Visuo-haptic integration in object identification using novel objects

Although some studies have shown that haptic and visual identification seem to rely on similar processes, few studies have directly compared the two. We investigated haptic and visual object identification by asking participants to learn to recognize (Experiments 1, and 3), or to match (Experiment 2) novel objects that varied only in shape. Participants explored objects haptically, visually, or bimodally, and were then asked to identify objects haptically and/or visually. We demonstrated that patterns of identification errors were similar across identification modality, independently of learning and testing condition, suggesting that the haptic and visual representations in memory were similar. We also demonstrated that identification performance depended on both learning and testing conditions: visual identification surpassed haptic identification only when participants explored the objects visually or bimodally. When participants explored the objects haptically, haptic and visual identification were equivalent. Interestingly, when participants were simultaneously presented with two objects (one was presented haptically, and one was presented visually), object similarity only influenced performance when participants were asked to indicate whether the two objects were the same, or when participants had learned about the objects visually—without any haptic input. The results suggest that haptic and visual object representations rely on similar processes, that they may be shared, and that visual processing may not always lead to the best performance.     

Visual size perception and haptic calibration during development

It is still unclear how the visual system perceives accurately the size of objects at different distances. One suggestion, dating back to Berkeley’s famous essay, is that vision is calibrated by touch. If so, we may expect different mechanisms involved for near, reachable distances and far, unreachable distances. To study how the haptic system calibrates vision we measured size constancy in children (from 6 to 16 years of age) and adults, at various distances. At all ages, accuracy of the visual size perception changes with distance, and is almost veridical inside the haptic workspace, in agreement with the idea that the haptic system acts to calibrate visual size perception. Outside this space, systematic errors occurred, which varied with age. Adults tended to overestimate visual size of distant objects (over‐compensation for distance), while children younger than 14 underestimated their size (under‐compensation). At 16 years of age there seemed to be a transition point, with veridical perception of distant objects. When young subjects were allowed to touch the object inside the haptic workspace, the visual biases disappeared, while older subjects showed multisensory integration. All results are consistent with the idea that the haptic system can be used to calibrate visual size perception during development, more effectively within than outside the haptic workspace, and that the calibration mechanisms are different in children than in adults.     

Development of visuo-haptic transfer for object recognition in typical preschool and school-aged children

Object recognition is a long and complex adaptive process and its full maturation requires combination of many different sensory experiences as well as cognitive abilities to manipulate previous experiences in order to develop new percepts and subsequently to learn from the environment. It is well recognized that the transfer of visual and haptic information facilitates object recognition in adults, but less is known about development of this ability. In this study, we explored the developmental course of object recognition capacity in children using unimodal visual information, unimodal haptic information, and visuo-haptic information transfer in children from 4 years to 10 years and 11 months of age. Participants were tested through a clinical protocol, involving visual exploration of black-and-white photographs of common objects, haptic exploration of real objects, and visuo-haptic transfer of these two types of information. Results show an age-dependent development of object recognition abilities for visual, haptic, and visuo-haptic modalities. A significant effect of time on development of unimodal and crossmodal recognition skills was found. Moreover, our data suggest that multisensory processes for common object recognition are active at 4 years of age. They facilitate recognition of common objects, and, although not fully mature, are significant in adaptive behavior from the first years of age. The study of typical development of visuo-haptic processes in childhood is a starting point for future studies regarding object recognition in impaired populations.     

Are children's faces really more appealing than those of adults? Testing the baby schema hypothesis beyond infancy

This study examined adults’ evaluations of likeability and attractiveness of children’s faces from infancy to early childhood. We tested whether Lorenz’s baby schema hypothesis (Zeitschrift für Tierpsychologie (1943), Vol. 5, pp. 235-409) is applicable not only to infant faces but also to faces of children at older ages. Adult participants were asked to evaluate children’s faces from early infancy to 6 years of age in terms of their likeability and attractiveness, and these judgments were compared with those of adult faces. It was revealed that adults judged faces of younger children as more likeable and attractive than faces of older children, which were in turn judged as more likeable and attractive than adult faces. However, after approximately 4.5 years of age, the baby schema no longer affected adults’ judgments of children’s facial likeability and attractiveness. These findings suggest that the baby schema affects adults’ judgments of not only infant faces but also young children’s faces. This influence beyond infancy is likely due to the fact that facial cranial growth is gradual during early childhood and certain crucial infantile facial cues remain readily available during this period. Future studies need to identify these specific cues to better understand why adults generally show positive responses to infantile faces and how such positive responses influence the establishment and maintenance of social relationships between young children and adults.     

