Модель рабочей памяти Бэддели и Хича

Model of human memory

Baddeley's model of working memory is a model of human memory proposed by Alan Baddeley and Graham Hitch in 1974, in an attempt to present a more accurate model of primary memory (often referred to as short term memory). Working memory splits primary memory into multiple components, rather than considering it to be a single, unified construct. Baddeley and Hitch proposed their three part working memory model as an alternative to the short term store in Atkinson and Shiffrin's 'multi store' memory model (1968). This model is later expanded upon by Baddeley and other co workers to add a fourth component, and has become the dominant view in the field of working memory. However, alternative models are developing, providing a different perspective on the working memory system. The original model of Baddeley & Hitch was composed of three main components: the central executive which acts as a supervisory system and controls the flow of information from and to its slave systems: the phonological loop and the visuo spatial sketchpad. The phonological loop stores verbal content, whereas the visuo spatial sketchpad caters to visuo spatial data. Both the slave systems only function as short term storage centers. Baddeley and Hitch's argument for the distinction of two domain specific slave systems in the older model was derived from experimental findings with dual task paradigms. Performance of two simultaneous tasks requiring the use of two separate perceptual domains (i. e. a visual and a verbal task) is nearly as efficient as performance of the tasks individually. In contrast, when a person tries to carry out two tasks simultaneously that use the same perceptual domain, performance is less efficient than when performing the tasks individually. A fourth component of Baddeley's model was added 25 years later to complement the central executive system. It was designated as episodic buffer. It is considered a limited capacity system that provides temporary storage of information by conjoining information from the subsidiary systems, and long term memory, into a single episodic representation.

An accumulation of literature across decades has lent strong support to the theory of phonological STS. In a 1971 study, Stephen Madigan demonstrated that a larger recency effect is seen during forward serial recall when people are presented a list auditorally as opposed to visually. (A smaller effect is seen in backwards serial recall.) In his study, auditory presentation led to greater recall of the most recently studied items. Catherine Penney expanded on this discovery to observe that modality effects can also be found in the case of free recall tasks. In 1965, Dallett had discovered that this observed modality effect is greatly reduced by the addition of a "suffix" item to the presented list; this suffix is a distractor item that is not to be recalled. Robert Greene utilized this observation in 1987 to discover that this suffix effect has a larger impact on lists learned auditorally as opposed to visually. The culmination of all of these findings results in strong support of the theory that there is a short term store that phonologically stores recently learned items. In addition, Bloom and Watkins found that the suffix effect is greatly diminished when the suffix is not interpreted as linguistic sound, which agrees with the phonological short term store theory as it would be largely unaffected by non linguistic distractors.

In 2000 Baddeley added a fourth component to the model, the episodic buffer. This component is a limited capacity passive system, dedicated to linking information across domains to form integrated units of visual, spatial, and verbal information with time sequencing (or episodic chronological ordering "The episodic buffer appears capable of storing bound features and making them available to conscious awareness but not itself responsible for the process of binding". It is assumed that "conscious access to the phonological loop or sketchpad may operate via the buffer". This is based on the assumption that both the visuo spatial sketchpad and phonological loop act as minor buffers, combining information within their sensory area. The episodic buffer may also interact with smell and taste. In terms of genetics, the gene ROBO1 has been associated with phonological buffer integrity or length.

The strength of Baddeley's model is its ability to integrate a large number of findings from work on short term and working memory. Additionally, the mechanisms of the slave systems, especially the phonological loop, has inspired a wealth of research in experimental psychology, neuropsychology, and cognitive neuroscience. However, criticisms have been raised, for instance of the phonological loop component, because some details of the findings are not easily explained by the original Baddeley and Hitch model, including the controversy regarding the 7±2 rule. The episodic buffer is seen as a helpful addition to the model of working memory, but it has not been investigated extensively and its functions remain unclear.