Trajectory forms as a source of information about events

The ability to use trajectory forms as visual information about events was tested. A trajectory form is defined as the variation in velocity along a path of motion. In Experiment 1, we tested the ability to detect trajectory form differences between simulations of a freely swinging pendulum and a hand-moved pendulum. The trajectory form of the freely swinging pendulum was symmetric around the mid-point, whereas the hand moved was not. In Experiment 2, we isolated trajectory form information by varying the amplitudes of events while holding their periods constant. Straight path versions of the harmonic events from Experiment 1 were tested. In Experiment 3, we tested sensitivity to symmetrical peakening or flattening of trajectory forms. Participants detected small differences in all three experiments. In Experiment 4, we tested the ability to identify specific events based only on differences in trajectory forms. Participants were able to identify four different events. We investigated properties of trajectory forms that might potentially be detected and used as information, and we found that the curvature yielded good results.     

Family or friends: who plays a greater supportive role for Latino college students?

This study compared the relative contribution of perceived family and friend support to psychological well-being and distress and examined whether family or friend support moderated the effects of stress on psychological adjustment in 338 Latino (228 Mexican American, 110 Central American) college students from a predominantly Latino university. Two multiple regressions, controlling for gender, socioeconomic level, acculturation level, and stresses (generic college, acculturative, and minority status), showed that friend support made a slightly greater contribution to well-being than family support, and friend support and not family support protected against psychological distress. Neither family nor friend support moderated the effects of stress on psychological adjustment. Further examination of these variables that assess common-specific stresses within a culture-specific theoretical framework is recommended.     

Calibrating reach distance to visual targets

The authors investigated the calibration of reach distance by gradually distorting the haptic feedback obtained when participants grasped visible target objects. The authors found that the modified relationship between visually specified distance and reach distance could be captured by a straight-line mapping function. Thus, the relation could be described using 2 parameters: bias and slope. The authors investigated whether calibration generalized across reach space with respect to changes in bias and slope. In Experiment 1, the authors showed that both bias and slope recalibrate. In Experiment 2, they tested the symmetries of reach space with respect to changes in bias. They discovered that reach space is asymmetric, with the bias shifting inward more readily than outward. The authors measured how rapidly the system calibrated and the stability of calibration once feedback was removed. In Experiment 3, they showed that bias and slope can be calibrated independently of one another. In Experiment 4, the authors showed that these calibration effects are not cognitively penetrable.     

Developmental change in identifying main ideas in picture stories

Although young children frequently have more difficulty in correctly identifying main ideas than do older children and adults, the reasons underlying this difference in performance have usually not been investigated. The present study was designed to formulate a task involving both the form and content of good main ideas, so that the development of skills used in their identification could be examined in greater detail. Four categories of main idea statements were developed from a joint theory combining research on story grammar kernels with research on summarization rules. These categories were then applied to a series of simple narratives from the WISC-R picture arrangement task. College students (Experiment 1) and 2nd, 5th, and 8th grade students (Experiment 2) examined the narratives and rank ordered the four alternatives for each story. It was found that adults confirmed the predicted ordering of the alternatives and that, with age, children improved in their identification of the best main idea statement, and developed in their ability to distinguish both between important and unimportant story elements and between superordinate and subordinate types of statements.     

On Paulo Freire's Debt to Psychoanalysis: Authority on the Side of Freedom

Paulo Freire's major work, Pedagogy of the Oppressed, owes adebt to psychoanalysis. In particular, as this paper argues,Freire's account of teacher authority needs to be understoodthrough psychoanalytic sensibilities. Paulo Freire maintains thatteacher authority can be ``on the side of freedom.' This is ahighly charged claim given that liberalist traditions generallycast authority as the enemy of freedom. Breaking with liberalunderstandings of authority, Freire's ``authority on the sideof freedom' is a matter of maintaining the delicate psychicbalance that leads neither to domination nor to submission.This paper investigates how such an authoritative balance functions.     

Large continuous perspective transformations are necessary and sufficient for accurate perception of metric shape

We investigated the ability to perceive the metric shape of elliptical cylinders. A large number of previous studies have shown that small perspective variations (< or =10 degrees) afforded by stereovision and by head movements fail to allow accurate perception of metric shape. If space perception is affine (Koenderink & van Doom, 1991), observers are unable to compare or relate lengths in depth to frontoparallel lengths (i.e., widths). Frontoparallel lengths can be perceived correctly, whereas lengths in depth generally are not. We measured reaches to evaluate shape perception and investigated whether larger perspective variations would allow accurate perception of shape. In Experiment 1, we replicated previous results showing poor perception with small perspective variations. In Experiment 2, we found that a 90 degrees continuous change in perspective, which swapped depth and width, allowed accurate perception of the depth/width aspect ratio. In Experiment 3, we found that discrete views differing by 90 degrees were insufficient to allow accurate perception of metric shape and that perception of a continuous perspective change was required. In Experiment 4, we investigated continuous perspective changes of 30 degrees, 45 degrees, 60 degrees, and 90 degrees and discovered that a 45 degrees change or greater allowed accurate perception of the aspect ratio and that less than this did not. In conclusion, we found that perception of metric shape is possible with continuous perspective transformations somewhat larger than those investigated in the substantial number of previous studies.     

Derrida on teaching: The economy of erasure

This article explores Derrida's claim that teaching is a deconstructive process. In order to explore this claim, the Derridean concept of "erasure" is explored. Using the concept of erasure, this article examines two important aspects of teaching: the name that teachers establish for themselves, and, teaching against social power from a Derridean (erasure-oriented) perspective. Ultimately, the paper confirms Derrida's claim that teaching is indeed a deconstructive practice.

Development of the Multidimensional Acculturative Stress Inventory for adults of Mexican origin

The Multidimensional Acculturative Stress Inventory (MASI), a 36-item stress measure that was developed to assess acculturative stress among persons of Mexican origin living in the United States, was tested on a community sample of 174 adults (117 women, 57 men). Principal-components analyses yielded 4 stable and internally consistent factors: Spanish Competency Pressures (7 items), English Competency Pressures (7 items), Pressure to Acculturate (7 items), and Pressure Against Acculturation (4 items). These 4 factors accounted for 64.4% of the variance and correlated in the expected directions with criterion measures of acculturation and/or psychological adjustment. Further reliability and validity testing of the MASI is discussed as well as the utility of this measure in assessing acculturative stress among adults of Mexican origin.