Processing modes and parallel processors in producing familiar keying sequences

Recent theorizing indicates that the acquisition of movement sequence skill involves the development of several independent sequence representations at the same time. To examine this for the discrete sequence production task, participants in Experiment 1 produced a highly practiced sequence of six key presses in two conditions that allowed little preparation so that interkey intervals were slowed. Analyses of the distributions of moderately slowed interkey intervals indicated that this slowing was caused by the occasional use of two slower processing modes, that probably rely on independent sequence representations, and by reduced parallel processing in the fastest processing mode. Experiment 2 addressed the role of intention for the fast production of familiar keying sequences. It showed that the participants, who were not aware they were executing familiar sequences in a somewhat different task, had no benefits of prior practice. This suggests that the mechanisms underlying sequencing skills are not automatically activated by mere execution of familiar sequences, and that some form of top-down, intentional control remains necessary.     

SLOT: A research platform for investigating multimodal communication

In this article, we present the spatial logistics task (SLOT) platform for investigating multimodal communication between 2 human participants. Presented are the SLOT communication task and the software and hardware that has been developed to run SLOT experiments and record the participants’ multimodal behavior. SLOT offers a high level of flexibility in varying the context of the communication and is particularly useful in studies of the relationship between pen gestures and speech. We illustrate the use of the SLOT platform by discussing the results of some early experiments. The first is an experiment on negotiation with a one-way mirror between the participants, and the second is an exploratory study of automatic recognition of spontaneous pen gestures. The results of these studies demonstrate the usefulness of the SLOT platform for conducting multimodal communication research in both human-human and human-computer interactions.     

Burgeoning skepticism

This paper shows that the resources mobilized by recent arguments against individualism in the philosophy of mind also suffice to construct a good argument against a Humean-style skepticism about our knowledge of extra-mental reality. The argument constructed, however, will not suffice to lay to rest the attacks of a truly global skeptic who rejects the idea that we usually know what our occurrent mental states are.     

Burhoe's Legacy: Lessons for Europeans

Ralph Burhoe's ideas have not been well received in European Protestant theology. His approach has been at odds with the dominant resistance to natural theology on the Continent, and it has not fit well with reconciling attempts from the United Kingdom either. However, Burhoe's interest in the role of religions in the emergence of human nature and culture, including the interest in noncognitive functions of religion, should be taken to heart. Besides, he has set an example for Europeans with respect to method in dealing with first-rate science.     

Socio-cognitive conflict and structure of individual and collective performances

A previous experiment (Doise, Mugny and Perret-Clermont, 1975) has shown that pairs of subjects perform better on a spatial representation task than subjects alone. As a conclusion the hypothesis was put forward that conflicts of cognitive centrations, embedded in a social situation, lead children to coordinate their centrations. The present research was planned to verify several predictions following from this general hypothesis. Results show that indeed more progress takes place when children with different cognitive strategies work together than when children with the same strategies do so, and that not only the less advanced but also the more advanced child progresses when they interact with each other.     

Inverse statistics and misperception of exponential growth

Exponential growth presented by numerical series or graphs is grossly underestimated by human subjects. This misperception was considerably lessened by presenting decreasing functions; this conclusion holds for both numeric and graphic stimuli. In the numerical conditions, about 25% of the subjects performed according to the statistical norm. In contrast with previous results, considerable individual differences with respect to sensitivity for rate of growth were observed. This finding was interpreted in terms of task difficulty: Extrapolation of ascending series is too difficult a task to be discriminative. Extrapolation of descending series is much easier, and may therefore better discriminate among subjects.     

Stable individual differences in situation-behaviour,construct-behaviour,and goal-behaviour relations

This study starts from a cognitive-social-learning conceptualization of the contribution of static person by situation interaction to overt behaviour variance. Individual differences in the relation between, on the one hand, situational variation in behaviour and, on the other hand, situational variation in objective situational characteristics, situational variation in construed situational characteristics, and situational variation in goals-in-situations were systematically investigated. Thirty-six first-year psychology students had to freely generate and briefly describe 20 interpersonal situations that they had encountered during the last year. Afterwards, they had to rate each situation for four basic behavioural continua, eight supplied objective situational characteristics, eight supplied constructs, and eight supplied goals. Correlational analysis revealed many stable individual differences, not only in degree, but also in direction (sign) of situation-behaviour, construct–behaviour, and goal–behaviour relations. These relational variables could be reduced to seven relational factorial dimensions. The theoretical and practical implications of these findings are discussed.     

A generalized majorization method for least souares multidimensional scaling of pseudodistances that may be negative

The usual convergence proof of the SMACOF algorithm model for least squares multidimensional scaling critically depends on the assumption of nonnegativity of the quantities to be fitted, called the pseudodistances. When this assumption is violated, erratic convergence behavior is known to occur. Three types of circumstances in which some of the pseudodistances may become negative are outlined: nonmetric multidimensional scaling with normalization on the variance, metric multidimensional scaling including an additive constant, and multidimensional scaling under the city-block distance model. A generalization of the SMACOF method is proposed to resolve the difficulty that is based on the same rationale frequently involved in robust fitting with least absolute residuals.I am grateful to Patrick Groenen and Rian van Blokland-Vogelesang for their help with some of the computations, and to the anonymous referees for their very useful comments.