Representation of Object Orientation in Children: Evidence from Mirror-Image Confusions

Although many cognitive functions require information about the orientations of objects, little is known about representation or processing of object orientation. Mirror-image confusion provides a potential clue. This phenomenon is typically characterized as a tendency to confuse images related by left-right reflection (reflection across an extrinsic vertical axis). However, in most previous studies the stimuli were inadequate for identifying a specific mirror-image (or other) relationship as the cause of the observed confusions. Using stimuli constructed to resolve this problem, Gregory and McCloskey (2010) found that adults' errors were primarily reflections across an object axis, and not left-right reflections. The present study demonstrates that young children's orientation errors include both object-axis reflections and left-right reflections. We argue that children and adults represent object orientation in the same coordinate-system format (McCloskey, 2009), with orientation errors resulting from difficulty encoding or retaining one (adults) or two (children) specific components of the posited representations.     

Mirror-image confusions: Implications for representation and processing of object orientation

Perceiving the orientation of objects is important for interacting with the world, yet little is known about the mental representation or processing of object orientation information. The tendency of humans and other species to confuse mirror images provides a potential clue. However, the appropriate characterization of this phenomenon is not entirely clear, in part because the stimuli used in most previous studies were not adequate for distinguishing various forms of mirror-image and non-mirror-image error. In the present study we explore the nature of mirror-image confusion and what the phenomenon can reveal about object-orientation representations. We report several experiments in which participants reported the orientations of pictures. In all of the experiments mirror-reflection errors were more frequent than other orientation errors. However, whereas mirror-image confusion has previously been described as a tendency to confuse stimuli that are related by reflection across an extrinsic (usually vertical) axis, the vast majority of mirror-image errors in our experiments were reflections across an object axis. This finding calls into question several hypotheses proposed to explain mirror-image confusion. We describe a coordinate-system orientation representation (COR) hypothesis that can account for our results (McCloskey, Valtonen, & Sherman, 2006). COR assumes that orientation representations map an object-centered reference frame onto a reference frame extrinsic to the object, with this mapping specified by several parameters. According to COR, mirror-image confusions and other orientation errors arise from failures in representing or processing specific parameters. Considered in light of COR, our results suggest that orientation representations are compositional, and that object-centered reference frames play a central role in orientation representation.     

Attention-referenced visual representations: evidence from impaired visual localization

Spatial representations in the visual system were probed in 4 experiments involving A. H., a woman with a developmental deficit in localizing visual stimuli. Previous research (M. McCloskey et al., 1995) has shown that A. H.'s localization errors take the form of reflections across a central vertical or horizontal axis (e.g., a stimulus 30 degrees to her left localized to a position 30 degrees to her right). The present experiments demonstrate that A. H.'s errors vary systematically as a function of where her attention is focused, independent of how her eyes, head, or body are oriented, or what potential reference points are present in the visual field. These results suggest that the normal visual system constructs attention-referenced spatial representations, in which the focus of attention defines the origin of a spatial coordinate system. A more general implication is that some of the brain's spatial representations take the form of coordinate systems.     

Much ado about mirrors michael

Takano (1998) has suggested four different kinds of reversal to explain why mirrors reverse left and right and not up and down or back and front. In fact, mirrors perform only one kind of reversal: They simply reverse about their own planes, and reflection about one plane is equivalent to reflection about any other, plus a translocation and rotation. The reflection of an object is termed its enantiomorph. Perception of the enantiomorphic relation normally requires an act, either physical or mental, of alignment. In deciding whether two objects are enantiomorphs, there is a tendency to align them so that the reversal is about the axis of least asymmetry. But in deciding whether a single object is one of two possible enantiomorphic forms, people generally rotate it to some canonical orientation. In the case of objects with defined top-bottom, back-front, and left-right axes, the canonical orientation is determined by the top-bottom and back-front axes, leaving the left-right axis to carry the reversal. The main reason for this, I suggest, is that the top-bottom and back-front axes have functional priority, and the left-right axis cannot be defined until top-bottom and back-front are established. This means that the latter two axes have priority in establishing the canonical orientation. The left-right axis is usually, but not always, the axis of least asymmetry.     