Visuo-haptic transfer for object recognition in children with periventricular leukomalacia and bilateral cerebral palsy

Object recognition is a complex adaptive process that can be impaired in children with neurodevelopmental disabilities. Recently, we found a significant effect of time on the development of unimodal and crossmodal recognition skills for common objects in typical children and this was a starting point for the study of visuo-haptic object recognition skills in impaired populations. In this study, we investigated unimodal visual information, unimodal haptic information and visuo-haptic information transfer in 30 children, from 4.0 to 10.11 years of age, with bilateral Periventricular Leukomalacia (PVL) and bilateral cerebral palsy. Results were matched with those of 116 controls. Participants were tested using a clinical protocol, adopted in the previous study, involving visual exploration of black-and-white photographs of common objects, haptic exploration of real objects and visuo-haptic transfer of these two types of information. Results show that in the PVL group as in controls, there is an age-dependent development of object recognition abilities for visual, haptic and visuo-haptic modalities, even if PVL children perform worse in all the three conditions, in comparison with the typical group. Furthermore, PVL children have a specific deficit both in visual and haptic information processing, that improves with age, probably thanks to everyday experience, but the visual modality shows a better and more rapid maturation, remaining more salient compared to the haptic one. However, multisensory processes partially facilitate recognition of common objects also in PVL children and this finding could be useful for planning early intervention in children with brain lesion.     

Visual capture of haptically judged depth

Using a graduated scale. S was required to match with his left hand the depth of three objects of equal physical depth (or thickness) held with the right hand. While making these haptic depth judgments the objects were viewed. Due to its optical properties. one object was of greater apparent visual depth than the other two, which served as controls. The critical object was judged to be of greater haptic depth than the control objects, thus demonstrating visual capture of haptic depth. This outcome is similar to that noted previously for haptically judged direction, size, and orientation with transformed visual input.     

Children's haptic and cross-modal recognition with familiar and unfamiliar objects

Five-year-old children explored multidimensional objects either haptically or visually and then were tested for recognition with target and distractor items in either the same or the alternative modality. In Experiments 1 and 2, haptic, visual, and cross-modal recognition were all nearly with familiar objects; haptic and visual recognition were also excellent with unfamiliar objects, but cross-modal recognition was less accurate. In Experiment 3, cross-modal recognition was also less accurate than within-mode recognition with familiar objects that were members of the same basic-level category. The results indicate that children's haptic recognition is remarkably good, that cross-modal recognition is otherwise constrained, and that cross-modal recognition may be accomplished differently for familiar and unfamiliar objects.     

The eyes grasp,the hands see: Metric category knowledge transfers between vision and touch

Categorization of seen objects is often determined by the shapes of objects. However, shape is not exclusive to the visual modality: The haptic system also is expert at identifying shapes. Hence, an important question for understanding shape processing is whether humans store separate modality-dependent shape representations, or whether information is integrated into one multisensory representation. To answer this question, we created a metric space of computer-generated novel objects varying in shape. These objects were then printed using a 3-D printer, to generate tangible stimuli. In a categorization experiment, participants first explored the objects visually and haptically. We found that both modalities led to highly similar categorization behavior. Next, participants were trained either visually or haptically on shape categories within the metric space. As expected, visual training increased visual performance, and haptic training increased haptic performance. Importantly, however, we found that visual training also improved haptic performance, and vice versa. Two additional experiments showed that the location of the categorical boundary in the metric space also transferred across modalities, as did heightened discriminability of objects adjacent to the boundary. This observed transfer of metric category knowledge across modalities indicates that visual and haptic forms of shape information are integrated into a shared multisensory representation.     

Are children’s memory illusions created differently from those of adults? Evidence from levels-of-processing and divided attention paradigms

In two experiments, we investigated the robustness and automaticity of adults’ and children’s generation of false memories by using a levels-of-processing paradigm (Experiment 1) and a divided attention paradigm (Experiment 2). The first experiment revealed that when information was encoded at a shallow level, true recognition rates decreased for all ages. For false recognition, when information was encoded on a shallow level, we found a different pattern for young children compared with that for older children and adults. False recognition rates were related to the overall amount of correctly remembered information for 7-year-olds, whereas no such association was found for the other age groups. In the second experiment, divided attention decreased true recognition for all ages. In contrast, children’s (7- and 11-year-olds) false recognition rates were again dependent on the overall amount of correctly remembered information, whereas adults’ false recognition was left unaffected. Overall, children’s false recognition rates changed when levels of processing or divided attention was manipulated in comparison with adults. Together, these results suggest that there may be both quantitative and qualitative changes in false memory rates with age.     

