What's in a shape? Children represent shape variability differently than adults when naming objects

Children and adults often generalize a word to objects of the same shape. However, the shape properties on which generalization is based are unknown. We investigated the degree to which two shape dimensions were represented categorically by children and adults when learning names for objects. Multidimensional scaling techniques were used to establish the perceptual similarity of two sets of objects in Experiment 1. In Experiments 2 and 3, children (from 2;8 to 4;5 years of age) and adults participated in two tasks in which they learned a novel name for an exemplar. We then examined how often the novel name was generalized to different objects and to line drawings of the objects. In one task, participants generalized the names from memory; in a second task the exemplar was in front of the participant during generalization. Adults accepted names more often to objects that fell "within" the proposed shape boundaries than to objects that fell "across" the boundaries. Children, however, were just as likely to generalize names to novel objects that fell within as to objects that crossed the boundaries.     

What is the shape of developmental change?

Developmental trajectories provide the empirical foundation for theories about change processes during development. However, the ability to distinguish among alternative trajectories depends on how frequently observations are sampled. This study used real behavioral data, with real patterns of variability, to examine the effects of sampling at different intervals on characterization of the underlying trajectory. Data were derived from a set of 32 infant motor skills indexed daily during the first 18 months. Larger sampling intervals (2-31 days) were simulated by systematically removing observations from the daily data and interpolating over the gaps. Infrequent sampling caused decreasing sensitivity to fluctuations in the daily data: Variable trajectories erroneously appeared as step functions, and estimates of onset ages were increasingly off target. Sensitivity to variation decreased as an inverse power function of sampling interval, resulting in severe degradation of the trajectory with intervals longer than 7 days. These findings suggest that sampling rates typically used by developmental researchers may be inadequate to accurately depict patterns of variability and the shape of developmental change. Inadequate sampling regimes therefore may seriously compromise theories of development.     

Can shape be perceived by dynamic touch?

The possibility that some aspects of the shapes of solid objects can be perceived through dynamic touch, even when the objects are not touched, but simply wielded with a handle, was investigated in four experiments. Wooden solids were constructed of three sizes and five shapes: hemisphere, cylinder, parallelepiped, cone, and pyramid. Experiments 1 and 2 involved comparisons (judgments of same or different) between and among wielded objects of the same mass. In Experiments 3 and 4, subjects were required to wield an object and to select a match from a visible arrangement of objects of the five shapes; the wielded objects were of two sizes, each different from that of the visible objects. The success of subjects at these tasks, and the patternings of errors, are seen to involve the characteristic moment of inertia profiles of each shape, and a ratio of the object's resistances to rotation around orthogonal axes is shown to be a strong predictor of performance in the identification experiments. The results are discussed with reference to dynamic touch and to the notion of shape invariants that do not reduce to aspects of object surface.     

What constrains children's learning of novel shape terms?

In this study, 3-year-olds matched on vocabulary score were taught three new shape terms by one of three types of linguistic contrast: corrective, semantic, or referential. A 5-week training paradigm implemented four training sessions and four assessment sessions. Corrective contrast ("This is concave, it is not square," where square is the child's label for the target) produced more learning than did either semantic or referential contrast. In addition, regardless of group, more was learned about those targets that were classified more variably at pretest. Avoidance of lexical overlap (i.e., using more than one term for the same dimension) might make it more difficult for children to learn new dimensional adjectives, and a "shape bias" might make learning shape terms easier. However, children's expectations about the speaker's communicative intent interacted with the potential benefits of contrast in the semantic condition, and children in that group learned no more than did controls.     

Does learning to read shape verbal working memory?

Many experimental studies have investigated the relationship between the acquisition of reading and working memory in a unidirectional way, attempting to determine to what extent individual differences in working memory can predict reading achievement. In contrast, very little attention has been dedicated to the converse possibility that learning to read shapes the development of verbal memory processes. In this paper, we present available evidence that advocates a more prominent role for reading acquisition on verbal working memory and then discuss the potential mechanisms of such literacy effects. First, the early decoding activities might bolster the development of subvocal rehearsal, which, in turn, would enhance serial order performance in immediate memory tasks. In addition, learning to read and write in an alphabetical system allows the emergence of phonemic awareness and finely tuned phonological representations, as well as of orthographic representations. This could improve the quality, strength, and precision of lexical representations, and hence offer better support for the temporary encoding of memory items and/or for their retrieval.     

