Radical anti-realism, Wittgenstein and the length of proofs

After sketching an argument for radical anti-realism that does not appeal to human limitations but polynomial-time computability in its definition of feasibility, I revisit an argument by Wittgenstein on the surveyability of proofs, and then examine the consequences of its application to the notion of canonical proof in contemporary proof-theoretical-semantics.     

A cognitive-based model of tool use in normal aging

While several cognitive domains have been widely investigated in the field of aging, the age-related effects on tool use are still an open issue and hardly any studies on tool use and aging is available. A significant body of literature has indicated that tool use skills might be supported by at least two different types of knowledge, namely, mechanical knowledge and semantic knowledge. However, neither the contribution of these kinds of knowledge to familiar tool use, nor the effects of aging on mechanical and semantic knowledge have been explored in normal aging. The aim of the present study was to fill this gap. To do so, 98 healthy elderly adults were presented with three tasks: a classical, familiar tool use task, a novel tool use task assessing mechanical knowledge, and a picture matching task assessing semantic knowledge. The results showed that aging has a negative impact on tool use tasks and on knowledge supporting tool use skills. We also found that aging did not impact mechanical and semantic knowledge in the same way, confirming the distinct nature of those forms of knowledge. Finally, our results stressed that mechanical and semantic knowledge are both involved in the ability to use familiar tools.     

What about proactive language control?

Psychonomic Bulletin & Review - While several reviews provide an in-depth discussion on reactive language control, which is the language control process that is initiated when the non-target...     

Time-dependence between upper arm muscles activity during rapid movements: Observation of the proportional effects predicted by the kinematic theory

Rapid human movements can be assimilated to the output of a neuromuscular system with an impulse response modeled by a Delta-Lognormal equation. In such a model, the main assumption concerns the cumulative time delays of the response as it propagates toward the effector following a command. To verify the validity of this assumption, delays between bursts in electromyographic (EMG) signals of agonist and antagonist muscles activated during a rapid hand movement were investigated. Delays were measured between the surface EMG signals of six muscles of the upper limb during single rapid handwriting strokes. From EMG envelopes, regressions were obtained between the timing of the burst of activity produced by each monitored muscle. High correlation coefficients were obtained supporting the proportionality of the cumulative time delays, the basic hypothesis of the Delta-Lognormal model. A paradigm governing the sequence of muscle activities in a rapid movement could, in the long run, be useful for applications dealing with the analysis and synthesis of human movements.     

Pleasant emotional induction broadens the visual world of young children

These experiments aimed at studying the influence of emotional context on global/local visual processing in children. Children 5 years old, known to present an immature global visual bias, and 8 years old, known to pay attention predominantly to global information, were placed in either a neutral or pleasant emotional context and subsequently presented with a global/local visual judgement task. As with previous findings for adults, both age groups presented a pronounced perceptual bias toward global information following exposure to emotionally pleasant pictures. Interestingly, younger children, who do not present a global bias during the neutral exposure, presented the same preference for global information as older children when exposed to the pleasant context. These findings indicate that emotion may strongly affect visual perception in children, with important implications for educational practice and models of cognition.     

Simultaneous completions of modal and amodal figures: Visual evoked potentials reveal asymmetrical interference effects

Modal and amodal completion processes are thought to affect the emergence and the potency of each other. To see whether one dominates over the other, we measured the Npd, that is, the negativity of visual-evoked potentials whose amplitude increases with perceptual difficulty. In the first experiment, the Npds to illusory (modal) squares and diamonds placed over amodal diamonds and squares, respectively, were found to be greater when targets were the amodal figures than when targets were the modal figures, thus suggesting that modal figures created more interference. A second experiment showed that greater Npds were specific to interference and not to the greater difficulty at focusing on amodal figures rather than on modal figures. A third experiment showed that the interference also occurs with real figures in replacement of modal ones. Overall, the results suggest a certain dominance of modal completion over amodal completion when both occur in the same display.     

Assessing the way people look to judge their intentions

Faces of unknown persons are processed to infer the intentions of these persons not only when they depict full-blown emotions, but also at rest, or when these faces do not signal any strong feelings. We explored the brain processes involved in these inferences to test whether they are similar to those found when judging full-blown emotions. We recorded the event-related brain potentials (ERPs) elicited by faces of unknown persons who, when they were photographed, were not asked to adopt any particular expression. During the ERP recording, participants had to decide whether each face appeared to be that of a positively, negatively, ambiguously, or neutrally intentioned person. The early posterior negativity, the EPN, was found smaller for neutrally categorized faces than for the other faces, suggesting that the automatic processes it indexes are similar to those evoked by full-blown expressions and thus that these processes might be involved in the decoding of intentions. In contrast, in the same 200-400 ms time window, ERPs were not more negative at anterior sites for neutrally intentioned faces. Second, the peaks of the late positive potentials (LPPs) maximal at parietal sites around 700 ms postonset were not significantly smaller for neutrally intentioned faces. Third, the slow positive waves that followed the LPP were larger for faces that took more time to categorize, that is, for ambiguously intentioned faces. These three series of unexpected results may indicate processes similar to those triggered by full-blown emotions studies, but they question the characteristics of these processes.     

Managing a new collaborative entity in business organizations: understanding organizational communities of practice effectiveness

Companies worldwide are turning to organizational communities of practice (OCoPs) as vehicles to generate learning and enhance organizational performance. OCoPs are defined as groups of employees who share a concern, a set of problems, or a passion about a topic and who strengthen their knowledge and expertise by interacting on a consistent basis. To date, OCoP research has drawn almost exclusively from the community of practice (CoP) literature, even though the organizational form of CoPs shares attributes of traditional CoPs and of organizational teams. Drawing on Lave and Wenger's (1991) original theory of legitimate peripheral participation, we integrate theory and research from CoPs and organizational teams to develop and empirically examine a model of OCoP effectiveness that includes constructs such as leadership, empowerment, the structure of tasks, and OCoP relevance to organizational effectiveness. Using data from 32 OCoPs in a U.S.-based multinational mining and minerals processing firm, we found that external community leaders play an important role in enhancing OCoP empowerment, particularly to the extent that task interdependence is high. Empowerment, in turn, was positively related to OCoP effectiveness. We also found that OCoPs designated as "core" by the organization (e.g., working on critical issues) were more effective than those that were noncore. Task interdependence also was positively related to OCoP effectiveness. We provide scholars and practitioners with insights on how to effectively manage OCoPs in today's organizations.     

The use of visual and automatized behavioral markers to assess methodologies: a study case on PIT-tagging in the Alpine newt

In various research fields, biomarkers are now widely used as tools for assessing individual integrity. The recent advances in quantification methods for behavioral patterns, such as computerized video-tracking procedures, make them valuable biomarkers. However, the corollary of these novelties is that they remain relatively unknown and unused. In this study, we show that such tools can assess the validity of research methods, such as individual recognition. To demonstrate this, we employed, as a model, a marking method (passive integrated transponder [PIT] tagging) widely used in amphibians. Detailed visual observations and video-tracking methods were complementary in highlighting components at different behavioral scales: locomotion, feeding, and breeding. We illustrate the scientific and ethical adequacy of the targeted marking method but also suggest that more studies should integrate behavioral analyses. Such biomarkers are a powerful tool for assessing conservation concerns when other techniques cannot detect detrimental effects.