¶ … Knowledge and Learning and Teaching a Second Language: Researchers have divided the skills necessary for the acquisition of second language comprehension, particularly in the reading area, into two general theories: bottom-up, text-based, psycholinguistic approaches or top-down, socially-oriented conceptual approaches. In each case, lack of second language comprehension is attributed to misunderstanding of some key variable of the approach. For example, bottom-up studies tend to trace miscomprehension to misunderstanding of grammar (syntax), vocabulary (semantics), or other textual aspects. Accordingly, comprehension from the bottom-up is a data-driven process (Carrell and Eisterhold, 1983).

In contrast, top-down studies primarily attribute miscomprehension to the lack of specific background knowledge or cultural familiarity that is necessary to understand the text. Top-down understanding is seen as a process that is driven by concepts (Carrell and Eisterhold, 1983). Goodman (1967) is credited with first recognizing this additional aspect to reading comprehension, although he did not use the term "top-down" (Adamson, 1993, p. 45). Another early researcher in this area, Steffenson, Joag-dev, and Anderson (1979), focused on the cultural barriers to reading comprehension. Later work solidified this type of approach into the Schema Theory Model, where understanding involves an interaction between background knowledge of the reader, described as the reader's "schema," and the text. This model has been applied to second language reading comprehension by Carrell (1983a) and Johnson (1982), among many others.

More recently, it has become obvious that the division between these two approaches is somewhat artificial and true comprehension involves a combination of both types of these skills. Thus, more current research, such as the work of Bernhardt (2001), attempts to provide models that take into account the contribution of both approaches. However, investigating of true role of background knowledge, specifically determining the correct amount of emphasis that should be placed on these types of variables, remains a central area of study in the acquisition of comprehension within a second language.

What is Background Knowledge?

Investigators in this area use the terms "background knowledge" or "prior knowledge" to mean a variety of contributors to the comprehension of a reader's second language (L2). Specifically, background knowledge relates to the reader's knowledge of their first language (L1). There are two levels of interest in this particular background knowledge. First, there is the effect of merely knowing L1 and this can alter the acquisition process of L2. This type of background knowledge brings up issues of transfer, avoidance, language loss, and rate of learning, which can collectively be termed cross-linguistic influence (Gass and Selinker, 2001).

The second interest in background knowledge in this area involves the proficiency of the student in L1 and how this alters the acquisition of L2. To study this variable, testing of the comprehension of text in L1 are done followed by attempts to find parallels between this proficiency and the ability to understand text in L2. The work of Lee and Schallert (1997) is an example of this type of study, and will be discussed more extensively below.

Background knowledge can also mean general knowledge of the subject matter of the text, and has been broken down into three characteristic components: familiarity, context, and transparency (Carrell, 1983b). Studies have found significant relationships between these providing or not providing these aspects of background knowledge and the overall percentage recall of passages in L2. One study relatively recent study that used this classification of background knowledge is Roller and Matambo (1992).

A third type of background knowledge that is discussed in the literature is one of cultural familiarity. Although this may be a subset of Carrell's "familiarity" component discussed above, the studies looking that this aspect of background knowledge focus upon the effect of the experience of living in the culture expressed by the writer of the passage being tested. A well-known example of this definition of "background knowledge" is the work by Johnson (1982). There, students who had or had not personally participated in the celebration of Halloween read a text related to this holiday. The effect of the actual cultural experience on reading comprehension was tested.

Adamson (1993) reports a fourth possible component of background knowledge that appears to be a subset of the cultural aspects -- scripts for school. In general, when students understood how they should act in the

Conflicts between scripts for school learned in other cultures and those in play in the United States were numerous. These included misinterpretation of group study as being able to do whatever the student wanted in the classroom, misunderstanding that girls need not be overly respectful to boys in the U.S., and misinterpretation of what is appropriate subject matter for study where highly moralistic and patriotic information was expected (p. 50-51). So these school scripts form a fundamental component of the cultural aspects of background knowledge that are important to success for English as a Second Language (ESL) students. Whether examining the knowledge related to L1 to L2 transfer, L1 proficiency, knowledge about the text subject, a cultural experience, or school scripts, each researcher attempts to find a connection between second language comprehension and having particular background information.
The Schema Theory Model

Full understanding of the contribution of background knowledge to second language comprehension requires a working familiarity with the Schema Theory Model. On this subject, Carrell and Eisterhold (1983) state that one of the fundamental tents of this model is that text, either spoken or written, does not by itself carry meaning. Rather... A text provides direction for listeners or readers as to how they should retrieve or construct meaning from their own previously acquired knowledge (p. 556).

This approach differs from older work that tended to focus on the language and the meaning that can be found "within" the text, rather than on the person perceiving the language and his or her background knowledge (p. 553-554).

A second important aspect of the schema-theoretic model is that comprehension is an interactive event between the reader or listener's background knowledge and the text itself. Each type of input is mapped against a structure of background knowledge, seeking a logical fit for the incoming information (Carrell and Eisterhold, 1983). These structures are called schemata. Although technically distinct, other researchers have alternatively called very similar cognitive constructs "scripts, plans, and goals" (Schank and Abelson, 1977), "frames" (Minsky, 1975), "expectations" (Tannen, 1978) and "event chains" (Warren, Nicholas, and Trabasso, 1979).

The function of a schema is best illustrated with an example. Originally used by Collins and Quillian (1972), often cited is the alternative schema that could be used to interpret this mini-text:

The policeman held up his hand and stopped the car.

Here, the reader could posit two different schemas that would significantly alter the way the meaning of the text is interpreted. One would be the mental image of a traffic cop putting up his hand as a signal to the driver to stop the car. However, if the policeman was known to be a superhero, and the car was known to be driverless, a very different schema follows. There, the policeman physically places his hands on the car to bring it to a halt. Which of these two schemas the reader activates depends upon the reader having the necessary background knowledge for that schema and knowing which provides a consistent reading of the text (Carrell and Eisterhold, 1983, p. 559). Through these schemas, a reader or listener comprehends, or fail to comprehend, the message of the communication.

A final issue about schema is that researchers have identified several types (Singal, 1998). These types include content schema, formal or textual schema, and linguistic or language schema. Content schemas are what are formed based on the reader's world knowledge and form a basis for comparison (para. 3). Formal schema involve the organizational forms or structures of written texts that help reveal its meaning and can include vocabulary, grammar, and communication style (para. 4). Linguistic schema are more specific for decoding strategies and are what allow students to guess at the meaning of a word based on its context in a text (para. 5). All three of these schema types are applicable when all interpretations of background knowledge: language proficiency, knowledge of the subject of the text, and cultural issues are examined from the point-of-view of acquiring second language comprehension.

With this grounding in the general models of background knowledge and their application to L2 education, what follows is a summary of important work examining the effect of the various types of background knowledge on L2 acquisition.

Background Knowledge and its Effect on L2 Acquisition

Cross-Linguistic Influence. In its early stages, the study of language transfer from L1 to L2 dismissed the effect of the native language as background knowledge on the acquisition of L2 (Gass and Selinker, 2001). This approach has been termed a behavioristic, in that the acquisition of various English morphemes (meaningful linguistic units) seemed to follow a set behavior pattern no matter what the L1 of the student (Gass and Selinker, 2001, p. 112). However, more recent research has indicated that if the right research questions are asked, significant differences can be detected,…