Mental rotation: Effects of dimensionality of objects and type of task.

The original studies of mental rotation estimated rates of imagining rotations that were much slower when two simultaneously portrayed three-dimensional shapes were to be compared (R. Shepard & J. Metzler) than when one two-dimensional shape was to be compared with a previously learned two-dimensional shape (Cooper and her associates). In a 2?×?2 design, we orthogonally varied dimensionality of objects and type of task. Both factors affected reaction times. Type of task was the primary determiner of estimated rate of mental rotation, which was about three times higher for the single-stimulus task. Dimensionality primarily affected an additive component of all reaction times, suggesting that more initial encoding is required for three-dimensional shapes. In the absence of a satisfactory way of controlling stimulus complexity, the results are at least consistent with the proposal that once three-dimensional objects have been encoded, their rotation can be imagined as rapidly as the rotation of two-dimensional shapes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mental rotation in pigeons (Columba livia)?

Previous research has shown pigeons to be insensitive to the orientation of visual test stimuli both for response latency and for discrimination ratio. Discrimination of stimulus orientation has been more difficult to learn than discrimination of small arbitrary differences between stimuli. This has suggested that the visual processing of pigeons is orientation invariant, which would obviate the need for mental rotation such as is often observed in studies with human subjects. Contrary to previous findings, the current experiment obtained linear effects of orientation on response latency and discrimination ratio, with a go/no-go procedure. Pigeons (Columbia livia) first learned to discriminate among line drawings of similar objects and then were tested with rotated versions of the drawings. The pattern of data is similar to that found in studies of human recognition of rotated objects. One speculative explanation of this finding is the mental rotation of stimuli by pigeons. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of depth rotation on object identification

Five experiments are reported in which the time to verify the name of different three-dimensional common objects shown rotated in depth was investigated. Views of computer-generated images of elongated objects rotated in steps of 30 degrees along six axes of rotation were used as stimuli. A significant main effect of view was found in all experiments. This effect was initially attributed to the relatively slower verification times to the end-on views of objects but further analysis revealed that views 30 degrees off the end-on views were significantly slower to verify than other views. Objects with gravitational uprights yielded the same effects as objects without gravitational uprights. The results were not dependent on practice with the stimuli prior to the experiment or on repeated exposure of the views during the experiment. Also, there was no benefit found for the identification of shaded over silhouetted images of objects when shown in more-conventional views but unconventional views were more recognisable when shaded than when silhouetted. Last, initial verification times for familiar views of a set of novel objects were faster than for unfamiliar views even when the views were unconventional. With practice on unfamiliar views, however, the same function relating view to verification time found for familiar objects was found for the novel objects. The results suggest that for recognition purposes visual memory stores discrete views of objects but it characteristically favours a canonical range of views of elongated objects that are based on the salient geometry of the objects so that more unconventional or foreshortened views are less readily recognised.     

Naming and locating the tops of rotated pictures.

Investigated whether and how pictures are mentally rotated to upright before they can be named. Four experiments were conducted with 12 college students in each, who were given the tasks of naming pictures of common objects with various orientations and locating their tops. In the naming task, Ss required more time the farther the picture was from upright, but the rotation effect was reduced after Ss had named each picture once, indicating that rotation may be required only for unfamiliar stimuli. The top locating task was faster with upright figures, but otherwise-oriented pictures required the same time regardless of orientation. Top-locating was faster than naming, indicating that "topness" may be guessed even in unfamiliar figures, while naming also involves searching one's semantic memory for a name. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mental rotation, physical rotation, and surface media.