Tactile recognition of mirror images by children: intermanual transfer and rotation of the palm

In order to evaluate the importance of the axis of stimulus presentation, inter- and intramanual recognition of mirror pairs was studied with the stimulus materials aligned along the front/back axis (whereas in previous work the mirror pairs were aligned along the left/right axis). Children were allowed to feel shapes with the whole hand, with only four fingers (excluding the thumb), or with only the index finger. After learning with one hand, recognition was tested in experiment 1 with the other hand; after learning with one orientation of the hand (palm down or up), recognition was tested in experiment 2 with the other orientation (palm up or down) of the same hand; after learning with one coronal alignment of the hand (to the left or right), recognition was tested in experiment 3 with the other alignment (to the right or left), but without rotation, of the same hand. Significantly fewer intermanual recognition errors were made on mirror pairs with the materials oriented along the front/back axis than in previous work when oriented along the left/right axis. This supports the suggestion that such errors arise when the stimuli are oriented along the left/right axis during formation of the memory trace. The same trend was unexpectedly obtained for intramanual recognition errors (after rotation of the hand). These errors (after hand rotation) are largely due to coding with respect to the hand; they are reduced when the hand is not aligned with the body axis, since then coding can also occur in relation to the environment.     

Do top and bottom contribute to object perception more than left and right?

To examine whether the top–bottom axis has an inherent advantage in object perception over the left–right one, three experiments were conducted. In all of them, on each trial one of two alternative stimuli, identical in shape but opposite in direction (viz, related by reflection), was presented. Both reflection about the vertical axis and reflection about the horizontal axis were applied, in different blocks. In Experiment 1, objects with an orientation-free definition (arrows, incomplete squares) were presented. Subjects were to respond when the stimulus pointed in a specific direction, and to refrain from responding when it was reflected, namely pointed in the opposite direction. Axis of reflection (vertical, horizontal) was varied between blocks. In Experiment 2, the object was a Hebrew character asymmetric on both axes, presented either in its normal appearance or reflected. Subjects were to respond only when the stimulus was normal. Both axis of reflection (vertical, horizontal) and orientation angle (upright, tilted by 90°) were varied between blocks. In Experiment 3, stimuli were the same as in Experiment 2, but the task explicitly asked for a binary reflection judgment (normal vs. reflected). No sign for the presence of an axis effect was observed in any of those experiments, which seems incompatible with the hypothesis of vertical advantage in object perception. It is suggested that most vertical advantage observed before is due to extra-perceptual processing.

---

Functional significance of stimulus orientation: effects on orientation discrimination.

Children (6- and 9-year-olds) and adults were required to discriminate identical pairs of visual stimuli from mirror images. It was hypothesized that a key factor in performance would be the extent to which orientation was a functionally significant attribute of the stimuli. Two variables were manipulated, type of orientation discrimination and stimulus class. The first variable refers to the fact that the mirror images could be produced by either left/right or top/bottom reversals. Three classes of stimuli, varying in the extent to which a particular orientation was emphasized, were used: mobile objects (for which left/right orientation is assumed to be important); stationary objects (which lack comparable relevance for left/right orientation); and novel, abstract forms. The prediction was that if the discrimination task involved left/right reversals, as contrasted with top/bottom reversals, subjects would show an advantage for mobile objects, producing an interaction between stimulus class and orientation discrimination. In the first study, the subjects were children and performance was measured in terms of error rates. In the second study adults were tested, and reaction times were measured. Both studies manifested the predicted interaction. Results are discussed in terms of an information-processing framework, in which the incorporation of orientation-related features in the code representing a stimulus varies with the functional significance of the orientation to the stimulus class.     

"Mirror-image" errors without mirror-image stimuli

Recent work has indicated that discrimination between upright and inverted stimuli is difficult when stimuli are one above the other, and discrimination between stimuli turned left and right is difficult when stimuli are side by side. That is, errors are frequent under conditions in which mirror-image confusions can be made. Young children were given a task requiring the matching of orientation of (a) identical realistic figures that could form mirror images of each other or (b) nonidentical realistic figures that could not form mirror images. The same pattern of errors appeared for the identical and nonidentical figures, indicating that the errors are not mirror-image confusions. It is argued that the errors are due to a strategy of matching analogous parts of the two figures.     

The perception of mirror-reflected objects.