Did the early Eucharist ever have a sevenfold shape?

Ever since the publication of Gregory Dix's The Shape of the Liturgy in 1945, it has been commonly assumed that the pattern of the Last Supper (bread ritual–meal–cup ritual) constituted the model which was adopted for the shape of the first-century Christian eucharist, and that this was later modified when the meal eventually disappeared. This article questions that assumption and suggests an alternative hypothesis.     

Does the brain's ventral visual pathway compute object shape?

A rich behavioral literature has shown that human object recognition is supported by a representation of shape that is tolerant to variations in an object's appearance. Such 'global' shape representations are achieved by describing objects via the spatial arrangement of their local features, or structure, rather than by the appearance of the features themselves. However, accumulating evidence suggests that the ventral visual pathway – the primary substrate underlying object recognition – may not represent global shape. Instead, ventral representations may be better described as a basis set of local image features. We suggest that this evidence forces a reevaluation of the role of the ventral pathway in object perception and posits a broader network for shape perception that encompasses contributions from the dorsal pathway.     

Zero-sum beliefs shape advantaged allies’ support for collective action

Three studies (N₁ = 1,019; N₂ = 312; N₃ = 494) tested whether seeing intergroup relations as inherently antagonistic shaped advantaged social groups’ allyship intentions. More specifically, we tested whether endorsing zero-sum beliefs related to their willingness to support system-challenging and system-supporting collective action. Zero-sum beliefs were negatively correlated with system-challenging and positively correlated with system-supporting collective action intentions. Zero-sum beliefs were more common among advantaged than disadvantaged groups and translated into lower allyship intentions. Advantaged group members with higher levels of zero-sum beliefs were also more likely to experience anger and fear when considering the demographic racial shift in the United States. Increased fear was associated with greater support for system-supporting and lower support for system-challenging collective action. We find consistent evidence that advantaged group members see intergroup relations as a zero-sum game and that these beliefs are negatively related to their intentions to become allies.     

How little do we need for 3-D shape perception?

How little do we need to perceive 3-D shape in monocular natural images? The shape-from-texture and shape-from-shading perspectives would motivate that 3-D perception vanishes once low-level cues are disrupted. Is this the case in human vision? Or can top-down influences salvage the percept? In this study we probe this question by employing a gauge-figure paradigm similar to that used by Koenderink et al (1992, Perception & Psychophysics 52 487-496). Subjects were presented degraded natural images and instructed to make local assessments of slant and tilt at various locations thereby quantifying their internal 3-D percept. Analysis of subjects' responses reveals recognition to be a significant influence thereby allowing subjects to perceive 3-D shape at high levels of degradation. Specifically, we identify the 'medium-blur' condition, images approximately 32 pixels on a side, to be the limit for accurate 3-D shape perception. In addition, we find that degradation affects the perceived slant of point-estimates making images look flatter as degradation increases. A subsequent condition that eliminates texture and shading but preserves contour and recognition reveals how bottom-up and top-down cues can combine for accurate 3-D shape perception.     

How do natural environments shape adaptive cognition across the lifespan?

How does human cognition adapt to idiosyncratic features of our real-world experiences across our lifetimes? The dynamic interaction between individuals and their natural environments is rarely the focus of study within cognitive science, but I argue that a more ecological approach will be critical for advancing developmental science and revealing the adaptive nature of cognition.     

What does the occluding contour tell us about solid shape?

A new theorem is discussed that relates the apparent curvature of the occluding contour of a visual shape to the intrinsic curvature of the surface and the radial curvature. This theorem allows the formulation of general laws for the apparent curvature, independent of viewing distance and regardless of the fact that the rim (the boundary between the visible and invisible parts of the object) is a general, thus twisted, space curve. Consequently convexities, concavities, or inflextions of contours in the retinal image allow the observer to draw inferences about local surface geometry with certainty. These results appear to be counterintuitive, witness to the treatment of the problem by recent authors. It is demonstrated how well-known examples, used to show how concavities and convexities of the contour have no obvious relation to solid shape, are actually good illustrations of the fact that convexities are due to local ovoid shapes, concavities to local saddle shapes.     

