Spatial reorientation in large and small enclosures: comparative and developmental perspectives

Several vertebrate species, including humans, following passive spatial disorientation appear to be able to reorient themselves by making use of the geometric shape of the environment (i.e., metric properties of surfaces and directional sense). In some circumstances, reliance on such purely geometric information can overcome the use of local featural cues (landmarks). The relative use of geometric and non-geometric information seems to depend upon, among other factors, the size of the experimental space. Evidence in non-human animals and in human infants for primacy in encoding either geometric or landmark information depending on the size of the environment is reviewed, together with possible theoretical accounts of this phenomenon.     

Low is large: spatial location and pitch interact in voice-based body size estimation

Attention, Perception, & Psychophysics - The binding of incongruent cues poses a challenge for multimodal perception. Indeed, although taller objects emit sounds from higher elevations,...     

Roles of egocentric and allocentric spatial representations in locomotion and reorientation

Four experiments investigated the nature of spatial representations used in locomotion. Participants learned the layout of several objects and then pointed to the objects while blindfolded in 3 conditions: before turning (baseline), after turning to a new heading (updating), and after disorientation (disorientation). The internal consistency of pointing in the disorientation condition was relatively high and equivalent to that in the baseline and updating conditions, when the layout had salient intrinsic axes and the participants learned the locations of the objects on the periphery of the layout. The internal consistency of pointing was disrupted by disorientation when participants learned the locations of objects while standing amid them and the layout did not have salient intrinsic axes. It was also observed that many participants retrieved spatial relations after disorientation from the original learning heading. These results indicate that people form an allocentric representation of object-to-object spatial relations when they learn the layout of a novel environment and use that representation to locate objects around them. Egocentric representations may be used to locate objects when allocentric representations are not of high fidelity.     

Converting between word and syllable counts in children's conversational speech samples

Several authors have suggested that it is possible to convert between word and syllable counts for basic clinical measurements such as the frequency of speech disfluencies or speaking rate in conversational speech samples. Based primarily on results from adults' speech samples, proposed conversion factors have averaged approximately 1.5 syllables per word. Because children produce fewer multisyllabic words than adults, this conversion factor is probably not appropriate for children's speech samples. This study sought to develop a more accurate conversion factor for children's speech by comparing syllable and word counts in spontaneous speech samples produced by 50 children, age 3 to 5. Analyses revealed an average ratio of 1.15 syllables per word, which was consistent across different subjects, across subject groups (children who stutter and children who do not stutter) and also, somewhat surprisingly, across age groups (3-year olds, 4-year olds, and 5-year olds). Results suggest that this constant conversion factor of 1.15 can be used to convert between word and syllable with sufficient precision to allow clinicians to compare their data to published guidelines and benchmarks about childhood stuttering.     

Early developments in children's spatial monitoring

This research focused on children's ability to monitor both stable and changing aspects of the spatial field as movements occur. In two experiments, children ranging from 30 months to 5 years of age were tested on spatial transposition problems involving either a single hidden object or a different object in each of three cups. Three developmental trends were identified. First, there was some evidence of developmental improvements in children's understanding of the movements they observed. Although all age groups gave some evidence of understanding that objects move with their containers in Experiment 1, the older children's understanding appeared to be more solid than the 30-montholds in that their performance was not misled by conflicting cues to search at the initial hiding place in Experiment 2. Second, children get better at allocating their attention to the key parts of the spatial field when there is only one object to monitor. Third, children's attentional capacity expands so that they can monitor multiple objects at the same time. These latter two trends produce continuing developments in spatial cognitive performance long after children have achieved an essentially correct understanding of the movements they observe. In addition, they help clarify variations in children's performance on many spatial-cognitive tasks used with age groups ranging from infants to elementary school children.     

Modularity and spatial reorientation in a simple mind: encoding of geometric and nongeometric properties of a spatial environment by fish

When disoriented in environments with distinctive geometry, such as a closed rectangular arena, human infants and adult rats reorient in accord with the large-scale shape of the environment, but not in accord with nongeometric properties such as the colour of a wall. Human adults, however, conjoined geometric and nongeometric information to reorient themselves, which has led to the suggestion that spatial processing tends to become more flexible over development and evolution. We here show that fish tested in the same tasks perform like human adults and surpass rats and human infants. These findings suggest that the ability to make use of geometry for spatial reorientation is an ancient evolutionary tract and that flexibility and accessibility to multiple sources of information to reorient in space is more a matter of ecological adaptations than phylogenetic distance from humans.     

