Mechanisms Underlying Transfer of Task-Defined Rules Across Feature Dimensions

Author(s):  
Giulia Baroni ◽  
Motonori Yamaguchi ◽  
Jing Chen ◽  
Robert W. Proctor

The Simon effect can be reversed, favoring spatially noncorresponding responses, when people respond to stimulus colors (e.g., green) by pressing a key labeled with the alternative color (i.e., red). This Hedge and Marsh reversal is most often attributed to transfer of logical recoding rules from the color dimension to the location dimension. A recent study showed that this transfer of logical recoding rules can occur not only within a single task but also across two separate tasks that are intermixed. The present study investigated the conditions that determine the transfer of logical recoding rules across tasks. Experiment 1 examined whether it occurs in a transfer paradigm, that is when the two tasks are performed separately, but provided little support for this possibility. Experiment 2 investigated the role of task-set readiness, using a mixed-task paradigm with a predictable trials sequence, which indicated that there is no transfer of task-defined rules across tasks even when they are highly active during the Simon task. Finally, Experiments 3 and 4 used a mixed-task paradigm, where trials of the two tasks were mixed randomly and unpredictably, and manipulated the amount of feature overlap between tasks. Results indicated that task similarity is a determining factor for transfer of task-defined rules to occur. Overall, the study provides evidence that transfer of logical recoding rules tends to occur across two tasks when tasks are unpredictably intermixed and use stimuli that are highly similar and confusable.

Author(s):  
Luisa Lugli ◽  
Stefania D’Ascenzo ◽  
Roberto Nicoletti ◽  
Carlo Umiltà

Abstract. The Simon effect lies on the automatic generation of a stimulus spatial code, which, however, is not relevant for performing the task. Results typically show faster performance when stimulus and response locations correspond, rather than when they do not. Considering reaction time distributions, two types of Simon effect have been individuated, which are thought to depend on different mechanisms: visuomotor activation versus cognitive translation of spatial codes. The present study aimed to investigate whether the presence of a distractor, which affects the allocation of attentional resources and, thus, the time needed to generate the spatial code, changes the nature of the Simon effect. In four experiments, we manipulated the presence and the characteristics of the distractor. Findings extend previous evidence regarding the distinction between visuomotor activation and cognitive translation of spatial stimulus codes in a Simon task. They are discussed with reference to the attentional model of the Simon effect.


Author(s):  
Davide R. Mussi ◽  
Barbara F. M. Marino ◽  
Lucia Riggio

Abstract. Recently, the Simon effect (SE) has been observed in social contexts when two individuals share a two-choice task. This joint SE (JSE) has been interpreted as evidence that people co-represent their actions. However, it is still not clear if the JSE is driven by social factors or low-level mechanisms. To address this question, we applied a common paradigm to a joint Simon task (Experiments 1 and 4), a standard Simon task (Experiment 2), and a go/no-go task (Experiment 3). The results showed that both the JSE and the SE were modulated by the repetition/non-repetition of task features. Moreover, the JSE was differently modulated by the gender composition of the two individuals involved in the shared task and by their interpersonal relationship. Taken together, our results do not support a pure social explanation of the JSE, nevertheless, they show the independent role of different social factors in modulating the effect.


Author(s):  
Liang Zhao ◽  
Yang Bai ◽  
Jie Ma ◽  
Yonghui Wang

Congruency sequence effects are observed when the congruency effects following incongruent trials are smaller than those following congruent trials. It is typically assumed that such flexible adjustments are evidence of cognitively controlled dynamic modulations. The present study investigated whether cognitive control acts locally or globally when implicit and explicit conflicts exist simultaneously within a system. The implicit SNARC task and explicit Simon task were combined in a single task. The results showed that congruency effects of one type (e.g., SNARC effect) were only smaller following an incongruent trial of the same type (e.g., SNARC effect), but not when following an incongruent trial of the other type (e.g., Simon effect). These results indicate the operation of local control mechanisms triggered by implicit and explicit conflicts.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Shugang Zhao ◽  
Hongxia Wang ◽  
Kai Liu ◽  
Linqing Li ◽  
Jinbing Yang ◽  
...  

Abstract Background Tissue culture is an effective method for the rapid breeding of seedlings and improving production efficiency, but explant browning is a key limiting factor of walnut tissue culture. Specifically, the polymerization of PPO-derived quinones that cause explant browning of walnut is not well understood. This study investigated explants of ‘Zanmei’ walnut shoot apices cultured in agar (A) or vermiculite (V) media, and the survival percentage, changes in phenolic content, POD and PPO activity, and JrPPO expression in explants were studied to determine the role of PPO in the browning of walnut explants. Results The results showed that the V media greatly reduced the death rate of explants, and 89.9 and 38.7% of the explants cultured in V media and A media survived, respectively. Compared with that of explants at 0 h, the PPO of explants cultured in A was highly active throughout the culture, but activity in those cultured in V remained low. The phenolic level of explants cultured in A increased significantly at 72 h but subsequently declined, and the content in the explants cultured in V increased to a high level only at 144 h. The POD in explants cultured in V showed high activity that did not cause browning. Gene expression assays showed that the expression of JrPPO1 was downregulated in explants cultured in both A and V. However, the expression of JrPPO2 was upregulated in explants cultured in A throughout the culture and upregulated in V at 144 h. JrPPO expression analyses in different tissues showed that JrPPO1 was highly expressed in stems, young leaves, mature leaves, catkins, pistils, and hulls, and JrPPO2 was highly expressed in mature leaves and pistils. Moreover, browning assays showed that both explants in A and leaf tissue exhibited high JrPPO2 activity. Conclusion The rapid increase in phenolic content caused the browning and death of explants. V media delayed the rapid accumulation of phenolic compounds in walnut explants in the short term, which significantly decreased explants mortality. The results suggest that JrPPO2 plays a key role in the oxidation of phenols in explants after branch injury.


