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)     

Latency to categorize disoriented alphanumeric characters as letters or digits.

Previous research has shown that if Ss must decide quickly whether a disoriented alphanumeric character is normal or backward, they "mentally rotate" an internal representation of the character to its normal upright position before making the decision. The present study with 12 undergraduates showed that latency to decide whether a disoriented character was a letter or a digit was barely affected by angular orientation, implying that mental rotation is not necessary for this task. However, latency was significantly shorter for normal than for backward characters, regardless of angular orientation, suggesting that the difference between normal and backward characters does register prior to mental rotation. (7 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A violation of pure insertion: Mental rotation and choice reaction time.

Six experiments tested the assumption that the mental rotation process is purely inserted into a mirror–normal discrimination task. In Exp 1, Ss took significantly longer to respond to upright characters in blocks containing rotated stimuli than in blocks containing only upright stimuli. Exps 2 and 3 showed that this rotational uncertainty effect was not caused by the need to determine stimulus orientation, and Exp 4 showed that it was independent of the visual quality of the stimulus. Exp 5 showed that the effect was greatly reduced when Ss performed a go–no-go task rather than choice reaction time (RT), and Exp 6 showed that it was independent of the complexity of the response required in the choice task. Results suggest that response selection in a choice RT mirror–normal discrimination task is altered when mental rotation is added, violating the assumption of pure insertion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A hemispheric division of labor aids mental rotation.

In the present study, we investigated whether a hemispheric division of labor is most advantageous to performance when lateralized inputs place unequal resource demands on the left and right cerebral hemispheres. In each trial, participants decided whether 2 rotated letters, presented either in the same visual field (within-field trials) or in opposite visual fields (across-field trials), were both of normal orientation, or whether one was normal and the other was mirror-reversed. To discriminate a letter's orientation, one must rotate the letter to the upright position. Therefore, we manipulated whether the two letters imposed similar or dissimilar demands on cognitive resources by varying the number of degrees that each letter needed to be rotated to reach the upright position. As predicted, in 2 experiments we found that the across-field advantage increased as the number of degrees each letter needed to be rotated became more dissimilar. These findings support a current model of hemispheric interactions, which posits that an unequal hemispheric distribution of cognitive load allows the cerebral hemispheres to take the lead for different aspects of cognitive processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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 manipulation of spatial information in young and elderly adults.

Investigated the ability of 20-, 60-, and 70-yr-olds (12 men and 12 women at each age level) to mentally manipulate spatial information in a large-scale environment. In a perspective-taking task, Ss were asked to determine the location of target objects from imagined locations. In an array rotation task, Ss were asked to imagine that the array of objects rotated relative to their current position. Young and elderly Ss performed with equivalent accuracy on the array rotation task, but young Ss were more accurate on the perspective-taking task. Ss who were taken to each object location prior to testing were more accurate in the perspective-taking task than Ss who did not have this experience. There was no effect of prior experience on performance in the array rotation task. (4 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mental rotation interferes with response preparation.

Reaction times (RTs) and lateralized readiness potentials (LRPs) were studied to find out whether response preparation begins after mental rotation finishes, as assumed by discrete-stage models. Stimuli were disoriented normal or mirror-image characters, with character name determining which hand would respond. In Experiment 1, the normal/mirror-image information determined whether the response was to be executed (go) or withheld (no-go), and LRPs indicated that responses were weakly prepared before the end of mental rotation. Mental rotation was not required in Experiment 2, and significantly more response preparation was observed. In Experiment 3, probe RT trials embedded in the mental rotation task indicated that hand information is available to the response preparation process during rotation. Apparently, some response preparation occurs before mental rotation finishes, but rotation interferes with response preparation. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Choice reaction-time study assessing the verbal behavior of the minor hemisphere in normal adult humans.

Conducted 2 choice RT experiments in which a total of 12 right-handed college students scanned a memory set of 1 or 6 letters for the presence of a test letter. The memory set was presented binaurally and the test letter visually to either the right or left visual field. S indicated with his left hand whether or not the test letter was contained in the memory set. Results show the RT was shorter for the left visual field test letter when the set contained only 1 letter and for the right visual field test letter when the set contained 6 letters. The possibility that Ss matched the set and test letters visually when the set contained only 1 letter and verbally when the set contained 6 letters is discussed. Results suggest that the minor hemisphere displays little, if any, verbal abilities. (31 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Location dominance in attending to color and shape.

