Coordination and timing of spine and hip joints during full body reaching tasks

Coupling of spine and hip joints during full body reaching tasks was investigated in 16 participants (8 male and 8 female) who performed reaching tasks at comfortable and fast-paced movement speeds to three targets located in a para-sagittal plane. The participants paused at target contact for 500ms and then returned to an upright posture. Three-dimensional joint motions of the spine and hip were recorded using an electromagnetic tracking device. We found an effect of movement phase (i.e., reach and return) on the onset timing of the spine and hip joints. For most target locations and movement speeds, spine motion onset preceded hip motion onset during the reaching phase of the movement task. In the reach phase, when averaged across all movement conditions, spine joint motion preceded hip joint motion by an average of 48.9ms. In contrast, in the return phase, hip joint motion preceded spine joint motion by an average of 63.0ms. Additionally, when participants were instructed to use either a knee flexion or knee extension strategy to perform the reaching tasks there was no effect of movement strategy on timing of the spine and hip. There was also no effect of target height on the spine-hip ratio, but as movement speed increased, the spine/hip ratio decreased for all target locations due primarily to an increase in hip joint excursion. The findings indicate clear differences in onset timing of the spine and hip joints during reaching tasks that necessitate some forward bending of the trunk and that onset timing is reversed for the return to an upright posture.     

Rats (Rattus norvegicus) encode the shape of an array of discrete objects

To navigate efficiently, a traveler must establish a heading using a frame of reference. A large body of evidence has indicated that humans and a variety of nonhuman animals utilize the geometry, or shape, of enclosed spaces as a frame of reference to determine their heading. An important and yet unresolved question is whether shape information from arrays of discrete objects and enclosed environments are represented, and utilized, in the same way. In the present study, rats were presented with a reference memory task in which they had to find water that was hidden in 1 of 4 discrete and unique objects placed at the vertices of a rectangle. The results indicate that rats could utilize both feature and geometry cues to locate the hidden goal. The rats' performance declined during transformation tests using a triangular array, indicating that the rats may have encoded the primary axis of the object array, rather than local cues, to direct their search.     

Symbolic control of visual attention: Semantic constraints on the spatial distribution of attention

Humans routinely use spatial language to control the spatial distribution of attention. In so doing, spatial information may be communicated from one individual to another across opposing frames of reference, which in turn can lead to inconsistent mappings between symbols and directions (or locations). These inconsistencies may have important implications for the symbolic control of attention because they can be translated into differences in cue validity, a manipulation that is known to influence the focus of attention. This differential validity hypothesis was tested in Experiment 1 by comparing spatial word cues that were predicted to have high learned spatial validity (“above/below”) and low learned spatial validity (“left/right”). Consistent with this prediction, when two measures of selective attention were used, the results indicated that attention was less focused in response to “left/right” cues than in response to “above/below” cues, even when the actual validity of each of the cues was equal. In addition, Experiment 2 predicted that spatial words such as “left/right” would have lower spatial validity than would other directional symbols that specify direction along the horizontal axis, such as “←/→” cues. The results were also consistent with this hypothesis. Altogether, the present findings demonstrate important semantic-based constraints on the spatial distribution of attention.     

The role of individual differences in sandbagging on selective avoidance of self-evaluative information

In the current experiment (N = 86), I evaluated the hypothesis that high and low sandbaggers differ in their preference for self-evaluative information. Results demonstrate that low sandbaggers sought accurate self-assessment information in private and in public, but high sandbaggers bypassed such information when it would be made public. These data support the notion that high sandbaggers are self-protective and tend to focus on social evaluation, while low sandbaggers seek accurate self-assessment regardless of the potential for social evaluation. Furthermore, data help to distinguish between sandbagging and self-handicapping. Discussion focuses on the motivation of sandbaggers, along with how this motivation differs from that of self-handicappers.     

Pigeons and people select efficient routes when solving a one-way "traveling salesperson" task

The authors presented people (Experiment 1) and pigeons (Experiments 2 and 3) with a large number of 1-way traveling salesperson problems that consisted of 3, 4, and 5 identical stimuli (nodes) on a computer monitor. The sequence of nodes that each traveler selected was recorded, and the distance of the route was subsequently determined. The routes the pigeons and people selected were reliably more efficient than those used by a Monte Carlo model given the same problems. The pigeons' routes were significantly less efficient than a nearest neighbor model of performance, however. In Experiment 3, pigeons were required to select a route that was within the top 33% of all possible solutions for a given problem. The pigeons' solutions were significantly more efficient than those observed in Experiment 2, in which the behavioral criterion was not imposed. The mechanisms that pigeons and people may have been using to solve the traveling salesperson problems are discussed.     

