Human biological and nonbiological point-light movements: Creation and validation of the dataset

Human action perception is so powerful that people can identify movement efficiently in the absence of pictorial information, such as in point-light displays. Interest is growing in this type of stimulus for research in neuroscience. This interest stems from the advantage of separating the component of pure human action kinematics from other pictorial information, such as facial expression and muscle contraction. Although several groups have previously developed datasets of human point-light actions, due to the lack of datasets composed of daily actions with short durations, we developed 20 biological and 40 control (scrambled) point-light movements by using the technique of recording people wearing reflector patches. The videos are about 1 s long. Subsequently, we performed a judgment task in which 100 participants (50 male and 50 female) evaluated each video according to three categories: human action resemblance, performed action, and gender of actor. We present the mean scores of each evaluation for each video, and further propose a selection of the most suitable videos to be used as human point-light action displays and scrambled point-light displays for control. Finally, we discuss our findings on the gender attributions of the point-light displays.     

Implicit connectives of algebraizable logics

An extensions by new axioms and rules of an algebraizable logic in the sense of Blok and Pigozzi is not necessarily algebraizable if it involves new connective symbols, or it may be algebraizable in an essentially different way than the original logic. However, extension whose axioms and rules define implicitly the new connectives are algebraizable, via the same equivalence formulas and defining equations of the original logic, by enriched algebras of its equivalente quasivariety semantics. For certain strongly algebraizable logics, all connectives defined implicitly by axiomatic extensions of the logic are explicitly definable.Special issue of Studia Logica: Algebraic Theory of Quasivarieties Presented by M. E. Adams, K. V. Adaricheva, W. Dziobiak, and A. V. Kravchenko     

Following and joining the informed individual in semifree-ranging tonkean macaques (Macaca tonkeana)

The authors investigated whether Tonkean macaques (Macaca tonkeana) can distinguish between 2 group mates with different knowledge and improve their foraging performance. The subjects were 8 young individuals belonging to a group raised in a 2-acre park. The authors carried out 192 tests in which subgroups of 3 individuals were released in a food search situation. Two leaders could be informed about 2 different food sites. A naive follower could choose to follow 1 leader or another. The follower could find the correct site when 1 leader was informed about food location. There was no evidence that the follower identified the best leader, however. The less well-informed leader generally joined the other leader, prompting the follower to follow them. The followers' pathways were mainly determined by the interactions of leaders.     

Numerosity-duration interference: a Stroop experiment

The existence of a possible common mechanism for duration and numerosity processing was tested with a Stroop task. Participants had to compare either the duration or the numerosity of sequences of flashing dots for which the duration and numerosity were independently manipulated to create congruent, incongruent or neutral pairs. Results show that the numerical cues interfered with duration processing, whereas the temporal cues did not interfere with numerosity processing. These findings extend the idea of an automatic access to magnitude to non-symbolic sequentially presented material, and reflect a probable difference in the mandatory processing of numerosity and duration.     

Numerical order and quantity processing in number comparison

We investigated processing of numerical order information and its relation to mechanisms of numerical quantity processing. In two experiments, performance on a quantity-comparison task (e.g. 2 5; which is larger?) was compared with performance on a relative-order judgment task (e.g. 2 5; ascending or descending order?). The comparison task consistently produced the standard distance effect (faster judgments for far relative to close number pairs), but the distance effect was smaller for ascending (e.g. 2 5) compared to descending pairs (e.g. 5 2). The order task produced a pair-order effect (faster judgments for ascending pairs) and a reverse distance effect for consecutive pairs in ascending order. The reverse effect implies an order-specific process, such as serial search or direct recognition of order for successive numbers. Thus, numerical quantity and order judgments recruited different cognitive mechanisms. Nonetheless, the reduced distance effect for ascending pairs in the quantity task implies involvement of order-related processes in magnitude comparison. Accordingly, distance effects in the quantity-comparison task are not necessarily a process-pure measure of magnitude representation.     

