A formalisation of violation, error recovery, and enforcement in the bit transmission problem

The design of complex multi-agent systems is increasingly having to confront the possibility that agents may not behave as they are supposed to. In addition to analysing the properties that hold if protocols are followed correctly, it is also necessary to predict, test, and verify the properties that would hold if these protocols were to be violated. We illustrate how the formal machinery of deontic interpreted systems can be applied to the analysis of such problems by considering three variations of the bit transmission problem. The first, an example in which an agent may fail to do something it is supposed to do, shows how we deal with violations of protocols and specifications generally. The second, an example in which an agent may do something it is not supposed to do, shows how it is possible to specify and analyse remedial or error-recovery procedures. The third combines both kinds of faults and introduces a new component into the system, a controller, whose role is to enforce compliance with the protocol. In each case the formal analysis is used to test whether critical properties of the system are compromised, in this example, the reliable communication of information from one agent to the other.     

The effects of feature type in operant serial feature-positive discriminations

In two experiments, rats were trained on two operant serial feature positive discriminations in which one feature was a flavored solution and the second feature was a visual or auditory cue. As in a previous study ([Goddard and Holland, 1996]), transfer of a feature’s control to the target of the other discrimination was not observed when the flavor feature and the reinforcer were flavored sucrose solutions (Experiment 1). The performance of comparison groups showed that this lack of transfer was not due to confounded differences in the event contingencies resulting from having similar stimuli serve as feature and reinforcer. By contrast, in Experiment 2, transfer was observed between visual and flavor features when the flavor feature was unsweetened and the reinforcer was plain sucrose. These results suggest that the lack of transfer in Experiment 1 and in [Goddard and Holland, 1996] study were related to the biological significance or hedonic properties of the sucrose feature.     

A novel integrated knowledge explanation of factors leading to suicide

Psycho-social and biological theories of suicide are sometimes presented in a dichotomous manner. It is hypothesised that there is a base rate of suicide in all communities which is influenced not only by biological factors, but also by psycho-social factors. However, various countries or specific groups or regions within a country whose suicide rate diverges significantly from this base rate do so predominantly because of psycho-social factors. This theory has practical implications in terms of where certain countries or regions should focus their suicide prevention programmes.     

Painful semantic context modulates the relationship between action words and biological movement perception

Studies have revealed a close relationship between action–word processing and the detection of point-light biological movements and that this effect can be modulated by the context of action-verb presentation. The goal of the present study was to further examine the extent to which motor representation activation plays a role in this relationship by testing the influence of painless/painful sentence understanding during a listening task. Participants judged the presence or absence of a point-light biological movement that was embedded in a scrambled mask after a congruent or incongruent action sentence was presented. The sentences varied according to the context of action-verb presentation (painful, painless). Perceptual judgments of human movements improved after a prior presentation of a congruent action sentence but only in the painless context. Thus, our findings show that pain included in a semantic context of sentence presentation can preclude the relationship between action–word understanding and point-light biological movement judgments.     

He throws like a girl (but only when he's sad): emotion affects sex-decoding of biological motion displays

Gender stereotypes have been implicated in sex-typed perceptions of facial emotion. Such interpretations were recently called into question because facial cues of emotion are confounded with sexually dimorphic facial cues. Here we examine the role of visual cues and gender stereotypes in perceptions of biological motion displays, thus overcoming the morphological confounding inherent in facial displays. In four studies, participants’ judgments revealed gender stereotyping. Observers accurately perceived emotion from biological motion displays (Study 1), and this affected sex categorizations. Angry displays were overwhelmingly judged to be men; sad displays were judged to be women (Studies 2–4). Moreover, this pattern remained strong when stimuli were equated for velocity (Study 3). We argue that these results were obtained because perceivers applied gender stereotypes of emotion to infer sex category (Study 4). Implications for both vision sciences and social psychology are discussed.     

