A Possible Connection between Categorical and Coordinate Spatial Relation Representations

Kosslyn (1987) theorized that the visual system uses two types of spatial relations. Categorical spatial relations represent a range of locations as an equivalence class, whereas coordinate spatial relations represent the precise distance between two objects. Data indicate a left hemisphere (LH) advantage for processing categorical spatial relations and a right hemisphere (RH) advantage for processing coordinate spatial relations. Although generally assumed to be independent processes, this article proposes a possible connection between categorical and coordinate spatial relations. Specifically, categorical spatial relations may be an initial stage in the formation of coordinate spatial relations. Three experiments tested the hypothesis that categorical information would benefit tasks that required coordinate judgments. Experiments 1 and 2 presented categorical information before participants made coordinate judgments and coordinate information before participants made categorical judgments. Categorical information sped the processing of a coordinate task under a range of experimental variables; however, coordinate information did not benefit categorical judgments. Experiment 3 used this priming paradigm to present stimuli in the left or right visual field. Although visual field differences were present in the third experiment, categorical information did not speed the processing of a coordinate task. The lack of priming effects in Experiment 3 may have been due to methodological changes. In general, support is provided that categorical spatial relations may act as an initial step in the formation of more precise distance representations, i.e., coordinate spatial relations.     

Lateralization of spatial categories: A comparison of verbal and visuospatial categorical relations

Many reports show that spatial relations between and within objects show differences in hemispheric lateralization. Coordinate, metric relations concerning distances are processed with a right-hemisphere advantage, whereas a left-hemisphere advantage is thought to be related to categorical, abstract relations (Kosslyn, 1987). Kemmerer and Tranel (2000) argued that the left-hemisphere advantage for categorical processing might apply only for verbal spatial categories, however, whereas a right-hemisphere advantage is related to visuospatial categories. To test this idea, we examined categorical processing for stimuli in both verbal and visuospatial formats, with a visual half-field, match-to-sample design. In Experiment 1, we manipulated the format of the second stimulus to compare response patterns for both verbal and visuospatial stimuli. In Experiment 2, we varied the expectancy of the format of the second stimulus, allowing for an assessment of strategy use. The results showed that a left-hemisphere advantage was related to verbal stimulus format only, but not in all conditions. A right-hemisphere advantage was found only with a visuospatial expectancy, visuospatial format, and brief interval. The theory we present to explain these results proposes that the lateralization related to basic categorical processing can be strongly influenced by verbal characteristics and, to some extent, by additional coordinate processing. The lateralization measured in such cases does not represent lateralization related purely to categorical processing, but to these additional effects as well. This stresses the importance of careful task and stimulus design when examining categorical processing in order to reduce the influence of those additional processes.     

The nature of categorical and coordinate spatial relation processing: An interference study

Spatial relation information can be encoded in two different ways: categorically, which is abstract, and coordinately, which is metric. Although categorical and coordinate spatial relation processing is commonly conceived as relying on spatial representations and spatial cognitive processes, some suggest that representations and cognitive processes involved in categorical spatial relation processing can be verbal as well as spatial. We assessed the extent to which categorical and coordinate spatial relation processing engages verbal and spatial representations and processes using a dual-task paradigm. Participants performed the classical dot-bar paradigm and simultaneously performed either a spatial tapping task, or an articulatory suppression task. When participants were requested to tap blocks in a given pattern (spatial tapping), their performance decreased in both the categorical and coordinate tasks compared to a control condition without interference. In contrast, articulatory suppression did not affect performance in either spatial relation task. A follow-up experiment indicated that this outcome could not be attributed to different levels of difficulty of the two interference tasks. These results provide strong evidence that both coordinate and categorical spatial relation processing relies mainly on spatial mechanisms. These findings have implications for theories on why categorical and coordinate spatial relations processing are lateralised in the brain.     

The role of stimulus factors in making categorical and coordinate spatial judgments

We report three experiments which investigate the lateralization of categorical and coordinate processing. In all experiments, participants judged the position of a dot relative to a line. We manipulated display luminance (controlling for contrast), polarity (black-on-white versus white-on-black displays), and exposure duration (100, 150, and 200 ms). The results showed a left visual field-right hemisphere advantage for coordinate judgments, but only under highly prescribed conditions. We argue that stimulus and procedural factors are critical in determining the hemisphere by task interaction.     

