Perceived relative distance on the ground affected by the selection of depth information

Our visual space does not appear to change when we scan or shift attention between locations. This appearance of stability implies that the depth information selection process is not crucial for constructing visual space. But we present evidence to the contrary. We focused on space perception in the intermediate distance, which depends on the integration of depth information on the ground. We propose a selection hypothesis that states that the integration process is influenced by where the depth information is selected. Specifically, the integration process inaccurately represents the ground when one samples depth information only from the far ground surface, instead of sequentially from the near to the far ground. To test this, observers matched the depth/length of a sagittal bar (test) to the width of a laterally oriented bar (reference) in three conditions in a full-cue environment that compelled the visual system to sample from different parts of the ground. These conditions had the lateral reference bar placed (1) adjacent to the test bar, (2) at the far ground, and (3) at the near ground. We found that the sagittal bar was perceived as shorter in conditions (1) and (2) than in Condition 3. This finding supports the selection hypothesis, since only Condition 3 led to more accurate ground surface integration/representation and less error in relative distance/depth perception. Also, we found that performances in all three conditions were similar in the dark, which has no depth information on the ground, indicating that the results cannot be attributed to asymmetric visual scanning but, rather, to differential information selection.     

The effect of location on the discrimination of spatial vibrotactile patterns

The present study examined whether the locations of patterns on the skin affected the ability to process information about their shapes. In Experiment 1, pairs of spatial vibrotactile patterns, using the array from the Optacon, were presented sequentially to subjects’ left index fingerpads. The location of each pattern in a pair was varied randomly among four locations on the skin. The subjects responded “same” or “different” on the basis of the shapes of patterns, regardless of their locations. Discrimination accuracy was highest and response time fastest when patterns occupied identical locations (ILs), and performance suffered with increasing distance between patterns. In Experiment 2, pairs were presented to corresponding points or to noncorresponding points on separate fingerpads. When patterns occupied corresponding points on separate fingers, accuracy was lower than when patterns occupied ILs on a single finger, but higher than when patterns occupied noncorresponding points on separate fingers. The results suggested that discriminability declined partly because patterns did not occupy ILs, and partly because separate locations had different densities of innervation.     

Path completion after haptic exploration without vision: implications for haptic spatial representations

Subjects haptically explored two legs of a triangular path and responded by returning to the origin. Seven conditions were tested, varying in (1) whether the path was imaginally displaced between the initial exploration and the response; (2) the nature of the displacement, if present--rotation or translation; (3) variability in the origin location across trials; and (4) instructions to complete a triangle versus remembering the origin location. Mean distance and angle responses were modeled by the encoding-error model (Fujita, Klatzky, Loomis, & Golledge, 1993), which attributes errors to misencoding of the path legs and angle. The model failed to predict the finding of systematic errors in response distance but not response angle, a dissociation that held when the path was undisplaced or imaginally translated. Rotation before responding produced errors more consistent with the model. The data suggest use of a body-centered representation to complete undisplaced or imaginally translated paths, but adoption of an object-centered representation after imagined rotation, as is more consistent with pathway completion using whole-body locomotion.     

Place and summation coding for canonical and non-canonical finger numeral representations

Fingers can be used to express numerical magnitudes, and cultural habits about the fixed order in which fingers are raised determine which configurations become canonical and which non-canonical. Although both types of configuration carry magnitude information, it has been shown that the canonical ones are recognized faster and directly linked to number semantics. Here we tested whether this difference is a consequence of differences in the qualitative way of processing the two types of configurations. When participants named Arabic digits (Experiment 1) or verbal numerals (Experiment 2) primed by canonical and non-canonical finger configurations, qualitatively different priming patterns were observed for the two types of configurations. Canonical configurations activated a place coding representation, with priming spreading to close smaller and larger magnitudes as a function of the prime–target distance. Conversely, non-canonical configurations activated a summation coding representation priming smaller and equal magnitudes independently of the prime–target distance, and larger targets depending on this distance.     

Time—distance relations in shifting attention between locations on one’s body

Does the time to discriminate the presence or absence of a tactile stimulus depend on its distance from the bodily location to which one has been attending? Subjects were tested by the presentation of air puffs at four of eight possible locations on the body. In each trial of Experiment 1, (1) subjects attended auditorily to an announcement of one of the eight locations; (2) 2 sec later, a second location was announced and, simultaneously, air puffs were presented at a randomly selected four of the eight locations; (3) the subjects reported as quickly as possible on whether or not air puffs had been presented at the second-announced location. Overall, reaction times increased with the distance between the just-attended and the tested locations. Experiment 2 was undertaken to determine whether the operative distance was distance through the subject’s body or directly through three-dimensional space. The subjects were tested as in Experiment 1, but with their arms or legs either side-by-side in front or spread out to each side. Reaction times then depended more on straight-line distance in space than on distance through the body.     

