Visual mental rotation of possible and impossible objects

Participants were tested on two visual mental rotation tasks using three-dimensional "possible" and "impossible" shapes. Both types of stimuli can be easily encoded by their parts and how they are spatially organized. However, while possible shapes can also be easily encoded as a global image, it is more difficult to encode impossible shapes in such a way. Participants visually rotated both types of stimuli at comparable rates, reflecting that local representations were used in the process of visual mental rotation.     

Discrimination of possible and impossible objects in infancy

Adults can use pictorial depth cues to infer three-dimensional structure in two-dimensional depictions of objects. The age at which infants respond to the same kinds of visual information has not been determined, and theories about the underlying developmental mechanisms remain controversial. In this study, we used a visual habituation/novelty-preference procedure to assess the ability of 4-month-old infants to discriminate between two-dimensional depictions of structurally possible and impossible objects. Results indicate that young infants are sensitive to junction structures and interposition cues associated with pictorial depth and can detect inconsistent relationships among these cues that render an object impossible. Our results provide important insights into the development of mechanisms for processing pictorial depth cues that allow adults to extract three-dimensional structure from pictures of objects.     

Mental rotation of faces

The effect of orientation upon face recognition was explored in two experiments, which used a procedure adapted from the mental rotation literature. In the first experiment, a linear increase in the RT of same-different judgments was found as the second of a pair of sequentially presented faces was rotated away from the vertical. Also, it was found that the effect of changing facial expression did not interact with orientation. In the second experiment, a linear relationship between RT and orientation was found in a task involving the recognition of famous faces. This recognition task was found to be more affected by inversion than was an expression classification task. These results are interpreted as evidence against the view that inverted faces are processed in a qualitatively different manner from upright faces, and are also inconsistent with the hypothesis that inversion makes faces difficult to recognize because facial expression cannot be extracted from an inverted face.     

Mental rotation and real-world wayfinding

Sex differences in mental rotation skills are a robust finding in small-scale laboratory-based studies of spatial cognition. There is almost no evidence in the literature, however, relating these skills to performance on spatial tasks in large-scale, real-world activities such as navigating in a new city or in the woods. This study investigates the connections between mental rotation skills as measured by the Vandenburg-Kuse Mental Rotations test and the performance of college students (n=211) navigating a 6-km orienteering course. The results indicate that mental rotation skills are significantly correlated with wayfinding performance on an orienteering task. The findings also replicate sex differences in spatial ability as found in laboratory-scale studies. However, the findings complicate the discussion of mental rotation skills and sex because women often performed as well as men despite having lower mean test scores. This suggests that mental rotation ability may not be as necessary for some women's wayfinding as it is for men's navigation.     

Mental rotation and perceptual uprightness

Performance in Cooper and Shepard’s (1973) mental rotation task was examined in the context of a model that defined the extent to which alphabet letters could be tilted from their normal orientation and still be perceptually upright. For letters with a broad range of orientations for which they remain perceptually upright, a nonlinear effect of orientation on reaction time was obtained (as in Cooper and Shepard). However, for letters with a narrow range of orientations for which they remain perceptually upright, reaction time was linearly related to orientation. The results supported the hypothesis that subjects in the Cooper and Shepard task would mentally rotate alphabet letters only when they were presented in orientations for which they were not perceptually upright.     

Mental rotation in schizophrenia

Motor imagery provides a direct insight into action representations. The aim of the present study was to investigate the level of impairment of action monitoring in schizophrenia by evaluating the performance of schizophrenic patients on mental rotation tasks. We raised the following questions: (1) Are schizophrenic patients impaired in motor imagery both at the explicit and at the implicit level? (2) Are body parts more difficult for them to mentally rotate than objects? (3) Is there any link between the performance and the hallucinating symptom profile? The schizophrenic patients (n = 13) displayed the same pattern of performance as the control subjects (n = 13). More particularly, schizophrenic patients’ reaction time varied as a function of the angular disparity of the stimuli. On the other hand, they were significantly slower and less accurate. Interestingly, patients suffering from hallucinations made significantly more errors than non-hallucinatory patients. We discussed these latter results in terms of deficit of the forward model. We emphasized the necessity to distinguish different levels of action, more or less impaired in schizophrenia.     

Mental rotation of tactual stimuli

Three experiments involving different angular orientations of tactual shapes were performed. In experiment 1 subjects were timed as they made 'same-different' judgments about two successive rotated shapes. Results showed that no rotation effect is obtained, i.e., reaction times and error percentage do not increase linearly with rotation angle. The same negative results were found in experiment 2, in which subjects were similarly timed while they made mirror-image discriminations. In experiment 3 a single-stimulus paradigm was used and subjects were asked to decide if a rotated stimulus was a 'normal' or 'reversed' version. Reaction times increased linearly with angular departure from the vertical. Therefore, for tactual stimuli too, this study confirms previous results, which suggest that a mental rotation strategy only occurs if it is facilitated by both type of task and type of stimulus. Results also show a significant difference between hands, and between hands and type of response. Implied hemispheric differences are discussed.     

Mental rotation, physical rotation, and surface media.

