The virtual haptic display: A device for exploring 2-D virtual shapes in the tactile modality

In order to understand better the processes involved in the perception of shape through touch, someelement of control is required over the nature of the shape presented to the hand and the presentation timing. To that end, we have developed a cost-effective, computer-controlled apparatus for presenting haptic stimuli using active touch, known as a virtual haptic display (VHD). The operational principle behind this device is that it translates black and white visual images into topographic, 2-D taxel (tactile pixel) arrays, along the same principle using in Braille letters. These taxels are either elevated or depressed at any one time representing white and black pixel colors of the visual image, respectively. To feel the taxels, the participant places their fingers onto a carriage which can be moved over the surface of the device to reveal a virtual shape. We conducted two experiments and the results show that untrained participants are able to recognize different, simple and complex, shapes using this apparatus. The VHD apparatus is therefore ideal at presenting 2-Dshapes through touch alone. Moreover,this device and its supporting software can also be used for presenting computer-controlled stimuli in cross-modal experiments.     

Something more than the 'Something more than interpretation' is needed: A comment on the paper by the Process of Change Study Group

A critique is offered of the paper on non-interpretive mechanisms in psychoanalytic therapy by the Process of Change Study Group (Stern et al., 1998a). The attention paid to procedural learning and to the need to attend to implicit relational knowledge is welcomed but a number of the group's assumptions are questioned. In particular, it is argued that the differences between mother-infant and therapist-patient relationships are inadequately considered, that the polarisation of non-symbolic and verbal memory is unhelpful and that the separation of the therapy relationship into three strands is problematic. The assumption that pursuing the goal of intersubjective understanding is in itself therapeutic is questioned. It is suggested that the recognition of the importance of implicit relational knowledge calls for a wider reappraisal of important aspects of theory and practice and that direct means of making such knowledge explicit should be considered.     

Processing time as influenced by the number of elements in a visual display

In a visual-detection experiment. a display of several letters was presented. and S was to report the presence or absence of a given target letter. Results clearly are incompatible with a self-terminating visual-scanning process as hypothesized by Sternberg (1967). Two models are considered. a serial exhaustive scanning process and a parallel exhaustive process, but findings from the present study do not provide a basis for differentiating between them.     

There is more to green reading than meets the eye! Exploring the gaze behaviours of expert golfers on a virtual golf putting task

Gaze patterns and verbal reports of golfers at three skill levels (professional, elite amateur and club) were recorded as they read the slope of a virtual golf green from six different positions. The results showed that the professional golfers used a more economical gaze pattern consisting of fewer fixations of longer duration than the amateur and club players. Gaze pattern was accompanied by verbal reports that were not significantly more accurate in terms of aiming accuracy, although the professionals were accurate on 76.5 % of putts compared to 57.1 % for the elite and club groups. Two read positions lead to more accurate predictions by the professional golfers only, suggesting distinctive periods of visual perceptual–cognitive attention may underly higher levels of putting skill. Theoretical implications of these results are discussed in relation to the application of visual attention theory to practise, as well as suggestions provided for further research.     

1 + 2 is more than 2 + 1: Violations of commutativity and identity axioms in mental arithmetic

Over the past decade or so, a large number of studies have revealed that conceptual meaning is sensitive to situational context. More recently, similar contextual influences have been documented in the domain of number knowledge. Here we show such context dependency in a length production task. Adult participants saw single digit addition problems of the form n1 + n2 and produced the sum by changing bi-directionally the length of a horizontally extended line, using radially arranged buttons. We found that longer lines were produced when n1 < n2 compared to n1 > n2 and that unit size increased with result size. Thus, the mathematical axioms of commutativity and identity do not seem to hold in mental addition. We discuss implications of these observations for our understanding of cognitive mechanisms involved in mental arithmetic and for situated cognition generally.     

