Bottom-Up vs. Top-Down Processing


A prominent theory on the psychological processes that enable successful listening (and reading) comprehension designates two types of processing that seem to be at work.

Bottom-Up processes describe the ways in which the linguistic competence of a listener works to 'build' toward comprehension of a message. According to Peterson (2001), these are the lower level processes that work to construct meaning from recognition of sounds and words, which, when identified, are fit into larger phrasal units and then matched with related ideas stored in long term memory. Peterson (2001) identifies three successive stages of Bottom-Up processing: perceptual processing, parsing, and utilization (p. 88). Brown (2007) notes that Bottom-Up processing "focuses on sounds, words, intonation, grammatical structures, and other components of spoken language (p. 312). At lower levels of language proficiency, the activation of Bottom-Up processing is thought to impose a great strain on conscious attention and therefore, working memory. With practice comes greater degrees of automaticity and a freeing-up of working memory for attention to higher level processing (called Top-Down) (Peterson, 2001).

Top-Down processes work in the opposite direction, drawing on the listener's own prior knowledge and expectations to help decode the message. The listener's repository of background information (sometimes called schemata) can relate to the context, the topic, the type of text, conventions of rhetoric and discourse organization. This knowledge becomes useful in decoding a message--even when a message hasn't been heard in its entirety (Peterson, 2001). Knowledge of facts, propositions and expectations allow prediction and inferencing that "enable the listener or reader to bypass some aspects of Bottom-Up processing" (Chaudron and Richards, 1986). This allows listeners to "fill in the gaps" which are often present in spontaneous unrehearsed speech, helping them arrive at global meanings and interpretation that don't rely on comprehension of every subsection of the message. Without paying attention to grammatical form, listeners can often assemble a meaning just from the context and their knowledge of key words (Newton, 2009).

Overall, it seems that the most skilled listeners rely on both Bottom-Up and Top-Down processing simultaneously to successfully arrive at meaning (Peterson, 2001).


References


Brown, D. H. (2007). Teaching by principles: An interactive approach to language pedagogy. White Plains, NY: Longman.

Chaudron, C., and Richards, J. C. (1986) The effect of discourse markers on the comprehension of lectures. Applied Linguistics 7(2): 112-127.

Nation, I.S.P., and Newton, J. (2009). Teaching ESL/EFL listening and speaking. New York and London: Routledge.

Peterson, P.W. (2001). Skills and strategies for proficient listening. In Celce-Murcia, M. (Ed.), Teaching english as a second or foreign language (pp. 87-100). Boston: Heinle & Heinle.