entered each gate at the direct center, and we used the left/right deviations from that point as our dependent measure. In the passive condition, participants watched playback of standardized trajectories along the same course. We systematically varied deviation from midpoint at gate entry, and participants made 2AFC left/right judgments. We fitted cumulative normal functions to individual distributions and extracted the point of subjective equality (PSE) as our dependent measure. To our surprise, the magnitude of displacement was consistently larger under active than under passive conditions. Importantly, control conditions ruled out the possibility that such amplification results from lack of motor control or differences in global trajectories as performance estimates were equivalent in the two conditions in the absence of local motion. Our results suggest that the illusion penetrates multiple levels of the perception-action cycle, indicating that one important direction for the future of perceptual illusions may be to more fully explore their influence during active vision. [ABSTRACT FROM AUTHOR]

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Predators are known to select food of the same type in non-random sequences or “runs” that are longer than would be expected by chance. If prey are conspicuous, predators will switch between available sources, interleaving runs of different prey types. However, when prey are cryptic, predators tend to focus on one food type at a time, effectively ignoring equally available sources. This latter finding is regarded as a key indicator that animal foraging is strongly constrained by attention. It is unknown whether human foraging is equally constrained. Here, using a novel iPad task, we demonstrate for the first time that it is. Participants were required to locate and touch 40 targets from 2 different categories embedded within a dense field of distractors. When individual target items “popped-out” search was organized into multiple runs, with frequent switching between target categories. In contrast, as soon as focused attention was required to identify individual targets, participants typically exhausted one entire category before beginning to search for the other. This commonality in animal and human foraging is compelling given the additional cognitive tools available to humans, and suggests that attention constrains search behavior in a similar way across a broad range of species. [ABSTRACT FROM AUTHOR]

For the past century, researchers have extensively studied human face processing and its development. These studies have advanced our understanding of not only face processing, but also visual processing in general. However, most of what we know about face processing was investigated using static face images as stimuli. Therefore, an important question arises: to what extent does our understanding of static face processing generalize to face processing in real-life contexts in which faces are mostly moving? The present article addresses this question by examining recent studies on moving face processing to uncover the influence of facial movements on face processing and its development. First, we describe evidence on the facilitative effects of facial movements on face recognition and two related theoretical hypotheses: the supplementary information hypothesis and the representation enhancement hypothesis. We then highlight several recent studies suggesting that facial movements optimize face processing by activating specific face processing strategies that accommodate to task requirements. Lastly, we review the influence of facial movements on the development of face processing in the first year of life. We focus on infants' sensitivity to facial movements and explore the facilitative effects of facial movements on infants' face recognition performance. We conclude by outlining several future directions to investigate moving face processing and emphasize the importance of including dynamic aspects of facial information to further understand face processing in real-life contexts. [ABSTRACT FROM AUTHOR]

We introduce a new task for exploring the relationship between action and attention. In this interactive multiple object tracking (iMOT) task, implemented as an iPad app, participants were presented with a display of multiple, visually identical disks which moved independently. The task was to prevent any collisions during a fixed duration. Participants could perturb object trajectories via the touchscreen. In Experiment 1, we used a staircase procedure to measure the ability to control moving objects. Object speed was set to 1°/s. On average participants could control 8.4 items without collision. Individual control strategies were quite variable, but did not predict overall performance. In Experiment 2, we compared iMOT with standard MOT performance using identical displays. Object speed was set to 2°/s. Participants could reliably control more objects (M = 6.6) than they could track (M = 4.0), but performance in the two tasks was positively correlated. In Experiment 3, we used a dual-task design. Compared to single-task baseline, iMOT performance decreased and MOT performance increased when the two tasks had to be completed together. Overall, these findings suggest: 1) There is a clear limit to the number of items that can be simultaneously controlled, for a given speed and display density; 2) participants can control more items than they can track; 3) task-relevant action appears not to disrupt MOT performance in the current experimental context. [ABSTRACT FROM AUTHOR]

Video visualization is a computation process that extracts meaningful information from original video data sets and conveys the extracted information to users in appropriate visual representations. This paper presents a broad treatment of the subject, following a typical research pipeline involving concept formulation, system development, a path-finding user study, and a field trial with real application data. In particular, we have conducted a fundamental study on the visualization of motion events in videos. We have, for the first time, deployed flow visualization techniques in video visualization. We have compared the effectiveness of different abstract visual representations of videos. We have conducted a user study to examine whether users are able to learn to recognize visual signatures of motions, and to assist in the evaluation of different visualization techniques. We have applied our understanding and the developed techniques to a set of application video clips. Our study has demonstrated that video visualization is both technically feasible and cost-effective. It has provided the first set of evidence confirming that ordinary users can be accustomed to the visual features depicted in video visualizations, and can learn to recognize visual signatures of a variety of motion events. [ABSTRACT FROM AUTHOR]

