"According to Paivio (1991), (NL)
DCT evolved from his studies on the role of imagery in associative
learning. These studies marked the first systematic objective measurement
of the effects of imagery on memory. Before reviewing these effects, a brief
description of the assumptions and components of this theory is needed.
Dual Coding Theory proposes that memory consists of two separate but
interrelated codes for processing informationone verbal and the other visual. The
verbal and visual systems can be activated independently, but there are interconnections
between the two systems that allow dual coding of information. The interconnectedness of
the two systems permits cueing from one system to the other, which in turn facilitates the
interpretation of our environment (Rieber, 1994; Simpson, 1995).
Each system has different functions, storage processing characteristics and memory units
(Rieber, 1994). The verbal system specializes in processing and storing linguistic
information (words, sentences, etc.,). Information is stored in discrete, sequential units
that are called logogens. In contrast, the visual system specializes in processing and
storing image or picture-like representations. Processing in the visual system
is believed to be more holistic and based on continuous organizational units termed
imagens. Chan Lin (1994) illustrates this
point through the example of a face which, if processed visually, is perceived
concurrently as a whole made up of distinctive sub-elements (eyes, nose, mouth), often to
an astonishing level of detail. A verbal representation, on the other hand, requires a
sequential description of each individual element. Thus, in this type of representation,
the level of detail is directly proportional to the length of the description. "
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