A new definition of visual short-term memory

Waarschijnlijk heb je het zelf wel eens meegemaakt dat je gestoord werd tijdens je favoriete tv-programma met een vraag van een ouder, kind of echtgenoot. Gelukkig ging je zo op in het programma dat je de vraag niet eens hebt ‘gehoord’. Als diezelfde persoon vervolgens aan je vraagt: ‘Hoorde je me niet, of zo!?’, dan weet je toch de vraag te herhalen en antwoord te geven. Dit voorbeeld toont aan dat informatie die geen aandacht heeft gekregen nog enige tijd rondsluimert in ons sensorisch geheugen. Informatie waar we aandacht voor hebben (gehad), komt in ons werkgeheugen terecht. Ilja Sligte vindt dat deze discrete, twee-stadiumbeschrijving van korte-termijngeheugen een beetje simplistisch is. Korte-termijngeheugen lijkt volgens hem eerder een continu proces te zijn. De capaciteit en eigenschappen van korte-termijngeheugen hangen samen met de diepte waarmee sensorische input doordringt in het brein. In de primaire sensorische gebieden houden loops van hersenactiviteit heel kort een heleboel simpele informatie vast. Iets hoger in het brein, houden deze loops langere tijd geheugensporen in stand die al wat complexere eigenschappen hebben. Tot slot selecteren aandachtsgebieden maximaal vier stukjes informatie om in abstracte vorm te representeren en zolang aandacht beschikbaar blijft, leidt dit tot loops die een groot deel van het brein omvatten

Aprendizagem organizacional e criação de conhecimento

Este artigo enfoca o processo de aprendizagem organizacional e de criação de conhecimento em uma instituição privada de ciência e tecnologia. Esse processo é examinado por meio do Instituto Stela, um start-up universitário da Universidade Federal de Santa Catarina. O delineamento do estudo é qualitativo e utiliza a abordagem do estudo de caso. Baseia-se em evidências coletadas por meio da triangulação de técnicas (entrevistas, reuniões casuais, análise de documentos e observação direta). Os resultados indicam que a estrutura organizacional matricial e adocrática e os valores organizacionais formam um substrato condutivo à aprendizagem organizacional. O entrelaçamento entre o planejamento das atividades de pesquisa e desenvolvimento e sua execução vinculada a projetos de desenvolvimento de produtos e serviços favorece o processo de construção do saber, ou knowing, como atividade integral e diária dos colaboradores. Além de expandir o conhecimento acerca do construto da aprendizagem organizacional em um instituto de C&T privado, este estudo contribui para a geração de insumos que possibilitem a realização de novas pesquisas em um universo maior de institutos privados de C&T e com instituições intensivas em conhecimento de outros setores da economia

Transcranial direct current stimulation of the right temporoparietal junction impairs third-person perspective taking

Contains fulltext : 166289.pdf (publisher's version ) (Open Access)Given the current debates about the precise functional role of the right temporoparietal junction (rTPJ) in egocentric and exocentric perspective taking, in the present study we manipulated activity in the rTPJ to investigate the effects on a spatial perspective-taking task. Participants engaged in a mental body transformation task, requiring them to mentally rotate their own body to the position of an avatar, while undergoing anodal, cathodal, or sham transcranial direct current stimulation (tDCS) of the rTPJ. As a control task, participants judged the laterality of a stimulus feature with respect to a fixation cross on the screen. For the first half of the experiment (only during online tDCS), a task-selective effect of tDCS was observed, reflected in slower reaction times following anodal than following cathodal and sham tDCS for the mental body transformation task, but not for the control task. The effects of tDCS were most pronounced for stimuli implying a more difficult mental body transformation. No effects of tDCS were observed during the second half of the experiment. The effects of tDCS were most pronounced for participants scoring low on aberrant perceptual beliefs and spiritual transcendence, suggesting a relation between third-person perspective taking and bodily and perceptual experiences. The finding that anodal stimulation of the rTPJ impairs third-person perspective taking indicates a key role of this region in exocentric spatial processing.15 p

Manipulations of attention dissociate fragile visual short-term memory from visual working memory

People often rely on information that is no longer in view, but maintained in visual short-term memory (VSTM). Traditionally, VSTM is thought to operate on either a short time-scale with high capacity - iconic memory - or a long time scale with small capacity - visual working memory. Recent research suggests that in addition, an intermediate stage of memory in between iconic memory and visual working memory exists. This intermediate stage has a large capacity and a lifetime of several seconds, but is easily overwritten by new stimulation. We therefore termed it fragile VSTM. In previous studies, fragile VSTM has been dissociated from iconic memory by the characteristics of the memory trace. In the present study, we dissociated fragile VSTM from visual working memory by showing a differentiation in their dependency on attention. A decrease in attention during presentation of the stimulus array greatly reduced the capacity of visual working memory, while this had only a small effect on the capacity of fragile VSTM. We conclude that fragile VSTM is a separate memory store from visual working memory. Thus, a tripartite division of VSTM appears to be in place, comprising iconic memory, fragile VSTM and visual working memory