Type-specific proactive interference in patients with semantic and phonological STM deficits

Prior neuropsychological evidence suggests that semantic and phonological components of short-term memory (STM) are functionally and neurologically distinct. The current paper examines proactive interference (PI) from semantic and phonological information in two STM-impaired patients, DS (semantic STM deficit) and AK (phonological STM deficit). In Experiment 1 probe recognition tasks with open and closed sets of stimuli were used. Phonological PI was assessed using nonword items, and semantic and phonological PI was assessed using words. In Experiment 2 phonological and semantic PI was elicited by an item recognition probe test with stimuli that bore phonological and semantic relations to the probes. The data suggested heightened phonological PI for the semantic STM patient, and exaggerated effects of semantic PI in the phonological STM case. The findings are consistent with an account of extremely rapid decay of activated type-specific representations in cases of severely impaired phonological and semantic STM.     

Do objects in working memory compete with objects in perception?

It is generally assumed that “perceptual object” is the basic unit for processing visual information and that only a small number of objects can be either perceptually selected or encoded in working memory (WM) at one time. This raises the question whether the same resource is used when objects are selected and tracked as when they are held in WM. In two experiments, we measured dual-task interference between a memory task and a Multiple Object Tracking task. The WM tasks involve explicit, implicit, or no spatial processing. Our results suggest there is no resource competition between working memory and perceptual selection except when the WM task requires encoding spatial properties.     

Switching on and off … : Does smartphone use obstruct the possibility to engage in recovery activities?

This study examines the impact of work-related smartphone use on daily recovery from work-related efforts. The literature shows that work–home interference (WHI) is an important inhibitor of the recovery process. We propose that the extensive use of smartphones with its implicit request of 24/7 availability inhibits the process of engaging in activities that are required for daily recovery. A total of 80 employees (40 smartphone users, 40 controls) completed a 6-day diary questionnaire over a time period of 2 weeks. Contrary to our hypothesis, smartphone users did not experience more overall WHI than nonusers. Furthermore, four activities aimed at recovery were examined. We predicted that daily WHI would increase employees’ engagement in recovery activities, but only if they did not use a smartphone. Results showed that, for the control group, WHI was positively related to psychological detachment, relaxation, mastery, and control activities, whereas smartphone users facing high WHI did not succeed in engaging in these recovery activities. This implies that being connected to work in the evening hours through smartphones has consequences for the extent to which employees succeed in undertaking recovery activities.     

Individualized Challenge Point Practice as a Method to Aid Motor Sequence Learning

We conducted two studies to investigate if and how: (1) the rate of skill acquisition was related to motor performance at retention of a serial RT task (Study 1); and (2) whether rate of skill acquisition and baseline performance could be used to design schedules of practice related to contextual interference (CI) to enhance motor learning (Study 2). In Study 1, a slower rate of skill acquisition of repeating sequences in practice was related to faster response times at retention. Based on performance in Study 1, three levels of individualized CI were created for Study 2. Compared to low and moderate levels of CI, the higher CI practice condition led to faster response times in retention. We conclude that an individualized ‘challenge point’, which generates high CI enhances motor learning by optimizing challenge.     

Spatial Conceptual Influences on the Coordination of Bimanual Actions: When a Dual Task Becomes a Single Task

When the left and right hands produce 2 different rhythms simultaneously, coordination of the hands is difficult unless the rhythms can be integrated into a unified temporal pattern. In the present study, the authors investigated whether a similar account can be applied to the spatial domain. Participants (N = 8) produced a movement trajectory of semicircular form in single-limb and bimanual conditions. In the bimanual tasks, 1 limb moved above the other in the frontal plane. Bimanual unified tasks were constructed so that the spatial paths to be produced by the 2 limbs could be easily conceptualized as parts of a unified circle pattern. Bimanual distinct tasks availed a less obvious spatial pattern that would unify the 2 tasks. Performance of the spatial patterns was more accurate in the unified task, despite similar demands placed on the coordination dynamics between the limbs in the 2 cases (e.g., the phase relations). The authors conclude that a dual task becomes a single task, and interlimb interference is reduced, when the spatial patterns produced by the 2 hands form a geometric arrangement that can be conceptualized as a unified representation.     