Central executive involvement in children's spatial memory

Previous research with adults found that spatial short-term and working memory tasks impose similar demands on executive resources. We administered spatial short-term and working memory tasks to 8- and 11-year-olds in three separate experiments. In Experiments 1 and 2 an executive suppression task (random number generation) was found to impair performances on a short-term memory task (Corsi blocks), a working memory task (letter rotation), and a spatial visualisation task (paper folding). In Experiment 3 an articulatory suppression task only impaired performance on the working memory task. These results suggest that short-term and working memory performances are dependent on executive resources. The degree to which the short-term memory task was dependent on executive resources was expected to be related to the amount of experience children have had with such tasks. Yet we found no significant age-related suppression effects. This was attributed to differences in employment of cognitive strategies by the older children.     

Central executive involvement in children's spatial memory

Previous research with adults found that spatial short-term and working memory tasks impose similar demands on executive resources. We administered spatial short-term and working memory tasks to 8- and 11-year-olds in three separate experiments. In Experiments 1 and 2 an executive suppression task (random number generation) was found to impair performances on a short-term memory task (Corsi blocks), a working memory task (letter rotation), and a spatial visualisation task (paper folding). In Experiment 3 an articulatory suppression task only impaired performance on the working memory task. These results suggest that short-term and working memory performances are dependent on executive resources. The degree to which the short-term memory task was dependent on executive resources was expected to be related to the amount of experience children have had with such tasks. Yet we found no significant age-related suppression effects. This was attributed to differences in employment of cognitive strategies by the older children.     

Environment size and the use of feature and geometric cues for reorientation

We tested associative-based accounts of orientation by investigating the influence of environment size on the use of feature and geometric cues for reorientation. Two groups of participants were trained in dynamic three-dimensional virtual rectangular environments that differed in size to find a distinctly colored bin located at one of the four corners. Subsequently, we probed the reliance on feature and geometric cues for reorientation during test trials by presenting six trial types: Small Geometry Only, Large Geometry Only, Small Cue Conflict, Large Cue Conflict, Small Distal, and Large Distal. During Geometry Only test trials, all bins were black; thus, all distinctive featural information was removed leaving only geometric cues. For Cue Conflict test trials, all colored bins were shifted counter-clockwise one corner; thus, the geometric cues from the trained corner and the trained color were in direct conflict. During Distal test trials, the bin in the geometrically incorrect corner farthest from the trained corner was colored the same as during training; the remaining three bins were black. Thus, only this distant feature cue could be used to determine the location of the goal bin. Results suggested that geometric cues were used across changes in environment size, featural cues exerted greater influence when in conflict with geometric cues, and the far featural cue was used to disambiguate the correct from the rotationally equivalent location. In short, both feature and geometric cues were used for reorientation, and environment size influenced the relative use of feature and geometric cues. Collectively, our results provide evidence against associative-based accounts of orientation.     

Dissecting the geometric module: a sense linkage for metric and landmark information in animals' spatial reorientation

Disoriented children can use geometric information in combination with featural information to reorient themselves in large but not in small spaces; somewhat similar effects have been found in nonhuman animals. These results call for an explanation. We trained young chicks to reorient to find food in a corner of a small or a large rectangular room with a distinctive featural cue (a blue wall) -- a task similar to that used with children. Then we tested the chicks after displacement of the feature to an adjacent wall. In the large enclosure, chicks chose the corner that maintained the correct arrangement of the featural cue with respect to sense, whereas in the small enclosure, they chose the corner that maintained the correct metrical arrangement of the walls with respect to sense. On the basis of these findings, we propose a simple model that can explain the effects of room size on spatial reorientation.     