Reasons for sequence preferences

Much research shows that when it comes to preferences over sequences of money, such as a monthly paycheck, people do not always maximize present value. Rather, they often choose the lower‐valued of a pair of sequences, especially when it has attractive properties such as an increasing trend. To unearth the reasons for sequence preferences we conducted a verbal‐protocol analysis of choices between money sequences, including lifetime and one‐year earnings and one‐year lottery winnings, as well as lifetime health sequences. Participants thought aloud while choosing between visual representations of sequences. Their verbalizations contained reference to a wide range of previously hypothesized, as well as new, reasons for choice. These reasons were also correlated in sensible ways with the choices made. There was some evidence of solid economic reasoning (which we called maximization), although this was largely restricted to choices for one‐year earnings. More commonly, respondents did not distinguish between earnings and consumption, and thought about money as if they would automatically spend it at the rate it was received. This meant the most frequently given reason was what we called appropriateness—how well the money received at a given point matched the desired consumption at that point. Other common explanations include the expectedness of a sequence (we argue this is mediated by appropriateness), the way that parts of the sequence constitute reference points for other parts, and the ease with which incoming money can be managed (convenience). Copyright © 2002 John Wiley & Sons, Ltd.     

Analyse des prélèvements biologiques médico-légaux : quel cadre juridique à l’ère de la qualité?

Medico-legal autopsy sometimes requires the use of the Parasitology-Mycology specialty. Two recent medico-legal clinical cases, involving this specialty, have questioned us. First of all, may a non-conformity biological analytical (compared to accepted and accredited standards by COFRAC) fail the whole biological expertise, and thereafter, the medico-legal expertise of the file? The answer must consider that the raw result obtained as a result of a medical biology technique must be interpreted and discussed by the expert in the discipline (in this case by the parasitologist) before being included in the medical discussion and discussed by the medical examiner. The judgment is secondarily delivered by the judge according to his intimate conviction and without determining the probative value of the examination. Should a post-mortem biological examination be part of an expertise in medical biology or is it a technical and scientific examination? This answer is based on the previous one, considering the significant contribution of the expert who will bring his knowledge, interpreting and discussing the raw result. A simple technical and scientific examination would only provide the raw result without any assessment of the context and circumstances of the biological sample.     

Newborns’ attention is driven by the translational movement

The present study investigated whether 2-day-old newborns are able to discriminate two translating meaningless Point-Light Displays (PLD) videos, in which the shape of one of them changes compared to that of the other along the trajectory, independently from movement kinematics, and if this ability is present both when stimuli differed at the end or at the beginning of the movement. To manipulate the instant in which along the movement the difference between stimuli was evident, and to maintain every unspecific dissimilarity possibly determining the preference, videos were played in a loop either forward or backwards. In Experiment 1, PLD stimuli moved with natural accelerated-decelerated kinematics; in Experiment 2 they moved at constant velocity. Four groups of newborns were submitted to the preferential looking technique experiments. Results showed that newborns looked longer at natural kinematics and that, irrespective of the type of kinematics, they discriminated the two stimuli only when videos were played forward, that is, only when stimuli differed at the end of the movement. These data suggest that, independently from kinematics, movement translational components induce newborns to allocate attention at the end of the observed movement. Given the strict link between attention and eye movements, we suggest that this effect may bootstrap the system and give rise to proactive gaze, the typical gaze behaviour present during executed and observed goal-directed actions.     

A teleological account of Cartesian sensations?

Alison Simmons, in Simmons (1999), argues that Descartes in Meditation Six offered a teleological account of sensory representation. According to Simmons, Descartes’ view is that the biological function of sensations explains both why sensations represent what they do (i.e., their referential content) and why they represent their objects the way they do (i.e., their presentational content). Moreover, Simmons claims that her account has several advantages over other currently available interpretations of Cartesian sensations. In this paper, I argue that Simmons’ teleological account cannot be sustained for both theoretical and textual reasons and that it does not have the advantages it is claimed to have.