Is surface-based orientation influenced by a proportional relationship of shape parameters?

We investigated the extent to which parameters of environmental shape – namely the major and minor principal axes of space which pass through the centroid and approximate length and width of the entire space, respectively, were subject to similar psychophysical principles as those involved in distance discriminations. We developed an orientation task that allowed us to manipulate the ratio of the major to the minor principal axes of an enclosure during training and control for orientation by alternative cues other than principal axes such as wall lengths or corner angles during testing. Participants trained in an environment with a larger hypothetical discriminability ratio allocated more responses to locations specified by the principal axes of space across novel enclosure types compared to a group trained with a smaller hypothetical discriminability ratio. Results suggest that psychophysical principles may operate on the discrimination of environmental shape parameters and delineate a potential mechanism for experiential and developmental changes in orientation ability.     

Is the anisotropy of perceived 3-D shape invariant across scale?

A number of studies have resulted in the finding of a 3-D perceptual anisotropy, whereby spatial intervals oriented in depth are perceived to be smaller than physically equal intervals in the frontoparallel plane. In this experiment, we examined whether this anisotropy is scale invariant. The stimuli were L shapes created by two rods placed flat on a level grassy field, with one rod defining a frontoparallel interval, and the other, a depth interval. Observers monocularly and binocularly viewed L shapes at two scales such that they were projectively equivalent under monocular viewing. Observers judged the aspect ratio (depth/width) of each shape. Judged aspect ratio indicated a perceptual anisotropy that was invariant with scale for monocular viewing, but not for binocular viewing. When perspective is kept constant, monocular viewing results in perceptual anisotropy that is invariant across these two scales and presumably across still larger scales. This scale invariance indicates that the perception of shape under these conditions is determined independently of the perception of size.     

Professional standards: Can they shape practice in an international context?

A summary of the career of a Russian engineer who practiced a century ago in western Europe, as well as in Russia, provides an example of how ethical standards can influence practice across national boundaries. An examination of his career and his conception of engineering, of the evolution of engineering standards and codes, and of the process of formulating codes in particular instances explains how international standards can shape practice in an international context. An earlier version of this paper was presented at the Engineering Foundation Conference on “Ethics for Science and Engineering Based International Industries”, Durham, NC, USA, 14–17 September 1997.     

Does language shape thought? Mandarin and English speakers' conceptions of time

Does the language you speak affect how you think about the world? This question is taken up in three experiments. English and Mandarin talk about time differently--English predominantly talks about time as if it were horizontal, while Mandarin also commonly describes time as vertical. This difference between the two languages is reflected in the way their speakers think about time. In one study, Mandarin speakers tended to think about time vertically even when they were thinking for English (Mandarin speakers were faster to confirm that March comes earlier than April if they had just seen a vertical array of objects than if they had just seen a horizontal array, and the reverse was true for English speakers). Another study showed that the extent to which Mandarin-English bilinguals think about time vertically is related to how old they were when they first began to learn English. In another experiment native English speakers were taught to talk about time using vertical spatial terms in a way similar to Mandarin. On a subsequent test, this group of English speakers showed the same bias to think about time vertically as was observed with Mandarin speakers. It is concluded that (1) language is a powerful tool in shaping thought about abstract domains and (2) one's native language plays an important role in shaping habitual thought (e.g., how one tends to think about time) but does not entirely determine one's thinking in the strong Whorfian sense.     

