Left gaze bias in humans, rhesus monkeys and domestic dogs

While viewing faces, human adults often demonstrate a natural gaze bias towards the left visual field, that is, the right side of the viewee’s face is often inspected first and for longer periods. Using a preferential looking paradigm, we demonstrate that this bias is neither uniquely human nor limited to primates, and provide evidence to help elucidate its biological function within a broader social cognitive framework. We observed that 6-month-old infants showed a wider tendency for left gaze preference towards objects and faces of different species and orientation, while in adults the bias appears only towards upright human faces. Rhesus monkeys showed a left gaze bias towards upright human and monkey faces, but not towards inverted faces. Domestic dogs, however, only demonstrated a left gaze bias towards human faces, but not towards monkey or dog faces, nor to inanimate object images. Our findings suggest that face- and species-sensitive gaze asymmetry is more widespread in the animal kingdom than previously recognised, is not constrained by attentional or scanning bias, and could be shaped by experience to develop adaptive behavioural significance.     

The Unity of a Tractarian Fact

It is not immediately clear from Wittgenstein’s Tractatus how to connect his idea there of an object with the logical ontologies of Frege and Russell. Toward clarification on this matter, this paper compares Russell’s and Wittgenstein’s versions of the thesis of an atomic fact that it is a complex composition. The claim arrived at is that whilst Russell (at times at least) has one particular of the elements of a fact – the relation – responsible for the unity of the whole, for Wittgenstein the unity of a fact is the product of copulative powers inherent in all its elements. All kinds of constituents of Tractarian facts – all kinds (forms) of object – are, to use Fregean terminology, unsaturated.     

I Recognize Your Face, But I Can't Remember Your Name: A Grown up Explanation

Contemporary models of face recognition explain everyday difficulties in name retrieval by proposing that name information can only be accessed after semantic information (e.g. Bruce & Young, 1986) or by proposing an architecture which puts name retrieval at a disadvantage (e.g. Burton& Bruce,1992). Experiments reportedhere examined the time requiredto access name and semantic details by adult and child subjects. In Experiment 1 adult subjects took more time to match familiar faces to names than to other semantic details (e.g. occupation), a finding consistent with all the previous literature on name retrieval. Experiment 2, however, showed that the youngest subjects were significantly faster in matching familiar faces to names than to semantic details. Experiment 3 also showed that children were faster at accessing names than occupations when giving vocal responses to presentations of familiar faces. These findings are not predicted by rigidly sequential models of face recognition and are discussed with specific reference to the ontogenesis of models based on a more flexible connectionist architecture.     

Behavioral competition in a case of Rett syndrome

Major behavioral features of Rett syndrome are the loss of instrumental reaching and grasping and the presentation of some variant of hand-hand or hand-mouth stereotypy. As part of an experimental home intervention program, a 3-year-old girl with Rett syndrome was exposed to four types of contingency games designed to elicit instrumental reaching, kicking, vocalization, and eye movement, respectively. Parent and subject performance were videorecorded on seven occasions over the initial 2-month period. Evaluation of these records provided evidence of contingency learning in all but the vocalization games. Stereotypic hand clasping was examined in relation to the performance of instrumental behavior (reaching, kicking, looking). Coincidental (short-term mutual inhibition arising by chance co-occurrence), associative (short-term mutual inhibition arising by having elicitor in common), and foundational (long-term mutual inhibition arising by having neural network in common) forms of specific behavioral competition were defined and examined. Evidence for coincidental and foundational competition was found in the relation between reaching and hand clasping. Implications for the support of functional hand use are discussed.     

Parent characteristics and parent-child interactions in families of nonproblem children and ADHD children with higher and lower levels of oppositional-defiant behavior

This study examined parent-child interactions and parent characteristics in families of nonproblem children and attention deficit hyperactivity disorder (ADHD) children with lower (ADHD-LOD) and higher (ADHD-HOD) levels of oppositional-defiant behavior. Families of ADHD children were recruited from a parent training program. Observed and parent-reported child behavior problems were highest in the ADHD-HOD group. Observed parent behavior revealed few differences, but daily reports indicated that parents in both ADHD groups used more negative-reactive and fewer positive parenting strategies than control parents. Maternal psychological functioning differed between the ADHD and nonproblem groups, but not between the two ADHD groups. Fathers of ADHD-HOD children reported more psychological disturbance than controls. Parenting self-esteem was lowest in the ADHD-HOD group and highest in the nonproblem group. The results support the LOD and HOD distinction, but also suggest that, although certain difficulties are more common in the families of ADHD-HOD children, families of ADHD-LOD children also differ from controls on a number of dimensions.This research was supported by grants from the Medical Research Council of Canada and the British Columbia Health Research Foundation. Appreciation is extended to Josie Geller, Kim Behrenz, Susan Greaves, and Sonia Pietzsch who assisted with data collection and coding, and to the families who generously gave their time to participate in the research. Thanks also to two anonymous reviewers for their comments.     

Reception of Morse code through motional, vibrotactile, and auditory stimulation

The potential for communication through the kinesthetic aspect of the tactual sense was examined in a series of experiments employing Morse code signals. Experienced and inexperienced Morse code operators were trained to identify Morse code signals that were delivered as sequences of motional stimulation through up-down displacements (roughly 10 mm) of the fingertip. Performance on this task was compared with that obtained for both vibrotactile and acoustic presentation of Morse code using a 200-Hz tone delivered either to the fingertip through a minishaker or diotically to the two ears under headphones. For all three modalities, the ability to receive Morse code was examined as a function of presentation rate for tasks including identification of single letters, random three-letter sequences, common words, and sentences. Equivalent word-rate measures (i.e., product of percent correct scores and stimulus presentation rate) were nearly twice as high for auditory presentation as for vibrotactile stimulation, which in turn was about 1.3 times that for motional stimulation. The experienced subjects outperformed the inexperienced subjects by amounts that increased with task complexity. For example, the former were able to receive sentences at 18 words/min with motional stimulation, whereas the latter, following 75 h of training, were unable to perform this task. The present results and those of other research with tactual communication systems are compared, particularly regarding estimates of information-transfer rates.