The effect of explicitly varying the proportion of “same” and “different” responses on sex differences in the Shepard and Metzler mental rotation task

The mental rotation of three-dimensional objects is consistently identified as the most salient cognitive sex difference in humans. The Shepard and Metzler task (1971) requires participants to rotate an object in their “mind's eye” and then compare the shape to a second object to identify if the two objects can be aligned in an identical orientation (warranting a “same” response) or represent mirror image shapes of one another (warranting a “different” response). The mental rotation task not only involves a rotational component but also nonrotational components such as comparison and decision making. Recent research has suggested that the sex difference in mental rotation resides in the nonrotational aspects of “different” decisions specifically. This experiment examined this proposal by varying the proportion of “different” decisions across conditions. Participants were ether exposed to the traditional format (50:50 same/different) or a bias towards (75:25) or away from (25:75) different responses. Contrary to previous research, the sex difference was found to reside in “same” responses that required a greater degree of rotation when assessing error rates in mental rotation. Sex differences in mental rotation error rates were particularly sensitive to the rotational aspect of same responses, not rotational aspects of different responses nor nonrotational aspects of both same and different responses. For reaction time, however, a sex difference emerged in the nonrotational aspects of the task. The bias described here affected these nonrotational aspects of the task, but not the rotational aspects, in line with prediction. A second study reran the experiment without making the bias explicit. Under this implicit bias, no sex differences were identified between conditions.     

Real three-dimensional objects: effects on mental rotation

The current experiment investigated real three-dimensional (3D) objects with regard to performance on a mental rotation task and whether the appearance of sex differences may be mediated by experiences with spatially related activities. 40 men and 40 women were presented with alternating timed trials consisting of real-3D objects or two-dimensional illustrations of 3D objects. Sex differences in spatially related activities did not significantly influence the finding that men outperformed women on mental rotation of either stimulus type. However, on measures related to spatial activities, self-reported proficiency using maps correlated positively with performance only on trials with illustrations whereas self-reported proficiency using GPS correlated negatively with performance regardless of stimulus dimensionality. Findings may be interpreted as suggesting that rotating real-3D objects utilizes distinct but overlapping spatial skills compared to rotating two-dimensional representations of 3D objects, and real-3D objects can enhance mental rotation performance.     

Mental rotation is not easily cognitively penetrable

When participants take part in mental imagery experiments, are they using their “tacit knowledge” of perception to mimic what they believe should occur in the corresponding perceptual task? Two experiments were conducted to examine whether such an account can be applied to mental imagery in general. These experiments both examined tasks that required participants to “mentally rotate” stimuli. In Experiment 1, instructions led participants to believe that they could reorient shapes in one step or avoid reorienting the shapes altogether. Regardless of instruction type, response times increased linearly with increasing rotation angles. In Experiment 2, participants first observed novel objects rotating at different speeds, and then performed a mental rotation task with those objects. The speed of perceptually demonstrated rotation did not affect the speed of mental rotation. We argue that tacit knowledge cannot explain mental imagery results in general, and that in particular the mental rotation effect reflects the nature of the underlying internal representation and processes that transform it, rather than participants’ pre-existing knowledge.     

Decisions about the axes of disoriented shapes

Subjects were timed as they made decisions about the location of an asterisk placed to the left, right, top, or bottom of disoriented shapes, and their reaction times were plotted as a function of the angular departure of the shapes from the upright. In Experiment 1, the shapes were letters, and the functions suggested that the subjects generally mentally rotated some internal representation of each letter to the upright in order to decide whether the asterisk was to the left or the right, regardless of whether the letters were vertically symmetrical (A, T, U, V), horizontally symmetrical (B, C, D, E), or asymmetrical (F, G, R, L). For decisions about top and bottom, mental rotation rarely occurred, although there was some evidence for it in the case of horizontally symmetrical letters. Experiment 2 showed that mental rotation was not involved when subjects made one response if the asterisk was to the left or right, and another if it was at the top or bottom. In Experiment 3, the shapes were relatively unfamiliar architectural symbols, and in this case mental rotation was most strongly induced by those decisions requiring mirror-image discrimination, that is, left-right decisions for vertically symmetrical shapes and top-bottom decisions for horizontally symmetrical ones. Taken overall, the results suggest that there are two task ingredients that may induce mental rotation: One is the labeling of the left and right sides of a disoriented shape, and the other is the discrimination of mirror images.     

