Activation And Inhibition In The Retrieval Of Working Memory

There is a limit on the amount of information which can be simultaneously processed when people perform a series of cognitive tasks. In most cases it's impossible to hold all recently processed information in memory dynamically. Therefore, the object which is processed by current task need to be switched between information available. The focus of attention (FOA) represents the item in memory set which acts as the object of current processing task. According to previous research, the mechanism of FOA was mainly reflected through its switching. The switching of FOA in working memory concerns both content and course of cognitive process, brings together the functions of storage, process and executive control, relate itself to the functions of sharing/competing/distributing resource within working memory. So to make research on switching of FOA within working memory is not only a valid way to reveal complex rules of cognitive processing, but also one of the basic tasks of comprehending the complex mechanisms.Based on the mechanisms of selective attention and the focus of attention (FOA) in working memory, this article summarizes recent researches on the switching of FOA in working memory: (1) the concept of switching of FOA in working memory and its basic research methods. (2) the cognitive factors (or processes) which might affect the focus switch costs, mainly including retrieval, rehearsal, processing, update of memory and size of memory set et al. (3) the relation between FOA switching and the functions of working memory, including the relation between FOA switching and the executive functions of working memory, the relations between storage, processing and the executive functions of working memory, which are reflected through FOA switching, and the relation between FOA switching and the distributing of resource in working memory.With a modified Sternberg task, combined with the near year's research paradigm of FOA switching, current study designs two experiments to explore the characteristics of FOA switching which occurs either within one domain or between two different domains of working memory. Results show that (1)both domains of working memory show switch costs of FOA, so this switching effect is common to both domains, which supports Baddeley's (1996) hypothesis that the shift of attention is one of the executive functions of working memory, (2) two domains of working memory concerned (verbal working memory and visual-spatial working memory ), items in the same domain compete attention resource, while the attention resource of different domain may be parallel and independent to one another. Thus when FOA is switched to another item of the same domain, the previous item in FOA will be inhibited. As different domain is independent, when such switching occur between two domain, the previous item in FOA only gets a small influence and it will have a superiority of repeated activation when it is retrieved again.