Recently there has been growing interest in the role that motion might play in the perception and representation of facial identity. Most studies have considered old/new recognition as a task. However, especially for non-rigid motion, these studies have often produced contradictory results. Here, we used a delayed visual search paradigm to explore how learning is affected by non-rigid facial motion. In the current studies we trained observers on two frontal view faces, one moving non-rigidly, the other a static picture. After a delay, observers were asked to identify the targets in static search arrays containing 2, 4 or 6 faces. On a given trial target and distractor faces could be shown in one of five viewpoints, frontal, 22° or 45° to the left or right. We found that familiarizing observers with dynamic faces led to a constant reaction time advantage across all setsizes and viewpoints compared to static familiarization. This suggests that non-rigid motion affects identity decisions even across extended periods of time and changes in viewpoint. Furthermore, it seems as if such effects may be difficult to observe using more traditional old/new recognition tasks. [ABSTRACT FROM AUTHOR]

The article highlights the 13th annual meeting "Object Perception, Attention, and Memory 2005," held at Toronto, Canada. The meeting was organized by Kate Arrington, Andrew Leber, Stephen Mitroff, and Aude Oliva. During the meeting, professors Anthony Cate and Marlene Behrmann discusses the unlikely perception of figural shape from 3-D concavities. The research about emotional processes was also presented during the meeting.

Observers often tend to misremember the visual stopping point of a movement in the direction of movement (representational momentum). We investigated whether this forward displacement also occurs in grasping. We asked participants to close virtual pliers after the pliers had been opening or closing. The participants' thumbs and index fingers were attached to robot arms which allowed us to provide haptic feedback about the location of the pliers' handles. In a visual task, participants judged the remembered final opening width of the pliers relative to a comparison stimulus. For grasping, we found forward displacement: participants opened their fingers wider if the pliers had been opening compared to when they had been closing. In contrast, we did not find clear forward displacement in the visual task. The effects in grasping and the visual task were not correlated between participants. These results seem to argue against the existence of one form of anticipation that serves both perception and grasping. [ABSTRACT FROM AUTHOR]

In four experiments we explored the accuracy of memory for human action using displays with continuous motion. In Experiment 1, a desktop virtual environment was used to visually simulate ego-motion in depth, as would be experienced by a passenger in a car. Using a task very similar to that employed in typical studies of representational momentum we probed the accuracy of memory for an instantaneous point in space/time, finding a consistent bias for future locations. In Experiment 2, we used the same virtual environment to introduce a new "interruption" paradigm in which the sensitivity to displacements during a continuous event could be assessed. Thresholds for detecting displacements in ego-position in the direction of motion were significantly higher than those opposite the direction of motion. In Experiments 3 and 4 we extended previous work that has shown anticipation effects for frozen action photographs or isolated human figures by presenting observers with short video sequences of complex crowd scenes. In both experiments, memory for the stopping position of the video was shifted forward, consistent with representational momentum. Interestingly, when the video sequences were played in reverse, the magnitude of this forward bias was larger. Taken together, the results of all four experiments suggest that even when presented with complex, continuous motion, the visual system may sometimes try to anticipate the outcome of our own and others' actions. [ABSTRACT FROM AUTHOR]

The ecology of Coyote-Wolf (Canis latrans x C. lupus) hybrids has never fully been typified. We studied morphological and ecological variation in Canis within a region of Coyote-Wolf hybridization in southeastern Ontario. We assessed Canis morphology from standard body measurements and ten skull measurements of adult specimens and found that Canis in this region are morphologically intermediate between Algonquin Provincial Park Wolves (C. lupus lycaon) and Coyotes, indicating a latrans x lycaon hybrid origin; however, there is a closer morphological affinity to latrans than lycaon. Analysis of 846 scats indicated dietary habits also intermediate between lycaon and Coyotes. We used a geographic information system (GIS) to assess spatial landscape features (road density, land cover and fragmentation) for six study sites representing three landscape types. We found noticeable variation in Canis morphology and diet in different landscape types. In general, canids from landscape type A (lowest road density, more total forest cover, less fragmentation) displayed more Wolf-like body morphology and consumed a greater proportion of larger prey (Beaver [Castor canadensis] and White-tailed Deer [Odocoileus virginianus]). In comparison, canids from landscape types B and C (higher road density and/or less total forest cover, more fragmentation) were generally more Coyote-like in body and skull morphology and made greater use of medium to small-sized prey (Groundhog [Marmota monax], Muskrat [Ondatra zibethicus] and lagomorphs). These landscape trends in Canis types suggest selection against Wolf-like traits in fragmented forests with high road density. The range of lycaon southeast of Algonquin Provincial Park appears to be limited primarily due to human access and consequent exploitation. We suggest that road density is the best landscape indicator of Canis types in this region of sympatric, hybridizing and unprotected Canis populations. [ABSTRACT FROM AUTHOR]