Language counts: Early language mediates the relationship between parent education and children's math ability

Children's early math skills have been hailed as a powerful predictor of academic success. Disparities in socioeconomic context, however, also have dramatic consequences on children's learning. It is therefore critical to investigate both of these distinct contributors in order to better understand the early foundations of children's academic outcomes. This study tests an integrated model of children's developing math ability so as to (1) identify the specific skills and abilities most clearly linked to early math achievement and (2) measure the influence of children's socioeconomic context on each of these skills. We first evaluated the early vocabulary, number word knowledge (knower level), and Approximate Number System (ANS) acuity of a diverse group of preschoolers. Then, approximately 1 year later as they entered Kindergarten, we administered a test of early math achievement. We find that children's early language (general vocabulary and number word knowledge) fully mediates the relationship between parent education and math ability. Additionally, number word knowledge mediates the relationship between ANS acuity and early math. We argue that increased focus on number word knowledge, as well as general vocabulary, may help to minimize disparities in math ability as children enter kindergarten. We also highlight the role of parent education on children's learning and note that this may be an important locus for intervention.     

Breakdown of spatial parallel coding in children's drawing

When drawing real scenes or copying simple geometric figures young children are highly sensitive to parallel cues and use them effectively. However, this sensitivity can break down in surprisingly simple tasks such as copying a single line where robust directional errors occur despite the presence of parallel cues. Before we can conclude that this directional bias is a limiting case it needs to be shown that any given parallel cues are indeed being processed. We achieved this by using a texture-defined contour where parallel cues are integral to the stimulus and thus cannot be ignored. Here we report that even when prolific parallel cues must have been processed, young children make robust directional errors when copying single lines. This finding demonstrates a major constraint on young children's spatial parallel coding.     

The importance of gesture in children's spatial reasoning

On average, men outperform women on mental rotation tasks. Even boys as young as 4 1/2 perform better than girls on simplified spatial transformation tasks. The goal of our study was to explore ways of improving 5-year-olds' performance on a spatial transformation task and to examine the strategies children use to solve this task. We found that boys performed better than girls before training and that both boys and girls improved with training, whether they were given explicit instruction or just practice. Regardless of training condition, the more children gestured about moving the pieces when asked to explain how they solved the spatial transformation task, the better they performed on the task, with boys gesturing about movement significantly more (and performing better) than girls. Gesture thus provides useful information about children's spatial strategies, raising the possibility that gesture training may be particularly effective in improving children's mental rotation skills.     

Geometry,landmarks and the cerebral hemispheres: 2D spatial reorientation in split‐brain patients

A right‐hemispheric superiority in spatial encoding based on geometric cues has been largely documented in a variety of species, together with a left‐hemispheric specialization for encoding based on landmarks. In humans, hemispheric asymmetries for spatial encoding have been little explored. In this study, we compared a patient with a complete callosal resection (D.D.C.) and a patient with a wide callosal resection saving the splenium (A.P.), with healthy participants. In two 2D versions of the ‘reorientation task’, participants were asked to find the target corner of a rectangle‐shaped environment, by exploiting either geometric information alone or the combination of geometric and landmark information. In Experiment 1, the landmark consisted of a coloured side of the rectangle; in Experiment 2, this cue was replaced by a coloured disc located inside the rectangle. In both experiments, the rectangular shape ensured the geometric cue. D.D.C. was always unable to recall the target, whereas A.P. correctly solved the task when only the geometric information was available, without difference with respect to the controls. Importantly, the performance of A.P. did not differ from controls’ when the right hemisphere was tested with the landmark cues (the task being carried out using the left hand), whereas when the left hemisphere was tested (right‐hand session) his performance was worse than controls’ with the coloured side of the space, but it was better than controls’ with the coloured disc. The results are discussed comparing them with data collected on other species, and with theories of spatial processing.     