In what ways and under what conditions does an object appear to differ from its enantiomorph (its mirror reflection)? This 'mirror question' or its popular counterpart, "Why does a mirror reverse left and right but not up and down?" is frequently encountered, but an acceptable answer is not to be found in the literature. The question is approached as an experimental problem in visual psychophysics. A mirror optically reverses the axis perpendicular to its surface. What are the perceptual consequences of this stimulus transformation? This question is examined in four experiments by using stimuli of varying complexity and familiarity. Apparent reversals are demonstrated along right-left, front-back, top-bottom, and oblique axes, depending on the perceived asymmetries of the stimulus object. Perceived asymmetry is shown to depend both on structural asymmetries and on canonical axes and orientations defined by social convention. It is concluded that an object appears to differ from its enantiomorph by an apparent reversal along the axis of least perceived asymmetry. Implications for perceptual frames of reference and for the perception of symmetry are discussed.     

Naïve predictions of motion and orientation in mirrors: From what we see to what we expect reflections to do

The study aimed to investigate naïve beliefs regarding the dynamic and static behavior of reflections. In the first three experiments, participants in the study made predictions about the correspondence between real and reflected movements or about the orientation of the reflection of a static object placed in front of a mirror. In Experiments 1 and 2, paper-and-pencil tasks were used and in Experiment 3 participants were asked to make their predictions while imagining that they were facing a mirror. Results revealed that a percentage of undergraduates (ranging from 25% to 35%) were unable to make correct predictions. We classified the errors into types and found that responses either conform to the belief that reflections do the same or that they do the opposite. This suggests an oversimplification of the geometry of mirror reflections in two directions: participants either generalize what they see when movements are parallel to the mirror or what they see when movements are orthogonal to the mirror. Findings from Experiment 4 confirmed that these two expectations fit in with what people perceive in mirrors. Findings from Experiment 5 confirmed that this is also in agreement with the relationship perceived when looking at similar movements and orientations “outside” mirrors.     

Why does visual working memory ability improve with age: More objects,more feature detail,or both? A registered report

We investigated how visual working memory (WM) develops with age across the early elementary school period (6–7 years), early adolescence (11–13 years), and early adulthood (18–25 years). The work focuses on changes in two parameters: the number of objects retained at least in part, and the amount of feature-detail remembered for such objects. Some evidence suggests that, while infants can remember up to three objects, much like adults, young children only remember around two objects. This curious, nonmonotonic trajectory might be explained by differences in the level of feature-detail required for successful performance in infant versus child/adult memory paradigms. Here, we examined if changes in one of two parameters (the number of objects, and the amount of detail retained for each object) or both of them together can explain the development of visual WM ability as children grow older. To test it, we varied the amount of feature-detail participants need to retain. In the baseline condition, participants saw an array of objects and simply were to indicate whether an object was present in a probed location or not. This phase begun with a titration procedure to adjust each individual's array size to yield about 80% correct. In other conditions, we tested memory of not only location but also additional features of the objects (color, and sometimes also orientation). Our results suggest that capacity growth across ages is expressed by both improved location-memory (whether there was an object in a location) and feature completeness of object representations.     

Developmental differences in memory for cross‐modal associations

Associative learning is critical to normal cognitive development in children. However, young adults typically outperform children on paired‐associate tasks involving visual, verbal and spatial location stimuli. The present experiment investigated cross‐modal odour–place associative memory in children (7–10 years) and young adults (18–24 years). During the study phase, six odours were individually presented and paired with one of 12 spatial locations on a board. During the test phase, participants were presented with the six stimuli individually and were asked to place each stimulus on the correct spatial location. Children committed significantly more errors on the odour–place task than did young adults. However, item recognition memory for the odours or spatial locations involved in the odour–place associative memory task was similar between children and young adults. Therefore, poor odour–place associative memory in children did not result from impaired memory for the individual odours or spatial locations involved in the associations. The results suggest that cross‐modal associative memory is not fully developed in children.     