Subjects made mirror-normal discriminations on alphanumeric characters shown in different orientations in the picture plane. Either the characters or the background rotated during stimulus presentation in Experiments 1-3. Character rotation in the direction of mental rotation facilitated mental rotation, whereas rotation in the opposite direction inhibited it. In Experiment 4, characters were presented in different surface media so as to stimulate only one representation at a time. Mental rotation performance was similar whether the stimuli were defined by luminance, color, texture, relative motion, or binocular disparity, suggesting that mental rotation occurs at a level beyond that of the independent analyses of these different media. These results support those of Experiments 1-3 in excluding the participation of low-level motion analysis centers in the mental rotation processes.     

Mental rotation and the perspective problem

Experiment I contrasts the difficulty of problems in which a child must anticipate the appearance of an array of objects that is rotated (rotation problems) to the difficulty of problems in which a child must anticipate the appearance of a fixed array to an observer who has been rotated with respect to it (perspective problems). Perspective problems are much more difficult and show a different error pattern. Experiment II contrasts standard perspective problems, in which a child must anticipate the appearance of the array to an observer whose position differs from his own, to “perspective-move” problems, in which a child must anticipate the appearance of the array from his own new position; i.e., he himself moves. The latter problems are much easier, and the error pattern is much like that for rotation problems. The mental operations involved in solving these various types of problems are discussed.     

Mental rotation of static and dynamic figures

Previous studies comparing performance on standard (i.e., static) and dynamic spatial test items have concluded that the two item types measure different abilities. Such conclusions about the uniqueness of static and dynamic spatial abilities seem premature, however, since only a limited number of dynamic spatial tasks have been utilized in research and these have differed markedly from their static counterparts. In the present studies, tasks were designed to require a common mental operation (mental rotation) under static and dynamic conditions. Correlations between static and dynamic performance ranged from .80 to .90. This appears to suggest that the emergence of a unique dynamic ability factor depends on the utilization of certain specialized tasks (e.g., arrival time tasks) with mental operations much different than those required by conventional spatial tests. In other words, it is apparently the requirement for different cognitive processes and not the processing of stimulus motion per se that distinguishes performance onsome dynamic tasks from performance on some standard static tasks.     

Mental rotation in perspective problems

The present paper demonstrates that mental rotation as used in the processing of disoriented objects (Cooper and Shepard 1973) can also be used as an explanatory concept for the processing of perspective problems in which the task is to imagine how an environment will appear from another vantage point. In a cognitive map, subjects imagined an initial line of vision and subsequently processed a reorientation stimulus, requesting them to imagine a turn over 0, 45, 90, 135, or 180 degrees. Time for a reorientation increased linearly with the size of the imaginary turn up to 135 degrees and decreased for turns of 180 degrees; apparently, about-faces were relatively easy to imagine. The increment of reorientation time between 0 and 135 degrees was larger for maps presented in unfamiliar orientations such as South-West up. Both the increment and the interaction with familiarity are consistent with an explanation in terms of mental rotation.     

Mental rotation of random two-dimensional shapes

Two experiments are reported in which Ss were required to determine whether a random, angular form, presented at any of a number of picture-plane orientations, was a “standard” or “reflected” version. Average time required to make this determination increased linearly with the angular departure of the form from a previously learned orientation. The slope and intercept of the reaction-time (RT) function were virtually constant, regardless of the perceptual complexity of the test form and the orientation selected for initial learning.When Ss were informed in advance as to the identity and the orientation of the upcoming test form and, further, were permitted to indicate when they were prepared for its external presentation, RT for determining the version of the form was constant for all test-form orientations. However, the time needed to prepare for the test-form presentation increased linearly with the angular departure of the form from the learned orientation.It is argued that the processes both of preparing for and of responding to a disoriented test form consist of the mental rotation of an image, and that both sorts of mental rotation (pre-stimulus and post-stimulus) are carried out at essentially the same constant rate.     

Mental rotation of random lined figures

The present study investigated the possible occurrence of mental rotation in judgments of whether pairs of line figures were identical. The feasibility of two discrete cognitive explanations based on holistic transformation and on feature computation was examined with varied levels of complexity controlled by the numbers of lines in a figure. In the experiment, participants were required to judge whether simultaneously presented pairs of figures were the same or different. When the participants' data were collapsed for regression analyses, evidence for mental rotation was not detected at any level of complexity, but reanalysis of the data revealed that some participants employed mental rotation in the cognition of complex figures. A monotonous increase in reaction times as a function of the number of lines was evident in identical pairs of figures but not in nonidentical pairs. It is argued that the feature computation explanation would better account for these results than would the holistic transformation explanation.     

