The tuning-fork model of human social cognition: a critique

The tuning-fork model of human social cognition, based on the discovery of mirror neurons (MNs) in the ventral premotor cortex of monkeys, involves the four following assumptions: (1) mirroring processes are processes of resonance or simulation. (2) They can be motor or non-motor. (3) Processes of motor mirroring (or action-mirroring), exemplified by the activity of MNs, constitute instances of third-person mindreading, whereby an observer represents the agent's intention. (4) Non-motor mirroring processes enable humans to represent others' emotions. After questioning all four assumptions, I point out that MNs in an observer's brain could not synchronically resonate with MNs in an agent's brain unless they discharged in a single brain in two distinct tasks at different times. Finally, I sketch a conceptualist alternative to the resonance model according to which a brain mechanism active in both the execution and the perception of e.g., the act of grasping is the neural basis of the concept of e.g., grasping.     

Working memory in children: a time-constrained functioning similar to adults

Within the time-based resource-sharing (TBRS) model, we tested a new conception of the relationships between processing and storage in which the core mechanisms of working memory (WM) are time constrained. However, our previous studies were restricted to adults. The current study aimed at demonstrating that these mechanisms are present and functional before adulthood. For this purpose, we investigated the effect on maintenance of the duration of the attentional capture induced by processing. In two experiments using computer-paced WM span tasks, 10-year-olds were asked to maintain letters while performing spatial location judgments. The duration of this processing was manipulated by varying either the discriminability between target locations or the contrast between targets and background. In both experiments, longer processing times resulted in poorer recall, as we observed previously in adults. These findings suggest that the core mechanisms of WM described by the TBRS model are already settled during childhood.     

Lengthening the duration of response execution does not modulate blindness to action-compatible stimuli.

Action-compatible blindness refers to the finding that target stimuli are perceived less frequently if they are presented during the planning or execution of a compatible action (e.g., a left arrow presented during a left manual key press) than during an incompatible action (Müsseler & Hommel, 1997 a, b). We investigated the effect of lengthening the response execution phase in the action-compatible blindness paradigm by requiring subjects to tap a response key once or three times on the assumption that tapping three times would increase the duration of the execution phase of the response. Prior research (e.g., Stevanovski, Oriet, & Jolicoeur, 2002; Wühr & Müsseler, 2001) has shown that larger blindness effects are observed for targets presented during the execution phase of a response than after the response has been made. We investigated whether a larger blindness effect would be observed in the three-tap condition than in the one-tap condition, or whether lengthening the duration of the response would extend the time course of the blindness effect. Neither of these possibilities was supported by the data irrespective of whether the number of taps to be made was blocked or mixed within a block of trials. The results are discussed in terms of current accounts of action-compatible blindness and the possible cognitive differences between making a single response and repeating a response.     

A role for backward transitional probabilities in word segmentation?

A number of studies have shown that people exploit transitional probabilities between successive syllables to segment a stream of artificial continuous speech into words. It is often assumed that what is actually exploited are the forward transitional probabilities (given XY, the probability that X will be followed by Y), even though the backward transitional probabilities (the probability that Y has been preceded by X) were equally informative about word structure in the languages involved in those studies. In two experiments, we showed that participants were able to learn the words from an artificial speech stream when the only available cues were the backward transitional probabilities. Learning is as good under those conditions as when the only available cues are the forward transitional probabilities. Implications for some current models of word segmentation, particularly the simple recurrent networks and PARSER models, are discussed.     

Development of children's mental representations: effects of age, sex, and school experience

In the present study mental representations in drawings by 158 young children, ages 2 1/2 to 6 yr. old were analysed. The aim was to investigate whether the accuracy of mental representations increased with age and how this development progressed. Also tested were whether the inferred mental representations differed for boys and girls and whether preschool experience affected the drawings. As expected, mental representation increased in complexity with age as measured by Goodenough's score, and girls' mental representations (drawings) were significantly more elaborate than boys. Moreover, attending school early seemed to affect mental representations of the 3-yr.-olds but not the 4-yr.-olds. Results are discussed in terms of internal and external factors in mental representation in drawing a man.     

Perceptual processing of partially and fully assimilated words in French

Models of speech perception attribute a different role to contextual information in the processing of assimilated speech. This study concerned perceptual processing of regressive voice assimilation in French. This phonological variation is asymmetric in that assimilation is partial for voiced stops and nearly complete for voiceless stops. Two auditory-visual cross-modal form priming experiments were used to examine perceptual compensation for assimilation in French words with voiceless versus voiced stop offsets. The results show that, for the former segments, assimilating context enhances underlying form recovery, whereas it does not for the latter. These results suggest that two sources of information -- contextual information and bottom-up information from the assimilated forms themselves -- are complementary and both come into play during the processing of fully or partially assimilated word forms.     

The scope and limits of enactive approaches to visual experience

I pursue here three related aims. First, I criticise some of the metaphysical claims made on behalf of the so-called 'enactive' approach to visual experience. Secondly, I explain why the enactive view of visual experience is hard to square with the evidence in favour of the two-visual-systems model of human vision. Finally, I explore one possible way to develop the 'pre-emptive perception' framework and explain why, contrary to first appearances, some of the fundamental discoveries of brain mechanisms, whose function might be to underlie pre-emptive perception, do not really support the enactive approach to visual experience.     

Shades of disengagement: high school dropouts speak out

The purpose of this study was to describe how dropouts navigate their educational journeys. Eighty dropouts participated to individual interviews which were recorded and transcribed. The data analysis yielded three broad categories in answering the research question. Setting the stage in the family and the school, the dropouts described their teetering between in and out of school contexts and proceeded to explain how they ended their educational journey. For 20 dropouts, family turmoil represented a pervasive force negatively influencing their schooling. For 24 dropouts, problems in school set the stage for dropping out. Teetering represented juggling strategies to prolongand to sabotage the journey, while the end of the journey occurred as a result of a pivotal moment (48%) or a gradual fade out (52%) from the school context.