Bimanual Training Reduces Spatial Interference

The authors investigated whether training can reduce bimanual directional interference by using a star-line drawing paradigm, Participants (N = 30) were required to perform rhythmical arm movements with identical temporal but differing directional demands. Moreover, the effectiveness of part-task training in which each movement was practiced in isolation was compared with that of whole-task training in which only combined movements were performed. Findings revealed that bimanual training substantially reduced spatial interference, but unimanual training did not. The authors therefore concluded that the spatial coupling of the limbs is not implemented in a rigid way; instead, the underlying neural correlate can undergo plastic changes induced by training. Moreover, the practical implication that emerged from the present study is that athletic, musical, or ergonomic skills that require a high degree of interlimb coordination are best served by whole-task practice.     

The Utility of Connectionism for Motor Learning: A Reinterpretation of Contextual Interference in Movement Schemas

Using the general framework of schema theory, and building on it, the present article takes a connectionist approach to motor learning and to contextual interference effects. These phenomena were simulated in an exploratory manner in neural networks. The outcome closely reflects previous research with humans. In a simulated ballistic movement task, networks performed worse during practice but showed better transfer when target movement distances were presented in a random rather than a blocked fashion. Connectionism provides a parsimonious account of the effect in terms of properties inherent in the parallel distributed network.     

Interactions Between Modality of Working Memory Load and Perceptual Load in Distractor Processing

The present study investigated interactions between working memory load and perceptual load. The load theory (Lavie, Hirst, de Fockert, &; Viding, 2004 Lavie, N., Hirst, A., de Fockert, J.W., &; Viding, E. (2004). Load theory of selective attention and cognitive control. Journal of Experimental Psychology: General, 133, 339–354.[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) claims that perceptual load decreases distractor interference, whereas working memory load increases interference. However, recent studies showed that effects of working memory might depend on the relationship between modalities of working memory and task stimuli. Here, we examined whether the relationship between working memory load and perceptual load would remain the same across modalities. The results of Experiment 1 showed that verbal working memory load did not affect a compatibility effect for low perceptual load, whereas it increased the compatibility effect for high perceptual load. In Experiment 2, the compatibility effect remained the same regardless of visual working memory load. These results suggest that the effects of working memory load and perceptual load depend on the relationship between the modalities of working memory and stimuli.     

Distraction Affects the Performance of Obstacle Avoidance During Walking

In this study, dual-task interference in obstacle-avoidance tasks during human walking was examined. Ten healthy young adults participated in the experiment. While they were walking on a treadmill, an obstacle suddenly fell on the treadmill in front of their left leg during either midswing, early stance, or late stance of the ipsilateral leg. Participants were instructed to avoid the obstacle, both as a single task and while they were concurrently performing a cognitive secondary task (dual task). Rates of failure, avoidance strategy, and a number of kinematic parameters were studied under both task conditions. When only a short response time was available, rates of failure on the avoidance task were larger during the dual task than during the single task. Smaller crossing swing velocities were found during the dual task as compared with those observed in the single task. The difference in crossing swing velocities was attributable to increased stiffness of the crossing swing limb. The results of the present study indicated that divided attention affects young and healthy individuals' obstacle-avoidance performance during walking.     

The Development of a Simple Ballistic Skill with and Without Visual Control

80 randomly selected male Ss discriminated the “effort” required to perform a simple 1-handed ballistic aiming task: aligning a Fletcher’s Trolley with a pointer placed at varying distances adjacent to an inclined wooden track. Groups were aged 5-6, 10-11, 15-16, and 18 or more yr., with 10 Ss able to see both hands and target while the other 10 could see neither. A split-plot factorial design was used. On excluding the 5-6 yr.-old “Nonvision” children, the remaining 7 sub-groups were shown to be homogeneous. Mean absolute error scores increased with Distance, and also with a decrease in Age. In the “Non-vision” condition accuracy was reduced still further for all Ss. Age, Vision, and Distance and the interaction of Age with Vision were all significant, p<.01.