Individual differences in spatial relation processing: effects of strategy, ability, and gender

Numerous studies have focused on the distinction between categorical and coordinate spatial relations. Categorical relations are propositional and abstract, and often related to a left hemisphere advantage. Coordinate relations specify the metric information of the relative locations of objects, and can be linked to right hemisphere processing. Yet, not all studies have reported such a clear double dissociation; in particular the categorical left hemisphere advantage is not always reported. In the current study we investigated whether verbal and spatial strategies, verbal and spatial cognitive abilities, and gender could account for the discrepancies observed in hemispheric lateralization of spatial relations. Seventy-five participants performed two visual half field, match-to-sample tasks (Van der Ham, van Wezel, Oleksiak, & Postma, 2007; Van der Ham, Raemaekers, van Wezel, Oleksiak, and Postma, 2009) to study the lateralization of categorical and coordinate relation processing. For each participant we determined the strategy they used in each of the two tasks. Consistent with previous findings, we found an overall categorical left hemisphere advantage and coordinate right hemisphere advantage. The lateralization pattern was affected selectively by the degree to which participants used a spatial strategy and by none of the other variables (i.e., verbal strategy, cognitive abilities, and gender). Critically, the categorical left hemisphere advantage was observed only for participants that relied strongly on a spatial strategy. This result is another piece of evidence that categorical spatial relation processing relies on spatial and not verbal processes.     

Sequence-sensitive exemplar and decision-bound accounts of speeded-classification performance in a modified Garner-tasks paradigm

Among the most fundamental results in the area of perceptual classification are the “correlated facilitation” and “filtering interference” effects observed in Garner’s (1974) speeded categorization tasks: In the case of integral-dimension stimuli, relative to a control task, single-dimension classification is faster when there is correlated variation along a second dimension, but slower when there is orthogonal variation that cannot be filtered out (e.g., by attention). These fundamental effects may result from participants’ use of a trial-by-trial bypass strategy in the control and correlated tasks: The observer changes the previous category response whenever the stimulus changes, and maintains responses if the stimulus repeats. Here we conduct modified versions of the Garner tasks that eliminate the availability of a pure bypass strategy. The fundamental facilitation and interference effects remain, but are still largely explainable in terms of pronounced sequential effects in all tasks. We develop sequence-sensitive versions of exemplar-retrieval and decision-bound models aimed at capturing the detailed, trial-by-trial response-time distribution data. The models combine assumptions involving: (i) strengthened perceptual/memory representations of stimuli that repeat across consecutive trials, and (ii) a bias to change category responses on trials in which the stimulus changes. These models can predict our observed effects and provide a more complete account of the underlying bases of performance in our modified Garner tasks.     

Individual pattern representations are context independent, but their collective representation is context dependent.

We studied context dependency of the representations underlying perceptual "goodness". Three experiments used a same-different task with classical Garner 5-dot patterns presented with an interstimulus interval (ISI) of 500 ms. Same patterns were allowed to be rotated or reflected versions of each other. Pattern goodness was varied according to rotation and reflection equivalence, using Garner's equivalence set size (ESS) measure. The ESS of both first and second patterns affected reaction time and accuracy. A model based on assumptions that Garner's equivalence sets constitute the generic representation of these patterns and that items within these sets are accessed serially was fitted to the data. Excellent fits were obtained, which were robust against frequency-induced bias at the level of the individual pattern, but sensitive to such bias at the level of the equivalence set. It was concluded that individual pattern representations are context independent, whereas their collective representations are context dependent. Simplicity and likelihood principles, therefore, seem to apply to different levels of a representation hierarchy.     

Nominal and physical decision criteria insame-different judgments

We propose a model in which the physical and nominal dimensions of letter pairs are compared independently of whether subjects use physical (shape task) or nominal (name task) identity as the decision criterion. We attempt to explain the fast-same effect, the preponderance of false-different errors, and thenominal-physical disparity as results of congruent and incongruent outputs of physical and nominal comparison devices that function in both tasks. Subjects performed both tasks with and without response deadlines. The stimuli were presented foveally or unilaterally to one or the other hemisphere. With foveal presentations, thenominal-physical disparity disappeared when congruent and incongruent cells were compared, the fast-same effect occurred only in the shape task, and there was a preponderance offalse-different errors only in the name task. Response times and error patterns from centrally presented trials conformed to the predictions of the model. Performance patterns from the lateralized trials conformed only partially. The implications of the data are discussed in the context of several theoretical models ofsame/ different judgments.     