Ss 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 Exps 1–3. Character rotation in the direction of mental rotation facilitated mental rotation, whereas rotation in the opposite direction inhibited it. In Exp 4, characters were presented in different surface media so as to stimulate only 1 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 Exps 1–3 in excluding the participation of low-level motion analysis centers in the mental rotation processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Induction of COX-2 expression by mechanical tension force in human periodontal ligament cells

Spectral EEG powers were compared in 4 frequency ranges (8-13, 15-25, 25-35, and 35-45 Hz) in a group of 20 subjects during the performance of tasks requiring mental rotation of two- and three-dimensional objects. Only those EEG segments corresponding to tasks with identical solution times were analyzed. The spectral powers of oscillations in the alpha range were higher in control conditions than during task performance. Power in the frequency range 15-45 Hz was greater during task performance than in control conditions; this supports the concept that alpha rhythm desynchronization accompanies the synchronization of higher-frequency EEG rhythms. Frequency power during task performance with two-dimensional objects was greater than that during tasks with three-dimensional objects. Since the angle of rotation between two-dimensional objects was greater than that between three-dimensional objects, this factor, rather than the depth of the perceived space, increased the level of cortical activation. In all experimental situations, power at frequencies of 15-45 Hz was significantly greater in the occipital regions than any other regions, reflecting the visual modality of the stimulus. Particular changes were noted in the gamma range (35-45 Hz), where power in the first second of task performance was significantly higher than in the second second; this may provide evidence that this range is more closely associated with perception and recognition processes than with mental transformation of the image.     

The roles of stimulus-response compatibility and mental rotation in mirror-image and left-right decisions.

Examined the relative roles of mental rotation and stimulus-response (SR) compatibility in mirror-image and left-right decisions. 15 Ss, aged 19–43 yrs, were shown rotated letters and asked to indicate whether the letters were normal or backward (mirror-image task). Ss were then asked whether a dot would be located to the left or right of each letter if the letter was upright (viewer-centered left-right task) or if the letter was both upright and normal (letter-centered left-right task). The functions relating reaction time (RT) to angular orientation were parallel across the 3 tasks, suggesting that SR compatibility played no role, and that the Ss mentally rotated the letters to the upright in each case. A marked increase in RT to backward letters in the letter-centered task suggested a 2nd rotation in depth to restore the letters to normal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Priming of reach and grasp actions by handled objects.

Pictures of handled objects such as a beer mug or frying pan are shown to prime speeded reach and grasp actions that are compatible with the object. To determine whether the evocation of motor affordances implied by this result is driven merely by the physical orientation of the object's handle as opposed to higher-level properties of the object, including its function, prime objects were presented either in an upright orientation or rotated 90° from upright. Rotated objects successfully primed hand actions that fit the object's new orientation (e.g., a frying pan rotated 90° so that its handle pointed downward primed a vertically oriented power grasp), but only when the required grasp was commensurate with the object's proper function. This constraint suggests that rotated objects evoke motor representations only when they afford the potential to be readily positioned for functional action. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Visual Search for Object Orientation Can Be Modulated by Canonical Orientation.

The authors studied the influence of canonical orientation on visual search for object orientation. Displays consisted of pictures of animals whose axis of elongation was either vertical or tilted in their canonical orientation. Target orientation could be either congruent or incongruent with the object's canonical orientation. In Experiment 1, vertical canonical targets were detected faster when they were tilted (incongruent) than when they were vertical (congruent). This search asymmetry was reversed for tilted canonical targets. The effect of canonical orientation was partially preserved when objects were high-pass filtered, but it was eliminated when they were low-pass filtered, rendering them as unfamiliar shapes (Experiment 2). The effect of canonical orientation was also eliminated by inverting the objects (Experiment 3) and in a patient with visual agnosia (Experiment 4). These results indicate that orientation search with familiar objects can be modulated by canonical orientation, and they indicate a top-down influence on orientation processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An investigation of sex differences in spatial ability: Mental rotation of three-dimensional objects.

