At first glance, transparency enhances assimilation

We investigated the role of transparency, perceptual grouping, and presentation time on perceived lightness. Both transparency and perceptual grouping have been found to result in assimilation effects, but only for ambiguous stimulus displays and with specific attentional instructions. By varying the presentation times of displays with two partly overlapping transparent E-shaped objects, we measured assimilation in unambiguous stimulus displays and without specific attentional instructions. The task was to judge which of two simultaneously presented E-shaped objects was darker. With unrestrained presentation times, if a transparency interpretation was possible, assimilation was not found. Inhibiting a transparency interpretation by occluding the local junctions between the two E-shaped objects, did lead to assimilation. With short presentation times, if a transparency interpretation was possible, assimilation was now also found. Thus, we conclude that, although transparency appears to enhance assimilation, with unambiguous stimulus displays and without specific attentional instructions, perceptual grouping is more important for assimilation to occur.     

Event-related potentials, reaction time, and response selection of skilled and less-skilled cricket batsmen

The differences in P300 latency, P300 amplitude, response selection, and reaction time between skilled and less-skilled cricket batsmen have been investigated. Eight skilled and ten less-skilled right-handed batsmen each viewed 100 in-swing, 100 out-swing, and 40 slower deliveries displayed in random sequence from projected video footage whilst their responses and electroencephalograms were recorded. Logistic regression was used to derive a discriminative function for the P300 data. This was done to determine whether the skilled batsmen differed from the less-skilled batsmen on the basis of pooled P300 amplitude and latency data. All the batsmen were correctly characterised as being skilled or less-skilled. Logistic regression equations with reaction time and correctness of response data indicated that behavioural data do not correctly classify skilled performance. It is suggested that skilled cricket batsmen have a superior perceptual decision-making ability compared with less-skilled cricket batsmen, as measured by P300 latency and amplitude. This appears to be the first study showing a link between skill and cerebral cortical activity during a perceptual cricket batting task and it could pave the way for future studies on mental processing in cricket batsmen.     

The human Müller-Lyer illusion in goalkeeping

We examined whether a goalkeeper can influence a penalty-taker's actions by assuming postures that mimic Müller-Lyer configurations. The results of two studies indicate that (i) goalkeeper posture affects the perception of the goalkeeper's height in a manner consistent with the Müller-Lyer illusion; (ii) this influences penalty-taking accuracy; and (iii) a posture which resembles a wing-out Müller-Lyer configuration results in wider and lower throws.     

The many faces of interpolation

We present a number of, somewhat unusual, ways of describing what Craig’s interpolation theorem achieves, and use them to identify some open problems and further directions.     

Executive Functions in Preschool Children with Aggressive Behavior: Impairments in Inhibitory Control

The question whether executive function (EF) deficits in children are associated with conduct problems remains controversial. Although the origins of aggressive behavior are to be found in early childhood, findings from EF studies in preschool children with aggressive behavior are inconsistent. The current study aimed to investigate whether preschool children with aggressive behavior show impairments in EF. From a population-based sample, 82 preschool children who were showing aggressive behavior as indicated by scores at or above the 93rd percentile on the Aggressive Behavior Scale of the CBCL 1 1/2-5 were selected. These children with aggressive behavior were matched on IQ to a group of typically developing control children (N = 99). Six neuropsychological tasks were administered to assess set shifting, inhibition, working memory and verbal fluency. A factor analysis was conducted which yielded one clear factor: inhibition. Aggressive preschool children showed poorer performance on this inhibition factor than control children and boys performed worse on this factor than girls. This association between aggressive behavior and inhibition deficits was maintained after controlling for attention problems. In addition, gender differences in all EFs measured were found with boys exhibiting more impairment in EF than girls. These findings demonstrate that preschool children with aggressive behavior show impairments in inhibition, irrespective of attention problems.     