Investigated in 4 experiments whether Ss direct attention to stimulus location when attempting to attend to its color or shape. In the 1st 2 experiments, a given property (location, color, or shape) of a letter cue instructed Ss whether to report any letters from a subsequent display. Regardless of which property was relevant, Ss reported letters adjacent to the cue and not those similar to its color or shape. In the last 2 experiments, the varied location of a cue was irrelevant to the task, whereas its varied color instructed Ss to report a letter in a given location or of a given shape. Targets adjacent to the cue were reported faster than those remote from the cue. The results suggest that attempting to attend to any aspect of a stimulus entails directing attention to location. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hypnotic susceptibility and performance on various attention-specific cognitive tasks.

In 2 experiments, 52 undergraduates were administered the Harvard Group Scale of Hypnotic Susceptibility, Form A, and were divided into groups with high and low hypnotic susceptibility (HS). In Exp I (32 Ss), time-to-location of a target in a visual search was assessed. For this task, the letter Z was embedded within either straight- or round-form letters. Results indicate that Ss of high HS were significantly faster than those of low HS in locating the embedded letter. Exp II (20 Ss) investigated performance on single- and double-digit arithmetic problems as a function of HS level. Ss were presented with addition problems and asked to complete them within 60 sec. Ss of high HS completed a significantly greater number of double- but not single-digit problems within this time than did Ss of low HS. Results are discussed in terms of the 2 groups' differing strategies or operations in the performance of cognitive tasks. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Priming effects in schizophrenia: Associative interference and facilitation as a function of visual context.

Irrelevant stimuli that flank a fixated target may cause either facilitation or interference with target classification. 20 schizophrenic patients, 20 depressed control patients, and 20 normal control Ss were compared on a flanker priming task that involved the linear display of a target surrounded by 2 flanking letters or digits. Choice reaction time (RT) between letter and digit targets was examined as a function of flanker condition and onset asynchrony between flankers and target. Facilitative priming occurred only with prior exposure of flankers compatible with the response required and was greater in degree with schizophrenic and depressed than with normal Ss. Interference from flankers incompatible with the response required occurred less among schizophrenics than among other groups. Several different processes may be involved in the inhibition of irrelevant information by schizophrenics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the recognition of words with inverted letters.

Conducted 2 experiments in which 24 Ss were asked to identify words with all or some of their letters inverted. The experiments differed only in the explicitness of the instructions given to Ss. In some cases the letters appearing upside down were inverted as 1 unit, and in other cases they were inverted by letter. It was found that when all the letters were inverted, recognition time was faster for unit inversion. When just a few of the letters in the words were inverted, recognition time was shorter when the inversion was letter by letter rather than by unit. Data are consistent with a model that assumes that when the stimulus is homogeneously misoriented unit correction is applied, and when such homogeneity does not exist piecemeal correction is applied. (French abstract) (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Orientation congruency effects on the identification of disoriented shapes.

Effects of orientation on identification can be attenuated when other patterns at the same (or a similar) orientation are identified in close temporal contiguity. In Experiments 1 and 2, letters were presented simultaneously in brief masked displays. Identification accuracy was much higher when the letters had consistent orientations than when the letters had different orientations within a display. In Experiment 3, two letters were presented sequentially. Identification accuracy was higher with congruent than with incongruent orientations. The results are unexpected if one assumes that the patterns themselves are rotated until upright prior to their identification, unless pattern rotation processes can be primed, and that priming requires orientation congruence between the priming and primed stimulus. The results are expected if the orientation of a frame of reference can be adjusted to the orientation of the patterns during the identification process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A theory of order relations in perceptual matching.

Relates order relations to research on retrieval processes and the representation of order information in memory. In 2 experimental tests, presentation of a study string of letters was followed by a test string to which the 6 undergraduate Ss responded "same" or "different." When adjacent letters were switched, RT was long and accuracy low, suggesting that a test letter is not simply compared to the letter in the same position in the study string; rather, the comparison is distributed across positions. The memory model assumes that the representation of a letter is distributed over position and that the comparison process assesses the amount of overlap between the test string and the memory representation. The diffusion retrieval model and overlap memory model are fitted to the data and goodness-of-fit is assessed. Shortcomings of alternative models are considered and applications of the model to related matching tasks, such as D. Taylor's (1976) converse of the perceptual matching task, and Angiolillo-Bent and L. Rips's (1981) multiple-element comparison task, are described. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Do alphabet letters help prereaders acquire phonemic segmentation skill?