类别性空间记忆右侧化优势及其受威胁情境的影响

以往研究发现类别空间关系表征具有左半球激活优势,但在行为表现中是否存在对侧化的右侧化优势尚且不明确。本研究采用两个被试内实验,探讨空间记忆的行为表现是否具有右侧化优势以及这种优势是否受威胁情境的影响。实验1被试学习完一幅模拟地图中物体位置关系后进行相对位置判断任务,结果发现了显著的空间行为反应右侧化优势。实验2使被试在威胁情境中完成相同任务,发现右侧化优势消失。实验表明类别性空间记忆的行为表现具有右侧化优势,且具有情境不稳定性,这为空间记忆的偏侧化研究提供了一定的行为实验证据。     

Judgments of relative position and distance on representations of spatial relations

This article examines Kosslyn's (1987) hypothesis of the unequal capacity of cerebral hemispheres to process categorical and coordinate spatial relations. Experiment 1 comprised 4 different tasks and failed to support this hypothesis in normal Ss. With the same stimulus patterns as in Kosslyn's study, the results failed to confirm cerebral asymmetry for representing the 2 types of spatial relations, in normal (Experiment 2) and commissurotomized (Experiment 3) Ss. In Experiment 4, a reduction in stimulus luminance produced a partial confirmation of the hypothesis as the right hemisphere proved more adept than the left hemisphere at operating on coordinate representations, whereas both were equally competent at processing categorical spatial-relation representations. The results suggest that the 2 hemispheres can operate on both types of spatial relations, but their respective efficiency depends on the quality of the representations to be processed.     

Hemispheric specialization for categorical and coordinate spatial representations: A reappraisal

The purpose of the present study was to examine Kosslyn's (1987) claim that the left hemisphere (LH) is specialized for the computation of categorical spatial representations and that the right hemisphere (RH) is specialized for the computation of coordinate spatial representations. Categorical representations involve making judgements about the relative position of the components of a visual stimulus (e.g., whether one component is above/below another). Coordinate representations involve calibrating absolute distances between the components of a visual stimulus (e.g., whether one component is within 5 mm of another). Thirty-two male and 32 female undergraduates were administered two versions of a categorical or a coordinate task over three blocks of 36 trials. Within each block, items were presented to the right visual field-left hemisphere (RVF-LH), the left visual field-right hemisphere (LVF-RH), or a centralized position. Overall, results were more supportive of Kosslyn's assertions concerning the role played by the RH in the computation of spatial representations. Specifically, subjects displayed an LVF-RH advantage when performing both versions of the coordinate task. The LVF-RH advantage on the coordinate task, however, was confirmed to the first block of trials. Finally, it was found that males were more likely than females to display faster reaction times (RTs) on coordinate tasks, slower RTs on categorical tasks, and an LVF-RH advantage in computing coordinate tasks.     

Language, perception, and the schematic representation of spatial relations

Schemas are abstract nonverbal representations that parsimoniously depict spatial relations. Despite their ubiquitous use in maps and diagrams, little is known about their neural instantiation. We sought to determine the extent to which schematic representations are neurally distinguished from language on the one hand, and from rich perceptual representations on the other. In patients with either left hemisphere damage or right hemisphere damage, a battery of matching tasks depicting categorical spatial relations was used to probe for the comprehension of basic spatial concepts across distinct representational formats (words, pictures, and schemas). Left hemisphere patients underperformed right hemisphere patients across all tasks. However, focused residual analyses using voxel-based lesion-symptom mapping (VLSM) suggest that (1) left hemisphere deficits in the representation of categorical spatial relations are difficult to distinguish from deficits in naming these relations and (2) the right hemisphere plays a special role in extracting schematic representations from richly textured pictures.     

An investigation of immune system disorder as a "marker" for anomalous dominance

Geschwind and Galaburda (1987) proposed that immune disorder (ID) susceptibility, along with left handedness and familial sinistrality (FS), is a "marker" for anomalous dominance. The theory predicts lesser left lateralization for language processes, lessened left hemisphere abilities, and enhanced right hemisphere abilities. We assessed language laterality (dichotic consonant vowel task) and performances on spatial and verbal tasks. Subjects were 128 college students. The factors of handedness, sex, FS, and immune disorder history (negative or positive) were perfectly counterbalanced. Left-handers were significantly less lateralized for language and scored lower than right-handers on the spatial tasks. Females scored lower on mental rotation than males, but performed comparably to males on the spatial relations task. The only effect of ID was by way of interaction with FS on both spatial tasks--subjects who were either negative or positive on both FS and ID status factors scored significantly higher than subjects negative for one but positive for the other factor. A speculative explanatory model for this interaction was proposed. The model incorporates the notion that FS and ID factors are comparably correlated, but in opposite directions, with hormonal factors implicated by other research as relevant for spatial ability differences. Finally, no support for the "anomalous dominance" hypothesis predictions was found.     