Effects of action on children’s and adults’ mental imagery

The aim of this study was to investigate whether and which aspects of a concurrent motor activity can facilitate children’s and adults’ performance in a dynamic imagery task. Children (5-, 7-, and 9-year-olds) and adults were asked to tilt empty glasses, filled with varied amounts of imaginary water, so that the imagined water would reach the rim. Results showed that in a manual tilting task where glasses could be tilted actively with visual feedback, even 5-year-olds performed well. However, in a blind tilting task and in a static judgment task, all age groups showed markedly lower performance. This implies that visual movement information facilitates imagery. In a task where the tilting movement was visible but regulated by means of an on-and-off remote control, a clear age trend was found, indicating that active motor control and motor feedback are particularly important in imagery performance of younger children.     

Widgets: A new set of parametrically defined 3D objects for use in haptic and visual categorization tasks

IntroductionMost research to date on human categorization ability has concentrated on the visual and auditory domains. However, a limited – but non-negligible – range of studies has also examined the categorization of familiar or unfamiliar (i.e., novel) objects in the haptic (i.e., tactile-kinesthetic) modality.ObjectiveIn this paper, we describe how we developed a new set of parametrically defined objects, called widgets, that can be used as 3D (or 2D) materials for haptic (or visual) categorization purposes.MethodWidgets are unfamiliar complex 3D shapes with an ovoid body and four types of elements attached to it (eyes, tail, crest, and legs). The stimulus set comprises 24 objects divided into four categories of six exemplars each (the files used for 3D printing are provided as Supplementary Material).ResultsWe also assessed and demonstrated the validity of our stimulus set by conducting two separate studies of haptic and visual categorization, involving participants of different ages: young adults (Study 1), and children and adolescents (Study 2). Results showed that humans can categorize our 3D complex shapes on the basis of both haptically and visually perceived similarities in shape attributes.ConclusionWidgets are very useful new experimental stimuli for categorization studies using 3D printing technology.     

Manual exploration of objects is related to 7-month-old infants’ visual preference for real objects

The present study examined whether infants’ visual preferences for real objects and pictures are related to their manual object exploration skills. Fifty-nine 7-month-old infants were tested in a preferential looking task with a real object and its pictorial counterpart. All of the infants also participated in a manual object exploration task, in which they freely explored five toy blocks. Results revealed a significant positive relationship between infants’ haptic scan levels in the manual object exploration task and their gaze behavior in the preferential looking task: The higher infants’ haptic scan levels, the longer they looked at real objects compared to pictures. Our findings suggest that the specific exploratory action of haptically scanning an object is associated with infants’ visual preference for real objects over pictures.     

Haptic classification of common objects: Knowledge-driven exploration

In Experiment 1, haptically available object properties that would be diagnostic for constrained common object classification at the basic and subordinate levels were elicited in a questionnaire. The results are considered in terms of the nature of the haptically derived representations of common objects. Initial data are also presented regarding knowledge of the natural co-occurrence of properties in haptic object perception. In Experiment 2, the hand movements executed during haptic classification of manipulable common objects were examined. Manual exploration consisted of a two-stage sequence, an initial generalized "grasp-and -lift" routine, followed by a series of more specialized hand-movement patterns strongly driven by knowledge of the property diagnosticity for the specific object (obtained in Experiment 1). The current results may guide computational models of human haptic object classification and the development of perceptual systems for robots equipped with sensate dextrous hands, capable of intelligent exploration, recognition, and manipulation of concrete objects.     

Imagined haptic exploration in judgments of object properties

In Experiment 1, each subject rated a single, named object for its roughness, hardness, temperature, weight, size, or shape. In Experiment 2, each subject compared one pair of objects along the same dimensions. In both studies, a substantial proportion of subjects who judged the first four dimensions imagined a hand making exploratory movements appropriate for the designated information. The proportion of hand-exploration images decreased substantially when judging size or shape, or when judgments could be made readily through general semantic knowledge. The results suggest that the incorporation of haptic exploration into visual imagery provides access to information about haptically accessible object properties.     

