Imagining physically impossible self-rotations: geometry is more important than gravity

Previous studies found that it is easier for observers to spatially update displays during imagined self-rotation versus array rotation. The present study examined whether either the physics of gravity or the geometric relationship between the viewer and array guided this self-rotation advantage. Experiments 1-3 preserved a real or imagined orthogonal relationship between the viewer and the array, requiring a rotation in the observer's transverse plane. Despite imagined self-rotations that defied gravity, a viewer advantage remained. Without this orthogonal relationship (Experiment 4), the viewer advantage was lost. We suggest that efficient transformation of the egocentric reference frame relies on the representation of body-environment relations that allow rotation around the observer's principal axis. This efficiency persists across different and conflicting physical and imagined postures.     

Reconstruction from the mental image

In three experiments young children were asked to reconstruct an array of objects after they had imagined its appearance following either a rotation of the array or a change in their own position (Huttenlocher & Presson, 1973). In reconstructing arrays, subjects first positioned that object which would be most prominent to an observer following the imagined transformation. Surprisingly, this occurred even when subjects made an egocentric error by reconstructing a copy of the original array. Hence young children, although apparently egocentric, can imagine themselves in a new position with a new perspective. The mental operations which underlie imagined spatial transformations are discussed in light of the results.     

Updating space during imagined self- and array translations

Previous work has demonstrated superior spatial updating performance during imagined viewer rotation versus imagined object/array rotation. Studies have also suggested that rotations are more difficult to process than translations. In three studies, we examined whether the advantage seen for updating during imagined self-rotations would generalize to translations. The participants updated the positions of objects in a line extending either to the front and back of the viewer or to the right and left after imagining viewer or array translation. Experiments 1 and 2 replicated the effects seen in imagined rotation tasks. A response time and accuracy advantage was found for imagined viewer translation versus imagined array translation. In Experiment 3, we directly compared real and imagined self- and array translations and demonstrated an advantage for real versus imagined array translation. The results suggest that the advantage for imagined viewer transformations is not a function of the specific transformation, but rather of the ability to imagine and predict the outcome of a moving frame of reference.     

Updating displays after imagined object and viewer rotations

Six experiments compared spatial updating of an array after imagined rotations of the array versus viewer. Participants responded faster and made fewer errors in viewer tasks than in array tasks while positioned outside (Experiment 1) or inside (Experiment 2) the array. An apparent array advantage for updating objects rather than locations was attributable to participants imagining translations of single objects rather than rotations of the array (Experiment 3). Superior viewer performance persisted when the array was reduced to 1 object (Experiment 4); however, an object with a familiar configuration improved object performance somewhat (Experiment 5). Object performance reached near-viewer levels when rotations included haptic information for the turning object. The researchers discuss these findings in terms of the relative differences in which the human cognitive system transforms the spatial reference frames corresponding to each imagined rotation.     

Thinking outside the body: an advantage for spatial updating during imagined versus physical self-rotation

Three studies examined effects of different response measures on spatial updating during self-rotation. In Experiment 1, participants located objects in an array with a pointer after physical self-rotation, imagined self-rotation, and a rotation condition in which they ignored superfluous sensorimotor signals. In line with previous research, updating performance was found to be superior in the physical self-rotation condition compared with the other 2. In Experiment 2, participants performed in identical rotation movement conditions but located objects by verbal labeling rather than pointing. Within the verbal modality, an advantage for updating during imagined self-rotation was found. In Experiment 3, participants performed physical and imagined self-rotations only and used a pointing response offset from their physical reference frames. Performance was again superior during imagined self-rotations. The results suggest that it is not language processing per se that improves updating performance but rather a general reduction of the conflict between physical and projected egocentric reference frames.     

不同平面心理旋转的角色效应

本研究采用实验方法,分别在水平面和冠状面内对第一人称角色和第三人称角色心理旋转进行对比性研究。实验结果表明：空间表征转换的角色方式对心理旋转产生显著影响,第三人称角色心理旋转易于第一人称角色心理旋转,即存在心理旋转的角色效应;心理旋转的角色效应并不是在特定旋转条件下才出现的,具有更大的普遍性     

An fMRI study of imagined self-rotation

In the present study, functional magnetic resonance imaging was used to examine the neural mechanisms involved in the imagined spatial transformation of one’s body. The task required subjects to update the position of one of four external objects from memory after they had performed an imagined self-rotation to a new position. Activation in the rotation condition was compared with that in a control condition in which subjects located the positions of objects without imagining a change in selfposition. The results indicated similar networks of activation to other egocentric transformation tasks involving decisions about body parts. The most significant area of activation was in the left posterior parietal cortex. Other regions of activation common among several of the subjects were secondary visual, premotor, and frontal lobe regions. These results are discussed relative to motor and visual imagery processes as well as to the distinctions between the present task and other imagined egocentric transformation tasks.     