Instructions,strategies, and pattern uncertainty in a visual discrimination task

A card-sorting task involved discrimination of patterns from the same equivalence set, patterns from different sets of the same size, and patterns from different sets of different sizes. Instructions, experimental conditions, and the number of different patterns to be sorted into two trays were varied in an attempt to change Ss’ strategies from whole-pattern processing to single-element processing. Instructions alone were ineffectual in preventing whole-pattern processing, and physical masks over most of the criterion stimuli (patterns used as guides in sorting) were only somewhat effective. Differences among tasks that were attributable to size of equivalence set were eliminated only by arranging the stimuli so that a whole-pattern strategy required a great deal more information processing, or so that such a strategy could not lead to the required discrimination. The results were interpreted as confirming the influence of the properties of sets of stimuli, as well as the strength of the tendency of human Ss to process and categorize patterns in their entirety. nt]mis|This research was supported in part by a University Research Council grant.     

Individual differences in children's mathematical competence are related to the intentional but not automatic processing of Arabic numerals

In recent years, there has been an increasing focus on the role played by basic numerical magnitude processing in the typical and atypical development of mathematical skills. In this context, tasks measuring both the intentional and automatic processing of numerical magnitude have been employed to characterize how children’s representation and processing of numerical magnitude changes over developmental time. To date, however, there has been little effort to differentiate between different measures of ‘number sense’. The aim of the present study was to examine the relationship between automatic and intentional measures of magnitude processing as well as their relationships to individual differences in children’s mathematical achievement. A group of 119 children in 1st and 2nd grade were tested on the physical size congruity paradigm (automatic processing) as well as the number comparison paradigm to measure the ratio effect (intentional processing). The results reveal that measures of intentional and automatic processing are uncorrelated with one another, suggesting that these tasks tap into different levels of numerical magnitude processing in children. Furthermore, while children’s performance on the number comparison paradigm was found to correlate with their mathematical achievement scores, no such correlations could be obtained for any of the measures typically derived from the physical size congruity task. These findings therefore suggest that different tasks measuring ‘number sense’ tap into different levels of numerical magnitude representation that may be unrelated to one another and have differential predictive power for individual differences in mathematical achievement.     

Garner interference and temporal information processing

The aim of the study was to explore whether temporal information processing can interfere with performance of a non-temporal task. A new methodology based on the Garner paradigm was employed. Participants were asked to classify two-dimensional stimuli according to either length or duration, with and without variation in the other (task-irrelevant) dimension. Garner interference was detected only with respect to classification by length when irrelevant variation in duration was present. Stroop interference was detected only in classification by length across compatible and non-compatible values of length and duration. Classification by length took more time when done with variation in duration than when duration was constant. Classification by length also took more time when length and duration were not compatible than when they were compatible. The findings indicate that the processing of duration is similar to the processing of other perceptual dimensions. The processing of duration consumes attentional resources and can interfere with the processing of other perceptual dimensions. The findings support attentional models of prospective duration judgment.     

Electrophysiological evidence of automatic early semantic processing

This study investigates the automatic-controlled nature of early semantic processing by means of the Recognition Potential (RP), an event-related potential response that reflects lexical selection processes. For this purpose tasks differing in their processing requirements were used. Half of the participants performed a physical task involving a lower-upper case discrimination judgement (shallow processing requirements), whereas the other half carried out a semantic task, consisting in detecting animal names (deep processing requirements). Stimuli were identical in the two tasks. Reaction time measures revealed that the physical task was easier to perform than the semantic task. However, RP effects elicited by the physical and semantic tasks did not differ in either latency, amplitude, or topographic distribution. Thus, the results from the present study suggest that early semantic processing is automatically triggered whenever a linguistic stimulus enters the language processor.     

Task-invariant aspects of goodness in perceptual representation.