Tested the assumptions that phonemic segmentation skill is learned best in the oral mode and that teaching segmentation with alphabet letters confuses learners. Three treatment groups of 8 prereaders (mean age 67.8 mo) were formed. The letter group was taught to segment nonword blends using letter tokens. The nonletter group was taught to segment blends with tokens lacking letters. A control group received no training. Experimental groups took about the same time and number of trials to reach criterion during training, indicating that neither method was more difficult or time consuming. Errors indicated that letters helped Ss learn to distinguish phoneme-size units and to remember the correct sounds during the task. On a segmentation posttest, letter and nonletter Ss segmented unpracticed blends better than controls, indicating that both groups acquired general segmentation skill. Letter Ss were superior to nonletter Ss in segmenting practiced sounds, with both groups surpassing controls. It is suggested that letters provide learners with a mental symbol system for representing and thinking about specific phonemes. (53 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatial repetition blindness for colour and shape.

The authors investigated three experiments on repetition blindness for briefly-presented masked displays containing only two coloured letters (one on either side of fixation). In Experiment 1, a single coloured letter (or nothing) was displayed on each side of fixation. Experiment 2 used a task in which subjects had to attend to Cl but not report it. They were either asked to report i) the colour of C2 if Cl was coloured, but the letter of C2 if Cl was white, or ii) the letter of C2 if Cl was a letter but the colour of c2 if cl was a nonletter symbol. RB was found for the features of the reported dimension, showing that attention to an item is sufficient to produce RB even if that item is not itself reported. And, in experiment 3, subjects reported either the colour of cl and the letter of C2 or vice versa, a task which required them to switch attended dimensions between Cl and C2. It is a question for future research whether RH simply requires prior attention to an object containing the repeated feature, or prior attention to the actual repeated feature itself. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Span of apprehension in schizophrenic patients as a function of distractor masking and laterality.

Compared 20 schizophrenic patients, 10 depressed control patients, and 20 normal control Ss in a forced-choice, target-detection method for assessing the span of apprehension. The detection task required the S to report which of 2 target letters was presented among 7 other (distractor) letters. Performance accuracy was examined as a function of target location and whether the distractor letters were masked after their presentation. The backward masking of the distractors improved target-detection accuracy of both control groups but reduced accuracy of the schizophrenic group. In addition, schizophrenics performed particularly poorly on targets located in the left half or lower half of the display. Results suggest that response to the masking of distractors may be a new index of attentional shortcoming in schizophrenia. Various theoretical explanations for the target location findings are also discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sensibilité et diagnosticité de la mesure de la charge mentale par la tache secondaire de frappe cadencée.

Studied the sensitivity of finger tapping performance as a measure of the mental workload produced by a concurrent memory task. Ss were 8 normal male and female adults (aged 22–39 yrs). Over 4 experimental sessions, Ss were asked to complete 240 series of 13 finger taps at a rate of 1 tap every 2 sec. The concurrent primary task required Ss to search for a target item (presented after each tap) in a 3-digit set memorized before each series of taps. Processing load was varied by including letter targets among positive and negative digit targets. Intertap intervals for letter targets, positive digit targets, and negative digit targets were compared. (English abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Making letters distinctive.

Results of a study with 77 kindergartners, 24 1st graders, 21 2nd graders, and 6 college students show that small graphic changes made in normal letters of the alphabet changed the similarity relations among those letters. All Ss classified letters of this distinctive font faster and with fewer errors than they classified normal letters. It is shown that it is not features alone but relations between features within letters, and relations between letters in the stimulus set, that determine how difficult any particular letter is to classify. The advantage of the distinctive font is such that many children had less difficulty classifying distinctive letters into bins labeled with normal letters than doing the conceptually easier match-to-sample task of placing normal letters into bins labeled with normal letters. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Communication length as an index of communicator attitude: A replication.

Attempted a replication of a study by A. Mehrabian (see 40:2) who extended studies of speech behavior to apply to letters of recommendation. 69 undergraduates were asked to write 2 letters, both positive. For the 1st letter they were asked to assume strong liking for the person they were describing; for the 2nd letter they were to assume strong dislike for the person being described. Mehrabian's Ss wrote significantly more words in the 1st letters. The replication fully confirms his results. These findings suggest that the written channel of communication may be as sensitive a mirror of S's underlying attitudinal state as earlier research had revealed was the case with the spoken channel of communication. (PsycINFO Database Record (c) 2010 APA, all rights reserved)