Investigating speech motor practice and learning in people who stutter

In this exploratory study, we investigated whether or not people who stutter (PWS) show motor practice and learning changes similar to those of people who do not stutter (PNS). To this end, five PWS and five PNS repeated a set of non-words at two different rates (normal and fast) across three test sessions (T1, T2 on the same day and T3 on a separate day, at least 1 week apart). The results indicated that PWS and PNS may resemble each other on a number of performance variables (such as movement amplitude and duration), but they differ in terms of practice and learning on variables that relate to movement stability and strength of coordination patterns. These findings are interpreted in support of recent claims about speech motor skill limitations in PWS.

Educational objectives: The reader will be able to: (1) define oral articulatory changes associated with motor practice and learning and their measurement; (2) summarize findings from previous studies examining motor practice and learning in PWS; and (3) discuss hypotheses that could account for the present findings that suggest PWS and PNS differ in their speech motor learning abilities.     

Modelling relations between sensory processing, speech perception, orthographic and phonological ability, and literacy achievement

The general magnocellular theory postulates that dyslexia is the consequence of a multimodal deficit in the processing of transient and dynamic stimuli. In the auditory modality, this deficit has been hypothesized to interfere with accurate speech perception, and subsequently disrupt the development of phonological and later reading and spelling skills. In the visual modality, an analogous problem might interfere with literacy development by affecting orthographic skills. In this prospective longitudinal study, we tested dynamic auditory and visual processing, speech-in-noise perception, phonological ability and orthographic ability in 62 five-year-old preschool children. Predictive relations towards first grade reading and spelling measures were explored and the validity of the global magnocellular model was evaluated using causal path analysis. In particular, we demonstrated that dynamic auditory processing was related to speech perception, which itself was related to phonological awareness. Similarly, dynamic visual processing was related to orthographic ability. Subsequently, phonological awareness, orthographic ability and verbal short-term memory were unique predictors of reading and spelling development.     

Substantive and procedural norms in normative multiagent systems

Procedural norms are instrumental norms addressed to agents playing a role in the normative system, for example to motivate these role playing agents to recognize violations or to apply sanctions. Procedural norms have first been discussed in law, where they address legal practitioners such as legislators, lawyers and policemen, but they are discussed now too in normative multiagent systems to motivate software agents. Procedural norms aim to achieve the social order specified using regulative norms like obligations and permissions, and constitutive norms like counts-as obligations. In this paper we formalize procedural, regulative and constitutive norms using input/output logic enriched with an agent ontology and an abstraction hierarchy. We show how our formalization explains Castelfranchi's notion of mutual empowerment, stating that not only the agents playing a role in a normative system are empowered by the normative system, but the normative system itself is also empowered by the agents playing a role in it. In our terminology, the agents are not only institutionally empowered, but they are also delegated normative goals from the system. Together, institutional empowerment and normative goal delegation constitute a mechanism which we call delegation of power, where agents acting on behalf of the normative system become in charge of recognizing which institutional facts follow from brute facts.     

How Should We Do Nanoethics? A Network Approach for Discerning Ethical Issues in Nanotechnology

There is no agreement on how nanoethics should proceed. In this article I focus on approaches for discerning ethical issues in nanotechnology, which is as of yet one of the most difficult and urging tasks for nanoethics. I discuss and criticize two existing approaches for discerning ethical issues in nanotechnology and propose a network approach as alternative. I discuss debates in nanoethics about the desirable role of ethics in nanotechnological development and about the newness of ethical issues in nanotechnology. On basis of a critical analysis of both debates, I formulate a number of desiderata for a method for discerning ethical issues in nanotechnology and argue that the network approach that my colleagues and I have developed for ethical issues in research and development networks is also appropriate in nanotechnology.

“When Strangers Meet”: John Bowlby and Harry Harlow on Attachment Behavior

From 1957 through the mid-1970s, John Bowlby, one of the founders of attachment theory, was in close personal and scientific contact with Harry Harlow. In constructing his new theory on the nature of the bond between children and their caregivers, Bowlby profited highly from Harlow’s experimental work with rhesus monkeys. Harlow in his turn was influenced and inspired by Bowlby’s new thinking. On the basis of the correspondence between Harlow and Bowlby, their mutual participation in scientific meetings, archival materials, and an analysis of their scholarly writings, both the personal relationship between John Bowlby and Harry Harlow and the cross-fertilization of their work are described.