Understanding Reading Comprehension
The goal of reading is comprehension - the ability to understand what one is reading. Gough and Tunmer's (1986) widely accepted and influential Simple View of Reading shows that there are two essential components of reading comprehension: decoding and language comprehension.
decoding x language comprehension =
reading comprehension
This view of reading shows that once skilled decoding is in place, reading comprehension is largely dependent on language comprehension, or one's ability to understand language. Scarborough (2001) clarified that language comprehension involves factors such as background knowledge (or knowledge of real-world facts and concepts), vocabulary, language structure (e.g., grammar), verbal reasoning (e.g., inferring), and literacy knowledge (e.g., words are read from left to right).
Unlike decoding, which is based on a set of discrete skills that can be systematically taught over a limited period of time, reading comprehension develops over many years as we increasingly acquire greater knowledge of the world and expand our vocabularies. Background knowledge, especially, is a significant contributor to our ability to understand what we hear and read. In fact, it is so important that a seminal study (Recht & Leslie, 1988) showed that when weak decoders have more knowledge of the reading topic than do strong decoders, the weak decoders are able to comprehend better.
The importance of background knowledge to reading comprehension can be illustrated with the following sentence:
Some animals that live in the desert conserve water by sleeping during the day and moving about at night.
In order to make sense of this sentence, in addition to knowing the meaning of conserve, a reader would also need to have enough background knowledge to connect what the author says to the fact that animals have water in their bodies and can lose this water through evaporation when they move about during the heat of the day, a process that is less likely to occur during the cooler nighttime. The author does not provide this information explicitly, and as students progress from grade to grade, the writers of the texts they read will increasingly take a certain level of background knowledge for granted and, therefore, be less likely to elaborate. More and more, students will be required to 'read between the lines', supplying what is left out of a passage by using their own prior knowledge.
So, can reading comprehension be taught? Strictly speaking, it cannot - not in the way that decoding can. However, reading comprehension can be promoted through various means, including any language-rich experience, such as shared book reading, that develops an individual's language abilities. Another way is through judicious use of comprehension strategy instruction. These strategies do not work by guaranteeing that a student will understand any text that s/he reads because comprehension is text- and knowledge-dependent (think of trying to understand a paper on Einstein's theory of relativity, but without the requisite background in modern physics). Instead, the value of strategies is that they help students to recognize that reading is a meaning-making process, not a word-calling activity, so what they read should make sense. Many students who are weak comprehenders often do not realize this.
In an effort to help such students improve their comprehension, many reading educators embraced a view of comprehension as an ability similar to decoding, i.e., made up of sub-skills that can be taught. An example would be the skill of making inferences. In reality, inferring is not so much a skill that is taught as it is a thinking move that we make as long as we have enough information available and there is no interference from unfamiliar vocabulary or complex sentence structures. The average reader who knows about heat and evaporation will automatically infer that desert animals sleep during the day in order to reduce evaporation of water from their bodies. However, a weak comprehender might read the passage about desert animals straight through without pausing to think about why sleeping during the day enables them to conserve water. This is where strategy instruction comes in.
Students can, for example, be taught the 'questioning strategy' whereby they self-generate questions about whatever they read. This is something that good readers often unconsciously do. Such a strategy promotes comprehension by leading students to process more deeply the information they are reading. To prompt inferences, students need to ask themselves 'Why?' questions such as 'Why does sleeping during the day help desert animals conserve water?' Notice, however, that using this strategy will not necessarily supply the student with the answer if s/he does not already know about how heat causes evaporation of water from the body. Without background knowledge, readers cannot make effective use of comprehension strategies such as questioning and visualizing.
With regard to a wise use of comprehension strategy instruction, research shows that prolonging this type of instruction does not make it more effective, leading some researchers to recommend that instructional time be spent instead on content-rich activities that build knowledge and language skills (Willingham, 2006). The ineffectualness of too much strategy instruction is understandable if we consider that strategies really serve the primary functions of 1) making students aware that they should be reading for meaning, and 2) showing them a few effective ways in which they can do this. Therefore, once students have the ability to decode, the keys to becoming better readers are to read (and be read to) and to be engaged in enriching conversations and experiences that boost language comprehension.
Click here to read an illuminating article on this topic by E. D. Hirsh, Jr., founder of the Core Knowledge Foundation and one of the first educators to bring to public attention the role of knowledge in reading comprehension.