In two experiments, pairs of Garner's classical 5-dot patterns were presented with an interstimulus interval of 500 ms in a same-different task in which a physical sameness criterion was used: Rotated or reflected versions of the same pattern were rated as different. Patterns varied in "goodness" according to Garner's equivalence set size measure. Both first and second pattern goodness affected reaction time and accuracy. This result and fits of models to reaction time data indicate that equivalence set representations are used in the task, as in a related categorical matching task in previous studies. Two effects were observed that contrast with the categorical matching task: One is a conflict between the need to respond different to patterns that are categorically equivalent under the equivalence set representation; the other is that extra time is needed for rechecking of the representation if pattern structures are hard to distinguish. In combination with previous studies, the present results show that even though the processes differ, the same representational mechanism is used across tasks.     

A comparison of discrimination and identification of vibrotactile patterns

Both discrimination and identification tasks have been used to assess subjects' abilities to perceive vibratory spatial patterns presented to the skin. The present study examined discrimination and identification performance under comparable conditions. In Experiment 1, subjects attempted to discriminate a pair of patterns on some blocks of trials and to identify both members of a pair on other blocks. For both tasks, the time between the members of the pair was varied. Discrimination performance could be predicted accurately from identification data. Analysis of performance on identification trials indicated that subjects used discriminability information to identify pairs. In Experiment 2, discrimination and identification were compared when the temporal separation between patterns was fixed and a masking stimulus followed each pattern after a variable delay. Results suggest that temporal masking, rather than the time available for processing pattern information, is the major limitation in both discrimination and identification of sequences of tactile patterns.     

Consumer decision making and aging: A commentary

Yoon, Cole and Lee's review suggests two strategies to address elderly individuals' limitations in processing information and decision making. One is accommodation, which entails designing information processing and judgment tasks so that they are compatible with the elderly's resource limitations. The other strategy involves stimulating self-regulation. Here the premise is that elderly individuals often have the resources necessary to engage in a task, but only activate them in response to explicit directions. We discuss whether this observation reflects older individuals' inability to activate self-regulation strategies spontaneously, or their purposive rationing of their limited resources so they remain available for more profound activities.     

Developmental dyslexics do not fit in boxes: Evidence from six new case studies

Abstract

Six subjects with a reading problem were tested on a variety of reading and other tasks including tests of phonological awareness and processing, short-term memory, visual analysis and synthesis, memory for faces and pictures, and matching of letters and shapes. The subjects demonstrated differences in their reading strategies, but these showed no relation to any differences in the patterns of deficit on non-reading tasks. Five of them showed severe problems on tasks involving phonological processing and short-term memory but the seventy of these was unrelated to reading strategy. There were some indications of visual weaknesses, but these were severe in only one subject who had a pronounced defect in memory for faces; there was no evidence that the visual weaknesses were consistently related to reading ability or strategy.

It is concluded that all the subjects in this sample (with one 'possible exception) had a deficit in phonological processing but adopted different strategies to cope with this when faced with the task of converting print to sound. Differences in strategy are likely to be affected by the relative efficiency of other cognitive processes, personality and introdctional factors.     

Distinctiveness of processing,processing time and memory performance

The research reported here, explored the conditions where processing time can be used as a predictive measure for retention performance. The results showed that, in similar but quantitatively different tasks, both processing time and retention performance increased with increasing task difficulty. The strongly suggests that processing time can be used as an independent measure for extensiveness of processing, and as a predictor for later retention performance. This relationship, however, is restricted to the comparison of similar processing tasks that differ only in the amount of processing necessary to perform the task.It is hypothesized that longer processing times are indicative of more extensive processing, leading to the formation of more distinctive memory representations. These, in turn, cause higher retention performance because they allow better discrimination from other memory traces, and because they are retrieved more easily.Although distinctiveness of memory representations is an important variable in determining retention performance, it is not the only one. In a recall test, semantic relations between items had an effect on performance independent of distinctiveness.     

Goodness takes effort: perceptual organization in dual-task settings

We adopted the Psychological Refractoriness Paradigm to study whether perceptual Goodness affects the load of central processing resources. In three dual-task experiments, 2-Alternative Forced Choice auditory classification was followed by a same-different task in which Garner's classical five-dot patterns were presented. Goodness of these patterns and stimulus-onset asynchrony (SOA) between the first and second task were varied between trials. These factors had additive effects on response latencies and accuracy, indicating that pattern Goodness determines central processing load in performing the same-different task. In a fourth experiment, same-different judgment with Garner patterns was the single task. SOA between the first and second pattern was varied. Over-additive effects of Goodness with decreasing SOA were obtained, indicating sharing of central resources between consolidation of the first Garner pattern and performing the same-different task. Whereas, the resources needed for the latter, again, depend on Goodness, those needed for consolidation are independent of it.     

