Cognitive Load and Prism Adaptation

Subjects wore goggles with prisms that laterally displaced the visual field (rightward by 11.4°) and with full view of the limb engaged in paced (2-s rate) sagittal pointing at either an implicit (“straight ahead of the nose”) target (Experiment 1) or an explicit (positioned leftward by 11.4°) target (in Experiment 2). In experimental conditions, subjects performed a secondary cognitive task (mental arithmetic) simultaneously during target pointing. In control conditions, no cognitive load was imposed. Aftereffect measures of adaptation to the prismatic displacement were not substantially different when problem solving was required, but terminal error of the exposure pointing task was reliably affected by cognitive load. These results are consistent with the hypothesis of separable mechanisms for adaptive coordination and adaptive alignment. Adaptive coordination may be mediated by strategically flexible coordinative linkage between sensory–motor systems (eye–head and hand—head), but spatial alignment seems to be mediated by adaptive encoders within coordinatively linked subsystems. If the coordination task involves predominately automatic processing, coordinative linkage can be frequent enough under cognitive load for substantial realignment to occur even though exposure performance (adaptive coordination) may be less than optimal.     

Effects of Movement Duration and Visual Feedback on Visual and Proprioceptive Components of Prism Adaptation

While looking through laterally displacing prisms, subjects pointed sagittally 80 times at an objectively straight-ahead target, completing a reciprocal out-and-back pointing movement every 1, 3, or 6 s. Visual feedback was available early in the pointing movement or only late at the end of movement. Aftereffect measures of adaptive shift (obtained after every 10 pointing trials) showed adaptive change only in limb position sense (i.e., proprioceptive adaptation) when movement duration was 1 s, regardless of visual feedback condition; but as movement duration increased, adaptive change in the eye position sense (i.e., visual adaptation) increased while proprioceptive adaptation decreased, especially for the late visual feedback condition. Regardless of visual feedback condition, proprioceptive adaptation showed the maximal rate of growth with the 1-s movement duration, whereas visual adaptation showed maximal growth with the 6-s movement duration. These results provide additional support for a model of adaptive spatial mapping in which the direction of strategically flexible coordination (guidance) between eye and limb (and consequently the locus of adaptive spatial mapping) is jointly determined by movement duration and timing of visual feedback. An additional effect of movement duration is to determine the rate of discordant inputs. Maximal growth of adaptation occurs when the input rate matches the response time of the spatial mapping function.     

Training the Parents of Juvenile Offenders: State of the Art and Recommendations for Service Delivery

Parent training is consistently highlighted as one of the most effective means of preventing delinquency and treating young children with conduct problems, and it has proven to be one of the most cost-effective interventions for doing so. There is, however, far less evidence supporting the efficacy of parent-training programs with adolescents and juvenile offenders. Nonetheless, it still seems to be one of the more promising methods for treating the behavior problems of adolescent delinquents, especially when used in conjunction with other carefully selected program components. We begin with an overview of parent training, highlighting the key components of successful programs. Research on the efficacy of parent training in the treatment of behavior problems among children and adolescents is discussed, particularly the differential impact of parental-training programs with specific groups of youths and families. We then discuss the ways in which parent training has been combined with other interventions in the treatment of delinquency. We conclude with a discussion of the problems encountered in implementing parent training, including recommendations for meeting the unique challenges of effective program implementation. The findings and conclusions of the research reported here are those of the authors and do not reflect the official positions or policies of the National Institute of Justice, The Office of Justice Programs, or the U.S. Department of Justice.     

Rethinking Sellars’ Myth of the Given: From the Epistemological to the Modal Relevance of Givenness in Kant and Hegel

ABSTRACT

Here, I pursue consequences, for the interpretation of Sellars’ critique of the ‘Myth of the Given’, of separating the modal significance that Kant attributed to empirical intuition from the epistemological role it also played for him. It is argued that Kant’s approach to modality in the Critique of Pure Reason can best be understood as a transcendental variation on Leibniz’s earlier ‘possibilist’ approach that treated the actual world as just one of a variety of possible alternative worlds. In this context, empirical intuitions seem to work like the mythical Givens subject to Sellars’ critique. This Kantian possibilism is then contrasted with an ‘actualist’ alternative approach to modality found in the contemporary work of Robert Stalnaker, but also recognizable in Hegel. In particular, the role of immediate perceptual judgments in Hegel is likened to that played by ‘witness statements’ in Robert Stalnaker’s attempt to distinguish the logic of judgments about the actual world from those about its alternate possibilities.     

Virtual and drawing structures for the Müller-Lyer illusions

This research assessed the relative contribution of 3-D virtual structure that generated the stimulus drawings (scene-based and picture-based theories) and 2-D structure of the drawings (object-based theories). Virtual structures were right-angle convex and concave corners in front of and behind the picture plane, respectively. Virtual corner size was manipulated directly (Experiment 1) and indirectly by manipulating drawing station point distance (Experiments 2 and 3), corner depth (Experiment 4), and corner distance from the picture plane (Experiments 5 and 6). Experiments 2 and 4 held the size of the projected corner edge (interior target line) constant, causing virtual corner size to vary, whereas Experiments 3, 4, 5, and 6 held size of the virtual corners constant, causing size of the projected corner edge or interior target line to vary. Subjects reproduced the length of the projected corner edge (interior target line). The illusions (difference between reproduced size of the projected corner edge and T-junction control) were generally well fit by the weighted sum of virtual corner size and size of the projected corner edge, but the projected distance between boundary line terminations (intertip distance) appeared as an additional contributing factor in Experiments 5 and 6. The implications of this methodological approach are discussed for theories of the illusions.     

Age of acquisition in sport: starting early matters

Although the age at which a skill is learned (age of acquisition [AoA]) is one of the most studied predictors of success in domains ranging from language to music, very little work has focused on this factor in sports. In order to uncover how the age at which a skill is learned relates to how athletes cognitively represent that skill, we asked a group of skilled golfers who learned to play golf before (early learners) or after (late learners) the age of 10 to take a series of putts on an indoor putting green. Golfers putted in isolation (single-task condition), while monitoring a stream of words presented over a loudspeaker (dual-task condition), or while being instructed to attend to specific aspects of their golf swing (skill-focused condition). Early and late learners putted equally well in the single-task and dual-task conditions. However, in the skill-focused condition, golfers who learned earlier performed worse than those who learned later. The results are consistent with the notion that AoA influences the manner in which sports, like other domains such as language and music, are represented in memory.     

Calibration and Alignment are Separable: Evidence From Prism Adaptation

In 2 prism adaptation experiments, the authors investigated the effects of limb starting position visibility (visible or not visible) and visual feedback availability (early or late in target pointing movements). Thirty-two students participated in Experiment 1 and 24 students participated in Experiment 2. Independent of visual feedback availability, constant error was larger and variable error was smaller for target pointing when limb starting position was visible during prism exposure. Independent of limb starting position visibility, aftereffects of prism exposure were determined by visual feedback availability. Those results support the hypothesis that calibration is determined by limb starting position visibility, whereas alignment is determined separately by visual feedback availability.