Wobble cones and wobble holes: the stereokinetic effect revisited

It is well-known that patterns of eccentric circles when slowly rotated give rise to compelling three-dimensional impressions of cones or conical holes which can 'wobble' as the pattern rotates. The wobble can be considered as part of the overall phenomenon of depth elicited from a rotating display, the 'stereokinetic' effect (SKE). This paper considers the three-dimensional appearance as being the result of the sliding of contours and thus it imitates the motion parallax found in real three-dimensional objects in motion. New variants of SK figures are used to examine these points. An analogy with computer programs is proposed which questions earlier views on the location of perceptual invariance.     

Depression in aphasic patients: Frequency, severity, and clinical-pathological correlations

Twenty-five hospitalized nonfluent, fluent, and global aphasic patients who were several months past the onset of their illness were compared for presence and severity of depression based on four psychopathological measures. The nonfluent aphasic patients had both greater frequency and severity of depression than the other two groups. CT scans showed that the global aphasic patients had the largest lesion size (volumetric) and showed a strong correlation between lesion size and degree of depression. In contrast, patients with fluent aphasias showed an inverse correlation between severity of depression and lesion size; among the nonfluent aphasic patients there was no significant correlation. Depression appears to be common in this population of hospitalized aphasic patients with chronic illness and nonfluent patients are the most depressed group within this population. The increased frequency and severity of depression in the nonfluent patients did not appear to be related to their overall physical or cognitive impairment; two possible mechanisms are discussed.     

Mellor and Dennett on the Perception of Temporal Order

I discuss theories about the way in which we determine the precedence ofperceived events. I examine Mellor's account, which claims that it is thetiming of our perceptions of events that enables us to determine their order,and Dennett's criticism of this. Dennett cites psychological experimentswhich suggest that it is the content of our perceptions, rather than theirtiming, which allows us to determine the order of the events perceived. Iargue that by distinguishing between two different ways of construing'perception' we can see not only that the two accounts are compatible, but that Dennett's account presupposes Mellor's.     

The effect of memory load on negative priming: An individual differences investigation

The effect of a verbal (Experiment 1) and a nonverbal (Experiment 2) memory load on negative priming was investigated by employing a concurrent memory task with a letter naming task. Across both experiments, negative priming was reliable only under conditions of zero memory load, suggesting that the processes that contribute to negative priming are resource demanding and dependent on a domain-free resource pool. Individual differences in negative priming were observed, such that high working memory capacity subjects showed reliable negative priming whereas low working memory capacity subjects did not. The results suggest that the negative priming effect results from allocation of controlled attention and that individual differences in working memory capacity correspond to the ability to efficiently handle irrelevant information.     

The effect of prior experience on recognition thresholds for plane-disoriented pictures of familiar objects

We investigated plane rotation effects on the minimum presentation duration that is required in order to recognize pictures of familiar objects, using the method of ascending limits. Subjects made unspeeded verification responses, selecting from 126 written alternatives. Replicating similar identification studies in which brief, masked pictures (Lawson & Jolicoeur, 1998) were presented, disorientation reduced the efficiency of recognition. Mirroring the findings in speeded picture naming studies (e.g., Jolicoeur, 1985; Jolicoeur & Milliken, 1989), but in contrast to those of Lawson and Jolicoeur (1998), orientation effects were found over a wide range of views and were attenuated but not eliminated with experience with a given object. The results bridge the findings from unspeeded verification and speeded naming tasks. They suggest that the same orientation-sensitive processes are tapped in both cases, and that practice effects on these processes are object specific.     

The Intersections of Dominant Discourses Across Race,Gender, and Other Identities

A discussion of dominant discourses across race, gender, and other identities is provided, especially in terms of consequences. Distinctions are made between consequences of social constructions and identity. An example of a counselor working with a client is provided to illustrate several points made by the author.     

Children's ability to infer utterance veracity from speaker informedness

Children between the ages of 3 years 7 months and 6 years 5 months experienced a contradiction between what they knew or guessed to be inside a box and what they were told by an adult. The authors investigated whether children believed what they were told by asking them to make a final judgment about the box's content. Children tended to believe utterances from speakers who were better informed than they themselves were and to disbelieve those from less well-informed speakers, with no age-related differences. This behavior implies an understanding of the speaker's knowledge and suggests that children can learn from oral input while being appropriately skeptical of its truth. Children also gave explicit knowledge judgments on trials on which no utterances were given. Performance on knowledge trials was less accurate than, and unrelated to, performance on utterance trials. Research on children's developing explicit theory of mind needs to be broadened to include behavioral indexes of understanding the mind.     

Evaluating FACES III and the Circumplex Model: 2,440 families

Previous evaluations of the Circumplex Model's curvilinear hypothesis using FACES instruments have yielded conflicting results. A review of the different research procedures and samples used in those investigations revealed that none of the studies had samples large and/or heterogenous enough to test the curvilinear hypothesis adequately. The present study evaluates the curvilinear hypothesis of family functioning and the concurrent validity of FACES III with a sample of optimal size (N = 2,440 families) and diversity. The lack of support for the curvilinear hypothesis in this "greenhouse" sample is explained by different findings for the two FACES III subscales. There was no relationship between the study's measures of well-being and the adaptability subscale and a linear relationship between these measures and the cohesion subscale. Implications of these findings for the continuing use of the FACES III and for the Circumplex Model of Marital and Family Systems are discussed.     

Visual control of locomotion: strategies for changing direction and for going over obstacles.

Dynamics of gait adjustments required to go over obstacles and to alter direction of locomotion when cued visually were assessed through the measurement of ground reaction forces, muscle activity, and kinematics. The time of appearance of obstacles of varying heights, their position within the step cycle, and cue lights for direction change were varied. Direction change must be planned in the previous step to reduce the acceleration of the body center of mass toward the landing foot to 0. The inability of steering within the step cycle is due to the incapacity of muscles to rotate the body and translate it along the mediolateral axes. For obstacle avoidance, Ss systematically manipulated the gait patterns as a function of obstacle height and position and the time available within the ongoing step. Greater supraspinal involvement in control of locomotion is found.