自我优势效应对远近空间中空间参照框架的影响

联合颜色−标签匹配任务和空间参照框架判断任务,考察自我优势效应对远近空间中空间参照框架表征的影响。颜色−标签匹配任务要求被试对颜色（黑色/白色叉子）与标签词（自我/他人）之间建立稳定的联结,被试随机分为自我联结组和他人联结组,两组被试均需在远近空间中完成空间参照表征任务。结果发现：（1）与他人联结组相比,自我联结组表现出显著的自我优势效应;（2）自我优势效应对空间参照表征的影响仅体现在近处空间且对自我中心表征任务的影响更大。研究表明,自我优势效应优先影响近处空间表征,表现出近处优先性。     

Effects of visual deprivation on space representation: immediate and delayed pointing toward memorised proprioceptive targets

Congenitally blind, late-blind, and blindfolded-sighted participants performed a pointing task at proximal memorised proprioceptive targets. The locations to be memorised were presented on a sagittal plane by passively positioning the left index finger. A 'go' signal for matching the target location with the right index finger was given 0 or 8 s after left-hand demonstration. Absolute distance errors were smaller in the blind groups, with both delays pooled together; signed distance and direction errors were underestimated with the longer delay, and were overestimated by blind groups, whereas the blindfolded-sighted group underestimated them. Elongation of the scatters was stretched but not affected by delay or group. The surface scatter was greater with the longer delay; and orientation of the main axis of the pointing ellipses shows the use of an egocentric frame of reference by the congenitally blind group for both delays, the use of egocentric (0 s) and exocentric (8 s) frame of reference by the blindfolded-sighted group, with the late-blind group using an intermediate frame of reference for both delays. Therefore, early and late visual-deprivation effects are distinguished from transient visual-deprivation effects as long-term deprivation leads to increased capabilities (absolute distance estimations), unaltered organisation (for surface and elongation), and altered organisation (amplitude and direction estimations, orientation of pointing distribution) of the spatial representation with proprioception. Besides providing an extensive exploration of pointing ability and mechanisms in the visually deprived population, the results show that cross-modal plasticity applies not only to neural bases but extends to spatial behaviour.     

Serial memory for sound-specified locations: effects of spatial uncertainty and motor suppression

According to Parmentier and Jones (2000), serial recall of locations that are specified by a sequence of sounds is prone to temporal error and is unaffected by motor suppression during retention. Experiments are reported here that show that with increased spatial uncertainty at recall (Experiment 1) and presentation (Experiment 2), spatial rather than temporal errors predominate. This is also the case when serial recall of sound-specified locations is subject to interference from a motor suppression task (Experiment 3). Contrary to Parmentier and Jones's (2000) original report, these results suggest that the memory representation for location is not necessarily amodal but is influenced by the representational requirements of the task being performed. This is consistent with recent findings that provide evidence for a distinct spatial working memory.     

Young children's spontaneous use of geometry in maps

Two experiments tested whether 4-year-old children extract and use geometric information in simple maps without task instruction or feedback. Children saw maps depicting an arrangement of three containers and were asked to place an object into a container designated on the map. In Experiment 1, one of the three locations on the map and the array was distinct and therefore served as a landmark; in Experiment 2, only angle, distance and sense information specified the target container. Children in both experiments used information for distance and angle, but not sense, showing signature error patterns found in adults. Children thus show early, spontaneously developing abilities to detect geometric correspondences between three-dimensional layouts and two-dimensional maps, and they use these correspondences to guide navigation. These findings begin to chart the nature and limits of the use of core geometry in a uniquely human, symbolic task.     

Stimulus-dependent modulation of perceptual and motor learning in a serial reaction time task

In two experiments, we investigated the impact of spatial attributes on the representation acquired during a serial reaction time task. Two sequences were used, in which structural regularities occurred either in the horizontal or in the vertical locations of successive stimuli. After training with the dominant hand, participants were required to respond with the non-dominant hand to either the original sequence or to a mirror-ordered version of the original sequence that required finger movements homologous to those used during training. We observed that a difference in reaction times between the two transfer conditions was smaller in the vertical sequence than in the horizontal sequence. This pattern of results was independent of whether three fingers (Experiment 1) were used or only one finger (Experiment 2) was used for responding. This result suggests that perceptual and motor learning mechanisms may be weighted differently depending on the context in which the stimulus is presented.     