Awareness of change within a visual scene only occurs in the presence of focused attention. When two versions of a complex scene are presented in alternating sequence separated by a blank mask, unattended changes usually remain undetected, although they may be represented implicitly. To test whether awareness of change and focused attention had the same or separable neurophysiological substrates, and to search for the neural substrates of implicit representation of change, we recorded event-related brain potentials (ERPs) during a change blindness task. Relative to active search, focusing attention in the absence of a change enhanced an ERP component over frontal sites around 100-300 msec after stimulus onset, and in posterior sites at the 150-300 msec window. Focusing attention to the location of a change that subjects were aware of, replicated those attentional effects, but also produced a unique positive deflection in the 350-600 msec window, broadly distributed with its epicenter in mediocentral areas. The unique topography and time course of this latter modulation, together with its dependence on the aware perception of change, distinguishes this "awareness of change" electrophysiological response from the electrophysiological effects of focused attention. Finally, implicit representation of change elicited a distinct electrophysiological event: Unaware changes triggered a positive deflection at the 240-300 msec window, relative to trials with no change. Overall, the present data suggest that attention, awareness of change, and implicit representation of change may be mediated by separate underlying systems. [ABSTRACT FROM AUTHOR]

There have been many previous reports of mislocalization associated with moving objects (e.g. flash-lag effect, Fröhlich effect, representational momentum). Across four experiments, a new form of mislocalization - the onset repulsion effect (ORE) - is explored in which the error is always back along the observed path of motion. That is, when observers are asked to localize both the initial onset and the final offset positions of a moving object, by far the largest and most systematic error they make is in placing the onset point too early along the correct path of motion. Errors orthogonal to the path of motion and errors in localizing the offset point are minimal by comparison. Errors are also very small when motion is implied rather than continuous. The ORE can be observed with and without fixation, and as with other mislocalization effects, shows some dependence on direction and velocity. As the most obvious prediction in these studies, based on previous reports of mislocalization and the known properties of the visual system, would be for forward rather than backward errors, discussion will focus on the type of mechanism that may have given rise to the observed pattern of results. [ABSTRACT FROM AUTHOR]

Introduces a series of articles related to representational momentum (RM0. Discrete presentations of a rotating rectangle; Variables that influence RM; Explanations of RM; Topics discussed in a workshop on RM hosted by the Max Planck Institute for Biological Cybernetics in Germany; Results of attempts to measure forms of localization error.

Aim Long Island erupted catastrophically in c. 1645 with the probable destruction of its entire biota. While several expeditions have visited the island since, no survey of its flora has been published. In 1968 a small island, Motmot, emerged from its caldera lake. Motmot has been surveyed several times but not since 1988. The aim of this study was to investigate the colonization by vascular plants of this interesting nested pair of islands. Location Long Island is 55 km off the northeast coast of Papua New Guinea (PNG) and Motmot lies in its fresh water caldera lake, Lake Wisdom, c. 4 km from the rim of the surrounding volcano. Methods We conducted a complete survey of the vascular plants on Motmot and made ad hoc collections on Long Island, including surveying three small plots, over 15 days in 1999. In addition, we incorporated data from several collections lodged at the regional herbarium in Lae. Data on seed dispersal syndromes and plant habit were obtained from the literature. Results We recorded 305 species of vascular plants from Long Island, but most trees were small and the species diversity was low. Motmot was still very sparsely vegetated and only forty-five species of vascular plants were found. Communities on Motmot were unspecialized and common species widespread. The flora of Motmot was not significantly different from that on Long Island in terms of the number of species amongst higher taxa, seed dispersal syndromes or plant habits. Main conclusions Low rainfall combined with very porous soils may be responsible for the small stature and low diversity of the forest on Long Island's caldera rim. The absence of specialist littoral species on Motmot, as a result of its landlocked situation, is probably responsible for the very slow species recruitment on the island. This community appears to be functionally important for colonization by comparison with other small volcanic islands in a marine situation. [ABSTRACT FROM AUTHOR]