Observer age and the social transmission of attractiveness in humans: Younger women are more influenced by the choices of popular others than older women

Being paired with an attractive partner increases perceptual judgements of attractiveness in humans. We tested experimentally for prestige bias, whereby individuals follow the choices of prestigious others. Women rated the attractiveness of photographs of target males which were paired with either popular or less popular model female partners. We found that pairing a photo of a man with a woman presented as his partner positively influenced the attractiveness of the man when the woman was presented as more popular (Experiment 1). Further, this effect was stronger in younger participants compared to older participants (Experiment 1). Reversing the target and model such that women were asked to rate women paired with popular and less popular men revealed no effect of model popularity and this effect was unrelated to participant age (Experiment 2). An additional experiment confirmed that participant age and not stimulus age primarily influenced the tendency to follow others' preferences in Experiment 1 (Experiment 3). We also confirmed that our manipulations of popularity lead to variation in rated prestige (Experiment 4). These results suggest a sophisticated model‐based bias in social learning whereby individuals are most influenced by the choices of those who have high popularity/prestige. Furthermore, older individuals moderate their use of such social information and so this form of social learning appears strongest in younger women.     

VRVision: A new tool for the display of 3-D images in behavioral research

Researchers using three-dimensional (3-D) scenes in their studies often spend a lot of time prerendering the scenes into a set of images for later presentations. To improve efficiency, we have developed a new plugin program for MATLAB that eliminates this step. The program is able to manipulate and present 3-D scenes in real time. It allows fine control over numerous parameters, including the mode of projection, angular rotation, lighting, surface photo textures, and animation. Images can be presented with monoscopic or stereoscopic display. It can also dynamically track viewer position and update and display an appropriate 3-D projection. The program is fully compatible with existing MATLAB utilities such as the Psychophysics Toolbox (psychtoolbox.org). It is made freely available to the research community (www.hive.hull .ac.uk/software/vrvision).     

When the whole is more than the sum of its parts: Group motivation gains in the wild

Whereas negative effects of groups on individual motivation have been reported for many years, recent research has begun to show when and why working in a group can produce motivation gains compared to individual work. So far, this evidence has been limited to laboratory settings and rather simple tasks. Using data from swimming competitions at the 2008 Olympics, evidence is presented that motivation gains in groups also occur in field settings with more complex tasks. Based on an instrumentality × value approach, we expect that late positions in a relay trigger motivation gains in groups due to an increase in perceived indispensability for the group outcome. This idea has been initially tested in a pilot study with competitive swimmers, demonstrating that perceived indispensability for the relay outcome indeed increases with later serial positions in a relay. Moreover, the main study with data from the 2008 Olympics revealed performance times consistent with this pattern of indispensability perceptions: while starting swimmers in the swimming relays performed at similar levels as in their individual competitions, swimmers at the later positions showed higher performance in the relay compared to their individual competition heats.     

Scene memory is more detailed than you think: the role of categories in visual long-term memory

Observers can store thousands of object images in visual long-term memory with high fidelity, but the fidelity of scene representations in long-term memory is not known. Here, we probed scene-representation fidelity by varying the number of studied exemplars in different scene categories and testing memory using exemplar-level foils. Observers viewed thousands of scenes over 5.5 hr and then completed a series of forced-choice tests. Memory performance was high, even with up to 64 scenes from the same category in memory. Moreover, there was only a 2% decrease in accuracy for each doubling of the number of studied scene exemplars. Surprisingly, this degree of categorical interference was similar to the degree previously demonstrated for object memory. Thus, although scenes have often been defined as a superset of objects, our results suggest that scenes and objects may be entities at a similar level of abstraction in visual long-term memory.     