Enclosure size and the use of local and global geometric cues for reorientation

Multiple spatial cues are utilized to orient with respect to the environment, but it remains unclear why feature (i.e., objects in the environment) and geometric (i.e., shape of the environment) cues are differentially influenced by enclosure size, and the extent to which local (i.e., wall lengths and corner angles) and global (i.e., principal axis of space) geometric cues are influenced by enclosure size. In the present study, we investigated the extent to which environmental size influenced the use of corner angle (i.e., a local geometric cue) and the principal axis of space (i.e., a global geometric cue) for reorientation. We developed an orientation task that allowed the manipulation of enclosure size during training and the isolation of the use of the principal axis of space during testing. Participants were trained to respond to a location in either a small or a large trapezoid-shaped enclosure uniquely specified by both local (i.e., wall lengths and corner angles) and global (i.e., principal axis of space) geometric cues. During testing, we presented both groups with a small and large rectangle (to assess the use of principal axis of space) and a small and large parallelogram (to asses relative use of corner angles and the principal axis of space when in conflict). Enclosure size influenced the relative use of corner angles but not of the principal axis of space. Results suggest that corner angles function like features and that changes in the use of feature cues are the source of the relative reliance on feature and geometric cues during changes of enclosure size.     

Spatial reorientation: the effects of space size on the encoding of landmark and geometry information

The effects of the size of the environment on animals’ spatial reorientation was investigated. Domestic chicks were trained to find food in a corner of either a small or a large rectangular enclosure. A distinctive panel was located at each of the four corners of the enclosures. After removal of the panels, chicks tested in the small enclosure showed better retention of geometrical information than chicks tested in the large enclosure. In contrast, after changing the enclosure from a rectangular-shaped to a square-shaped one, chicks tested in the large enclosure showed better retention of landmark (panels) information than chicks tested in the small enclosure. No differences in the encoding of the overall arrangement of landmarks were apparent when chicks were tested for generalisation in an enclosure differing from that of training in size together with a transformation (affine transformation) that altered the geometric relations between the target and the shape of the environment. These findings suggest that primacy of geometric or landmark information in reorientation tasks depends on the size of the experimental space, likely reflecting a preferential use of the most reliable source of information available during visual exploration of the environment.     

Use of geometry for spatial reorientation in children applies only to symmetric spaces

Proponents of the geometric module hypothesis argue that following disorientation, many species reorient by use of macro‐environment geometry. It is suggested that attention to the surface layout geometry of natural terrain features may have been selected for over evolutionary time due to the enduring and unambiguous location information it provides. Paradoxically, however, tests of the hypothesis have been exclusively conducted in symmetric (hence ‘unnatural’ and geometrically ambiguous) environments. The present series of studies examines reorientation by 18‐month–3‐year‐old children in a rectangular versus irregular quadrilateral enclosure (Study 1), a rectangular versus irregular quadrilateral array (Study 2) and an isosceles versus irregular triangular array (Study 3). Children were successful in symmetric but not asymmetric environments, casting doubt on the functional argument for an empirical basis of the geometric module hypothesis.     

Starting small: Revisiting young children's perceptions of social withdrawal in China

In this reply to the commentaries by Xinyin Chen, Charissa Cheah, Yiyuan Xu, and Dawn Watling, we further discuss the conceptual and methodological challenges that arise when attempting to study beliefs about social withdrawal (1) in the unique cultural context of China and (2) in the unique developmental age period of early childhood.     

Selective spatial enhancement: Attentional spotlight size impacts spatial but not temporal perception

An important but often neglected aspect of attention is how changes in the attentional spotlight size impact perception. The zoom-lens model predicts that a small (“focal”) attentional spotlight enhances all aspects of perception relative to a larger (“diffuse” spotlight). However, based on the physiological properties of the two major classes of visual cells (magnocellular and parvocellular neurons) we predicted trade-offs in spatial and temporal acuity as a function of spotlight size. Contrary to both of these accounts, however, across two experiments we found that attentional spotlight size affected spatial acuity, such that spatial acuity was enhanced for a focal relative to a diffuse spotlight, whereas the same modulations in spotlight size had no impact on temporal acuity. This likely reflects the function of attention: to induce the high spatial resolution of the fovea in periphery, where spatial resolution is poor but temporal resolution is good. It is adaptive, therefore, for the attentional spotlight to enhance spatial acuity, whereas enhancing temporal acuity does not confer the same benefit.     

Linking large and small computers

A PDP-8/I was connected to an IBM/370 via telephone. Programs enable the PDP-8 to send data to practically any large-scale computer having timesharing capabilities. These programs can be used as models by others wishing to analyze data on a large computer.