Mental representations of spatial and nonspatial relations

Four experiments investigated the representation and integration in memory of spatial and nonspatial relations. Subjects learned two-dimensional spatial arrays in which critical pairs of object names were semantically related (Experiment 1), semantically and episodically related (Experiment 2), or just episodically related (Experiments 3a and 3b). Episodic relatedness was established in a paired-associate learning task that preceded array learning. After learning an array, subjects participated in two tasks: item recognition, in which the measure of interest was priming; and distance estimation. Priming in item recognition was sensitive to the Euclidean distance between object names and, for neighbouring locations, to nonspatial relations. Errors in distance estimations varied as a function of distance but were unaffected by nonspatial relations. These and other results indicated that nonspatial relations influenced the probability of encoding spatial relations between locations but did not lead to distorted spatial memories.     

Studies of the cognitive representation of spatial relations: II. A familiar environment

This experiment tested the ability of people to recall the locations of buildings in a familiar campus setting. Ten graduate students represented the relative locations of buildings by pairwise distance judgments (on a 100-point scale) and by direct mapping of locations on a Tektronix cathode ray terminal. As evaluated by Stevens's power law, both methods led to accurate judgments of relative distance (the average exponent was close to 1). In addition, the pairwise judgments were analyzed by multidimensional scaling (MDS) and the buildings were located in a two-dimensional map. When asked to choose between the MDS representation and the map created directly on the Tektronix, all 10 subjects chose the latter as the more accurate. Moreover, 6 out of 10 subjects thought the direct map was more accurate than the actual map of the building locations. These results suggest that either pairwise judgment or direct mapping yield accurative representations of spatial relations in a familial environment, but that subjects favor the direct map.     

反应-效应相容性范式下不同数字表征方式和身体经验对数字认知加工的影响

采用反应-效应相容性范式,探讨不同数字表征方式和身体经验对个体数字认知加工的影响。实验1首先采用木棒数字表征从知觉层面证明反应-效应相容性效应的存在;实验2采用累计手指数字表征考察手指数字表征在反应-效应相容性匹配中的优势;实验3则进一步排除了近似数量表征系统的影响,从语义层面探讨中国文化背景下语义概念手指数字表征的反应-效应相容性对数字认知加工的影响。结果发现,不同的数字表征系统中均存在反应-效应相容性效应,支持了观念运动理论;相比客体材料,手指数字表征在相容条件下具有明显的匹配优势,支持了具身数量的观点。     

Spatial modulation of tactile temporal-order judgments

We report a series of three experiments designed to examine the effect of posture on tactile temporal processing. Observers reported which of two tactile stimuli, presented to the left and right index fingers (experiments 1-3; or thumb, experiment 3), was perceived first while adopting one of two postures--hands-close (adjacent, but not touching) or hands-far (1 m apart)--in the dark. Just-noticeable differences were significantly smaller in the hands-far posture across all three experiments. In the first two experiments we compared hand versus foot responses and found equivalent advantages for the hands-far posture. In the final experiment the stimuli were presented to either the same or different digit on each hand (index finger or thumb) and we found that only when the same digit on each hand was stimulated was there an advantage for the hands-far posture. The finding that temporal precision was better with greater distance contradicts predictions based on attention-switching models of temporal-order judgments, and also contrasts with results from similar experimental manipulations in other modalities (eg vision). These results provide support for a rapid and automatic process that transforms the representation of a tactile stimulus from a skin-centred reference frame to a more external (eg body-centred or allocentric) one.     

Simon-type effects: chronometric evidence for keypress schemata in typewriting

In 4 experiments, chronometric evidence for keypress schemata in typing was sought by presenting stimuli to be typed in positions that were displaced from a central fixation point. Reaction times were shorter when stimulus positions corresponded to keyboard locations of the letters to be typed, suggesting that position was an important part of the internal representation of the response. Experiment 1 presented single letters left and right of fixation. Experiment 2 presented single letters above and below fixation. Experiment 3 presented words left and right of fixation and found evidence of parallel activation of keypress schemata. Experiment 4 found no effect of the eccentricity of the keyboard locations and responding fingers, suggesting that response-location codes are categorical, not metric. The results are consistent with D. E. Rumelhart and D. A. Norman's (1982) theory of typewriting.     