中文词汇切分对眼动数据的影响

该研究使用眼动研究中的“边界”技术范式,材料中的关键词为前两个字为双字词的三字词,如“服务员”,和非三字词,如“服务体”,考察可能存在的中文词汇切分策略对眼动时间指标的影响。实验使用2×2被试内设计,第一个因素是三字词的词频：高频和低频,第二个因素为不同词频条件下的非三字词基线。实验结果是三字词预视条件下的注视时间短于非三字词预视条件下的注视时间。结果表明自然阅读中的词汇切分策略确实存在,并且可以在眼动的时间指标上表现出来,结果还暗示在词汇切分过程中,读者在心理词典中对三字词的搜索是必需的过程。     

A whole face is more than the sum of its halves: Interactive processing in face perception

Facial information is processed interactively. Yet, such interactive processing has been examined for discrimination of face parts rather than complete faces. Here we assess interactive processing using a novel paradigm in which subjects discriminate complete faces. Face stimuli, which comprise unilateral facial information (hemifaces) or bilateral facial information from one face (consistent) or two different faces (inconsistent), are shown centrally in a face‐matching task. If each half of a complete face is processed independently, accuracy for complete faces can be predicted by the union of accuracies for right and left hemifaces. However, accuracy exceeded this independence prediction for consistent faces (facilitation) and fell below the prediction for inconsistent faces (interference). These effects were reduced or absent for inverted faces. Our findings are consistent with reports of stronger interactive processing for upright than for inverted faces and they quantify effects of interactive processing on the discrimination of complete faces.     

Comparison of grasping movements made by healthy subjects in a 3-dimensional immersive virtual versus physical environment

Virtual reality (VR) technology is being used with increasing frequency as a training medium for motor rehabilitation. However, before addressing training effectiveness in virtual environments (VEs), it is necessary to identify if movements made in such environments are kinematically similar to those made in physical environments (PEs) and the effect of provision of haptic feedback on these movement patterns. These questions are important since reach-to-grasp movements may be inaccurate when visual or haptic feedback is altered or absent. Our goal was to compare kinematics of reaching and grasping movements to three objects performed in an immersive three-dimensional (3D) VE with haptic feedback (cyberglove/grasp system) viewed through a head-mounted display to those made in an equivalent physical environment (PE). We also compared movements in PE made with and without wearing the cyberglove/grasp haptic feedback system. Ten healthy subjects (8 women, 62.1 ± 8.8 years) reached and grasped objects requiring 3 different grasp types (can, diameter 65.6 mm, cylindrical grasp; screwdriver, diameter 31.6 mm, power grasp; pen, diameter 7.5 mm, precision grasp) in PE and visually similar virtual objects in VE. Temporal and spatial arm and trunk kinematics were analyzed. Movements were slower and grip apertures were wider when wearing the glove in both the PE and the VE compared to movements made in the PE without the glove. When wearing the glove, subjects used similar reaching trajectories in both environments, preserved the coordination between reaching and grasping and scaled grip aperture to object size for the larger object (cylindrical grasp). However, in VE compared to PE, movements were slower and had longer deceleration times, elbow extension was greater when reaching to the smallest object and apertures were wider for the power and precision grip tasks. Overall, the differences in spatial and temporal kinematics of movements between environments were greater than those due only to wearing the cyberglove/grasp system. Differences in movement kinematics due to the viewing environment were likely due to a lack of prior experience with the virtual environment, an uncertainty of object location and the restricted field-of-view when wearing the head-mounted display. The results can be used to inform the design and disposition of objects within 3D VEs for the study of the control of prehension and for upper limb rehabilitation.     

Forming a stable memory representation in the first year of life: why imitation is more than child's play

Although 9-month-old infants are capable of retaining temporally ordered information over long delays, this ability is relatively fragile. It may be possible to facilitate long-term retention by allowing infants to imitate event sequences immediately after their presentation. The effects of imitation on immediate and delayed recognition and on long-term recall were investigated using event-related potentials (ERPs) and elicited imitation, respectively. Mnemonic facilitation resulting from the opportunity to imitate was apparent using both assessments. ERP assessments at immediate and delayed recognition tests suggested that infants who were allowed to imitate had stronger memory representations of familiar stimuli relative to infants who only viewed the presentation of the events. In addition, infants who were allowed to imitate evidenced higher levels of ordered recall after 1 month relative to infants who only watched the experimenter's demonstration. Therefore, imitation proved to have beneficial effects on explicit memory in 9(1/2)-month-olds, providing evidence of its effectiveness as a tool to augment mnemonic capabilities in infancy.     

