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。     

Let’s twist again! Embodiment effects in spatial judgments on human figures rotated along a vertical axis

We investigated whether individuals used mental rotation and embodiment for arm laterality judgments of human figures that were stepwise rotated from back view to front view along a vertical axis. In Experiment 1, figures’ heads were always shown in profile, while only the bodies were rotated. Judgments were faster and more correct when figures were presented in back view compared to front view, but the relation between reaction times (RTs) and rotation angles was not strictly linear. In addition, judgments on figures in anatomically possible postures were better than on figures in impossible postures. In Experiment 2, figures’ heads were turned together with their body. RTs and rotation angles were linearly related. Results suggest that individuals use both mental rotation and a more direct matching between their own body and that of the figures, when making arm laterality judgments of human figures that are rotated along a vertical axis.     

On the relation between spontaneous perspective taking and other visuospatial processes

Common processes and representations engaged by visuospatial tasks were investigated by looking at four frequently used visuospatial research paradigms, the aim being to contribute to a better understanding of which specific processes are addressed in the different paradigms compared. In particular, the relation between spontaneous and instructed perspective taking, as well as mental rotation of body-part/non-body-part objects, was investigated. To this end, participants watched animations that have been shown to lead to spontaneous perspective taking. While they were watching these animations, participants were asked to explicitly adopt another perspective (Experiment 1), perform a mental object rotation task that involved a non-body-part object (Experiment 2), or perform a mental rotation of a body-part object (Experiment 3). Patterns of interference between the tasks, reflected in the reaction time patterns, showed that spontaneous and instructed perspective taking rely on similar representational elements to encode orientation. By contrast, no such overlap was found between spontaneous perspective taking and the rotation of non-body-part objects. Also, no overlap in orientation representation was evident with mental body-part rotations. Instead of an overlap in orientation representations, the results suggest that spontaneous perspective taking and the mental rotation of body parts rely on similar—presumably, motor—processes. These findings support the view that motor processes are involved in perspective taking and mental rotation of body parts.     

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.     

Mental rotation and the motor system: Embodiment head over heels

We examined whether body parts attached to abstract stimuli automatically force embodiment in a mental rotation task. In Experiment 1, standard cube combinations reflecting a human pose were added with (1) body parts on anatomically possible locations, (2) body parts on anatomically impossible locations, (3) colored end cubes, and (4) simple end cubes. Participants (N = 30) had to decide whether two simultaneously presented stimuli, rotated in the picture plane, were identical or not. They were fastest and made less errors in the possible-body condition, but were slowest and least accurate in the impossible-body condition. A second experiment (N = 32) replicated the results and ruled out that the poor performance in the impossible-body condition was due to the specific stimulus material. The findings of both experiments suggest that body parts automatically trigger embodiment, even when it is counterproductive and dramatically impairs performance, as in the impossible-body condition. It can furthermore be concluded that body parts cannot be used flexibly for spatial orientation in mental rotation tasks, compared to colored end cubes. Thus, embodiment appears to be a strong and inflexible mechanism that may, under certain conditions, even impede performance.     

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.     

Viewpoint-dependent Priming Effects in the Perception of Human Actions and Body Postures

The identification of human actions and body postures viewed from different viewpoints was examined in four long-term priming experiments with static pictures of a human model. In Experiments 1 and 2 participants had to name or describe the pictures, and in Experiments 3 and 4 participants had to decide whether the pictures showed a possible or impossible body pose. Reliable priming effects were obtained only when priming and primed action or pose shared the same in-depth orientation (Experiments 1 and 4) and left-right reflection (Experiments 2 and 3). Having seen the same action or pose in a different orientation did not reliably facilitate identification performance later on. Also, there was no priming for poses that are impossible to perform with a human body, not even when an identical same-view prime was used. These findings suggest that the stored representations that mediate the identification of human actions and postures are viewpoint specific.     

Self-attributed body-shadows modulate tactile attention

Our body-shadows are special stimuli in the visual world. They often have anatomical resemblance with our own body-parts and move as our body moves, with spatio-temporal correlation. Here, we show that self-attributed body-shadows cue attention to the body-part they refer to, rather than the location they occupy. Using speeded spatial discrimination for tactile or visual targets at the hands, or for visual targets delivered near the hand-shadows, we demonstrate that mere viewing of task-irrelevant shadows can selectively facilitate tactile discrimination at the body-part casting the shadow (Experiment 1). In addition, such facilitation only develops through time for cast-shadows that have no resemblance with the body-part, but move in spatio-temporal correlation with it (Experiment 2). Conversely, facilitation fades away rapidly for shadow-like images that resemble the stimulated body-part, but are in fact static pictures (Experiment 3). Thus, recognising oneself as the owner of a shadow affects distribution of tactile attention.     