Aim To evaluate the arthropod community of Motmot m relation to primary colonization of young volcanic surfaces. Location Motmot, an island in Lake Wisdom which occupies the caldera of Long Island, Papua New Guinea. Methods Arthropod sampling by means of pitfall, water and tube traps, fallout collectors, and hand collecting. Results At least thirty-five species of arthropod were collected in 6 days between 23 June and 3 July 1999. Lycosid spiders and ants dominated in all areas. The predatorscavenger arthropod population is largely or entirely dependent on allochthonous input of aquatic insects from the surrounding lake. Main conclusions Major changes in the arthropod fauna since the pioneer surveys of Ball and his colleagues in the 1970s are the loss of a strand flotsam community as the island has eroded to form a predominantly cliffed coastline. Ant and spider diversity has increased. The current colonists include a number of widespread 'tramp' species sensu Diamond. [ABSTRACT FROM AUTHOR]

Biogeographical context Long Island, in Vitiaz Strait, is 55 km north of New Guinea, 60 km from Umboi Island and 125 km from New Britain. After its explosive caldera-forming eruption in about 1645, Long is being recolonized by animals and plants. Through renewed volcanic activity in the 1950s a new island emerged from Long's caldera lake, 4 km from the nearest lake shore and was recreated by eruptions in 1968. Long Island thus provides the opportunity to study a nested pair of natural colonization sequences. The geological background, eruptive history, course and results of the seventeenth century eruption, and the geographical features and climate of Long Island are summarized. Existing knowledge of Long's recolonization, confined almost entirely to surveys of its avifauna in 1933 and 1972, is reviewed. The geological history of Motmot is outlined, and published knowledge of its colonization by animals and plants from 1968 to 1988 is summarized. The 1999 expedition and aims An expedition to Long Island and Motmot in 1999 set out to investigate the hitherto little-known flora and present vertebrate fauna of Long Island and to survey the entire flora and fauna of Motmot for comparison with the results of previous surveys. The methods used in the 1999 survey are described, and the papers setting out the results briefly introduced. [ABSTRACT FROM AUTHOR]

Several paradigms (e.g. change blindness, inattentional blindness, transsaccadic integration) indicate that observers are often very poor at reporting changes to their visual environment. Such evidence has been used to suggest that the spatio-temporal coherence needed to represent change can only occur in the presence of focused attention. However, those studies almost always rely on explicit reports. It remains a possibility that the visual system can implicitly detect change, but that in the absence of focused attention, the change does not reach awareness and consequently is not reported. To test this possibility, we used a simple change detection paradigm coupled with a speeded orientation discrimination task. Even when observers reported being unaware of a change in an item's orientation, its final orientation effectively biased their response in the orientation discrimination task. Both in aware and unaware trials, errors were most frequent when the changed item and the probe had incongruent orientations. These results demonstrate that the nature of the change can be represented in the absence of awareness. [ABSTRACT FROM AUTHOR]

Discusses equilibrium theory and alternative stable equilibria in the study of ecology. Key issues of interest; Analysis of pertinent topics and relevant issues; Implications on biogeography.

The phylogeny of the phoracanthine genus Atesta (thirty-four species) is analysed using cladistic methods. The monophyly of Atesta is confirmed. Three major monophyletic species groups are recognized: (1) the thorntoni-group including twelve species: A.thorntoni, A.balteata, A.latifasciata, A.mediana, A.patula, A.newi, A.angasi, A.bifasciata, A.besti, A.ciliata, A.paratasmanica and A.tasmanica; (2) the sisyrioides-group consisting of seventeen species: A.ibidionoides, A.carteri, A.longoelytrata, A.pubescens, A.stigmosa, A.sita, A.vittata, A.sparsa, A.minuta, A.tropicalis, A.unifasciata, A.sisyrioides, A.nigrihumerus, A.apicalis, A.brittoni, A.antennalis and A.brooksi, and (3) the houstoni-group containing five species: A.mapida, A.houstoni, A.tripartita, A.dixoni and A.centroaustralica. The distribution patterns of Atesta are described and discussed. Five distinct areas of endemism are found for Atesta: the Torresian, Timorian, Kosciuskan, Western and Eyrean Subregions. The Torresian Subregion has nine species, three of which are endemic to the subregion; the Timorian has four species, two of which are endemic; the Kosciuskan has twenty-three species, sixteen of which are endemic, the Western has five species, four of which are endemic, and the Eyrean has three species, one of which is endemic. Two kinds of distribution patterns for Atesta are identified: the wet adapted (peripherial), including the thorntoni-group and sisyrioides-group, and the wide-adapted, consisting of the houstoni-group. The thorntoni-group is typically a southern Australian species group, distributed in south-eastern and south-western Australian continent and Tasmania. The sisyrioides-group is mainly distributed in southeastern, eastern and northern Australian continent and Tasmania. The distribution of the houstoni-group includes central and peripherial Australian continent. [ABSTRACT FROM AUTHOR]