Semantic interference during object naming in agrammatic and logopenic primary progressive aphasia (PPA)

This study examined the time course of object naming in 21 individuals with primary progressive aphasia (PPA) (8 agrammatic (PPA-G); 13 logopenic (PPA-L)) and healthy age-matched speakers (n = 17) using a semantic interference paradigm with related and unrelated interfering stimuli presented at stimulus onset asynchronies (SOAs) of −1000, −500, −100 and 0 ms. Results showed semantic interference (SI) (i.e. significantly slower RTs in related compared to unrelated conditions) for all groups at −500, −100 and 0 ms, indicating timely spreading activation to semantic competitors. However, both PPA groups showed a greater magnitude of SI than normal across SOAs. The PPA-L group and six PPA-G participants also evinced SI at −1000 ms, suggesting an abnormal time course of semantic interference resolution, and concomitant left hemisphere cortical atrophy in brain regions associated with semantic processing. These subtle semantic mapping impairments in non-semantic variants of PPA may contribute to the anomia of these patients.     

Discrete Process Model for Quantum Systems of Matter and Mind

Attempts to create a coherent scientific picture of the world as a whole on the basis of quantum physics has sped up at the turn of the millennium. There particularly seem to be expectations that the development of a new kind of quantum mechanics could make it possible to describe both matter and consciousness in one frame of reference (“dual aspect approach”). These ideas are often results of brilliant intuitive visions but as yet not able to produce testable hypotheses. Maybe “wave mechanics” is not very suitable in the study of consciousness from the quantum mechanical point of view. The aim of this article is to show how both the matter and the mind systems can be described with one coherent mathematical model if we assume both space and time to be discrete.     

Central executive involvement in children's spatial memory

Previous research with adults found that spatial short-term and working memory tasks impose similar demands on executive resources. We administered spatial short-term and working memory tasks to 8- and 11-year-olds in three separate experiments. In Experiments 1 and 2 an executive suppression task (random number generation) was found to impair performances on a short-term memory task (Corsi blocks), a working memory task (letter rotation), and a spatial visualisation task (paper folding). In Experiment 3 an articulatory suppression task only impaired performance on the working memory task. These results suggest that short-term and working memory performances are dependent on executive resources. The degree to which the short-term memory task was dependent on executive resources was expected to be related to the amount of experience children have had with such tasks. Yet we found no significant age-related suppression effects. This was attributed to differences in employment of cognitive strategies by the older children.     

Reminders can enhance or impair episodic memory updating: a memory-for-change perspective

ABSTRACT

The Memory-for-Change framework proposes that retrieving episodic memories can facilitate new learning when changes between existing memories and new information are integrated during encoding and later recollected. Four experiments examined whether reminders could improve memory updating and enhance new learning. Participants studied two study lists of word pairs and were given a cued recall test on responses from both lists. Reminders of List 1 words pairs (A-B) appeared immediately before List 2 words pairs that included repeated cues and changed responses (A-D). Across experiments, we varied the types of reminders to determine whether differences in their effectiveness as retrieval cues would influence memory for the list membership of responses. We found that presenting intact reminders (cue-response) enhanced the memory benefits associated with recollection-based retrieval of changes relative to when no reminders appeared and when partial reminders (cue-only) appeared with and without feedback. Importantly, cue-response reminders benefitted memory when they were recognised in List 2 and when changes were later recollected. This suggests that integrative encoding can be facilitated when substantial environmental support is available to cue retrieval of existing memories. These findings have practical implications for understanding which reminders best aid the correction of memories for inaccurate information.     

Increased susceptibility to proactive interference in adults with dyslexia?

Recent findings show that people with dyslexia have an impairment in serial-order memory. Based on these findings, the present study aimed to test the hypothesis that people with dyslexia have difficulties dealing with proactive interference (PI) in recognition memory. A group of 25 adults with dyslexia and a group of matched controls were subjected to a 2-back recognition task, which required participants to indicate whether an item (mis)matched the item that had been presented 2 trials before. PI was elicited using lure trials in which the item matched the item in the 3-back position instead of the targeted 2-back position. Our results demonstrate that the introduction of lure trials affected 2-back recognition performance more severely in the dyslexic group than in the control group, suggesting greater difficulty in resisting PI in dyslexia.     

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.