自我和物体为参照系的心理旋转分离：内旋效应

采用虚拟的旋转不同角度左、右手模型,构建“左右手判断(Left and right hand judgment: LR)”任务和“相同－不同判断(same and different judgment: SD)”任务,考察这两种实验任务是否都存在内旋效应和角度效应,以此推论被试采用何种旋转策略。结果发现：（1） 两种实验任务结果均表现出显著的角度效应。（2）在LR任务条件下,存在显著的内旋效应,而在SD任务中不存在内旋效应。从而表明当人手图片作为心理旋转材料时,它具有双重角色。被试心理旋转加工时究竟选用何种参照系的旋转策略,与实验材料和实验任务两者都密不可分     

Hemispheric asymmetry in the identification of four-letter names traced in the right and left palms

Forty right-handed males were asked to identify four-letter names traced in either the right or left palms while their eyes were closed. The name stimuli were traced in a right-side-up or upside-down orientation (i.e., vertical or rotated 180 degrees). Mean percentage of errors served as the dependent variable. On the first block of 40 trials, the left palm/right hemisphere (LP/RH) was significantly more accurate than the right palm/left hemisphere (RP/LH) at identifying these names. This advantage, however, was only manifest when the name stimuli were traced in the upside-down orientation. On the second block of 40 trials, as the name stimuli became more familiar and the subjects became more practiced, a similar LP/RH advantage was observed; however, the impact of the rotation variable was no longer in evidence (i.e., the LP/RH was slightly more accurate on both upright and inverted names). These results are interpreted in light of a process-oriented tactile asymmetry as proposed by M. W. O'Boyle, F. Van Wyhe-Lawler, and D. A. Miller (1987, Brain and Cognition, 6, 474-494).     

Spatial analysis after perinatal stroke: patterns of neglect and exploration in extra-personal space

This study was conducted to determine whether school-aged children who had experienced a perinatal stroke demonstrate evidence of persistent spatial neglect, and if such neglect was specific to the visual domain or was more generalized. Two studies were carried out. In the first, 38 children with either left hemisphere (LH) or right hemisphere (RH) damage and 50 age-matched controls were given visual cancellation tasks varying in two factors: target stimuli and stimulus array. In the second study, tactile neglect was evaluated in 41 children with LH or RH damage and 72 age-matched controls using a blindfolded manual exploration task. On the visual cancellation task, LH subjects omitted more target stimuli on the right, but also on the left, compared with controls. Children with RH lesions also produced a larger number of omissions on both the left and right sides than controls, but with poorer performance on the left. On the manual exploration task, LH children required significantly longer times to locate the target on both sides of the board than did controls. RH children had significantly prolonged search times on the left side, but not on the right, compared with controls. In both tasks, LH subjects employed unsystematic search strategies more often than both control and RH children. The search strategy of RH children also tended to be erratic when compared to controls, but only in the random arrays of the visual cancellation tasks; structure of the target stimuli improved their organization. These results demonstrate that children with early LH brain damage display bilateral difficulties in visual and tactile modalities; a pattern that is in contrast to that seen in adults with LH damage. This may result from disorganized search strategies or other subtle spatial or attentional deficits. Results of performance of RH children suggests the presence of contralateral neglect in both the visual and tactile modalities; a finding that is similar to the neglect in adult stroke patients with RH lesions. The fact that deficits in spatial attention and organizational strategies are present after very early focal damage to either the LH or the RH broadens our understanding of the differences in functional lateralization between the immature and mature brain. These results also add to evidence for limitations to plasticity in the developing brain. Our findings may have therapeutic and rehabilitative implications for the management of children with early focal brain lesions.     

Responsiveness and functional connectivity of the scene-sensitive retrosplenial complex in 7–11-year-old children

Brain imaging studies have identified two cortical areas, the parahippocampal place area (PPA) and the retrosplenial complex (RSC), that respond preferentially to the viewing of scenes. Contrary to the PPA, little is known about the functional maturation and cognitive control of the RSC. Here we used functional magnetic resonance imaging and tasks that required attention to scene (or face) images and suppression of face (or scene) images, respectively, to investigate task-dependent modulation of activity in the RSC and whole-brain functional connectivity (FC) of this area in 7–11-year-old children and young adults. We compared responsiveness of the RSC with that of the PPA. The RSC was selectively activated by scene images in both groups, albeit less than the PPA. Children modulated activity between the tasks similarly in the RSC and PPA, and to the same extent as adults in PPA, whereas adults modulated activity in the RSC less than in PPA. In children, the whole brain FC of the RSC was stronger in the Sf than Fs task between the left RSC and right fusiform gyrus. The between groups comparison suggested stronger FC in children than adults in the Sf task between the right RSC and the left inferior parietal lobule and intraparietal sulcus. Together the results suggest that the function of the RSC and the related networks undergo dynamic changes over the development from 7–11-year-old children to adulthood.     

