The visuo-spatial sketch pad is assumed to maintain and manipulate visual images. The phonological loop stores and rehearses verbal information. It has also been suggested that the phonological loop has an important function of facilitating the acquisition of language by maintaining a new word in working memory until it can be learned (Baddeley, Gathercole, &Papagno,
1998). Baddeley (2002) eventually proposed the addition of a third subsystem known as the episodic buffer, which has acquired some of the tasks that were originally attributed to the central executive (now seen as a purely attentional system). The episodic buffer functions as a storage structure which acts as a limited capacity interface to integrate multiple sources of information from other slave systems.