Body size as a determinant of aggression during heterosexual encounters in hormone-treated gonadectomized pigs

Aggressive and sexual behavior was studied in 5-minute paired encounters between testosterone-treated castrated boars and estrogen-treated ovariectomized gilts. The boars were either 15 kg heavier (N = 6), or lighter (N = 6), than the gilts (N = 8). Tests were carried out over a 4-week period, during which time each boar was paired once with each gilt; the procedure was replicated over a further 4 weeks. Gilts usually initiated the aggression, especially in the first 4-week period; however, the degree of aggression was positively correlated with body size, irrespective of sex. Aggression was reduced in the second 4-week period in both sexes in tests with large, but not with small, boars. Large boars were more sexually active than small boars, and their sexual performance improved markedly with time, unlike that of the small boars. Champing was positively correlated with aggression duration in pigs of both sexes, and salivation was seen more often in boars than gilts.     

Aggression during sexual encounters between hormone-treated gonadectomized pigs in the presence or absence of boar pheromones

Aggressive and sexual behaviour was studied in 5-min paired encounters between castrated prepubertal boars (N = 14) and normal (N = 2) or bulbectomized (N = 2) oestrogen-treated ovariectomized gilts. The boars were made sexually active by treatment with 17β-oestradiol + 5α-dihydrotestosterone. Half of the boars were sprayed on the snout with a solution containing a mixture of the boar pheromones 3α-androstenol and 5α-androstenone immediately before testing, and the remainder were treated with the vehicle solution. Aggression was almost always initiated by the gilts, and neither bulbectomy nor pheromone treatment of the boars reduced its occurrence. The results suggest that the display of aggression by gilts towards boars of similar body size is unlikely to be suppressed by the steroidal pheromones present in boar saliva.     

Object names and object functions serve as cues to categories for infants

Can object names and functions act as cues to categories for infants? In Study 1, 14- and 18-month-old infants were shown novel category exemplars along with a function, a name, or no cues. Infants were then asked to "find another one," choosing between 2 novel objects (1 from the familiar category and the other not). Infants at both ages were more likely to select the category match in the function than in the no-cue condition. However, only at 18 months did naming the objects enhance categorization. Study 2 shows that names can facilitate categorization for 14-month-olds as well when a hint regarding the core meaning of the objects (the function of a single familiarization object) is provided.     

Perception of the symmetrical patterning of human gait by infants

Two experiments tested 3- and 5-month-old infants' sensitivity to properties of point-light displays of human gait. In Experiment 1, infants were tested for discrimination of point-light displays of a walker and a runner, which, although they differed in many ways, were equivalent with regard to the phasing of limb movements. Results revealed that 3-month-old, but not 5-month-old, infants discriminated these displays. In Experiment 2, the symmetrical phase-patterning of the runner display was perturbed by advancing two of its limbs by 25% of the gait cycle. Both 3- and 5-month-old infants discriminated the walker display from this new phase-shifted runner display. These findings suggest that 3-month-old infants respond to the absolute and relative motions within a single limb, whereas 5-month-old infants respond primarily to the relations between limbs and, in particular, to the bilateral symmetry between the limbs.     

Ranking of stimuli that evoked memories in significant others after exposure to circumcerebral magnetic fields: correlations with ambient geomagnetic activity

To identify means to enhance the laboratory production of alleged paranormal phenomena, 15 pairs of men and women involved emotionally were tested by male and female experimenters who were not familiar with the hypothesis that ambient (geomagnetic) activity could modulate this production. While the female of the pair was exposed to six different patterns of complex magnetic fields designed to affect states of consciousness, the male wrote his reminiscences about shared experiences evoked by a postcard randomly selected from a collection of five. Increased global geomagnetic activity (k values between 0 and 5) at the time of the experiments was significantly and moderately correlated with the more accurate ranking of the stimulus cards. These results were similar to those of a previous study. We suggest that alleged paranormal phenomena involve processes that might be produced by experimentally altering the electroencephalographic correlates of consciousness with circumcerebral applications of counterclockwise weak magnetic fields. However, these processes may be enhanced if global geomagnetic activity is increasing during the periods of exposure.     

Constraints have different concurrent effects and aftereffects on variability

Three experiments showed that constraints imposed early in learning have different effects on variability when they are in effect and after they are removed. Task constraints, which determine how something can be done, limited the number of possible responses in a computer game. Variability constraints, which specify how differently something must be done, required that each response differ from some number of prior responses. Less restrictive constraints (Experiments 1 and 2) produced higher variability during the constraints. More restrictive constraints (Experiments 2 and 3) led to higher variability after the constraints were relaxed. The authors discuss how these differences reflect strategies acquired during the constraints (default rules) and modified in closely related ways (exception rules) afterward.     

Lateralization of narrow-band noise by blind and sighted listeners

The effects of varying interaural time delay (ITD) and interaural intensity difference (IID) were measured in normal-hearing sighted and congenitally blind subjects as a function of eleven frequencies and at sound pressure levels of 70 and 90 dB, and at a sensation level of 25 dB (sensation level refers to the pressure level of the sound above its threshold for the individual subject). Using an 'acoustic' pointing paradigm, the subject varied the IID of a 500 Hz narrow-band (100 Hz) noise (the 'pointer') to coincide with the apparent lateral position of a 'target' ITD stimulus. ITDs of 0, +/-200, and +/-400 micros were obtained through total waveform delays of narrow-band noise, including envelope and fine structure. For both groups, the results of this experiment confirm the traditional view of binaural hearing for like stimuli: non-zero ITDs produce little perceived lateral displacement away from 0 IID at frequencies above 1250 Hz. To the extent that greater magnitude of lateralization for a given ITD, presentation level, and center frequency can be equated with superior localization abilities, blind listeners appear at least comparable and even somewhat better than sighted subjects, especially when attending to signals in the periphery. The present findings suggest that blind listeners are fully able to utilize the cues for spatial hearing, and that vision is not a mandatory prerequisite for the calibration of human spatial hearing.     

Change in cognitive functioning associated with apoE genotype in a community sample of older adults

The influence of a genetic risk factor, apolipoprotein E (apoE) epsilon4 variant, was assessed in older adults aged 70 to 94 on 3 occasions over 7 years. The results of latent growth curve analyses are reported for individuals genotyped for apoE at the 2nd measurement occasion (n = 601) and for a subsample of individuals without probable or definite dementia during the 1st or 2nd occasion (n = 434). ApoE-epsilon4 status was a significant predictor of level and change in memory performance and change in speed performance in the full sample, and of initial level and change in memory performance in the nondemented subsample. These results support previous findings that apoE-epsilon4 is associated with accelerated memory deterioration in individuals without clinical dementia.     

Employment of persons with disabilities in information technology jobs: literature review for "IT works"

This article reviews relevant literature as to the labor pool of qualified individuals with disabilities and employment in information technology (IT) sector jobs. First, the article reviews the empirical literature on barriers to employment in IT for persons with disabilities. The examination then is extended to studies of barriers to employment for individuals with disabilities in other employment sectors. Findings illustrate the limited experiences that IT and non-IT companies have in employing and accommodating employees with disabilities. Implications are discussed for enhancing the employment of qualified workers with disabilities in IT through research, education, training, and mentoring programs.