The whole is indeed more than the sum of its parts: perceptual averaging in the absence of individual item representation

We tested Ariely's (2001) proposal that the visual system represents the overall statistical properties of sets of objects against alternative accounts of rapid averaging involving sub-sampling strategies. In four experiments, observers could rapidly extract the mean size of a set of circles presented in an RSVP sequence, but could not reliably identify individual members. Experiment 1 contrasted performance on a member identification task with performance on a mean judgment task, and showed that the tasks could be dissociated based on whether the test probe was presented before or after the sequence, suggesting that member identification and mean judgment are subserved by different mechanisms. In Experiment 2, we confirmed that when given a choice between a probe corresponding to the mean size of the set and a foil corresponding to the mean of the smallest and largest items only, the former is preferred to the latter, even when observers are explicitly instructed to average only the smallest and largest items. Experiment 3 showed that a test item corresponding to the mean size of the set could be reliably discriminated from a foil but the largest item in the set, differing by an equivalent amount, could not. In Experiment 4, observers rejected test items dissimilar to the mean size of the set in a member identification task, favoring test items that corresponded to the mean of the set over items that were actually shown. These findings suggest that mean representation is accomplished without explicitly encoding individual items.     

The human sense of the head's polarity is influenced by changes in the magnitude of gravity

The present investigation concerns the integrity of a primary mental function, the egocentric frame of reference and the sense of polarity of one's own head. The visually perceived eye level (VPEL) and the subjective antero-posterior axis of the head were measured by means of a visual indicator in darkness during two stimulus conditions: static pitch (sagittal-plane) tilting in the 1-g environment and gondola centrifugation (2G). It is demonstrated that an increase in the magnitude of the gravitoinertial (G) force, acting in the direction of the head and body long (z) axis, causes a substantial change not only in the VPEL but also in the perceived direction of the antero-posterior axis of the head.     

Effects of changes in size, speed, and distance on the perception of curved 3-D trajectories

Previous research on the perception of 3-D object motion has considered time to collision, time to passage, collision detection, and judgments of speed and direction of motion but has not directly studied the perception of the overall shape of the motion path. We examined the perception of the magnitude of curvature and sign of curvature of the motion path for objects moving at eye level in a horizontal plane parallel to the line of sight. We considered two sources of information for the perception of motion trajectories: changes in angular size and changes in angular speed. Three experiments examined judgments of relative curvature for objects moving at different distances. At the closest distance studied, accuracy was high with size information alone but near chance with speed information alone. At the greatest distance, accuracy with size information alone decreased sharply, but accuracy for displays with both size and speed information remained high. We found similar results in two experiments with judgments of sign of curvature. Accuracy was higher for displays with both size and speed information than with size information alone, even when the speed information was based on parallel projections and was not informative about sign of curvature. For both magnitude of curvature and sign of curvature judgments, information indicating that the trajectory was curved increased accuracy, even when this information was not directly relevant to the required judgment.     