Mental transformations in the identification of left and right hands.

Subjects determined as rapidly as possible whether each line drawing portrayed a left or a right hand when the drawings were presented in any of four versions (palm or back of either hand) and in any of six orientations in the picture plane. Reaction time varied systematically with orientation and, in the absence of advance information, was over 400 msec longer for the fingers-down orientation. However, when subjects were instructed to imagine a specified (palm or back) view of a specified (left or right) hand in a specified orientation, reaction times to test hands that were consistent with these instructions were short (about 500 msec), independent of orientation, and unacompanied by errors. It is proposed that subjects determine whether a visually presented hand is left or right by moving a mental "phantom" of one of their own hands into the portrayed position and by then comparing its imagined appearance against the appearance of the externally presented hand.     

Time Points: A Gestural Study of the Development of Space–Time Mappings

Human languages typically employ a variety of spatial metaphors for time (e.g., “I'm looking forward to the weekend”). The metaphorical grounding of time in space is also evident in gesture. The gestures that are performed when talking about time bolster the view that people sometimes think about regions of time as if they were locations in space. However, almost nothing is known about the development of metaphorical gestures for time, despite keen interest in the origins of space–time metaphors. In this study, we examined the gestures that English‐speaking 6‐to‐7‐year‐olds, 9‐to‐11‐year‐olds, 13‐to‐15‐year‐olds, and adults produced when talking about time. Participants were asked to explain the difference between pairs of temporal adverbs (e.g., “tomorrow” versus “yesterday”) and to use their hands while doing so. There was a gradual increase across age groups in the propensity to produce spatial metaphorical gestures when talking about time. However, even a substantial majority of 6‐to‐7‐year‐old children produced a spatial gesture on at least one occasion. Overall, participants produced fewer gestures in the sagittal (front‐back) axis than in the lateral (left‐right) axis, and this was particularly true for the youngest children and adolescents. Gestures that were incongruent with the prevailing norms of space–time mappings among English speakers (leftward and backward for past; rightward and forward for future) gradually decreased with increasing age. This was true for both the lateral and sagittal axis. This study highlights the importance of metaphoricity in children's understanding of time. It also suggests that, by 6 to 7 years of age, culturally determined representations of time have a strong influence on children's spatial metaphorical gestures.     

Visual localization of the center of mass of compact, asymmetric, two-dimensional shapes.

This study aimed at understanding how visual information is used to locate the center of mass. The center of mass is an important physical property of objects that must be taken into account when grasping and/or manipulating them. Participants were instructed to identify the point of equilibrium of compact, bidimensional, massless shapes displayed on a touch screen. The point of equilibrium was defined as the point on the face of the object that would allow one to balance the object in the horizontal position. Seven different triangles and 18 different quadrilaterals in different orientations were used as stimuli. It was found that participants can accurately and consistently estimate the position of the center of mass. The small observed errors were systematically influenced by the shape of the object. The participants tended to locate the center of mass at the center of an inscribed circle instead of the true center of mass. In general, the shape effect was impervious to the orientation of the figure and to the mode of response (left hand, right hand, or mouse).     

The visual perception coordinate system uses axes defined by the earth, trunk, and vision

Eight young adults adjusted a line located on one side of a computer display parallel to internally specified Earth-fixed vertical (display in frontal plane), to the horizontal trunk-fixed anterior-posterior axis (display in horizontal plane), and to an oblique line (display in horizontal and vertical planes). All tasks were completed in a dark room with the head and trunk in both a standard erect posture and varied postures. Errors were lowest when setting the line to internally specified vertical in the frontal plane and to an oblique line in the horizontal plane when head and trunk orientations were varied. Constant errors for setting one line parallel to a second line were in opposite directions when the second line was located on the left versus right side of the display, but did not differ in direction when setting the line parallel to internally specified axes. Also, the oblique effect was preserved when the head and trunk were tilted to various orientations, suggesting that it results from integration of an internally specified gravitational reference with visual input. We conclude that the visual perceptual coordinate system uses internally specified vertical and, when available, a visually specified horizontal reference axis to define object orientation.