Gender differences in global-local perception? Evidence from orientation and shape judgments

Direct examinations of gender differences in global-local processing are sparse, and the results are inconsistent. We examined this issue with a visuospatial judgment task and with a shape judgment task. Women and men were presented with hierarchical stimuli that varied in closure (open or closed shape) or in line orientation (oblique or horizontal/vertical) at the global or local level. The task was to classify the stimuli on the basis of the variation at the global level (global classification) or at the local level (local classification). Women’s classification by closure (global or local) was more accurate than men’s for stimuli that varied in closure on both levels, suggesting a female advantage in discriminating shape properties. No gender differences were observed in global-local processing bias. Women and men exhibited a global advantage, and they did not differ in their speed of global or local classification, with only one exception. Women were slower than men in local classification by orientation when the to-be-classified lines were embedded in a global line with a different orientation. This finding suggests that women are more distracted than men by misleading global oriented context when performing local orientation judgments, perhaps because women and men differ in their ability to use cognitive schemes to compensate for the distracting effects of the global context. Our findings further suggest that whether or not gender differences arise depends not only on the nature of the visual task but also on the visual context.     

Does "whole-word shape" play a role in visual word recognition?

To analyze the impact of outline shape on visual word recognition, the visual pattern of the stimuli can be distorted by size alternation. Contrary to the predictions of models that rely on outline shape (Allen, Wallace, & Weber, 1995), the effect of size alternation was greater for low-frequency words than for high-frequency words in a lexical decision task (Experiment 1). In Experiment 2, the effect of case type (lowercase vs. UPPERCASE) occurred for low-frequency words, but not for high-frequency words. The effect of neighborhood size was remarkably similar in the two experiments. The results can be readily explained in the framework of a resonance model (Grossberg & Stone, 1986), in which a mismatch between the original sensory pattern and the abstract orthographic code slows down the formation of a stable percept.     

Does “whole-word shape” play a role in visual word recognition?

To analyze the impact of outline shape on visual word recognition, the visual pattern of the stimuli can be distorted by size alternation. Contrary to the predictions of models that rely on outline shape (Allen, Wallace, & Weber, 1995), the effect of size alternationwas greater for low-frequency words than for high-frequency words in a lexical decision task (Experiment 1). In Experiment 2, the effect of case type (lowercase vs. UPPERCASE) occurred for low-frequency words, but not for high-frequency words. The effect of neighborhood size was remarkably similar in the two experiments. The results can be readily explained in the framework of a resonance model (Grossberg & Stone, 1986), in which a mismatch between the original sensory pattern and the abstract orthographic code slows down the formation of a stable percept.     

In any way,shape, or form? Toddlers’ understanding of shapes

Using the intermodal preferential looking paradigm, two-year-old children’s ability to discriminate valid (typical and atypical) squares, rectangles, triangles, and circles from invalid distractors was examined. The cognitive and environmental factors that might predict this ability were also investigated. Two-year-old children (N = 33) were able to discriminate squares, triangles, and circles, but not rectangles. No significant cognitive or environmental predictors of this ability were found. The results suggest that the ability to shape discriminate at age two is under considerable development and that other factors may be responsible for children’s ability to discriminate shapes.     

Strain rate response of a Ni–Ti shape memory alloy after hydrogen charging

In this work, we investigate the susceptibility of Ni–Ti superelastic wires to the strain rates during tensile testing after hydrogen charging. Cathodic hydrogen charging is performed at a current density of 10?A/m² during 2–12?h in 0.9% NaCl solution and aged for 24?h at room temperature. Specimens underwent one cycle of loading-unloading reaching a stress value of 700 MPa. During loading, strain rates from 10^?6 to 5?×?10^?2?^?s^?1 have been achieved. After 8?h of hydrogen charging, an embrittlement has been detected in the tensile strain rate range of 10^?6 to 10^?4?s^?1. In contrast, no embrittlement has been detected for strain rates of 10^?3?s^?1 and higher. However, after 12?h of hydrogen charging and 24?h of annealing at room temperature, the embrittlement occurs in the beginning of the austenite-martensite transformation for all the studied strain rate values. These results show that for a range of critical amounts of diffused hydrogen, the embrittlement of the Ni–Ti superelastic alloy strongly depends on the strain rate during the tensile test. Moreover, it has been shown that this embrittlement occurs for low values of strain rates rather than the higher ones. This behaviour is attributed to the interaction between the diffused hydrogen and growth of the martensitic domain.