2013 ◽  
Vol 18 (3) ◽  
pp. 118-129 ◽  
Author(s):  
Steven Roberts

A recent but growing trend in studies of young people's lives has been to highlight that there is a ‘missing middle’ in the youth studies research agenda. It has been argued that much youth research focuses on either successful or very troubled transitions to adulthood, with the lives of those who might simply be ‘getting by’ representing an empirical absence. Building on previous work that has addressed how such a missing middle can add to our understanding of educational experience and attainment, labour market engagement and participation, and issues of identity, this paper pays attention to the housing transitions, careers and aspirations of a group of ‘ordinary’ and apparently unproblematic working class young men. Because they do not represent groups that have been of especial interest in youth studies to date, their experiences problematize the on-going utility of dominant conceptual frameworks used to explain housing transitions. In addition to their ‘lack of fit’ with ideal type typologies, the young men also reveal the shifting nature of attitudes towards communal living ‘which is traditionally associated with middle class students’ in combination with the continuing role of social resources as a determining factor in their housing transition.


Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4651
Author(s):  
Yilin Deng ◽  
Wei Lai ◽  
Bin Xu

The energy crisis and environmental pollution have attracted much attention and have promoted researches on clean and sustainable hydrogen energy resources. With the help of highly active and stable transition metal nickel-based catalysts, the production of hydrogen from water electrolysis from electrolyzed water has become an inexpensive and efficient strategy for generating hydrogen energy. In recent years, heteroatom doping has been found to be an effective strategy to improve the electrocatalytic hydrogen evolution reaction (HER) performances of nickel-based catalysts in acidic, neutral, and alkaline media. This review will highlight many recent works of inexpensive and readily available heteroatom-doped nickel-based HER catalysts. The evaluation methods for the performances of HER catalyst will be briefly described, and the role of heteroatom doping and its application in nickel-based catalyst will be summarized. This article will also point out some heteroatom doping strategies, which may provide references and inspire the design of other catalysts with dopants.


1996 ◽  
Vol 54 (1) ◽  
pp. 37-41 ◽  
Author(s):  
Henrique B. Ferraz ◽  
Luiz A. F. Andrade ◽  
Vítor Tumas ◽  
Leandro C. Calia ◽  
Vanderci Borges

Although the precise etiology of Parkinson's disease (PD) is as yet unknown, it appears that certain environmental factors are involved. Prior living in a rural area has been implicated as a possible risk factor for PD, particularly in the early onset type. We evaluated the role of previous living conditions in the clinical correlates and outcome characteristics of 118 PD patients. All of them were seen from January 1987 to October 1992. The Rural Group (RG) comprised 71 patients (60.2%) who had lived in the rural area for at least 10 years (mainly in early phase of life) and the Urban Group (UG) consisted of 47 patients (39.8%) who had lived their entire life in an urban environment. The average age at the beginning of the symptoms was 58.8 in the RG and 54.1 in the UG. The mixed form of the disease (tremor, rigidity and akinesia) was the most frequent in both groups. A minimum 6-month follow-up period was undertaken with 63 patients (average 20 months) and no difference in response to treatment or in progression of the illness was detected between the two groups. Our data show that the previous living environment does not appear to be a determining factor in either the clinical or outcome characteristics of PD.


2013 ◽  
Vol 69 (1) ◽  
Author(s):  
S. Cobbing ◽  
V. Chetty ◽  
J. Hanass-Hancock ◽  
J. Jelsma ◽  
H. Myezwa ◽  
...  

Despite increased access to highly active anti-retroviral therapy (HAART) in South Africa, there remains a high risk of people living with HIV (PLHIV) developing a wide range of disabilities. Physiotherapists are trained to rehabilitate individuals with the disabilities related to HIV. Not only can South African physiotherapists play a significant role in improving the lives of PLHIV, but by responding proactively to the HIV epidemic they can reinforce the relevance and value of the profession in this country at a time when many newly qualified therapists are unable to secure employment. This paper offers recommendations that may help to fuel this response. These ideas include enhancing HIV curricula at a tertiary level, designing and attending continuing education courses on HIV and researching Southern African rehabilitation interventions for HIV at all levels of practice. furthermore, it is vital that physiotherapists are at the forefront of directing multi-disciplinary responses to the rehabilitation of PLHIV in order to influence stakeholders who are responsible for health policy formulation. it is hoped that this paper stimulates discussion and further ideas amongst physiotherapists and other health professionals in order to improve the quality and access to care available to PLHIV in South Africa.


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