Infants' detection of shearing motion in random-dot displays.

Random-dot kinematograms were used to estimate infants' thresholds for shearing motion in the absence of flicker and position cues. The principal advantage of these stimuli is that changes in dot position are camouflaged by the presence of numerous matching dots, thus necessitating the detection of motion before extraction of local pattern features. 13- and 20-wk-old infants were tested with a forced-choice preferential looking technique. The target stimulus resembled a vertically oriented corrugated pattern that oscillated at 1 Hz, if, and only if, shearing motion was detected. Infants were tested at different velocities, ranging from 0.7°/sec to 5.6°/sec, and the results revealed minimum velocity thresholds of 3.5°/sec and 1.2°/sec for 13- and 20-wk-old infants, respectively. Possible interpretations for these results based on position- or flicker-sensitive mechanisms are considered and are found inconsistent with the overall pattern of results. It is concluded that infants detect shearing motion in random-dot displays with a motion-sensitive mechanism. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Infants' encoding of kinetic displays varying in relative coherence.

Two experiments were conducted to assess 3-month-old infants' processing of moving point-light displays depicting the biomechanical motions of a person walking. The displays were computer-generated and varied in stimulus coherence as measured by a version of coding theory. An infant-control habituation paradigm was used to measure both encoding and discrimination of the stimuli. Experiment 1 involved two point-light displays with identical absolute motions but different degrees of relative coherence. The results revealed that these two displays were discriminable and that encoding was systematically related to their relative coherence. Experiment 2 revealed that two new displays varying less in their coherence were also differentially encoded but were not discriminated. It was concluded that infants' processing of kinetic displays varies as a function of their relative coherence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Young children can extend motion verbs to point-light displays.

In the first study using point-light displays (lights corresponding to the joints of the human body) to examine children's understanding of verbs, 3-year-olds were tested to see if they could perceive familiar actions that corresponded to motion verbs (e.g., walking). Experiment 1 showed that children could extend familiar motion verbs (e.g., walking and dancing) to videotaped point-light actions shown in the intermodal preferential looking paradigm. Children watched the action that matched the requested verb significantly more than they watched the action that did not match the verb. In Experiment 2, the findings of Experiment 1 were validated by having children spontaneously produce verbs for these actions. The use of point-light displays may illuminate the factors that contribute to verb learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Direction of motion relationships between controls and displays moving in different planes.

"… to investigate the direction of motion relationships for seven combinations of display pointer moving at right angles to plane of rotation of control knob, a total of 718 Ss were tested by sequential methods on an apparatus producing a single direction of movement of a pointer, moving along a linear scale, for either clockwise or anticlockwise rotation of the control… where the right hand was used, there was a significant tendency to turn the knob clockwise to produce movement away from the knob [but]… there was also a significant tendency for movement towards the knob to be mediated by clockwise turning… [there were, however] significantly more anticlockwise responses for movement towards the control… . Left-handed combinations gave rise to no significant tendencies; but left-handed Ss gave significantly more anticlockwise responses than right-handers, even when the right hand was used. On the whole it is not advisable to employ any of the combinations explored in this investigation, unless movement is to be restricted to adjustments in one direction only relative to the control." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mental animation: Inferring motion from static displays of mechanical systems.

Analyzed reaction time (RT) and eye-fixation data to investigate how people infer the kinematics of simple mechanical systems (pulley systems) from diagrams showing their static configuration. It is proposed that this mental animation process involves decomposing the representation of a pulley system into smaller units corresponding to the machine components and animating these components in a sequence corresponding to the causal sequence of events in the machine's operation. Although it is possible for people to make inferences against the chain of causality in the machine, these inferences are more difficult, and people have a preference for inferences in the direction of causality. The mental animation process reflects both capacity limitations and limitations of mechanical knowledge. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Judgments of proportions.

This study investigated the processes that underlie estimates of relative frequency. Ss performed 4 tasks using the same stimuli (squares containing black and white dots); they judged "percentages" of white dots, "percentages" of black dots, "ratios" of black dots to white dots, and "differences" between the number of black dots and white dots. Results were consistent with the theory that Ss used the instructed operations with the same scale values in all tasks. Despite the use of the correct operation, Ss consistently overestimated small proportions and underestimated large proportions. Variations in the distributions of actual proportions affected the extent to which Ss overestimated small proportions and underestimated large proportions in the direction predicted by range–frequency theory. Results suggest that proportion judgments, and by analogy probability judgments, should not be taken at face value. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Apparent relative motion from a checkerboard surround