Tactile gap detection and language lateralization

Recent work suggests that hemispheric language lateralization might be related to the fine-grained temporal discriminations that are required for linguistic processing (Nicholls, 1996). Studies concerning tactile processing have also shown a significant left-hemisphere (L-H) advantage for tactile gap detection (Nicholls & Whelan, 1997). We hypothesized that language and tactile processing are both preferentially processed by the left hemisphere because it is specialized for tasks requiring fine-grained temporal resolution. Thirty-two participants (16 right and 16 left handers) were tested for both linguistic processing (using the Fused Dichotic Words Test (FDWT)) and tactile gap detection. Both right and left handers showed a significant L-H advantage for both language processing and tactile gap detection. The present study supports recent claims that language lateralization is attributable to the left hemisphere's better suitability to process tasks that require fine-grained temporal resolution.     

类别空间关系加工系统和数量空间关系加工系统的分离 ——来自多领域的研究证据

Kosslyn认为人类的空间关系加工系统分为类别空间关系加工子系统和数量空间关系加工子系统,这两个子系统不仅存在功能上的分离,并且存在大脑神经水平的分离,这种神经水平的分离表现为两种空间关系加工的大脑半球偏向,即类别空间关系加工的左半球偏向与数量空间关系加工的右半球偏向。对两种空间关系加工的研究,涉及的领域从低水平的空间知觉,至表象、记忆、语言、行动及物体识别等,涉及的研究方法包括半视野速示法,神经网络模拟,PET, fMRI, ERP, rTMS,脑损伤病人的研究及比较动物研究。综合现有研究,虽然大多数研究中得到的脑半球偏向为两种加工子系统在神经水平的分离提供了证据,但不同研究中脑半球偏向的获得是相当不稳定的,并且受到研究方法因素的影响。尽管造成神经水平的分离似乎与大脑左右半球对具有不同感受野特征的神经元输出的偏向有一定的关系,但这仍需要进一步的研究证据     

Evidence for unusual spatial location coding in Williams syndrome: an explanation for the local bias in visuo-spatial construction tasks?

Individuals with Williams syndrome (WS) display poor visuo-spatial cognition relative to verbal abilities. Furthermore, whilst perceptual abilities are delayed, visuo-spatial construction abilities are comparatively even weaker, and are characterised by a local bias. We investigated whether this differentiation in visuo-spatial abilities can be explained by a deficit in coding spatial location in WS. This can be measured by assessing participants' understanding of the spatial relations between objects within a visual scene. Coordinate and categorical spatial relations were investigated independently in four participant groups: 21 individuals with WS; 21 typically developing (TD) children matched for non-verbal ability; 20 typically developing controls of a lower non-verbal ability; and 21 adults. A third task measured understanding of visual colour relations. Results indicated first, that the comprehension of categorical and coordinate spatial relations is equally poor in WS. Second, that the comprehension of visual relations is also at an equivalent level to spatial relational understanding in this population. These results can explain the difference in performance on visuo-spatial perception and construction tasks in WS. In addition, both the WS and control groups displayed response biases in the spatial tasks. However, the direction of bias differed across the groups. This finding is explored in relation to current theories of spatial location coding.     

Sex differences in the lateralization of spatial abilities: a spatial component analysis of extreme group scores

Sex differences in the cerebral lateralization of two discrete components of spatial processing were investigated in high and low ability males and females using the dual-task paradigm. In the first phase of the experiment, the results indicated a pattern of right hemispheric control for a spatial visualization component, regardless of sex and ability level. In the processing of the spatial orientation component of spatial ability, high ability males and females showed left hemispheric lateralization, whereas low ability males and females displayed right hemispheric control. In the second phase of this study, it was observed that high ability females and low ability males may use a verbal mediation strategy in processing spatial visualization tasks. No verbal mediation effects were found for the spatial orientation component.     

What types of visual recognition tasks are mediated by the neural subsystem that subserves face recognition?

Three divided visual field experiments tested current hypotheses about the types of visual shape representation tasks that recruit the cognitive and neural mechanisms underlying face recognition. Experiment 1 found a right hemisphere advantage for subordinate but not basic-level face recognition. Experiment 2 found a right hemisphere advantage for basic but not superordinate-level animal recognition. Experiment 3 found that inverting animals eliminates the right hemisphere advantage for basic-level animal recognition. This pattern of results suggests that the cognitive and neural mechanisms underlying face recognition are recruited when computational demands of a shape representation task are best served through the use of coordinate (rather than categorical) spatial relations.     