The influence of spatial reference frames on imagined object- and viewer rotations.

The human visual system can represent an object's spatial structure with respect to multiple frames of reference. It can also utilize multiple reference frames to mentally transform such representations. Recent studies have shown that performance on some mental transformations is not equivalent: Imagined object rotations tend to be more difficult than imagined viewer rotations. We reviewed several related research domains to understand this discrepancy in terms of the different reference frames associated with each imagined movement. An examination of the mental rotation literature revealed that observers' difficulties in predicting an object's rotational outcome may stem from a general deficit with imagining the cohesive rotation of the object's intrinsic frame. Such judgments are thus more reliant on supplementary information provided by other frames, such as the environmental frame. In contrast, as assessed in motor imagery and other studies, imagined rotations of the viewer's relative frame are performed cohesively and are thus mostly immune to effects of other frames.     

Implicit transfer of motor strategies in mental rotation

Recent research indicates that motor areas are activated in some types of mental rotation. Many of these studies have required participants to perform egocentric transformations of body parts or whole bodies; however, motor activation also has been found with nonbody objects when participants explicitly relate the objects to their hands. The current study used positron emission tomography (PET) to examine whether such egocentric motor strategies can be transferred implicitly from one type of mental rotation to another. Two groups of participants were tested. In the Hand-Object group, participants performed imaginal rotations of pictures of hands; following this, they then made similar judgments of pictures of Shepard-Metzler objects. The Object-Object group performed the rotation task for two sets of Shepard-Metzler objects only. When the second condition in each group (which always required rotating Shepard-Metzler objects) was compared, motor areas (Area 6 and M1) were found to be activated only in the Hand-Object group. These findings suggest that motor strategies can be covertly transferred to imaginal transformations of nonbody objects.     

序列本体感觉学习获得稳定的自我中心空间表征*

通过同步视觉或者序列本体感觉,被试学习不规则场景。学习完毕之后,在面对学习方向、自主旋转240°、和持续旋转直至迷向3种运动条件下,被试随机指出各个物体的位置。迷向导致同步视觉学习组指向的内部一致性显著变差,而序列本体感觉学习组不受迷向影响。离线的相对位置判断任务表明两组被试的环境中心空间表征没有差异。这证明通过序列本体感觉学习被试也可以形成稳定的自我中心空间表征,支持了空间快照理论的扩展和空间认知的功能等价假说。     

Mental rotation with egocentric and object-based transformations

Two experiments were conducted to address methodological issues with past studies investigating the influence of egocentric and object-based transformations on performance and sex differences in mental rotation. In previous work, the egocentric and object-based mental rotation tasks confounded the stimulus type (embodied vs. non-embodied) and transformation task (egocentric vs. object-based). In both experiments presented here, the same stimuli were used regardless of the type of transformation but task instructions were modified to induce either egocentric (left–right judgment) or object-based (same–different judgment) processing. Experiment 1 used pairs of letters whereas Experiment 2 presented pairs of line-drawings of human hands. For both experiments, it was hypothesized that the mental rotation slope for response time would be steeper for object-based than for egocentric transformations. This hypothesis was verified in both experiments. Furthermore, Experiment 2 showed a reduced male advantage for egocentric compared to object-based rotations, whereas this pattern was reversed for Experiment 1. In conclusion, the present study showed that the influence of the type of transformation involved in mental rotation can be examined with the same set of stimuli simply by modifying task instructions.     

Spatial egocentrism and the effect of an alternate frame of reference

The present study contrasted two possible explanations of spatial egocentrism in spatial perspective tasks. By one account children's judgments in perspectivetaking tasks are based on relations between the self (ego) and the target array. By the second account, children's judgments are based on relations between the target array and the larger spatial field. Sixty children in first, third, and fifth grades (ages 7, 9, and 11 years, respectively) solved both a standard and a modified version of a spatial perspective task. In the modified procedure, subjects observed a model of the experimental room that was rotated to appear as the actual room would appear to a hypothetical viewer. Using the model as an alternative frame of reference improved the performance of subjects in all age groups. In the standard procedure most errors were egocentric. In the modified procedure, subjects showed no systematic egocentric errors for rotations of 90 or 270°. The results supported the hypothesis that systematic egocentric errors are due to subjects realistically maintaining the relation of the array to the immediate spatial field, rather than maintaining the ego-array relation.     

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     

空间参照体系对心理旋转的影响

人类视觉系统不仅运用多重参照体系来建构客体的空间位置表征,也运用这些参照体系进行空间表征的动力转换.本研究采用实验方法,在心理旋转任务中对想象空间自我中心参照体系和客体中心参照体系的转换策略进行对比研究.实验结果表明:空间参照体系对心理旋转产生显著影响,自我中心参照体系转换易于客体中心参照体系转换,即存在心理旋转的视者优势.     