Dimensional interactions in language processing: investigating directions and levels of crosstalk

In this article we evaluate current models of language processing by testing speeded classification of stimuli comprising one linguistic and one nonlinguistic dimension. Garner interference obtains if subjects are slower to classify attributes on one dimension when an irrelevant dimension is varied orthogonally than when the irrelevant dimension is held constant. With certain linguistic-nonlinguistic pairings (e.g., Experiment 1: the words high and low spoken either loudly or softly), significant Garner interference obtained when either dimension was classified; this indicated two-directional crosstalk. With other pairings (e.g., Experiment 3: spoken vowels and loudness), only the nonlinguistic dimension (e.g., loudness) displayed interference, suggesting unidirectional crosstalk downstream from a phonemic/graphemic level of analysis. Collectively, these results indicate the interaction can occur either within or across levels of information processing, being directed toward either more advanced or more primitive processes. Although poorly explained by all current models of language processing, our results are strikingly inconsistent with models that posit autonomy among levels of processing.     

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 mean-integral representation of rectangles

To assess perceptual interaction between the height and width of rectangles, we used an accuracy variant of the Garner paradigm. We measured the discriminability of height and width (baseline tasks) and size and shape (correlated tasks). From thed′ values in these conditions, we estimated perceptual distances and inferred amean-integral representation in which height and width corresponded to nonindependent dimensions in a perceptual space. This model accounted well for performance in these two-stimulus conditions, and it also explained 70% –80% of the decline in performance in selective and divided attention. In a second experiment, conducted for purposes of comparison with the rectangle discrimination Experiment, we studied the discrimination of horizontal and vertical line segments connected in an L-shape. In size discrimination, observers were equally good with line pairs and rectangles, suggesting holistic perception; but in shape discrimination, they appeared to combine information from the two line-pair components of the rectangle independently. The mean-integral model was again successful in relating performance in the Garner tasks quantitatively.     

Solution strategies as possible explanations of individual and sex differences in a dynamic spatial task

When individuals perform spatial tasks, individual differences emerge in accuracy and speed as well as in the response patterns used to cope with the task. The purpose of this study is to identify, through empirical criteria, the different response patterns or strategies used by individuals when performing the dynamic spatial task presented in the Spatial Orientation Dynamic Test-Revised (SODT-R). Results show that participants can be classified according to their response patterns. Three different ways of solving a task are described, and their relation to (a) performance factors (response latency, response frequency, and invested time) and (b) ability tests (analytical reasoning, verbal reasoning, and spatial estimation) are investigated. Sex differences in response patterns and performance are also analyzed. It is found that the frequency with which men and women employ each one of the strategies described here, is different and statistically significant. Thus, employed strategy plays an important role when interpreting sex differences on dynamic spatial 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.     

Selective attention and the processing of integral and nonintegral dimensions: A developmental study

In two experiments, first- and fourth-grade subjects (age 6 and 9 years) performed a speeded card-sorting task with either integral or nonintegral dimensions. The dimensions were so arranged that subjects sorted on three types of task: (1) single dimension, (2) correlated dimensions, and (3) orthogonal dimensions. Results of the first experiment indicate that both first- and fourth-grade subjects sorted integral dimensions in a manner not qualitatively different from that of the adult (Garner & Felfoldy, Cognitive Psychology, 1970, 1, 225–241). In comparison with single-dimension tasks, performance was facilitated on the correlated-dimensions tasks and interference was observed on the orthogonal-dimensions tasks. Performances with nonintegral dimensions revealed an age-related processing difference. Fourth graders sorted nonintegral dimensions like the adult; no differences in performance were observed between the tasks. In contrast, first-graders sorted nonintegral dimensions as if they were integral. Interference was consistently observed on orthogonal-dimensions tasks. On correlated-dimensions tasks, interference was observed on easy tasks and redundancy facilitated difficult tasks. In the second experiment, first graders showed consistent facilitation on the correlated-dimensions task; all other results were indentical to those of Experiment I. The results were interpreted as consistent with perceptual learning theory (Gibson, Principles of perceptual learning and development. New York: Appleton-Century-Crofts, 1969).