Effects of Fluprazine Hydrochloride on Three Aversively Motivated Tasks

The Psychological Record - Treatment with 8.0 mg/kg fluprazine hydrochloride had no effect on the acquisition of a step-down avoidance response but retarded its extinction. The drug also impaired...     

When celebrities talk,children listen: An experimental analysis of children's responses to TV ads with celebrity endorsement

Two studies tested the effects of TV ads with celebrity endorsement on the product preference and understanding of 8- to 14-year-old boys. Study 1 compared two ads for a model racer. One had celebrity endorsement (by a famous race driver) and footage of real automobile racing featuring the celebrity (live action); the second had neither feature. Study 2 employed one ad for a different brand of model racer edited to generate a 2 (endorser presence) by 2 (inclusion of live racetrack action) factorial design. A total of 415 boys were exposed to one of the experimental ads or a control ad, embedded in a new animated children's adventure program. Preference for the advertised brand of model racer (pre- and postviewing) and a number of cognitive variables were assessed. Exposure to endorsement led to increased preference for the toy and belief that the celebrity was expert about the toy. Live action led to exaggerated estimates of the physical properties of the toy and the belief that the ad was not staged. The 8- to 10-year-olds associated the glamour of the endorser with the toy and were more reliant on his advice than were 11- to 14-year-olds. However, the two age groups were not differentially affected by the ads. Contrary to the speculation of many researchers, understanding about advertising intent and techniques and cynicism about ads had almost no influence on product preference after viewing.     

False physiological feedback and emotion: Experimenter demand and salience effects

Four experiments examined the hypothesis that the Valins (1966) false physiological feedback effect with attractiveness ratings of slides is due to experimenter demand. Experiments 1 and 2 showed significant feedback effects with 5-sec feedback periods, previously reported by Barefoot and Straub (1971) to be too brief a time to search the slides for a cause of the apparent physiological arousal. Experiments 3 and 4 had 17 variations of instructions (emotional, nonemotional), stimuli (slides of people, scenic tourist slides), and type of feedback information (heart rate, eyeblink, or none). The typical false feedback effect was found under many conditions that did not seem to meet the presumptive attributional requirements for the effect. In Experiment 4, only subjects who said they were supposed to rate feedback slides higher showed the effect, regardless of instructions, stimuli, or type of feedback. The overall results are interpreted in terms of experimenter demand and stimulus salience effects.     

Bilateral transfer in mentally retarded children of ages 7 to 17 years

The purpose of this study was to describe the effect of age on bilateral transfer of mildly mentally retarded girls (IQs of 70 to 90) after practice on a 45-rpm rotary pursuit task. Subjects were 96 girls from 7 to 17 yr. old. Each performed 14 trials on a rotary pursuit task (30-sec. trials, 10 sec. between trials), half performing the first seven trials with the nonpreferred hand, using the preferred hand on the next seven trials. The order was reversed for the remaining subjects. Nonsignificant differences between Trial 1 scores of the two groups indicated that the task was novel. Trial 1 scores of both groups were positively associated with age (r = 0.5). There was no transfer to preferred hand, with negative transfer occurring to the nonpreferred hand. It was concluded that, for the task used in this study, mentally retarded girls do not experience positive bilateral transfer as do normal, age-matched girls.     

Differences in matching-to-sample performance with element and compound sample stimuli in pigeons

This series of experiments examined zero-delay matching-to-sample performance in pigeons with element and compound sample stimuli. In Experiment 1, compound sample stimuli were consistently followed by compound comparison stimuli and matching accuracy during testing was equivalent to element sample-element comparison trials on the color dimension. In Experiment 2, element comparisons suddenly introduced following compound samples produced a decrement on the line dimension only. Subsequent testing at various sample durations revealed higher matching accuracy following element samples than following compound samples on both the color and line-tilt dimensions. Experiment 3 replicated the results of Experiments 1 and 2 and also demonstrated that the superiority of element over compound matching performance remains constant over the sample durations tested. In Experiment 4 testing at sample durations up to 30 sec produced an overall decrement in matching performance, but again the element vs compound matching difference remained constant. The stimulus-generalization decrement hypothesis provided a better explanation of these results than either the information-overload hypothesis or the rule hypothesis.