Does men’s advantage in mental rotation persist when real three-dimensional objects are either felt or seen?

In several spatial tasks in which men outperform women in the processing of visual input, the sex difference has been eliminated in matching contexts limited to haptic input. The present experiment tested whether such contrasting results would be reproduced in a mental rotation task. A standard visual condition involved two-dimensional illustrations of three-dimensional stimuli; in a haptic condition, three-dimensional replicas of these stimuli were only felt; in an additional visual condition, these replicas were seen. The results indicated that, irrespective of condition, men's response times were shorter than women's, although accuracy did not significantly differ according to sex. For both men and women, response times were shorter and accuracy was higher in the standard condition than in the haptic one, the best performances being recorded when full replicas were shown. Self-reported solving strategies also varied as a function of sex and condition. The discussion emphasizes the robustness of men's faster speed in mental rotation. With respect to both speed and accuracy, the demanding sequential processing called for in the haptic setting, relative to the standard condition, is underscored, as is the benefit resulting from easier access to depth cues in the visual context with real three-dimensional objects.     

Representation of anatomical constraints in motor imagery: mental rotation of a body segment

Classically, the mental rotation paradigm has shown that when subjects are asked to judge whether objects that differ in orientation are spatially congruent, reaction times increase with angular discrepancy, although some reports have shown that this is not always the case. Would similar results be obtained with realistic figures of body segments? In this work, the mental rotation of a hand attached to its forearm and arm in anatomically possible and impossible starting positions is compared with the mental rotation of a hammer. The main results show that reaction times increase monotonically with the angle of discrepancy for both stimuli and that the speed of rotation is higher for anatomically possible orientations in the case of the hand. Thus, mental rotation of body segments follows the same empirical rules as objects of another nature, and biomechanical constraints imposed to the motility of these segments can be considered as attributes of the mental representation.     

Dissociating viewpoint costs in mental rotation and object recognition

In a mental rotation task, participants must determine whether two stimuli match when one undergoes a rotation in 3-D space relative to the other. The key evidence for mental rotation is the finding of a linear increase in response times as objects are rotated farther apart. This signature increase in response times is also found in recognition of rotated objects, which has led many theorists to postulate mental rotation as a key transformational procedure in object recognition. We compared mental rotation and object recognition in tasks that used the same stimuli and presentation conditions and found that, whereas mental rotation costs increased relatively linearly with rotation, object recognition costs increased only over small rotations. Taken in conjunction with a recent brain imaging study, this dissociation in behavioral performance suggests that object recognition is based on matching of image features rather than on 3-D mental transformations.     

Evaluation of task performance during mentally imaging three-dimensional shapes from plane figures

Mental imagery is an important theme in psychology. Although the mental rotation task is well known, the complicated functions in mental images with higher spatial perception remain unknown. The aim of this study was to evaluate the task performances during the mental imaging of two- or three-dimensional shapes (14 healthy male students, M age = 24.2 yr., SD = 3.4). The mental-image task to frame a 3D object from actual 2D figures (2D-3D task) had the longest reaction time (p < .01); performance accuracy on this task was lower than for other tasks. The reaction time for the 2D-3D task differed statistically significantly from that on the typical working memory task using the mental image of three 2D figures. Compared with the 2D-3D task, illustration of a simple 3D object would be effective when a quick judgment of high accuracy is required. The feasibility study using an electroencephalogram suggests that the theta-band activity at the middle frontal lobe reflecting the acts of the working memory is related with mental images.     

The perception of rotated shapes: A process analysis of shape constancy

Ss made objective shape judgments of circular objects rotated in depth to provide a process analysis of shape constancy. The significant finding was that task difficulty, as reflected by proportion errors and correct reaction times; increased with increases in rotation from the frontal-parallel plane. This effect was located at the perceptual encoding stage of the shape judgment process. It was demonstrated that, in contrast to true shape information, the time to interpret slant and two-dimensional projected shape information was not critically dependent on degree of rotation. These results and a number of other additional observations demonstrate that the invariance hypothesis does not provide a sufficient account of shape constancy. Although projected shape and’ slant judgments can be made easily, perception of true shape involves encoding a figure-ground relationship by a process that does not rely exclusively on the discrete values of projected shape and slant.     

