Object individuation and event mapping: developmental changes in infants’ use of featural information

The present research examined the development of 4.5‐ to 7.5‐month‐old infants’ ability to map different‐features occlusion events using a simplified event‐mapping task. In this task, infants saw a different‐features (i.e. egg‐column) event followed by a display containing either one object or two objects. Experiments 1 and 2 assessed infants’ ability to judge whether the egg‐column event was consistent with a subsequent one‐column display. Experiments 3 and 4 examined infants’ ability to judge whether the objects seen in the egg‐column event and those seen in a subsequent display were consistent in their featural composition. At 7.5 and 5.5 months, but not at 4.5 months, the infants successfully mapped the egg‐column event onto the one‐column display. However, the 7.5‐ and 5.5‐month‐olds differed in whether they mapped the featural properties of those objects. Whereas the 7.5‐month‐olds responded as if they expected to see two specific objects, an egg and a column, in the final display the 5.5‐month‐olds responded as if they simply expected to see ‘two objects’. Additional results revealed, however, that when spatiotemporal information specified the presence of two objects, 5.5‐month‐olds succeeded at tagging the objects as being featurally distinct, although they still failed to attach more specific information about what those differences were. Reasons for why the younger infants had difficulty integrating featural information into their object representations were discussed.     

Prosodic structure and syntactic acquisition: the case of the head‐direction parameter

We propose that infants may learn about the relative order of heads and complements in their language before they know many words, on the basis of prosodic information (relative prominence within phonological phrases). We present experimental evidence that 6–12‐week‐old infants can discriminate two languages that differ in their head direction and its prosodic correlate, but have otherwise similar phonological properties (i.e. French and Turkish). This result supports the hypothesis that infants may use this kind of prosodic information to bootstrap their acquisition of word order.     

Effects of chronic administration with high doses of testosterone propionate on behavioral and physiological parameters in mice with differing basal aggressiveness

The effects of testosterone propionate, an anabolic‐androgenic steroid, on the behavior displayed during a social encounter by gonadally intact male mice were investigated. Animals were distributed into three groups according to their attack latency in a pre‐screening test (high‐, moderate‐, and low‐ attacking mice) and each group received weekly injections of 60 or 120 mg/kg of testosterone or sesame oil for 10 weeks. Behavioral tests were then carried out. Afterwards, organs were weighed and blood samples collected in order to obtain hormonal data. Treatment had a differential impact on attack in the three groups of animals. Only the high‐attacking testosterone‐treated mice showed lower total duration of attack than their controls. Those that received 60 mg/kg spent more time exhibiting exploratory behaviors. As an index of the anabolic activity of the drug, all testosterone‐treated mice had heavier kidneys and, as an index of the androgenic activity of testosterone propionate, they had heavier seminal vesicles, lighter testes, and showed higher testosterone levels in a dose‐dependent way than their controls. Hence, the effect of treatment on peripheral physiological parameters was similar in all three groups whereas behavioral effects differed depending on basal aggressiveness, considered a characteristic of coping style. Aggr. Behav. 29:173–189, 2003. © 2003 Wiley‐Liss, Inc.     

The Distillation of “VISCI”: Towards a Better Identification of Suicidal Inmates

The “Viennese Instrument for Suicidality in Correctional Institutions” (VISCI) presented here is based on the results of a large case‐control study and on research on literature examining suicide prevention in general and in the prison population in particular. The aim of this study was to validate the properties of the VISCI to differentiate between suicides and nonsuicides. The sensitivity and specificity of the VISCI was tested in the files of 55 correctional suicides, and 110 controls. VISCI differentiated well between suicides and nonsuicides. The routine administration of the VISCI may help to direct the existing professional attention to inmates with the highest need.     

Localization of a peripheral target during parametric adjustment of saccadic eye movements

The aim of the experiment was to find out whether saccadiceve movements have any effect on perceived visual directions. ihe method was to alter the parameters of the oculomotor system so that the eye movement made in response to a peripheral target was inappropriate to the retinal locus of its image. It was found that this procedure had no effect on the perceived location of the peripheral target; and it was concluded that a specific retinal locus is more or less rigidly associated with a corresponding visual direction, but not with a particular magnitude of ocular rotation.