To better understand the Ouchi illusion in which a stationary picture generates illusory relative motion, the spatial properties of the constituent elements of the rectangular checkerboard background were examined. Results of experiment 1 revealed that the largest illusion was obtained with elements of approximately 20-30 min in width and 4-6 min in height, an orientation of the constituents that was orthogonal to that of the test grating, and a phase shift of the alternate stripes that was close to 180 degrees. In experiment 2 it was found that the illusion increased in magnitude with increasing achromatic contrast but was minimal with a pattern of high chromatic contrast near isoluminance. In experiment 3, two test patches were presented simultaneously in the checkerboard background and were varied independently in their orientation to explore whether or not their motions were perceived as coherent (common fate). Patches having identical orientations, and nearly orthogonal to the surround, were synchronized more strongly than those having reflected orientations. Hysteresis related to the gain control of spatially overlapping visual units differing in their polarity (ON/OFF) was discussed as a possible cause of this phenomenon.     

An experimental analysis of a tactical blunder.

64 Ss engaged in a laboratory game which required strategy. The rules of the game made it possible to identify a class of responses which were, in every possible instance, inappropriate. It was found that these moves, which were classified as tactical blunders, were systematically related to the strategies which were presumably being used by other players. The behavior of the other players was, in fact, controlled by E. Paradoxically, more blunders were found in the condition where success in the game was empirically found to be more likely. A discussion based upon "correlated hypotheses" was given in an attempt to integrate the findings. (15 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Object search in nonscene displays.

When we look at a chair or a giraffe we cannot suppress a semantic interpretation of that image, although we need not name it (e.g., Smith & McGee, 1980). Given that classification of object images is mandatory, is it capacity free? Subjects attempted to detect the presence or absence of a target object, specified by basic-level name, in a 100-ms display of a nonscene (clock face) arrangement of one to six pictures of common objects. There was a sharp monotonic decrease in detectability as a function of the number of objects in the display, indicating that object detection under these conditions is an attention-demanding process. No benefit was observed for targets that were likely to co-occur with the distractors. This latter result is evidence against an account of the perceptual interference found for improbable objects in real-world scenes, which holds that the interference derives from an inventory listing of the objects without regard to their spatial relations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Judgments of facial expressions of emotion in profile.

Despite the fact that facial expressions of emotion have signal value, there is surprisingly little research examining how that signal can be detected under various conditions, because most judgment studies utilize full-face, frontal views. We remedy this by obtaining judgments of frontal and profile views of the same expressions displayed by the same expressors. We predicted that recognition accuracy when viewing faces in profile would be lower than when judging the same faces from the front. Contrarily, there were no differences in recognition accuracy as a function of view, suggesting that emotions are judged equally well regardless of from what angle they are viewed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Local and Global Judgments of Confidence.

Studies of calibration have shown that people's mean confidence in their answers (local confidence) tends to be greater than their overall estimate of the percentage of correct answers (global confidence). Moreover, whereas the former exhibits overconfidence, the latter often exhibits underconfidence. Three studies present evidence that global underconfidence reflects a failure to make an allowance for correct answers that are likely to result from mere guessing and can be eliminated by informing participants of the dubious normative status of estimates below 50% (i.e., chance). Previously reported discrepancies between global and local confidence, it is concluded, arise less from possible methodological artifacts in assessment of local confidence than from normatively inappropriate assessments of global confidence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Judgments of responsibility for activities in close relationships.

Three studies extended M. Ross and F. Sicoly's (see record 1980-23237-001) work on egocentric biases in close relationships. In Study 1 (157 individuals in an ongoing heterosexual relationship), egocentric biases in judging responsibility were evidenced for a number of activities in a relationship, and the percentage of self-instances recalled was related to the responsibility judgment. In Study 2 (56 romantically involved couples), visibility, desirability, and stressfulness of the activity did not contribute to overestimation of responsibility, thus further implicating selective retrieval as a cause of the phenomenon. In Study 3, 54 individual members of ongoing romantic relationships asked what information they had used to make their judgments. Over 90% of the time, typical or dispositional information was reported as the basis of the judgment. Results are discussed in terms of their implications for the causes of egocentric biases and for the process by which individuals make judgments about an ongoing relationship. (7 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Judgments of consensus during group discussion.

6 groups of Ss held discussions during which the individuals' opinions and estimates of the group consensus were privately taken on various issues. "The degree of estimation accuracy achieved was not noticeably different from the accuracy found by other investigators under conditions of no discussion." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Processing of biological motion point-light displays by baboons (Papio papio).