Effects of distance between objects and distance from the vertical axis on shape identity judgments

In three experiments, we independently manipulated the angular disparity between objects to be compared and the angular distance between the central axis of the objects and the vertical axis in a mental rotation paradigm. There was a linear increase in reaction times that was attributable to both factors. This result held whether the objects were rotated (with respect to each other and to the upright) within the frontal-parallel plane (Experiment 1) or in depth (Experiment 2), although the effects of both factors were greater for objects rotated in depth than for objects rotated within the frontal-parallel plane (Experiment 3). In addition, the factors interacted when the subjects had to search for matching ends of the figures (Experiments 1 and 2), but they were additive when the ends that matched were evident (Experiment 3). These data may be interpreted to mean that subjects normalize or reference an object with respect to the vertical upright as well as compute the rotational transformations used to determine shape identity.     

A high density ERP comparison of mental rotation and mental size transformation

To compare mental rotation and mental size transformation, 128-channel EEG was recorded while subjects performed both tasks using random two-dimensional shapes as stimuli. Behavioural results showed significant linear effects of both size transformation and mental rotation on reaction times. Rotation ERPs showed experimental effects at two latencies: a bilateral component distributed over posterior parietal electrodes at a latency of approximately 232-300ms and a second component at approximately 424-492ms distributed over right anterior parietal electrodes. The latency and spatial distribution of this second effect is consistent with previous research indicating a functional connection between this component and mental rotation. ERPs for the size-transformation task showed an effect at 180-228ms distributed bilaterally over occipital-temporal electrodes. These results are consistent with previous hemodynamic imaging studies that show involvement of parietal cortex in mental rotation and also the involvement of BA 19 in size-transformation tasks. However, the superior temporal resolution of the present data indicates that BA 19 activation may occur at a latency that is more likely related to apparent motion than to the size-transformation operation per se.     

身体部位心理旋转的认知与神经机制

除了经典的对于抽象几何图形或字母的心理旋转任务,还有一类心理旋转以手、脚等身体部位图片作为反应刺激。在身体部位心理旋转中,被试一般想象的是自身身体旋转,想象过程受当前身体姿势与身体生理局限性的影响。而在客体心理旋转中,被试往往将刺激作为外在的客体进行想象旋转。两类心理旋转任务都被发现存在顶叶区域的激活,但运动相关皮层的激活更多地在身体部位心理旋转任务中被发现。关于儿童身体部位心理旋转与实际运动的联系紧密性的讨论尚未得到一致的结论,未来研究需要继续探讨随着年龄增长,身体部位心理旋转受生理局限性的影响是增强还是减弱。身体图片加工的自动性,身体部位心理旋转的可塑性也是未来研究可以深入探讨的问题。对于身体部位心理旋转的深入了解也有助于这一任务在临床诊断治疗、运动员与飞行员训练和选拔中的应用。     

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.     

The effects of mental representation on performance in a navigation task

In three experiments, we investigated the mental representations employed when instructions were followed that involved navigation in a space displayed as a grid on a computer screen. Performance was affected much more by the number of instructional units than by the number of words per unit. Performance in a three-dimensional space was independent of the number of dimensions along which participants navigated. However, memory for and accuracy in following the instructions were reduced when the task required mentally representing a three-dimensional space, as compared with representing a two-dimensional space, although the words used in the instructions were identical in the two cases. These results demonstrate the interdependence of verbal and spatial memory representations, because individuals' immediate memory for verbal navigation instructions is affected by their mental representation of the space referred to by the instructions.     

实物形状的知觉相似性对视觉隐喻加工的影响

视觉隐喻是众多研究者比较关注的领域, 当前多以物体简笔画、漫画及广告等方面的研究为主, 但对与生活密切相关的实物的视觉隐喻研究甚少。因此研究采用掩蔽启动范式、李克特9点量表及语音生成等研究方法, 在物体概念类型(概念相同、概念相异)及形状类型(形状相似、形状相异)条件下, 针对实物图片的形状知觉相似性是否对视觉隐喻加工产生影响进行探讨。结果发现无论物体概念是否相同, 形状相似性对个体的物体识别具有“促进”作用, 并有利于视觉隐喻加工; 在物体识别中, 当两个物体概念不同时, 个体会试图建立一个特设类别来对形状相似的物体进行归类, 从而实现了视觉隐喻的加工。因此研究进一步证明了实物形状的知觉相似性有利于视觉隐喻的加工。     

