The Burden of Proof and Its Role in Argumentation

The notion of “the burden of proof” plays an important role in real-world argumentation contexts, in particular in law. It has also been given a central role in normative accounts of argumentation, and has been used to explain a range of classic argumentation fallacies. We argue that in law the goal is to make practical decisions whereas in critical discussion the goal is frequently simply to increase or decrease degree of belief in a proposition. In the latter case, it is not necessarily important whether that degree of belief exceeds a particular threshold (e.g., ‘reasonable doubt’). We explore the consequences of this distinction for the role that the “burden of proof” has played in argumentation and in theories of fallacy.     

Now I see it but you don't: 14-month-olds can represent another person's visual perspective

Twelve- and 14-month-old infants' ability to represent another person's visual perspective (Level-1 visual perspective taking) was studied in a looking-time paradigm. Fourteen-month-olds looked longer at a person reaching for and grasping a new object when the old goal-object was visible than when it was invisible to the person (but visible to the infant). These findings are consistent with the interpretation that infants 'rationalized' the person's reach for a new object when the old goal-object was out of sight. Twelve-month-olds did not distinguish between test conditions. The present findings are consistent with recent research on infants' developing understanding of seeing.     

Personality disorder and future-directed thinking in parasuicide

Parasuicide patients have been found to lack positive expectations for the future. The aim of the present study was to look at variations in this lack of positive future-thinking as a function of personality status. A sample (N = 442) of repeat parasuicide patients was assessed on positive and negative future-thinking and the presence of personality disorder or personality difficulty. Those with a Cluster B personality disorder (borderline or dissocial) were significantly lower in positive future-thinking than those with no Cluster B symptoms or those with Cluster B personality difficulty. Neither Cluster A nor Cluster C symptomatology was related to positive future-thinking. Negative future-thinking was not significantly related to any type of personality disorder or difficulty. The results are interpreted as evidence of the importance of personality status in influencing positive future-thinking and gives some indications of why those with Cluster B personality disorder have such high rates of recurrent self-harm.     

Does the use of natural stimuli facilitate amodal completion in pigeons?

Three experiments were carried out to investigate whether amodal completion in pigeons can be facilitated by the use of colour photographs instead of highly artificial stimuli such as geometrical shapes. Ten pigeons were trained in a go/no-go procedure to discriminate between photographs of complete and of incomplete pigeon figures. In the subsequent test, the birds classified pictures of partly occluded pigeons as though they were complete (experiment 1). However, we found evidence that classification was based on spurious stimulus features that paralleled the intended class rule of figural completeness versus incompleteness. In particular, classification was shown to be guided by white background gaps that separated the parts of the fragmented pigeon figures (experiment 2), as well as by cues related to overall Gestalt (experiment 3). In summary, the present results indicate that the use of more natural stimuli such as photographs instead of geometrical shapes is insufficient for providing amodal completion in pigeons. It is suggested that a combination of various cues, including, eg, 3-D information and common motion in addition to surface and contour properties, may be required to induce a perceptual bias favouring visual completion of occluded portions.     

What makes words sound similar?

Although similarity plays an important role in accounts of language processing, there are surprisingly few direct empirical studies of the phonological similarity between words, and it is therefore not clear whether similarity comparisons between words involve processes similar to those involved in other cognitive domains. In five experiments, participants chose which of two monosyllabic pseudo-words sounded more similar to a target pseudo-word. Our results are generally consistent with the structural alignment theory of comparisons between complex mental representations, suggesting that phonological word similarity parallels similarity involving other kinds of information including visual objects and scenes, events, and word meanings. We use our results to test new metrics of word similarity, and identify predictions for future similarity research both in the domain of word sounds and in other cognitive domains.     

Target-defining features in a "people-present/people-absent" discrimination task by pigeons

Aust and Huber (2001) demonstrated that in a people-present/people-absent discrimination task, pigeons actually attended to properties of the target (i.e., the human figure). The aim of the present effort was to specify what sort of information contained in the target was used for classification, as well as to investigate whether and in what way the target-defining features interacted. Six pigeons were trained in a go/no-go procedure to discriminate between color photographs characterized by the presence or absence of people. They were then presented with various types of test stimuli that contained some category-relevant features but lacked others. The results showed that properties related to target size and internal structure played an important role and that human silhouettes were insufficient for eliciting a people-present response. Furthermore, some properties of the human figure (e.g., hands/arms) made good predictors of the people-present category, whereas others (e.g., feet/legs or skin color) did not. Responses to test stimuli that belonged to the people-absent category but nevertheless contained some features normally typical for humans (e.g., nonhuman primates) provided evidence that various category-relevant features contributed to classification in an additive way. Taken together, the results suggest that the pigeons made use of a polymorphous class rule involving collections of differently weighted target features.     

Lactation and stress: protective effects of breast-feeding in humans

Whilst most research on breast-feeding has been designed to assess its importance for infant health or to find a human nutrient replacement for infant formula, the effects of breast-feeding on maternal health have received little scientific attention. In several animal studies lactation has been shown to be associated with a marked blunting of physiological and behavioral responses to physical and psychological stress. However, the literature on the effects of lactation on stress in humans remains limited. This review focuses primarily on recent findings on the effects of breast-feeding on neuroendocrine and behavioral responses to acute stress exposure in lactating women. The available data suggest that breast-feeding suppresses the hypothalamic-pituitary-adrenal (HPA) axis response to physical and psychosocial stress. However, lactation in women, in contrast to lactating rats, does not seem to result in a general restraint of the endocrine stress response during the whole period of lactation. Recent data strongly suggest that the blunted HPA axis response to stress in women seems to be counterbalanced if the acute stressor, at least when of a psychosocial nature, occurs later than 1 h after suckling. Further elucidation of the underlying psychobiological mechanisms involved in suppressed stress responses during lactation will no doubt lead to new insights into improved health sequelae of breast-feeding in women and to a better understanding of the psychobiology of human stress protection in general.     

Sex differences in theory of mind: A male advantage on Happé's “cartoon” task

It is a commonly held stereotype that women show superior performance on tests of social cognition such as face processing and theory of mind (ToM) compared to men. However, such purported differences have not been empirically tested. In this study 40 healthy men and 40 women matched for age and years of education completed a well-known experimental ToM test requiring the attribution of either physical or mental states (Happé's cartoon task). Men showed superior performance compared to women, with a medium effect size, on both the mental state and physical state cartoons. It is suggested that men may use a cognitive systemising strategy during these tasks. The results emphasise the task-specific nature of sex differences in social cognition and necessitate future work to elucidate individual differences at the interface of cognitive and affective processes.     

The topography of training-induced visual field recovery: Perimetric maps and subjective representations

The cognitive representation of blind regions varies considerably between patients with vision loss and may influence compensatory behaviour and treatment motivation. We therefore measured “objective” visual field topography (perimetry) in 19 patients with postgeniculate visual system lesions and related this to the subjective scotoma representation as expressed by patients’ drawings of the defect and monitored changes of these measures during training-induced recovery of function. Blind regions were mostly adequately represented; however, central regions were overestimated and peripheral areas underestimated in size. Perimetric and subjective defect size decreased significantly during training. Again, training-induced visual field border shifts in central regions were larger in subjective than in perimetric maps but vice versa in the peripheral field. Thus, vision restoration therapy improves “objective” visual field size along with its cognitive representation. The subjective topography is shaped by the functional importance of visual field regions and is a function of cortical magnification, thus resembling the neural representation in visual cortex.