This study investigates the procedural learning, retention, and reactivation of temporal sensorimotor sequences in children with and without developmental coordination disorder. Twenty typically-developing children and 12 children with DCD took part in this study. The children were required to tap on a keyboard, synchronizing with auditory or visual stimuli presented as an isochronous temporal sequence, and practice non-isochronous temporal sequences to memorize them. Immediate and delayed retention of the audio-motor and visuo-motor non-isochronous sequences were tested by removing auditory or visual (...) stimuli immediately after practice and after a delay of 2 h. A reactivation test involved reintroducing the auditory and visual stimuli after the delayed recall. Data were computed via circular analyses to obtain asynchrony, the stability of synchronization and errors. Firstly, an overall deficit in synchronization with both auditory and visual isochronous stimuli was observed in DCD children compared to TD children. During practice, further improvements were found for the audio-motor non-isochronous sequence compared to the visuo-motor non-isochronous sequence in both TD children and children with DCD. However, a drastic increase in errors occurred in children with DCD during immediate retention as soon as the auditory stimuli were removed. Reintroducing auditory stimuli decreased errors in the audio-motor sequence for children with DCD. Such changes were not seen for the visuo-motor non-isochronous sequence, which was equally learned, retained and reactivated in DCD and TD children. All these results suggest that TD children benefit from both auditory and visual stimuli to memorize the sequence, whereas children with DCD seem to present a deficit in integrating an audio-motor sequence in their memory. The immediate effect of reactivation suggests a specific dependency on auditory information in DCD. Contrary to the audio-motor sequence, the visuo-motor sequence was both learned and retained in children with DCD. This suggests that visual stimuli could be the best information for memorizing a temporal sequence in DCD. All these results are discussed in terms of a specific audio-motor coupling deficit in DCD. (shrink)

The present study investigates procedural learning of motor sequences in children with developmental coordination disorder and/or developmental dyslexia, typically-developing children and healthy adults with a special emphasis on the role of the nature of stimuli and the neuropsychological functions associated to final performance of the sequence. Seventy children and ten adults participated in this study and were separated in five experimental groups: TD, DCD, DD, and DCD + DD children and adults. Procedural learning was assessed with a serial reaction time (...) task that required to tap on a specific key as accurately and quickly as possible when stimuli appeared on the screen. Three types of stimuli were proposed as cues: the classical version of the SRTT with 4 squares aligned horizontally on the screen, giving visuospatial cues, and two modified versions, with 4 letters aligned horizontally on the screen and letters at the center of the screen. Reaction times during the repeated and random blocks allowed assessing three phases of learning: global learning, specific learning and retention of the sequence. Learning was considered as completed when RT evolved significantly in the three phases. Neuropsychological assessment involved, among other functions, memory and attentional functions. Our main result was that learning and retention were not influenced by the available cues in adults whereas learning improved with specific cues in children with or without neurodevelopmental disorders. More precisely, learning was not completed with L cues in children with neurodevelopmental disorders. For children with DD, learning was completed with the VS and VS + L cues whereas for children with DCD, learning was completed with combined VS + L cues. Comorbidity between DD and DCD had no more impact on procedural learning than DCD alone. These results suggest that learning depends on the nature of cues available during practice and that cues allowing learning and retention depend on the type of disorder. Moreover, selective attention was correlated with RT during retention, suggesting that this neuropsychological function is important for procedural learning whatever the available cues. (shrink)

SummaryA special theory of probability is propounded as a non‐deductive supplement to analytic judgments in epistemological systems. This theory combines ‘inductive’ probability and ‘effective’ probability in a total probability which is the ‘degree of certainty’ of our beliefs. For cases of false belief, the concept of ‘degree of credibility’, or assumed degree of certainty, is introduced. This quantity is mathematically combined with the ‘real’ degree of certainty to determine the flower) degree of certainty implicit in a mistaken credence.RésuméUne théorie spéciale (...) de la probabilité comme supplément non déductif des jugements analytiques en systèmes épistémologiques est proposée. Cette théorie combine la probabilité‘inductive’ et la probabilité‘effective’ dans une probabilité totale qui est le ‘degré de certitude’ de nos croyances. Pour les cas de fausse croyance, le concept de ‘degré de crédibilité’, ou degrésupposé de certitude, est introduit. Cette quantité est mathématiquement combinée avec le degré‘réel’ de certitude pour déterminer le degré de certitude implicite dans une croyance erronée.ZusammenfassungEine besondere Wahrscheinlichkeitstheorie wird vorgeschlagen als eine nichtdeduktive Ergänzung der analytischen Urteile in erkenntnistheoretischen Systemen. Diese Theorie kombiniert die 〈induktive〉 Wahrscheinlichkeit mit der 〈effektiven〉 Wahrscheinlichkeit , indem sie sie zu einer totalen Wahrscheinlichkeit verbindet, die den 〈Grad der Gewissheit〉 unseres Glaubens ausmacht. Der Begriff des 〈Grades der Glaubwiirdigkeit〉, oder der angenommene Gewissheitsgrad, wird für Falle von falschem Glauben eingeführt. Diese Quantität wird mathematisch mit dem 〈wirklichen〉 Gewissheitsgrad kombiniert, um den Gewissheitsgrad, der implizit in falschen Erwartungen vorhanden ist, zu bestimmen. (shrink)

The Possible Universe explores a hypothetical philosophical synthesis based on the largest conceivable domain—the realm of the possible. This book suggests a final and ultimate in the notion of the possible, by which all necessary and contingent entities coalesce into the universe as possibility.