Motor initiation and execution in patients with conversion paralysis

Motor initiation and motor execution in four patients with conversion paralysis were investigated in a non-affected motor modality (speech). In line with the hypothesis of dissociated control in conversion disorder [Cognit. Neuropsychiatry 8 (1) (2001) 21] motor initiation, but not response duration, was expected to be impaired. The motor initiation times (reaction time: RT) and motor execution times (response duration: RD) were compared on four RT-tasks that required the production of a verbal response: a simple choice RT-task, a mental letter rotation task, and an implicit and an explicit mental hand rotation task. Because conversion disorder is expected to primarily involve an impairment in the initiation of movement, we expected the following task characteristics to uniquely affect RT and not RD: type of instruction (implicit versus explicit instructed imagery), angle of rotation, and target arm (affected versus non-affected arm). The results indeed showed the task characteristics to significantly affect the participants' RT and not their RD. It was concluded that conversion paralysis is associated with a specific impairment in the explicit initiation of processes with a spatial and motor component.     

Coordinate systems in the long-term memory representation of three-dimensional shapes

Visual information can be stored relative to a particular point of view or independently of any particular point of view. Research on mental rotation has shown that people can store and use viewer-centered visual representations of objects and scenes. Some theories of object recognition posit that object-centered representations are also stored and used to represent the shape of three-dimensional objects. In this paper a series of experiments provides evidence that people can store and use both viewer-centered and object-centered representations of three-dimensional objects.     

Motor Processes in Children's Mental Rotation

Previous studies with adult human participants revealed that motor activities can influence mental rotation of body parts and abstract shapes. In this study, we investigated the influence of a rotational hand movement on mental rotation performance from a developmental perspective. Children at the age of 5, 8, and 11 years and adults performed a mental rotation task while simultaneously rotating their hand (guided by a handle). The direction of the manual rotation was either compatible or incompatible with the direction of the mental rotation. Response times increased with increasing stimulus orientation angles, indicating that participants of all age groups used mental rotation to perform the task. A differential effect of the compatibility of manual rotation and mental rotation was found for 5-year-olds and 8-year-olds, but not for 11-year-olds and adults. The results of this study suggest that the ability to dissociate motor from visual cognitive processes increases with age.     

Dynamic orientation cues decrease the viewpoint cost of mental rotation

Mental rotation, as a covert simulation of motor rotation, could benefit from spatial updating of object representations. We are interested in what kind of visual cue could trigger spatial updating. Three experiments were conducted to examine the effect of dynamic and static orientation cues on mental rotation, using a sequential matching task with three-dimensional novel objects presented in different views. Experiment 1 showed that a rotating orientation cue with constant speed reduced viewpoint costs in mental rotation. Experiment 2 extended this effect with a varied-speed rotating orientation cue. However, no such benefit was observed with a static orientation cue in Experiment 3. These findings indicated that a visually continuous orientation cue is sufficient to elicit spatial updating in mental rotation. Furthermore, there may be differences in the underlying mechanisms of spatial updating on the basis of constant-speed rotating cues and varied-speed rotating cues.     

Mental rotation in blind and sighted adolescents: The effects of haptic strategies

IntroductionWhen observing blind persons in a situation of mental rotation, it is more usual to emphasize their lack of visual experience than their expertise concerning tactile exploration. Nevertheless, it seems important to verify whether the procedures of tactile exploration developed by young blind persons enable them to recognize a shape whatever its orientation in space.ObjectiveThe objective of this study was to compare blind adolescents and sighted adolescents in a situation of mental rotation, with raised patterns.MethodIn this perspective, a group of blind adolescents and a group of sighted adolescents – matched for age and sex – have been observed during two task of mental rotation.ResultsThe results show that the blind adolescents are always faster, and they perform better when the rotation task concerns simple shapes. A fine analysis of the strategies of tactile exploration deployed by the subjects allows us to identify several procedures that are specific to the blind adolescents. These exploratory procedures allow them to compensate for the lack of visual experience, up to a certain level of complexity in the shapes.ConclusionThese results suggest that the recognition of 2D shapes after rotation in space is not necessarily problematic for the blind. These results are discussed in relation with recent work on the haptic competence of blind persons.