analysis by synthesis
any theory of information processing stating that both bottom-up processes and top-down processes interact in the recognition and interpretation of sensory input. According to theories of this type, which are associated particularly with speech perception and language processing, the person initially assesses (analyzes) the physical attributes and constituent elements of a stimulus (data-driven processing) and then, guided by contextual information and knowledge acquired from previous experience or learning (conceptually driven processing), determines the significant information from this preliminary analysis of the stimulus and assembles (synthesizes) it into an internal representation or interpretation of what the stimulus might be. This internal representation is compared to the stimulus input: If the two match, then the stimulus is recognized; if not, alternative representations are assembled for comparison until a match is found. In other words, one
analyzes the original stimulus input, hypothesizes what it is, determines what the input would be like if the hypothesis were correct, and then assesses whether the input is actually like that.