Implicit learning of complex information in amnesia

Implicit learning abilities of nine amnesic patients were explored by using an artificial grammar learning task in which the test strings were constructed in such a way that grammaticality judgments could not be based on a simple knowledge of bigrams and trigrams (chunks). Results show that amnesic patients and controls performed at the same level during the classification task, whereas amnesic patients performed worse than controls in an explicit generation task. Moreover, there was no correlation between the implicit and explicit measures. These results are compatible with the existence of two kinds of representation intervening in artificial grammar learning. The first one based on processes leading to fragment-specific knowledge (the chunks, which can be accessed explicitly), and the second based on the learning of simple associations and more complex conditional relations between elements.     

Sequential compatibility effects and cognitive control: does conflict really matter?

Although it is widely accepted that control mechanisms are necessary for human behavior to be adapted, very little is known about how such mechanisms are recruited. A suggestion to fill the gap was put forward by M. M. Botvinick, T. S. Braver, C. S. Carter, D. M. Barch, and J. D. Cohen (2001), who proposed the conflict-loop theory. This theory has been successful in accounting for the reduction of compatibility effects after an incompatible trial: The level of conflict being, on average, higher during an incompatible trial, more control occurs after such a trial. The authors have tested this prediction by sorting the trials on the basis of amount of conflict (quantified by the electromyographic activity) they presented. A reduction of the compatibility effect was observed after incompatible trials, but it was independent of the level of conflict on previous trials, suggesting that the conflict does not trigger changes in executive control. Consequences for the conflict monitoring model are discussed.     

Partial advance information,number of alternatives,and motor processes: an electromyographic study

We present evidence that advance information reducing the number of stimulus-response alternatives in a choice reaction time (RT) task can shorten the very latest motoric stages of RT. Effects of such advance information on late stages of RT have been demonstrated recently by Osman, Moore, and Ulrich (Acta Psychol. 90 (1995) 111), Leuthold, Sommer, and Ulrich (J. Exp. Psychol: Gen. 125 (1996) 307), Müller-Gethmann, Rinkenauer, Stahl, and Ulrich (Psychophysiology 37 (2000) 507). These studies found that advance information shortens the portion of the RT interval following onset of a movement-related brain potential (lateralized readiness potential). Osman et al. and Müller-Gethmann et al. also examined the portion of the RT interval following the start of electromyographic (EMG) activity and found no effect of advance information. Based on Osman et al.'s null result, Leuthold et al. speculated that advance information may shorten only the RT stages preceding EMG activity. This conclusion, however, is questionable because of limitations in the EMG measures employed by both Osman et al. and Müller-Gethmann et al. We have reanalyzed the results of a previously reported experiment (Acta Psychol. 101 (1999) 243) to show that advance information can in fact affect the rate of recruitment of motor units in the prime mover of the responding limb.     

Predictors of picture naming speed.

We report the results of a large-scale picture naming experiment in which we evaluated the potential contribution of nine theoretically relevant factors to naming latencies. The experiment included a large number of items and a large sample of participants. In order to make this experiment as similar as possible to classic picture naming experiments, participants were familiarized with the materials during a training session. Speeded naming latencies were determined by a software key on the basis of the digital recording of the responses. The effects of various variables on these latencies were assessed with multiple regression techniques, using a repeated measures design. The interpretation of the observed effects is discussed in relation to previous studies and current views on lexical access during speech production.     

Standardization and the democratic design of information and communication technology

The way information and communication technology (ICT) develops can promote or hinder the democratic potential of this critical societal infrastructure. Concerns about the role standards development organizations (SDOs) play in this context predate the “digital age” but are reemerging amid substantial changes in the institutional landscape of standardization. This article explores the increasingly critical link between the institutional design of SDOs and the democratic design of ICT. We review some principles of democracy in terms of the design of technology, apply these to standardization, and discuss the role public policy may play here, while distinguishing between input and output legitimacy. Eric J. Iversen is the guest editor of this issue of Knowledge, Technology, & Policy. His biographical sketch accompanies his Introduction. Thierry Vedel is a researcher with the National Center for Scientific Research (CNRS) in Paris. He is based at the Center for Political Research (CEVIPOF) at the National Foundation for Political Science. Having worked on public policies in the area of new communication technologies, he is currently engaged in research on electronic democracy and the governance of communication networks in a context of globalization. Thierry Vedel teaches communication and politics at the University of Paris 2 and at the Institut d’Etudes Politiques de Paris. He may be reached via http://www.cevipof.mshparis.fr/. His current research is focused on the interaction of technical and institutional innovations and on the evolution, development, and governance of the Internet.