Presented 2-dimensional computer-generated representations of 3-dimensional objects in pairs to 20 male and 20 female right-handed undergraduates. Ss were given 15 sec to make a same-different judgment of the objects, one of which was rotated 0°, 40°, 80°, 120°, or 160° from the other. Ss were also assessed on 2 standard spatial ability tests (the Spatial Relations subtest of the Differential Aptitude Tests, Form L, and the Standardized Road-Map Test of Direction Sense) and a verbal-imagery questionnaire. Analyses of the data showed that men were more accurate than women, and that the slope of the function relating response time to degree of rotation was steeper in women. There was a significant linear relation between performance and the degree of rotation. Rate of rotation and accuracy correlated with the other tests of spatial ability. Response time slope correlated with imagery in men but not in women, suggesting that frequent use of visual imagery was related to mental rotation rate in men, but not in women. There were no clear relations between performance and the strategy Ss professed to use in doing the mental rotation. (French summary) (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mental rotation and automatic updating of body-centered spatial relationships.

Blindfolded adult participants (7 male and 9 female) were asked to point to previously seen targets after a body rotation. In 1 condition, participants had to update their positions relative to the targets during rotation; in another condition, they had to ignore the rotation and to imagine that they were still in their initial orientation. In the updating condition, replicating research of J. J. Rieser (1989), response latencies were only slightly affected by the magnitude of the body rotation. In the ignoring condition, however, response latencies increased with the angular difference between the participants' new position and their original orientation, suggesting that the participants updated their positions and then retrospectively "undid" this updating to mentally reestablish their original orientation. The results are supportive of the idea that heading is updated automatically as a person moves so that she or he is always primarily oriented with respect to her or his actual position. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reference frame and effects of orientation on finding the tops of rotated objects.

Investigated effects of stimulus orientation across trial blocks and the spatial reference frame with a task in which Ss, with their heads upright or tilted, judged a dot to be near the top or the bottom of rotated line drawings of objects. Objects used in this task were also named. Response times from the 1st block of trials increased linearly for objects rotated from 0 to 120° from the upright. Across blocks, orientation effects diminished for naming but remained the same for top–bottom discriminations. Practice with top–bottom discriminations diminished orientation effects when the same objects were subsequently named. The spatial reference frame for top–bottom discrimination was midway between retinal and environmental coordinates. Specifying the location of object features is of greater importance for top–bottom discriminations than for naming and underlies orientation effects in these tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Representation of orientation and spatial frequency in perception and memory: a choice reaction-time analysis

Discrimination and short-term memory for the orientation of sinusoidal gratings that differed in spatial frequency, and for the spatial frequency of gratings that differed in orientation, were measured in a same-different task with 0-10 s interstimulus intervals (ISI) between test and reference stimuli. Introducing a difference between test and reference stimuli on a second dimension, or increasing ISI, did not impair spatial discrimination in terms of accuracy, but choice reaction times for correct decisions were prolonged by both manipulations. Results suggest that perceptual discrimination is based on representations in which orientation and spatial frequency are conjointly coded and that decisions are reached by a serial process scanning multiple-tuned, labeled channels; short-term memory may involve reactivation of these channels.     

Reference frames in mental rotation.

Four experiments are reported that investigate whether images or reference frames are transformed during a mental rotation task. In all experiments a display of four identical letters (P1) was presented at either +90° or –90° from upright, and subjects had to decide whether the letters were normal or mirror-image reflections. A single letter (P2) was then presented 100 ms later in a variable orientation with the same task instructions. Reaction times to P2 were assessed to determine whether an image of P2 was rotated to upright or whether an internal reference frame was rotated into congruence with P2 from the orientation of P1. The results as a whole suggest that transformations of P2 can be initiated either relative to upright or relative to the orientation of P1. They further indicate that the probability of using each reference orientation can be changed by procedural variations. The findings are most parsimoniously interpreted as suggesting that mental rotation involves the transformation of reference frames rather than the transformation of template-like representations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Identification of disoriented objects: Effects of context of prior presentation.

