Effects of load on the time course of attentional engagement,disengagement, and orienting in reading

Sensory-motor delays vary over the course of development and under different environmental conditions. Previous research has shown that humans can compensate for the resulting temporal misalignment while performing sensory-motor tasks (e.g., Cunningham, Billock, & Tsou, 2001a), but remains silent on the question of whether perceptual learning—similar to that involved in adaptation to spatial misalignment (e.g., Redding & Wallace, 1993) and in adaptation to purely intersensory misalignment (e.g., Fujisaki, Shimojo, Kashino, & Nishida, 2004)—is also involved in this adaptive response. Following an attempted replication of Cunningham et al.'s (2001a) study in a preliminary experiment, we present in this paper two experiments that demonstrate that after-effects of adaptation to temporal misalignment do not spontaneously decay. The literature on adaptation to spatial misalignment suggests that, while instrumental learning spontaneously decays in the absence of reinforcement, perceptual learning persists. Therefore our results are consistent with adaptation being effected through perceptual learning.     

High-resolution characterization of the precipitation behavior of an Al–Zn–Mg–Cu alloy

The metastable particles in an Al–Zn–Mg–Cu alloy have been examined at atomic-resolution using high-angle annular dark field (HAADF) imaging. In under-aged conditions, thin η′ plates were formed with a thickness of seven atomic planes parallel to the {111}_Al planes. The five inner planes of the η′ phase appear to be alternatively enriched in Mg and Zn, with two outer planes forming distinct Zn-rich interfacial planes. Similar Zn-rich interfacial enrichment has also been identified for the η phase, which is a minimum 11-plane thick structure. In rare instances, particles less than seven planes were found indicating a very early preference for seven-layer particle formation. Throughout the aging, the plate thickness appears constant, while the plate radius increases and no particles between 7 and 11 planes were observed. Based on the HAADF contrast, our observations do not support the η′ models previously set forth by other authors. Clear structural similarities between η′ and η were observed, suggesting that drawing distinctions between η′ and η phases may not be necessary or useful.     

Recovery of Lost Transfer Effects

Tracking tasks known to facilitate or interfere with one another were investigated under various sequences of alternation. Double and treble alternating sequences of 2 tasks were used. 6 groups of 12 Ss practiced for 20 10-sec. trials, with 50-sec. intertrial intervals. Trend analyses were employed in comparing the results of the double and treble alternating sequences with the single alternating sequence and postshift trials of the previous study (Laszlo & Pritchard, 1969). The results showed that facilitation or interference lost with single alternation was recovered with double or treble alternating sequences. Rate and degree of recovery appeared to depend upon the degree of transfer between tasks and strategies employed by S. These results were discussed in terms of motor program consolidation.     

First-Trial Adaptation to Prism Exposure

Terminal target-pointing error on the 1st trial of exposure to optical displacement is usually less than that expected from the optical displacement magnitude. Such 1st trial adaptation was confirmed in 2 experiments (N = 48 students in each) comparing pointing toward optically displaced targets and toward equivalent physically displaced targets (no optical displacement), with visual feedback delayed until movement completion. First-trial performance could not be explained by ordinary target undershoot, online correction, or reverse optic flow information about true target position and was unrelated to realignment aftereffects. Such adaptation might be an artifact of the asymmetry of the structured visual field produced by optical displacement, which induces a felt head rotation opposite to the direction of the displacement, thereby reducing the effective optical displacement.     

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.     

Transient and sustained cognitive control modulates task‐irrelevant process

In the cognitive conflict task, transient and sustained contexts modulate the congruency effect. Transient modulation is the effect of preceding trial types, while sustained modulation is the effect of context in an experimental block. The present study was conducted with two aims: The first was to reveal which processes, a task‐relevant one and a task‐irrelevant one, are changed by these contexts, and the second was to reveal the difference between the transient and the sustained modulations. The results of two experiments suggested that, although both transient and sustained modulations occurred during the task‐irrelevant process, these modulations may be different in nature. Transient modulation was caused by just an inhibition in using task‐irrelevant information, while sustained modulation showed a newly started use of task‐irrelevant information as a result of the participants' re‐adaptation to the context.     

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.     

The adaptation of non‐western and Muslim immigrant adolescents in the Netherlands: An immigrant paradox?

van Geel, M. & Vedder, P. (2010). The adaptation of non‐western and Muslim immigrant adolescents in the Netherlands: An immigrant paradox? Scandinavian Journal of Psychology, 51, 398–402. This article addresses the possible existence of an immigrant paradox in a sample of immigrant adolescents attending vocational schools in the Netherlands. An immigrant paradox is the finding that first generation immigrants show a more positive pattern of adaptation than nationals despite poorer economic conditions. Second generation immigrants regress to the nationals in terms of adaptation. A sample of 152 first generation immigrant adolescents, 285 second generation immigrant adolescents and 406 national adolescents completed self‐reports about socio‐economic status, psychological problems, behavioral problems and self‐esteem. The results supported the existence of an immigrant paradox in this sample. This indicates that further assimilation among immigrant adolescents does not necessarily lead to increased well being.     

Distinct consolidation outcomes in a visuomotor adaptation task: Off-line leaning and persistent after-effect

Consolidation is a time-dependent process responsible for the storage of information in long-term memory. As such, it plays a crucial role in motor learning. In two experiments, we sought to determine whether one’s performance influences the outcome of the consolidation process. We used a visuomotor adaptation task in which the cursor moved by the participants was rotated 30° clockwise. Thus, participants had to learn a new internal model to compensate for the rotation of the visual feedback. The results indicated that when participants showed good adaptation in the first session, consolidation resulted in a persistent after-effect in a no-rotation transfer test; they had difficulty returning to their normal no-rotation internal model. However, when participants showed poor adaptation in the first session, consolidation led to significant off-line learning (between sessions improvement) but labile after-effects. These observations suggest that distinct consolidation outcomes (off-line learning and persistent after-effect) may occur depending on the learner’s initial performance.     

儿童2岁时的不顺从对4～11岁间社会适应的预测

采用实验室观察、母亲报告和教师报告,对138名随机抽取的北京市2岁儿童进行追踪,考察2岁时的不顺从行为对4岁、7岁和11岁时社会适应的影响。结果表明:(1)2岁时的消极不顺从行为可正向预测7岁时母亲报告的外显问题行为、教师报告的攻击性-学习问题和11岁时母亲报告的学习问题。(2)2岁时的拒绝/协商行为可正向预测4岁时母亲报告的多动。(3)2岁时的反抗行为可正向预测11岁时教师报告的内隐问题行为。