Mental rotation: cross-task training and generalization

It is well established that performance on standard mental rotation tasks improves with training (Peters et al., 1995), but thus far there is little consensus regarding the degree of transfer to other tasks which also involve mental rotation. In Experiment 1, we assessed the effect of mental rotation training on participants' Mental Rotation Test (MRT) scores. Twenty-eight participants were randomly assigned to one of three groups: a "One-Day Training," "Spaced Training," or "No Training" group. Participants who received training achieved higher scores on the MRT, an advantage that was still evident after 1 week. Distribution of training did not affect performance. Experiment 2 assessed generalization of mental rotation training to a more complex mental rotation task, laparoscopic surgery. Laparoscopic surgical skills were assessed using Fundamentals of Laparoscopic Surgery (FLS) tasks. Thirty-four participants were randomly assigned to a "Full Mental Rotation Training, MRT and FLS," "MRT and FLS," or "FLS-only" group. MRT results from Experiment 1 were replicated and mental rotation training was found to elicit higher scores on the MRT. Further, mental rotation training was found to generalize to certain laparoscopic surgical tasks. Participants who obtained mental rotation training performed significantly better on mental-rotation dependent surgical tasks than participants who did not receive training. Therefore, surgical training programs can use simple computer or paper-based mental rotation training instead of more expensive materials to enhance certain aspects of surgical performance of trainees.     

Curiosity and exploratory behaviour towards possible and impossible events in children and adults

In four experiments with 4‐, 6‐, and 9‐year‐old children and adults, the hypothesis was tested that, all other conditions being equal, a novel and unusual event elicits stronger curiosity and exploratory behaviour if its suggested explanation involves an element of the supernatural than if it does not (the impossible over possible effect – the I/P effect). Participants were shown an unusual phenomenon (a spontaneous disintegration of a physical object in an apparently empty box) framed in the context of either a magical (the impossible event) or scientific (the possible event) explanation. In the verbal trial, participants showed a clear understanding of the difference between the effect of genuine magic and the effect of a trick. In the behavioural trial, both children and adults showed the I/P effect. They were more likely to run the risk of losing their valuable objects in order to explore the impossible event than the possible event. Follow‐up experiments showed that the I/P effect couldn't be explained as an artifact of the different degrees of cost of exploratory behaviour in the possible and impossible conditions or as a result of misinterpreting magic as tricks. The I/P effect emerged when the cost of exploratory behaviour was moderate and disappeared when the cost was perceived as too high or too low.     

Infant and adult perceptions of possible and impossible body movements: An eye-tracking study

This study investigated how infants perceive and interpret human body movement. We recorded the eye movements and pupil sizes of 9- and 12-month-old infants and of adults (N=14 per group) as they observed animation clips of biomechanically possible and impossible arm movements performed by a human and by a humanoid robot. Both 12-month-old infants and adults spent more time looking at the elbows during impossible compared with possible arm movements, irrespective of the appearance of the actor. These results suggest that by 12months of age, infants recognize biomechanical constraints on how arms move, and they extend this knowledge to humanoid robots. Adults exhibited more pupil dilation in response to the human's impossible arm movements compared with the possible ones, but 9- and 12-month-old infants showed no differential pupil dilation to the same actions. This finding suggests that the processing of human body movements might still be immature in 12-month-olds, as they did not show an emotional response to biomechanically impossible body movements. We discuss these findings in relation to the hypothesis that perception of others' body movements relies upon the infant's own sensorimotor experience.     

Effects of context on eye movements when reading about possible and impossible events

Plausibility violations resulting in impossible scenarios lead to earlier and longer lasting eye movement disruption than violations resulting in highly unlikely scenarios (K. Rayner, T. Warren, B. J. Juhasz, & S. P. Liversedge, 2004; T. Warren & K. McConnell, 2007). This could reflect either differences in the timing of availability of different kinds of information (e.g., selectional restrictions, world knowledge, and context) or differences in their relative power to guide semantic interpretation. The authors investigated eye movements to possible and impossible events in real-world and fantasy contexts to determine when contextual information influences detection of impossibility cued by a semantic mismatch between a verb and an argument. Gaze durations on a target word were longer to impossible events independent of context. However, a measure of the time elapsed from first fixating the target word to moving past it showed disruption only in the real-world context. These results suggest that contextual information did not eliminate initial disruption but moderated it quickly thereafter.     

Neuroanatomical correlates of implicit and explicit memory for structurally possible and impossible visual objects

Implicit memory refers to nonconscious retrieval of past experience demonstrated by facilitation in test performance on tasks that do not require intentional recollection of previous experiences. Explicit memory, in contrast, refers to the conscious retrieval of prior information, as demonstrated during standard recall and recognition tasks. In this experiment, positron emission tomographic (PET) measurements of regional cerebral blood flow (CBF), a marker of local neuronal activity, were used to identify and contrast brain regions that participate in the perception, implicit memory, and explicit memory for structurally possible and impossible visual objects. Ten CBF images were acquired in 16 normal women as they made possible/impossible and old/new recognition decisions about previously studied (old) and nonstudied (new) structurally possible and impossible objects. As reported previously, object decisions for familiar possible objects were associated with increased CBF in the vicinity of the left inferior temporal and fusiform gyri and recognition memory for familiar possible objects was associated with increased CBF in the vicinity of the right hippocampus. In this report, we provide more extensive analyses of the roles of the inferior temporal cortex, the hippocampus, the parahippocampus, and the pulvinar in encoding and retrieval operations. Additionally, patterns of CBF increases and decreases provide information regarding the neural structures involved in implicit and explicit memory.