Half of the Ss in the training phase of Exp 1 named objects shown in a number of orientations, whereas the other half named objects shown upright only. Ss named objects seen in a number of different orientations in the transfer phase. Half of the objects in the transfer phase were the ones seen in the training phase (old objects), whereas the other half were objects they had not seen before (new objects). Mean naming time in the transfer phase increased more as the objects were rotated further from the upright for new objects than for old objects when the old objects had been seen in a variety of orientations. A substantial and equivalent orientation effect on identification time was obtained for old and new objects when the old objects had been seen upright only. Results suggest that the extraction and use of orientation-invariant attributes to identify objects is not a default identification strategy employed by the visual system. In Exp 2, half of the objects named in the training phase were shown upright only; the other half were shown in a number of orientations. Both (upright vs rotated) were presented in a mixed fashion from trial to trial. Results reveal that prior naming of the objects in this context resulted in equivalent reductions in the magnitude of the orientation effect on identification time for both sets of objects. The results of these 2 experiments suggest that different representations of objects are encoded, depending on the context in which objects are seen. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fibronectin matrix regulates activation of RHO and CDC42 GTPases and cell cycle progression

This research concerned the use of mental rotation in recognizing rotated objects. Instead of the classic Shepard's paradigm in which subjects were still while observing rotated objects, here subjects had to move (or imagine moving) around stationary three-dimensional objects put in the middle of the trajectory. Thus, depending on the viewing positions, such objects were seen under six different perspectives (from 30 degrees to 180 degrees). The latter task has been thought to be closer to everyday life in which we obtain information regarding objects from their spatial properties. The results do not follow the classic rules of mental rotation of an object predicting a linear increase of the time needed to recognize distorted objects as a function of their angular displacement. They also differ from data in the literature about spatial imagery showing that access to spatial information is facilitated more when people actually move through a path than when they imagine moving. A probable explanation of this difference from the literature is discussed in relation to the particular involvement of the body in the experimental task.     

Orientation invariant pattern recognition by pigeons (Columba livia) and humans (Homo sapiens).

The orientation invariance of visual pattern recognition in pigeons and humans was studied using a conditioned matching-to-sample procedure. A rotation effect, a lengthening of choice latencies with increasing angular disparities between sample and comparison stimuli, was replicated with humans. The choice speed and accuracy of pigeons was not affected by orientation disparities. Novel mirror-image stimuli, rotation of sample shapes, a delayed display of comparison shapes, and a mixed use of original and reflected sample shapes did not lead to a rotation effect in pigeons. With arbitrarily different odd comparison shapes, neither humans nor pigeons showed a rotation effect. Final experiments supported the possibility that the complete absence of a rotation effect in pigeons is because they are relatively better than humans at discriminating mirror-image shapes compared with arbitrary shapes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of orientation on the identification of rotated objects depend on the level of identity

Matching names and rotated line drawings of objects showed effects of object orientation that depended on name level. Large effects, in the same range as object naming, were found for rotations between 0 degrees and 120 degrees from upright with subordinate names (e.g., collie), whereas nonsignificant effects were found with superordinate (e.g., animal) and basic names (e.g., dog). These results support image normalization, after contact with orientation-invariant representations, that provide basic-level identity. They consequently fail to support theories of object recognition in which rotated object images are normalized to the upright position before contact with long-term object representations.     

Mental-rotation deficits following damage to the right basal ganglia.

The authors report the case of a woman with a right basal ganglia lesion and severe mental-rotation impairments. She had no difficulty recognizing rotated objects and had intact left-right orientation in egocentric space but was unable to map the left and right sides of external objects to her egocentric reference frame. This study indicates that the right basal ganglia may be critical components in a cortico-subcortical network involved in mental rotation. We speculate that the role of these structures is to select and maintain an appropriate motor program for performing smooth and accurate rotation. The results also have important implications for theories of object recognition by demonstrating that recognition of rotated objects can be achieved without mental rotation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)