Embodied representation of the body contains veridical spatial information

In two experiments, the extent to which mental body representations contain spatial information was examined. Participants were asked to compare distances between various body parts. Similar to what happens when people compare distances on a real visual stimulus, they were faster as the distance differences between body parts became larger (Experiment 1), and this effect could not (only) be explained by the crossing of major bodily categories (umbilicus to knee vs. knee to ankle; Experiment 2). In addition, participants also performed simple animate/inanimate verification on a set of nouns. The nouns describing animate items were names of body parts. A spatial priming effect was found: Verification was faster for body part items preceded by body parts in close spatial proximity. This suggests automatic activation of spatial body information. Taken together, results from the distance comparison task and the property verification task showed that mental body representations contain both categorical and more metric spatial information. These findings are further discussed in terms of recent embodied cognition theories.     

Embodied representation of the body contains veridical spatial information

In two experiments, the extent to which mental body representations contain spatial information was examined. Participants were asked to compare distances between various body parts. Similar to what happens when people compare distances on a real visual stimulus, they were faster as the distance differences between body parts became larger (Experiment 1), and this effect could not (only) be explained by the crossing of major bodily categories (umbilicus to knee vs. knee to ankle; Experiment 2). In addition, participants also performed simple animate/inanimate verification on a set of nouns. The nouns describing animate items were names of body parts. A spatial priming effect was found: Verification was faster for body part items preceded by body parts in close spatial proximity. This suggests automatic activation of spatial body information. Taken together, results from the distance comparison task and the property verification task showed that mental body representations contain both categorical and more metric spatial information. These findings are further discussed in terms of recent embodied cognition theories.     

Improved mental rotation by near-sighted subjects

Several studies have shown significant correlations among factors such as sex, age, and hormone levels with performance on mental rotation tasks. To perform spatial rotation also seems to be related to cognitive abilities such as musical skills. The present experiment investigated a possible relationship for enhanced spatial abilities, as observed in near-sighted subjects, with mental rotation performance. 39 near-sighted and 21 normal-sighted subjects were tested on a mental rotation task using two-dimensional representations of three-dimensional objects. Near-sighted subjects displayed fewer errors in possible rotations than normal-sighted subjects. There was no difference in errors between groups in identification of mirror images ("impossible rotations"). Results were interpreted in terms of a relation between enhanced reliance on nonvisual information by near-sighted subjects and improved spatial representation.     

What’s up in mental rotation?

We report two experiments on the influence of head tilt on mental rotation. In Experiment I, subjects decided whether dot patterns were or were not repeated about a line. Their reaction times (RTs) were consistent with the interpretation that they mentally rotated the patterns so that the line was subjectively vertical before making their decisions. When the subjects tilted their heads, the RT functions shifted in the direction of the tilt, indicating that the subjective vertical lay closer to the retinal than to the gravitational vertical. In Experiment II, subjects decided whether singly presented alphanumeric characters in various orientations were standard or backward (mirror-reversed). Again, analysis of their RTs suggested mental rotation to the standard upright, but the function was unaffected by head tilt; in this case, the subjects operated in subjective gravitational rather than retinal coordinates. The choice of retinal or gravitational coordinates may depend on whether the stimuli are interpreted egocentrically or as part of the external world.     

Are the spatial features of bodily threat limited to the exact location where pain is expected?

Previous research has revealed that anticipating pain at a particular location of the body prioritizes somatosensory input presented there. The present study tested whether the spatial features of bodily threat are limited to the exact location of nociception. Participants judged which one of two tactile stimuli, presented to either hand, had been presented first, while occasionally experiencing a painful stimulus. The distance between the pain and tactile locations was manipulated. In Experiment 1, participants expected pain either proximal to one of the tactile stimuli (on the hand; near condition) or more distant on the same body part (arm; far condition). In Experiment 2, the painful stimulus was expected either proximal to one of the tactile stimuli (hand; near) or on a different body-part at the same body side (leg; far). The results revealed that in the near condition of both experiments, participants became aware of tactile stimuli presented to the “threatened” hand more quickly as compared to the “neutral” hand. Of particular interest, the data in the far conditions showed a similar prioritization effect when pain was expected at a different location of the same body part as well as when pain was expected at a different body part at the same body side. In this study, the encoding of spatial features of bodily threat was not limited to the exact location where pain was anticipated but rather generalized to the entire body part and even to different body parts at the same side of the body.     

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     

Phonetic recoding of print and its effect on the detection of concurrent speech in amplitude-modulated noise.

