Edwin J. Kay

PRISM interaction for enhancing control in immersive virtual environments

When directly manipulating 3D objects in an immersive environment we cannot normally achieve the accuracy and control that we have in the real world. This reduced accuracy stems from hand instability. We present PRISM, which dynamically adjusts the C/D ratio between the hand and the controlled object to provide increased control when moving slowly and direct, unconstrained interaction when moving rapidly. We describe PRISM object translation and rotation and present user studies demonstrating their effectiveness. In addition, we describe a PRISM-enhanced version of ray casting which is shown to increase the speed and accuracy of object selection.

The generality of learned helplessness in the rat

Abstract Two experiments were simultaneously conducted in which two different groups of 40 rats each were exposed to one of two different stressors. In both experiments half the subjects were pretreated with shock, half with underwater exposure. For each pretreatment stressor, half the subjects were allowed to escape, the other half were not. The experiments differed in the test task used. Approximately 24 hr after pretreatment, one-half the subjects from each pretreatment group received 20 water-escape trials in an underwater maze, the other half received 20 shock-escape trials in a two-way shuttle box. The subjects in each of the inescapable pretreatment conditions were slower to escape in the subsequent shock-escape and water-escape tasks when compared with subjects in the corresponding escapable pretreatment condition. The “learned helplessness” effect appeared to be no smaller when aversive stimuli were changed between pretreatment and test than when they remained the same.

External Sources of Individual Differences? A Cross-Linguistic Analysis of the Phonetics of Mothers' Speech to 1-Year-Old Children.

Wide individual differences in early word production characterize children learning the same language, but the role of specific adult input in this interchild variability is unknown. Sampling the speech of American, French, and Swedish mothers (5 in each language group) to their 1-year-old children, this study analyzed the distribution of consonantal categories, word length, and final consonants in running speech, content words, initial consonant of content words, and target words (adult models of words attempted by the children) as well as the childrens own early words (from age 9 months to about 18 months). Variability is greater in child words than adult speech, and individual mother-child dyads show no evidence of specific maternal influence on the phonetics of the childs speech

Pronounceability and the Visual Recognition of Nonsense Words.

Additional evidence is presented for the hypothesis that visual word recognition may involve recording into phonemic form. Specifically, the hypothesis that less pronounceable nonsense words are recognized as nonsense faster than more pronounceable nonsense words was confirmed. It is proposed that differences in pronounceability produce their effects during the sequencing of the neural instructions associated with each phoneme.

LiCl aversive conditioning has transitory effects on pheromonal responsiveness in male house mice (Mus domesticus)

Appetitive and aversive experiences influence whether odors elicit precopulatory behavior from male rodents. A role for aversive experience in odor-elicited reproductive behaviors had been demonstrated for hamsters and rats, but similar work on house mice had not been performed. Four experiments examined whether lithium chloride (LiCl) aversive conditioning would alter two precopulatory behaviors (ultrasonic vocalizations and olfactory preference) that male house mice normally exhibit to female urine. Lithium chloride was used to aversively condition male house mice to either female urine odor, female urine in drinking water, the female herself, or a novel odor. Independent tests of taste aversion establishment were also conducted. In these experiments, LiCl aversive conditioning produced robust taste aversions to water adulterated with either female urine or a novel odorant/tastant (isoamylacetate), but only transitory decrements in odor-elicited, male-typical precopulatory behaviors. We conclude that aversive conditioning is unlikely to be a significant factor affecting male mouse precopulatory behavior.

Aversive effects of repeated injections of THC in rats.

Exposure of rats to a novel substance (.1% sodium saccharin) was paired with 0, .25, .5, 1.0, 2.0, and 4.0 mg/kg of Δ9-THC (tetrahydrocannabinol) for 1, 6 or 12 days. In a subsequent test, all groups showed a decreased preference for saccharin as the dosage of THC was increased. The results indicated that THC is aversive in multiple as well as single injections.

Lithium chloride and delta-9-THC lead to conditioned aversions in the pigeon

Conditioned aversive effects of Δ9-tetrahy-drocannabinol (THC) and lithium chloride (LiCl) were demonstrated in pigeons. Pigeons injected with 0.15 M LiCl showed a reduction in preference for red water compared to pigeons injected with NaCl (P<0.001). Pigeons injected with saline or vehicle showed the same preference for red water while the pigeons injected with 2.0 mg/kg of THC showed a decreased preference (P<0.05).

The Category-Confound: A Design Error

Summary An experimental design problem, found to be frequent in some of the social psychology literature, occurs when only one sample from a population of possible samples is used to define a category of treatment factors. An example would be using one man and one woman as Es to test the effect of sex of E. This error, called the category-confound, leads to an inability to generalize treatment effects beyond the particular sample chosen, and to an inability to perform the appropriate significance tests. Several examples are discussed in detail, and the frequency of occurrence of this error in two recent journals in social psychology are surveyed. In most cases the category-confound can be dispelled simply by taking an adequately large sample from the population.

The roles of expectancy and aftereffects in alternation

Abstract In each of three experiments rats were pretreated in straight alleys to discriminate the brightness of an alley as signal for the magnitude of reward. Then the rats were tested in E-shaped mazes in which reward varied across trials and in which the brightness of the stem signaled the magnitude of reward. In all three experiments the rats alternated more on trials following a small reward on the previous trial, and in the third experiment the rats alternated more on those trials where a small reward was signaled. Rats choice responses on Trial n were also affected by the stimulus/reward and choice on Trial n − 2 and by the relationship between stimuli/rewards on Trials n − 2 and n . These results were interpreted as a tendency by the rat to change a less satisfactory situation by varying its response, and to retain a more satisfactory situation by perseverating in its choice response.

Treating rolling vs. sliding friction by the wave model

Abstract Modeling and simulation of friction resistance to sliding and rolling motions between a cylinder and a flat surface are presented. The power consumed by the relative motion is derived using the upper-bound method. The power for sliding and the power for rolling are compared. Rolling can be imparted by applying either a pushing force or a moment. The power consumed by rolling in those two cases are compared.