What's new? Children prefer novelty in referent selection

Determining the referent of a novel name is a critical task for young language learners. The majority of studies on children’s referent selection focus on manipulating the sources of information (linguistic, contextual and pragmatic) that children can use to solve the referent mapping problem. Here, we take a step back and explore how children’s endogenous biases towards novelty and their own familiarity with novel objects influence their performance in such a task. We familiarized 2-year-old children with previously novel objects. Then, on novel name referent selection trials children were asked to select the referent from three novel objects: two previously seen and one completely novel object. Children demonstrated a clear bias to select the most novel object. A second experiment controls for pragmatic responding and replicates this finding. We conclude, therefore, that children’s referent selection is biased by previous exposure and children’s endogenous bias to novelty.     

The development and robustness of young children’s understanding of aspectuality

We investigated whether 6-year-olds’ understanding of perceptual aspectuality was sufficiently robust to deal with the presence of irrelevant information. A total of 32 children chose whether to look or feel to locate a specific object (identifiable by sight or touch) from four objects that were hidden. In half of the trials, the objects were different on only one modality (e.g., four objects that felt different but were the same color). In the remainder of the trials, the objects also differed (partially) on one irrelevant modality (e.g., four objects that felt different, two red and two blue, where the goal was to locate the soft object). Performance was worse on the latter trials. We discuss children’s difficulty in dealing with irrelevant information.     

Delayed memory for visual—haptic exploration of familiar objects

Long-term memory of haptic, visual, and cross-modality information was investigated. In Experiment 1, subjects briefly explored 40 commonplace objects visually or haptically and then received a recognition test with categorically similar foils in the same or the alternative modality both immediately and after 1 week. Recognition was best for visual input and test, with haptic memory still apparent after a week's delay. Recognition was poorest in the cross-modality conditions, with performance on the haptic-visual and visual-haptic cross-modal conditions being nearly identical. Visual and haptic information decayed at similar rates across a week delay. In Experiment 2, subjects simultaneously viewed and handled the same objects, and transfer was tested in a successive cue-modality paradigm. Performance with the visual modality again exceeded that with the haptic modality. Furthermore, initial errors on the haptic test were often corrected when followed by the visual presentation, both immediately and after 1 week. However, visual test errors were corrected by haptic cuing on the immediate test only. These results are discussed in terms of shared information between the haptic and visual modalities, and the ease of transfer between these modalities immediately and after a substantial delay.     

汉语儿童6岁前范畴层次词汇的发展研究

本研究利用个案跟踪语料和控制实验数据,考察了汉语儿童6岁前范畴层次词汇的发展情况。研究表明,基本层次词汇在产出和理解方面均占优势,名词层级的发展主要表现为下位层次词语的增加。儿童对范畴层次词汇的正确产出和理解率从高到低排序依次为基本层次、下位层次和上位层次词汇。本研究为佐证基本层次词语在汉语儿童早期语言发展中占据概念的主导地位提供了经验支持,并支持原型理论对儿童范畴分类能力发展的阐释。     

Internal spatial relationships in young children's drawings

Attempts to represent the occlusion of a farther object by a nearer one are infrequent in the drawings of 5- and 6-year-olds. Instead they typically draw the objects side by side or one above the other. This does not appear to reflect a limitation of skill (P. Light & E. MacIntosh, Journal of Experimental Child Psychology, 1980, 30, 79–87) and it is hypothesized that it reflects the children's concern with the array of objects per se, as opposed to their own particular view of it. In the present study relatively complex objects were used in order to test the hypothesis that young children's drawings do in fact systematically reflect spatial relationships within the array. Ninety-seven children between 5 and 8 years of age drew two arrays, each being drawn four times in different orientations vis à vis the child. As predicted, the younger children's drawings contained much array-specific information but often no indication an all of the child's viewing position. In contrast, the older children's drawings were predominantly view specific, often containing little information about the arrays.     

Influence of intensity on children’s sensitivity to happy, sad, and fearful facial expressions

Most previous studies investigating children’s ability to recognize facial expressions used only intense exemplars. Here we compared the sensitivity of 5-, 7-, and 10-year-olds with that of adults (n = 24 per age group) for less intense expressions of happiness, sadness, and fear. The developmental patterns differed across expressions. For happiness, by 5 years of age, children were as sensitive as adults even to low intensities. For sadness, by 5 years of age, children were as accurate as adults in judging that the face was expressive (i.e., not neutral), but even at 10 years of age, children were more likely to misjudge it as fearful. For fear, children’s thresholds were not adult-like until 10 years of age, and children often confused it with sadness at 5 years of age. For all expressions, including even happy expressions, 5- and 7-year-olds were less accurate than adults in judging which of two expressions was more intense. Together, the results indicate that there is slow development of accurate decoding of subtle facial expressions.