When an amplitude-modulated noise generated from a spoken word is presented simultaneously with the word's printed version, the noise sounds more speechlike. This auditory illusion obtained by Frost, Repp, and Katz (1988) suggests that subjects detect correspondences between speech amplitude envelopes and printed stimuli. The present study investigated whether the speech envelope is assembled from the printed word or whether it is lexically addressed. In two experiments subjects were presented with speech-plus-noise and with noise-only trials, and were required to detect the speech in the noise. The auditory stimuli were accompanied with matching or non-matching Hebrew print, which was unvoweled in Experiment 1 and voweled in Experiment 2. The stimuli of both experiments consisted of high-frequency words, low-frequency words, and non-words. The results demonstrated that matching print caused a strong bias to detect speech in the noise when the stimuli were either high- or low-frequency words, whereas no bias was found for non-words. The bias effect for words or non-words was not affected by spelling to sound regularity; that is, similar effects were obtained in the voweled and the unvoweled conditions. These results suggest that the amplitude envelope of the word is not assembled from the print. Rather, it is addressed directly from the printed word and retrieved from the mental lexicon. Since amplitude envelopes are contingent on detailed phonetic structures, this outcome suggests that representations of words in the mental lexicon are not only phonological but also phonetic in character.     

Mental rotation of compound stimuli: The effects of task demands,practice, and figural goodness

Four experiments examined whether or not mental rotation of compound stimuli is a holistic process. Large letters (global aspect) composed of small letters (local aspect) were presented, and the format (normal vs. reflected) of each aspect was manipulated independently. In Experiment 1, the rate of mental rotation was compared under divided- and focused-attention instructions. The overall rate of mental rotation was faster under focused-attention instructions than under divided-attention instructions. Also, contrary to previous findings, in the divided-attention task, the slope of the rotation function was smaller when the stimulus configurations contained aspects with congruent formats (both aspects were normal or mirror-reversed letters) than when they contained aspects with incongruent formats (one normal and one mirror-reversed letter). This pattern of results is unlikely to be caused by the subjects' level of familiarity with the divided-attention task (Experiment 2), by postrotation processes (Experiment 3), or by stimulus attributes (figural goodness) confounded with the format-congruency variable (Experiment 4). The implications of these results for models of mental rotation of compound stimuli are discussed.     

The body-inversion effect

Researchers argue that faces are recognized via the configuration of their parts. An important behavioral finding supporting this claim is the face-inversion effect, in which inversion impairs recognition of faces more than nonface objects. Until recently, faces were the only class of objects producing the inversion effect for untrained individuals. This study investigated whether the inversion effect extends to human body positions, a class of objects whose exemplars are structurally similar to each other. Three experiments compared the recognition of upright and inverted faces, houses, and body positions using a forced-choice, same/different paradigm. For both reaction time and error data, the recognition of possible human body postures was more affected by inversion than the recognition of houses. Further, the recognition of possible human body postures and recognition of faces showed similar effects of inversion. The inversion effect was diminished for impossible body positions that violated the biomechanical constraints of human bodies. These data suggest that human body positions, like faces, may be processed configurally by untrained viewers.     

Mental rotation of possible and impossible four-cornered toruses

Possible and impossible four-cornered toruses were used as stimuli in a mental rotation paradigm. Rotation rates varied with number of “net changes in depth,” a variable that closely corresponds with ratings of impossibility, rather than with formal distinctions between the possible and the impossible. Rotation rates were also affected by perimeter shapes but not in accord with perimeter complexity as defined by number of vertices. Experiment 2 attempted to separate net changes in depth from figure symmetry and found symmetry to be the more reliable predictor of rotation rates, suggesting that symmetry may underlie the influence of net changes of depth.     

Holistic processes in the perception and transformation of disoriented figures

Two experiments tested whether mental rotation of complex, hierarchical stimuli occurs holistically or separately at global and local levels of structure. Large (global) letters were constructed from spatial arrangements of small (local) letters. Reflection conditions (normal vs. reflected) were produced by varying the two levels independently. The task was structured so that subjects could rotate one level of the stimulus in some conditions but had to rotate both levels in other conditions. Experiment 1 showed that rotation rate was not affected by the number of levels that had to be rotated to make a reflection decision. This result implies that the rotation of global and local levels occurred together rather than sequentially. Experiment 2 showed that the rotation of the two levels was holistic as opposed to parallel and independent. The results also demonstrate that global information is processed faster than local information regardless of whether or not a rotation is performed. These findings are discussed in relation to theories of mental rotation and global precedence.     

Repetition blindness for novel objects

When visual stimuli (letters, words or pictures of objects) are presented sequentially at high rates (8–12 items/s), observers have difficulty in detecting and reporting both occurrences of a repeated item: This is repetition blindness. Two experiments investigated the effects of repetition of novel objects, and whether the representations bound to episodic memory tokens that yield repetition blindness are viewpoint dependent or whether they are object centred. Subjects were shown coloured drawings of simple three‐dimensional novel objects, and rate of presentation (Experiment 1) and rotation in depth (Experiment 2) were manipulated. Repetition blindness occurred only at the higher rate (105 ms/item), and was found even for stimuli differing in orientation. We conclude that object‐centred representations are bound to episodic memory tokens, and that these are constructed prior to object recognition operating on novel as well as known objects. These results are contrasted with those found with written materials, and implications for explanations of repetition blindness are considered.