视觉空间关系判断的分离与协同

采用任务表征相互影响范式,通过三个实验探讨了类别空间关系判断和数量空间关系判断的加工特性和相互关系.结果表明:(1)先行类别关系启动有利于数量空间关系判断,对类别空间关系判断没有影响;先行数量关系启动对两个判断任务均无影响.(2)先行类别关系干扰降低两个空间关系判断的绩效,先行数量关系干扰对两个空间关系判断没有影响.(3)先行类别关系对空间关系判断的启动和干扰效应不局限于特定条件,具有普遍性.研究提示,右脑为优势半球的数量关系加工以左脑为优势半球的类别关系加工为基础,支持视觉空间认知加工既分离又协同的观点.     

The sad, the angry, and the asymmetrical brain: dichotic listening studies of negative affect and depression

Dichotic Listening (DL) is a valuable tool to study emotional brain lateralization. Regarding the perception of sadness and anger through affective prosody, the main finding has been a left ear advantage (LEA) for the sad but contradictory data for the anger prosody. Regarding an induced mood in the laboratory, its consequences upon DL were a diminished right ear advantage (REA) for the induction of sadness and an increased REA for the induction of anger. The global results fit with the approach-withdrawal motivational model of emotional processing, pointing to sadness as a right hemisphere emotion but anger processed bilaterally or even in the left hemisphere, depending on the subject's preferred mode of expression. On the other hand, the study of DL in clinically depressed patients found an abnormally larger REA in verbal DL tasks which was predictive of therapeutic pharmacological response. However, the mobilization of the available left hemisphere resources in these responders (reflected in a higher REA) would indicate a remission of the episode but would not assure the absence of new relapses.     

A lateralization of function approach to sex differences in spatial ability: a reexamination

The current study assessed the lateralization of function hypothesis (Rilea, S. L., Roskos-Ewoldsen, B., & Boles, D. (2004). Sex differences in spatial ability: A lateralization of function approach. Brain and Cognition, 56, 332–343) which suggested that it was the interaction of brain organization and the type of spatial task that led to sex differences in spatial ability. A second purpose was to evaluate explanations for their unexpected findings on the mental rotation task. In Experiment 1, participants completed the Water Level, Paper Folding, and mental rotation tasks (using an object-based or self-based perspective), presented bilaterally. Sex differences were only observed on the Water Level Task; a right hemisphere advantage was observed on Water Level and mental rotation tasks. In Experiment 2, a human stick figure or a polygon was mentally rotated. Men outperformed women when rotating polygons, but not when rotating stick figures. Men demonstrated a right hemisphere advantage when rotating polygons; women showed no hemisphere differences for either stimulus. Thus, hemisphere processing, task complexity, and stimulus type may influence performance for men and women across different spatial measures.     

Spatial tapping interferes with the processing of linguistic spatial relations.

Simple spatial relations may be represented either in a propositional format that is dependent on verbal rehearsal or in a picture-like format that is maintained by visual-spatial rehearsal. In sentence-picture and picture-picture verification tasks, we examined the effect of an articulatory suppression and a spatial tapping dual task on the encoding of simple spatial relations (e.g., triangle left of circle). Articulatory suppression did not interfere, while spatial tapping lowered performance in both tasks. Apparently, both linguistic and perceptual inputs of simple spatial relations engaged the visual-spatial working memory. In the sentence-picture verification experiments, spatial tapping only hampered performance of participants who were classified on the basis of their RT patterns as having used a visual-spatial strategy, while it had no effect for those who were classified as having applied a verbal strategy. Therefore, this study provides converging evidence, using a dual-task methodology, that both separate verbal and visual-spatial strategies exist for the processing of simple spatial sentences.     

The development of categorical and coordinate spatial relations

Two classes of spatial relations can be distinguished in between and within object representations. Kosslyn [Kosslyn, S. M. (1987). Seeing and imagining in the cerebral hemispheres: A computational approach. Psychological Review, 94, 148–175] suggested that the right hemisphere (RH) is specialized for processing coordinate (metric) spatial information and the left hemisphere (LH) processes categorical (abstract) information more effectively. The present study examined the developmental pattern of spatial relation processing in 6–8-year old, 10–12-year old and adults. Using signal detection analyses we calculated sensitivity and bias scores for all age groups. The results indicated that older children and adults showed a greater response bias than younger children. Also, discrimination sensitivity for spatial relation changes clearly improved with age. For the oldest children (10–12-year old) and adults this improvement was accompanied by a RH specialization. In contrast with Kosslyn's claim, this RH advantage also applied to the processing of categorical spatial information. The results are discussed in terms of a right hemispheric specialization for spatial relation processing which matures with age.