Social influences on parental and nonparental responses toward pups in virgin female prairie voles (Microtus ochrogaster)

Pair-bonded prairie voles (Microtus ochrogaster) are biparental after the birth of pups. However, whereas most adult virgin males are parental, most virgin females are not. In 6 experiments, influences on the parental behavior of virgin female prairie voles were examined. It was found that (a) young virgin females were more maternal than older females, (b) the postweaning sex ratio of cage-mates did not affect females' responses to pups, (c) females raised to adulthood with their parents and younger siblings present were highly parental, (d) 48-hr exposure to pups beginning at weaning increased some aspects of later maternal responding, (e) rearing to adulthood with the parents even in the absence of younger siblings also increased females' maternal responding, and (f) the increase was seen only if both parents were present. Continued parental presence promotes alloparental behavior, possibly important if daughters do not disperse from the natal nest.     

Acquired ‘theory of mind'' impairments following stroke

The ability to attribute thoughts and feelings to self and others (‘theory of mind') has been hypothesised to have an innate neural basis and a dedicated cognitive mechanism. Evidence in favour of this proposal has come from autism; a brain-based developmental disorder which appears to be characterised by impaired theory of mind, despite sometimes good general reasoning skills/IQ. To date no case of specific acquired theory of mind impairment has been reported. The present study examined theory of mind in adults who had suffered right hemisphere stroke, a group known to show pragmatic and social difficulties. In one study using story materials and two using cartoons, patients' understanding of materials requiring attribution of mental states (e.g. ignorance, false belief) was significantly worse than their understanding of non-mental control materials. Data from healthy elderly subjects, and a small group of left hemisphere patients (who received the tasks in modified form), suggest that this impairment on mental state tasks is not a function of task difficulty. The findings support the notion of a dedicated cognitive system for theory of mind, and suggest a role for the healthy right hemisphere in the attribution of mental states.     

Effects of the Novel Acetylcholinesterase InhibitorN-Octyl-1,2,3,4-tetrahydro-9-aminoacridine on Locomotor Activity and Avoidance Learning in Mice

The acetylcholinesterase reversible inhibitorN-octyl-1,2,3,4-tetrahydro-9-aminoacridine (THA-C8) is a new synthesized derivative of tacrine (THA) characterized by an alkyl chain in the molecular structure which ameliorates the penetrability of the compound into the central nervous system. THA-C8 (0.1–5 mg/kg) significantly reduced spontaneous locomotor activity in CD1 mice at a dose of 3 mg/kg. Moreover, THA-C8 (0.2–2 mg/kg) significantly improved shuttle-box avoidance acquisition at doses (0.25, 0.3, 1 mg/kg) not affecting locomotion and that are much lower than the doses reported to be effective for THA in animal models. From the data reported it seems that the new compound could be interesting for therapeutic purposes.     

The gap effect in newborns

In four experiments we investigated the gap effect in infants within the first 3 days of life. Reaction times (RTs) to make a saccade to a peripheral target were measured on gap trials, in which the central fixation stimulus went off 500 ms before target presentation, and on overlap trials, in which the central fixation stimulus remained on. In every experiment the fixation stimulus was a flashing light. The target stimulus was a schematic face in Experiment 1, a flashing light shown at 20° eccentricity in Experiment 2, a flashing light shown at 30° eccentricity in Experiment 3, and an upside-down schematic face in Experiment 4. In Experiments 1–3 a gap effect was found. That is, RT was faster on gap than on overlap trials. In contrast, the gap effect was absent in Experiment 4. These findings are consistent with the view that the superior colliculus plays a major role in producing the gap effect at birth.     

What is the speed to transparent and kinetic-boundary displays?

To compare transparent motion and kinetic boundaries with unidirectional motion, in many studies the relative motion is generated by superimposing or adjoining unidirectional motions oriented in opposite directions. The presumption, tacitly underlying this comparison, is that the two oppositely directed velocities are independent of one another as far as their speed is concerned, i.e. the speed of the relative motion is presumed to be equivalent to the speed of the unidirectional components. Here we report that the relative motion between dots moving in opposite directions augments perceived speed. A constant-stimuli procedure was used to pair transparent-motion or kinetic-boundary displays with unidirectional motion, and human observers were asked to match the speed of the relative and unidirectional motions. The results show that transparency and kinetic boundaries increase the perceived visual speed by about 50%, compared with the speed of the individual components.     

The import of infancy for individual, family, and societal development: commentary on the special section: does infancy matter?

Across their life spans humans actualize a rich potential for cognitive and behavioral plasticity, a set of developmental changes that require regulation of organism-context relations on the part of both the individual and society. An individual’s action on the context must be started in infancy and maintained in subsequent periods of life for adaptive functioning to occur across ontogeny. The process of the individual acting as an agent of his or her own development is continuous, although the particular ways in which such control is manifested will change in developmentally appropriate ways. As demonstrated by the papers in this special issue, the significance of infancy for the rest of the life-span rests on an integration of this continuity and discontinuity within the person-context developmental system.