Asymmetric learning transfer between imagined viewer- and object-rotations: Evidence of a hierarchical organization of spatial reference frames

Neural resources subserving spatial processing in either egocentric or allocentric reference frames are, at least partly, dissociated. However, it is unclear whether these two types of representations are independent or whether they interact. We investigated this question using a learning transfer paradigm. The experiment and material were designed so that they could be used in a clinical setting. Here, we tested healthy subjects in an imagined viewer-rotation task and an imagined object-rotation task. The order of the tasks was counterbalanced across subjects. The results showed that subjects who did the viewer-rotation task first had fewer errors and shorter latencies of response in the object-rotation task, whereas subjects who did the object-rotation task first had little if any advantage in the viewer-rotation task. In other words, the results revealed an asymmetric learning transfer between tasks, which suggests that spatial representations are hierarchically organized. Specifically, the results indicate that the viewer-rotation task engaged allocentric representations and egocentric representations, whereas the object-rotation task engaged only egocentric representations.     

Asymmetric learning transfer between imagined viewer- and object-rotations: Evidence of a hierarchical organization of spatial reference frames

Neural resources subserving spatial processing in either egocentric or allocentric reference frames are, at least partly, dissociated. However, it is unclear whether these two types of representations are independent or whether they interact. We investigated this question using a learning transfer paradigm. The experiment and material were designed so that they could be used in a clinical setting. Here, we tested healthy subjects in an imagined viewer-rotation task and an imagined object-rotation task. The order of the tasks was counterbalanced across subjects. The results showed that subjects who did the viewer-rotation task first had fewer errors and shorter latencies of response in the object-rotation task, whereas subjects who did the object-rotation task first had little if any advantage in the viewer-rotation task. In other words, the results revealed an asymmetric learning transfer between tasks, which suggests that spatial representations are hierarchically organized. Specifically, the results indicate that the viewer-rotation task engaged allocentric representations and egocentric representations, whereas the object-rotation task engaged only egocentric representations.     

The representation of uniform motion in vision

For veridical detection of object motion any moving detecting system must allocate motion appropriately between itself and objects in space. A model for such allocation is developed for simplified situations (points of light in uniform motion in a frontoparallel plane). It is proposed that motion of objects is registered and represented successively at four levels within frames of reference that are defined by the detectors themselves or by their movements. The four levels are referred to as retinocentric, orbitocentric, egocentric, and geocentric. Thus the retinocentric signal is combined with that for eye rotation to give an orbitocentric signal, and the left and right orbitocentric signals are combined to give an egocentric representation. Up to the egocentric level, motion representation is angular rather than three-dimensional. The egocentric signal is combined with signals for head and body movement and for egocentric distance to give a geocentric representation. It is argued that although motion perception is always geocentric, relevant registrations also occur at the three earlier levels. The model is applied to various veridical and nonveridical motion phenomena.     

空间相对位置效应的时间特征

用方位箭头作探测刺激,研究故事阅读产生的想象空间中物体搜索任务的反应时模式。结果发现：(1)方位箭头的指向对物体搜索有影响,反应时模式为：左=右=前＜后,说明方位箭头作探测刺激时的物体搜索过程不涉及人一物空间关系的转换;(2)目标物体与注意物体的相对位置对物体搜索有影响,反应时模式为注意点＜注意点对面＜注意点左侧=注意点右侧,说明相对位置效应与人物空间关系的转换无关。本研究结果支持了两阶段理论。     

Spatial updating in virtual reality: the sufficiency of visual information

Robust and effortless spatial orientation critically relies on "automatic and obligatory spatial updating", a largely automatized and reflex-like process that transforms our mental egocentric representation of the immediate surroundings during ego-motions. A rapid pointing paradigm was used to assess automatic/obligatory spatial updating after visually displayed upright rotations with or without concomitant physical rotations using a motion platform. Visual stimuli displaying a natural, subject-known scene proved sufficient for enabling automatic and obligatory spatial updating, irrespective of concurrent physical motions. This challenges the prevailing notion that visual cues alone are insufficient for enabling such spatial updating of rotations, and that vestibular/proprioceptive cues are both required and sufficient. Displaying optic flow devoid of landmarks during the motion and pointing phase was insufficient for enabling automatic spatial updating, but could not be entirely ignored either. Interestingly, additional physical motion cues hardly improved performance, and were insufficient for affording automatic spatial updating. The results are discussed in the context of the mental transformation hypothesis and the sensorimotor interference hypothesis, which associates difficulties in imagined perspective switches to interference between the sensorimotor and cognitive (to-be-imagined) perspective.