Humans apply complex conceptual judgments to point-light displays (PLDs) representing biological motion (BM), but how animals process this kind of display remains uncertain. Four baboons (Papio papio) were trained to discriminate BM from nonbiological motion PLDs using an operant computerized test system. Transfer tests were given after training with novel BM stimuli representing humans or baboons (Experiment 1), with inverted PLDs (Experiment 2), and with BM stimuli in which body parts had been spatially disorganized (Experiment 3). Very limited transfer was obtained with the novel and inverted displays in Experiments 1 and 2, but transfer was much higher after spatial disorganization in Experiment 3. It is suggested that the baboons did not retrieve and interpret the articulated shape of the human or monkey body from the BM PLD stimuli, but rather focused their attention on the configural properties of subparts of the stimuli. Limits in perceptual grouping and restricted abilities in picture-object equivalence might explain why the baboons did not map BM PLD displays onto what they represent. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatial localization in sequential letter displays.

Conducted 2 experiments with a total of 26 undergraduates to investigate the ability to locate letters presented successively along a horizontal row. The letters were displayed for 5 msec, and the inter-letter interval varied between 0 and 200 msec. In Exp I, localization decreased as the inter-letter interval was increased to 50 msec. With further increments in inter-letter interval, performance improved. However, there was a correlation between the positions of the letters in space and in time. Exp II indicated that the recovery in spatial localization with inter-letter intervals greater than 50 msec is spurious (i.e., it does not occur if the correlation is minimized). (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conceptual masking in brief visual displays.

Examined a paradigm used to study conceptual masking. This paradigm uses a variant of the partial report procedure, wherein a display of characters is preceded or followed by a probe character and Ss must report whether the probe was in the display or not. Ss were 7 undergraduates. Results show that neither specific orienting effects of the probe nor eye movements to the probe character could explain the pattern of data found in earlier studies (V. Di Lollo and M. Moscovitch; see record 1984-14011-001). Data are discussed in the context of P. Dixon's (see record 1986-21077-001) model of performance within this paradigm. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ratings of kinetic depth in multidot displays.

Subjects saw kinetic depth displays whose shape (sphere or cylinder) was defined by luminous dots distributed randomly on the surface or in the volume of the object. Subjects rated perceived 3-D depth, rigidity, and coherence. Despite individual differences, all 3 ratings increased with the number of dots. Dots in the volume yielded ratings equal to or greater than surface dots. Each rating varied with 3 of 4 factors (shape, distribution, numerosity, and perspective), but the ratings either between trials or between conditions were often uncorrelated. Object shape affected rigidity but not depth ratings. Veridically perceived polar displays had slightly lower rigidity but higher depth ratings than parallel projection displays. (Reversed polar displays were always grossly nonrigid.) The interaction of ratings and stimulus parameters requires theories and experiments in which different kinetic depth effect ratings are not treated interchangeably. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Anchoring of lightness values in center-surround displays.

Luminance ratios, by themselves, do not specify lightness values without an anchoring rule. The anchoring rule most often assumed for simple displays is that white is assigned to the highest luminance. It is proposed here that, for simple center–surround stimuli, the rule is based on geometry rather than photometry: White is assigned to the background, regardless of relative luminance values. Both a disk–annulus configuration and a disk–ganzfeld configuration were used to test the perceived lightness of centers and surrounds. In the disk–annulus case, assignment of white was based on a compromise between these 2 rules. For the disk–ganzfeld case, assignment of white seemed to be based entirely on the surround-as-white rule, and disks brighter than the ganzfeld background appeared luminous. It is argued that the disk–ganzfeld configuration, not the disk–annulus configuration, represents the minimal conditions for the appearance of surface lightness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Human information processing in navigational displays.

Studies of abstract picture–sentence verification tasks have shown that people exhibit directional biases in the way they think about spatial orientation; for example, they decide faster about diagrams involving the term "right" than the term "left." The roles of these and other human limitations in processing displays of target and own-ship movements were evaluated with 2 groups (experienced and inexperienced) of 7 submarine officers each. In 2 1-hr sessions, each officer made 192 judgments of computer-generated diagrams repesenting the linear movements of own ship and target ship. The standard picture verification task paradigm was used to measure response times. Direction of motion, right or left, per se did not reliably influence response time, but the S's level of experience, amount of practice at the task, display truth value, stimulus congruity, and stimulus–response compatibility did. The study demonstrates how the effects of factors isolated through basic research can be demonstrated in operationally relevant tasks. Implications for training are discussed. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)