立体视觉的心理物理和VEP比较研究

心理物理试验是研究立体视觉的主要方法。70年代VEP开始用于体视研究,并取得许多结果。由于VEP信号复杂,这些结果不能令人满意。本文使用心理物理试验和VEP对比方法对体视加以研究。我们的结果是:VEP波形中第一个正峰与刺激图形的亮度有关;N_2峰和P_3峰的潜伏期对判断体视存在与否有重要价值;本试验确定N_2峰潜伏期在体视存在时约为240ms—280ms,无体视存在时约为290ms—310ms;P_3峰潜伏期在体视存在时约为280ms—310ms,无体视存在时约为340ms—360ms;体视存在时的VEP与无体视存在时的VEP的互相关系数小于0.1;有体视的VEP其功率谱密度在8Hz附近有一峰;心理物理试验中使用强制选择得到的结果从VEP波形比较中可以确认是可靠的;有体视的VEP其N_2和P_3的潜伏期随视差变化呈现规律性改变。     

Alternation behavior, spatial discrimination, and reversal disturbances following 6-hydroxydopamine lesions in the nucleus accumbens of the rat

The effects of dopaminergic depletion of the nucleus accumbens was tested in various behavioral tasks such as alternation, spatial discrimination, and reversal learning, and in an extinction paradigm in a T maze. Animals with lesions showed impairment of spontaneous alternation behavior, disturbances in the acquisition of spatial discrimination, and great difficulty in reversing previously learned habits. In the extinction phase, experimental animals are unable to adjust their behavior, and continue to choose the previously reinforced arm of the T maze. It is suggested that the nucleus accumbens plays an important role in the transition of motivation into action, and that dopamine has a facilitatory influence on the mediation of these processes.     

Disturbances in exploratory behavior and functional recovery in the Y and radial mazes following dopamine depletion of the lateral septum

The effects of 6-hydroxydopamine (6-OHDA) injected into the lateral septum in rats were investigated for spontaneous alternation behavior in a Y maze and for spatially oriented behavior in an 8-arm radial maze. The performance of the animals in these tests was assessed under two physiological states, food-satiated and food-deprived. The selective depletion of septal dopaminergic concentrations leads to behavioral disturbances in both the Y and the radial mazes. These deficits disappeared when the animals with 6-OHDA lesions were food-deprived. These results confirm other studies from our laboratory and support two conclusions. First, lesions of dopaminergic neurons lead to behavioral impairments which resemble those found after the total lesion of the structure they innervate. Second, these behavioral impairments are responsive to therapeutic treatments, manipulations of the internal or external environment, or the level of arousal, since under certain conditions a recovery of function can occur in the absence of dopaminergic neurons. These two points provide additional support for a nonspecific role for the dopaminergic neurons originating in the ventral tegmental area. These neurons could have a permissive role in the functioning of the forebrain structures they innervate.     

#sustainablefashion on Instagram: A content and network analysis of user-generated posts

The social and environmental impacts of the global fashion industry face increasing scrutiny. As such, consumers and brands look towards ‘sustainable fashion’ for low-impact alternatives. Simultaneously, visual social media platforms such as Instagram have become prevalent places for fashion advertising and discourse. To investigate this under-researched area, the current study utilises visual content and social network analysis to explore how sustainable fashion is presented on Instagram, specifically: (a) what visual characteristics are present within sustainable fashion content, and (b) in what broader contexts and communities is discussion of sustainable fashion taking place? Posts included under the hashtag #sustainablefashion (N = 650) were inspected for visual characteristics, including type of clothing, presence of person, post setting, presence of nature, and post format. Most posts were photographs located indoors with no person and no nature-based elements. The hashtags used alongside #sustainablefashion were analysed with Gephi software to establish a social network and community groups of related topics. Network analysis revealed four key community groups: online-promotional, artisan-traditional, eco-ethical, and Malay-online-selling. Secondhand fashion also appeared to be the most prominent sustainable fashion alternative on Instagram. This study is one of the first to investigate the characteristics of user-generated #sustainablefashion content on Instagram. Whilst social media is a burgeoning avenue for research, existing studies primarily investigate how these platforms can be harnessed for advertising, rather than what users themselves are already posting. Implications for brands who use this platform and opportunities for future research are discussed.     

Semantic Organization, Strategy Use, and Productivity in Bilingual Semantic Verbal Fluency

This study of semantic verbal fluency addressed two research questions: (1) What are the between-language similarities and differences in the performance of balanced bilinguals? (2) What is the relationship between productivity and the use of a semantic grouping strategy to organize responses? Forty neurologically normal, bilingual adults were tested twice in each language (French/English), in a 2 (Language) by 2 (Test) by 2 (Group) design. On Test 2, half the 40 subjects were instructed to group items by subcategory, while half simply repeated the test. Results showed (1) many more between-language similarities than differences and (2) no between-group differences in productivity.     

Phonology and orthography in visual word recognition: Evidence from masked non-word priming

Three lexical decision experiments in French investigated the effects of briefly presented forward-masked non-word primes on latencies to phonologically and/or orthographically related targets. At 64-msec prime presentation durations, primes that are pseudohomophones of the target produced facilitatory effects compared to orthographic controls, but these orthographically similar non-word primes did not facilitate target recognition compared to unrelated controls. These results were obtained independently of target word frequency and independently of the presence or absence of pseudohomophone targets in the experimental lists. With a 32-msec prime duration, on the other hand, pseudohomophone and orthographic primes had similar effects on target recognition, both producing facilitation relative to unrelated controls. The results are discussed in terms of the time course of phonological and orthographic code activation in the processing of pronounceable strings of letters.     

Metastable attunement and real-life skilled behavior

In everyday situations, and particularly in some sport and working contexts, humans face an inherently unpredictable and uncertain environment. All sorts of unpredictable and unexpected things happen but typically people are able to skillfully adapt. In this paper, we address two key questions in cognitive science. First, how is an agent able to bring its previously learned skill to bear on a novel situation? Second, how can an agent be both sensitive to the particularity of a given situation, while remaining flexibly poised for many other possibilities for action? We will argue that both the sensitivity to novel situations and the sensitivity to a multiplicity of action possibilities are enabled by the property of skilled agency that we will call metastable attunement. We characterize a skilled agent’s flexible interactions with a dynamically changing environment in terms of metastable dynamics in agent-environment systems. What we find in metastability is the realization of two competing tendencies: the tendency of the agent to express their intrinsic dynamics and the tendency to search for new possibilities. Metastably attuned agents are ready to engage with a multiplicity of affordances, allowing for a balance between stability and flexibility. On the one hand, agents are able to exploit affordances they are attuned to, while at the same time being ready to flexibly explore for other affordances. Metastable attunement allows agents to smoothly transition between these possible configurations so as to adapt their behaviour to what the particular situation requires. We go on to describe the role metastability plays in learning of new skills, and in skilful behaviour more generally. Finally, drawing upon work in art, architecture and sports science, we develop a number of perspectives on how to investigate metastable attunement in real life situations.