Gradual training reduces practice difficulty while preserving motor learning of a novel locomotor task

Motor learning strategies that increase practice difficulty and the size of movement errors are thought to facilitate motor learning. In contrast to this, gradual training minimizes movement errors and reduces practice difficulty by incrementally introducing task requirements, yet remains as effective as sudden training and its large movement errors for learning novel reaching tasks. While attractive as a locomotor rehabilitation strategy, it remains unknown whether the efficacy of gradual training extends to learning locomotor tasks and their unique requirements. The influence of gradual vs. sudden training on learning a locomotor task, asymmetric split belt treadmill walking, was examined by assessing whole body sagittal plane kinematics during 24 hour retention and transfer performance following either gradual or sudden training. Despite less difficult and less specific practice for the gradual cohort on day 1, gradual training resulted in equivalent motor learning of the novel locomotor task as sudden training when assessed by retention and transfer a day later. This suggests that large movement errors and increased practice difficulty may not be necessary for learning novel locomotor tasks. Further, gradual training may present a viable locomotor rehabilitation strategy avoiding large movement errors that could limit or impair improvements in locomotor performance.     

"That's not a real body": identifying stimulus qualities that modulate synaesthetic experiences of touch

Mirror-touch synaesthesia is a condition where observing touch to another’s body induces a subjective tactile sensation on the synaesthetes body. The present study explores which characteristics of the inducing stimulus modulate the synaesthetic touch experience. Fourteen mirror-touch synaesthetes watched videos depicting a touch event while indicating (i) whether the video induced a tactile sensation, (ii) on which side of their body they felt this sensation and (iii) the intensity of the experienced sensation. Results indicate that the synaesthetes experience stronger tactile sensations when observing touch to real bodies, whereas observing touch to dummy bodies, pictures of bodies and disconnected dummy body parts elicited weaker sensations. These results suggest that mirror-touch synaesthesia is not entirely bottom-up driven, but top-down information, such as knowledge about real and dummy body parts, also modulate the intensity of the experience.     

Message Framing,Normative Advocacy and Persuasive Success

In a recent article in Argumentation, O’Keefe (Argumentation 21:151–163, 2007) observed that the well-known ‘framing effects’ in the social psychological literature on persuasion are akin to traditional fallacies of argumentation and reasoning and could be exploited for persuasive success in a way that conflicts with principles of responsible advocacy. Positively framed messages (“if you take aspirin, your heart will be more healthy”) differ in persuasive effect from negative frames (“if you do not take aspirin, your heart will be less healthy”), despite containing ‘equivalent’ content. This poses a potential problem, because people might be unduly (and unsuspectingly) influenced by mere presentational differences. By drawing on recent cognitive psychological work on framing effects in choice and decision making paradigms, however, we show that establishing whether two arguments are substantively equivalent—and hence, whether there is any normative requirement for them to be equally persuasive—is a difficult task. Even arguments that are logically equivalent may not be information equivalent. The normative implications of this for both speakers and listeners are discussed.     

Non-monotonicity and Informal Reasoning: Comment on Ferguson (2003)

In this paper, it is argued that Ferguson’s (2003, Argumentation 17, 335–346) recent proposal to reconcile monotonic logic with defeasibility has three counterintuitive consequences. First, the conclusions that can be derived from his new rule of inference are vacuous, a point that as already made against default logics when there are conflicting defaults. Second, his proposal requires a procedural “hack” to the break the symmetry between the disjuncts of the tautological conclusions to which his proposal leads. Third, Ferguson’s proposal amounts to arguing that all everyday inferences are sound by definition. It is concluded that the informal logic response to defeasibility, that an account of the context in which inferences are sound or unsound is required, still stands. It is also observed that another possible response is given by Bayesian probability theory (Oaksford and Chater, in press, Bayesian Rationality: The Probabilistic Approach to Human Reasoning, Oxford University Press, Oxford, UK; Hahn and Oaksford, in press, Synthese).     

Developmental changes of sleep spindles and their impact on sleep‐dependent memory consolidation and general cognitive abilities: A longitudinal approach

Sleep spindles are related to sleep‐dependent memory consolidation and general cognitive abilities. However, they undergo drastic maturational changes during adolescence. Here we used a longitudinal approach (across 7 years) to explore whether developmental changes in sleep spindle density can explain individual differences in sleep‐dependent memory consolidation and general cognitive abilities. Ambulatory polysomnography was recorded during four nights in 34 healthy subjects (24 female) with two nights (baseline and experimental) at initial recording (age range 8–11 years) and two nights at follow‐up recording (age range 14–18 years). For declarative learning, participants encoded word pairs with a subsequent recall before and after sleep. General cognitive abilities were measured by the Wechsler Intelligence Scale. Higher slow (11–13 Hz) than fast (13–15 Hz) spindle density at frontal, central, and parietal sites during initial recordings, followed by a shift to higher fast than slow spindle density at central and parietal sites during follow‐up recordings, suggest that mature spindle topography develops throughout adolescence. Fast spindle density increases from baseline to experimental night were positively related to sleep‐dependent memory consolidation. In addition, we found that the development of fast spindles predicted the improvement in memory consolidation across the two longitudinal measurements, a finding that underlines a crucial role for mature fast spindles for sleep‐dependent memory consolidation. Furthermore, slow spindle changes across adolescence were related to general cognitive abilities, a relationship that could indicate the maturation of frontal networks relevant for efficient cognitive processing. A video abstract of this article can be viewed at: https://www.youtube.com/watch?v=7NXJzm8HbIw and https://www.youtube.com/watch?v=iuMQY1OIJ0s