The ground dominance effect in the perception of relative distance in 3-D scenes is mainly due to characteristics of the ground surface

Previously, we (Bian, Braunstein, and& Andersen, 2005) reported a dominance effect of the ground plane over other environmental surfaces in determining the perceived relative distance of objects in 3-D scenes. In the present study, we conducted three experiments to investigate whether this ground dominance is due to inherent differences between ground and ceiling surfaces, or to the locations of these surfaces in the visual field. In Experiment 1, two vertical posts were positioned between a ground surface and a ceiling surface, and optical contact was manipulated so that the two surfaces provided contradictory information about the relative distances of the posts from the participant. The two surfaces were either both above, both below, or one above and one below fixation. In Experiment 2, only one surface was presented, either above, below, or at fixation. In Experiment 3, the posts were replaced by two red dots, and the eccentricity of the optical contact on the two surfaces was equated in each of five locations in the visual field. In all three experiments, participants judged which of the two objects appeared to be closer. Overall, we found a higher proportion of judgments consistent with a ground surface than with a ceiling surface in all locations, indicating that the ground dominance effect is mainly due to characteristics of the ground surface, with location in the visual field having only a minor effect.     

The role of head movements in the discrimination of 2-D shape by blind echolocation experts

Similar to certain bats and dolphins, some blind humans can use sound echoes to perceive their silent surroundings. By producing an auditory signal (e.g., a tongue click) and listening to the returning echoes, these individuals can obtain information about their environment, such as the size, distance, and density of objects. Past research has also hinted at the possibility that blind individuals may be able to use echolocation to gather information about 2-D surface shape, with definite results pending. Thus, here we investigated people’s ability to use echolocation to identify the 2-D shape (contour) of objects. We also investigated the role played by head movements—that is, exploratory movements of the head while echolocating—because anecdotal evidence suggests that head movements might be beneficial for shape identification. To this end, we compared the performance of six expert echolocators to that of ten blind nonecholocators and ten blindfolded sighted controls in a shape identification task, with and without head movements. We found that the expert echolocators could use echoes to determine the shapes of the objects with exceptional accuracy when they were allowed to make head movements, but that their performance dropped to chance level when they had to remain still. Neither blind nor blindfolded sighted controls performed above chance, regardless of head movements. Our results show not only that experts can use echolocation to successfully identify 2-D shape, but also that head movements made while echolocating are necessary for the correct identification of 2-D shape.     

How sweet it is to be loved by you: the role of perceived regard in the terror management of close relationships

Drawing from terror management theory, the present research examined whether people turn to close relationships to manage the awareness of mortality because they serve as a source of perceived regard. Studies 1 and 2 demonstrated that mortality salience (MS) leads people to exaggerate how positively their romantic partners see them and demonstrated that people are more committed to their partners to the extent that their romantic partners serve as a source of perceived regard after MS (Study 3). Study 4 revealed that activating thoughts of perceived regard from a partner in response to MS reduced death-thought accessibility. Studies 5 and 6 demonstrated that MS led high relationship contingent self-esteem individuals to exaggerate perceived regard from a partner, and this heightened regard led to greater commitment to one's partner. Study 7 examined attachment style differences and found that after MS, anxious individuals exaggerated how positively their parents see them, whereas secure individuals exaggerated how positively their romantic partners see them. Together, the present results suggest that perceptions of regard play an important role in why people pursue close relationships in the face of existential concerns.     

三维虚拟空间中转头选中远离和靠近运动目标的操作特性差异

通过转头选中运动目标是虚拟现实(VR)中的常见操作,然而运动目标包含远离和靠近运动,确定两类操作的时间特性差异对设计高效的用户接口有重要的意义。本研究选取17名被试在VR中通过转头将球体光标快速准确地放入水平运动的球体目标内,并改变初始距离、目标容差和目标速度。总时间结果显示,远离运动的操作难度更大,初始距离和目标容差对远离和靠近运动的影响相似,目标速度对两类运动的影响相反。进一步将光标的移动过程划分为加速、减速和调整阶段,结果发现,远离运动的加速和减速时间大于靠近运动,但是两类运动的调整时间接近,并且只有目标容差对两类运动的影响一致。最后构建了总时间与三因素的函数模型,成功解释了两类运动的操作时间特性。本研究证明了远离与靠近运动具有不同的操作时间特性,为两类运动的独立交互设计提供了重要参考。