Absolute distance perception to locations off the ground plane

Using vision, humans can accurately judge distances to locations on the ground surface up to distances of at least 20 m. Most theories of depth perception assume that this ability is associated with the fact that we live in a terrestrial world in which locations of interest often appear on the ground and for which feedback about distance is often available from nonvisual sources such as walking. Much less is known about the ability of humans to judge absolute distances to locations other than on or supported by the ground plane beyond a few meters, at which point binocular stereo provides at best limited information about distance scaling. We show that one commonly used action measure for probing absolute distance perception exhibits accurate performance, even for targets located on the ceiling of a large room. We follow this with evidence that distance to ceiling locations is recovered with a mechanism that depends, at least in part, on the angle from the line of sight to the target location and a gravity-based frame of reference.     

Independent coding of target distance and direction in visuo-spatial working memory

The organization of manual reaching movements suggests considerable independence in the initial programming with respect to the direction and the distance of the intended movement. It was hypothesized that short-term memory for a visually-presented location within reaching space, in the absence of other allocentric reference points, might also be represented in a motoric code, showing similar independence in the encoding of direction and distance. This hypothesis was tested in two experiments, using adult human subjects who were required to remember the location of a briefly presented luminous spot. Stimuli were presented in the dark, thus providing purely egocentric spatial information. After the specified delay, subjects were instructed to point to the remembered location. In Exp. 1, temporal decay of location memory was studied, over a range of 4–30 s. The results showed that (a) memory for both the direction and the distance of the visual target location declined over time, at about the same rate for both parameters; however, (b) errors of distance were much greater in the left than in the right hemispace, whereas direction errors showed no such effect; (c) the distance and direction errors were essentially uncorrelated, at all delays. These findings suggest independent representation of these two parameters in working memory. In Exp. 2 the subjects were required to remember the locations of two visual stimuli presented sequentially, one after the other. Only after both stimuli had been presented did the subject receive a signal from the experimenter as to which one was to be pointed to. The results showed that the encoding of a second location selectively interfered with memory for the direction but not for the distance of the to-be-remembered target location. As in Exp. 1, direction and distance errors were again uncorrelated. The results of both experiments indicate that memory for egocentrically-specified visual locations can encode the direction and distance of the target independently. Use of motor-related representation in spatial working memory is thus strongly suggested. The findings are discussed in the context of multiple representations of space in visuo-spatial short-term memory.     

心理长度对二年级儿童数字线估计表征的影响

从心理长度的角度探讨二年级儿童在0~100和0~1000数字范围存在不同表征方式的原因。实验一要求二年级儿童完成长度均为10cm,范围分别为0~100和0~1000的数字线估计任务。实验二要求儿童对长度分别为10cm和18cm,范围均为0~1000的数字线进行估计。结果发现在两个实验中二年级儿童的估计均存在心理长度,但与以往研究的一年级儿童相比,心理长度的范围有所缩小。随着数字范围的增大或长度的减小,儿童的表征方式出现了从线性表征向对数表征的转变趋势。这些结果表明不精确的表征方式可能与心理长度策略的使用有关,心理长度在一定程度上影响了二年级儿童的估计表征方式。     

心理长度对二年级儿童数字线估计表征的影响

从心理长度的角度探讨二年级儿童在0~100和0~1000数字范围存在不同表征方式的原因。实验一要求二年级儿童完成长度均为10cm,范围分别为0~100和0~1000的数字线估计任务。实验二要求儿童对长度分别为10cm和18cm,范围均为0~1000的数字线进行估计。结果发现在两个实验中二年级儿童的估计均存在心理长度,但与以往研究的一年级儿童相比,心理长度的范围有所缩小。随着数字范围的增大或长度的减小,儿童的表征方式出现了从线性表征向对数表征的转变趋势。这些结果表明不精确的表征方式可能与心理长度策略的使用有关,心理长度在一定程度上影响了二年级儿童的估计表征方式。     

静止与动态定位任务中飞行员视觉空间模板的表征计算

采用静止和动态空间定位任务对飞行员与普通被试进行对照研究,考察参照条件、目标数量、空间性质对空间定位的影响,探索静止和动态视觉空间模板表征建构特征及其个体差异。结果显示：（1）在静止空间,有距离参照定位任务是较易任务而无距离参照任务较难,飞行员的无距离参照任务完成较好;（2）在运动空间,有运动轨迹参照定位任务较易而无轨迹参照任务较难,飞行员两种任务均完成较好,无参照条件使控制组正确率大为下降。（3）两组在双目标任务上的差异比之单目标任务更大,且飞行员表现出双目标协同优势。结论：飞行员视觉空间模板的功能更强,表现为对静止空间形成较为准确距离表征、对运动空间即时建构运动轨迹表征。