Theories in Second Language Acquisition

An Introduction

Bill VanPatten, Jessica Williams

• Publisher: Routledge
• Year: 2014
• ISBN:
  9781135928605
• Edition: 2
• Topic: Bildung
• Subtopic: Bildungstheorie & -praxis

The second edition of Theories in Second Language Acquisition seeks to build on the strengths of the first edition by surveying the major theories currently used in second language acquisition research. This volume is an ideal introductory text for undergraduate and graduate students in SLA and language teaching. Each chapter focuses on a single theory, written by a leading scholar in the field in an easy-to-follow style – a basic foundational description of the theory, relevant data or research models used with this theory, common misunderstandings, and a sample study from the field to show the theory in practice. This text is designed to provide a consistent and coherent presentation for those new to the field who seek basic understanding of theories that underlie contemporary SLA research. Researchers will also find the book useful as a "quick guide" to theoretical work outside their respective domains.

1
Introduction

The Nature of Theories

Bill VanPatten and Jessica Williams

Almost everyone has heard of Einstein’s Theory of Relativity. People have also heard of things such as the “Theory of Evolution” and “Atomic Theory.” What is common to all these theories is that they are theories about what scientists call natural phenomena: things that we observe everyday. Theories are a fundamental staple in science, and all advances in science are, in some way or another, advances in theory development. If you asked scientists, they would tell you that the sciences could not proceed without theories. And if you ask applied scientists (such as those who develop medicines or attempt to solve the problem of how to travel from Earth to Mars), they would tell you that a good deal of their work is derived from theoretical insights.

Theories are also used in the social and behavioral sciences, such as psychology, sociology, and economics. As in the natural sciences, social sciences attempt to explain observed phenomena, such as why people remember some things better than others under certain conditions or why the stock market behaves the way it does.

In the field of second language acquisition (hereinafter SLA) research, theories have also come to occupy a central position. Some researchers, though by no means all, would even say that the only way SLA can advance as a research field is if it is theory driven. The purpose of the present book is to introduce the reader to certain current theories in SLA and provide a background for continued in-depth reading of the same. As a starting point, we will need to examine the nature of theories in general.

What Is a Theory?

At its most fundamental level, a theory is a set of statements about natural phenomena that explains why these phenomena occur the way they do. In the sciences, theories are used in what Kuhn (1996) calls the job of “puzzle solving.” By this Kuhn means that scientists look at observable phenomena as puzzles or questions to be solved. Why does the earth revolve around the sun and not fly off into space? Why are humans bipedal but gorillas knuckle-walkers? These are all questions about things that confront us every day, and it is the job of scientists to account for them.

In short, then, the first duty of a theory is to account for or explain observed phenomena. But a theory ought to do more than that. A theory also ought to make predictions about what would occur under specific conditions. Let’s look at three examples: one familiar, the other two perhaps less so. In the early part of the 19th century, scientists were already aware of the presence of microorganisms in the air and water, and they had an idea about the connection between the organisms and disease. However, they had no idea of how they came into existence; indeed, belief in the spontaneous generation of these organisms was widespread. Disease was thought to be caused by “bad air.” Careful experimentation by Louis Pasteur and other scientists demonstrated that microbes, though carried by air, are not created by air. Living organisms come from other living organisms. These discoveries led to the development of the germ theory of disease, which proposed that disease was caused by microorganisms. The acceptance of this theory had obvious important applications in public health, such as the development of vaccines, hygienic practices in surgery, and the pasteurization of milk. It not only could explain the presence and spread of disease, it could also predict, for example, that doctors who delivered babies without washing their hands after performing autopsies on patients who had died from childbirth fever would transmit the disease to new patients. Even more important, the same theory could be used to connect phenomena that, on the surface, appeared unrelated, such as the transmittal of disease, fermentation processes in wine and beer production, and a decline in silkworm production.

Now let’s take an example from psychology. It is an observed phenomenon that some people read and comprehend written text faster and better than others. As researchers began to explore this question, a theory of individual differences in working memory evolved. That theory says that people vary in their ability to hold information in what is called working memory (defined, roughly, as that mental processing space in which a person performs computations on information at lightening speed). More specifically, the theory says that people vary in their working memory capacity: Some have greater capacity for processing incoming information compared with others, but for everyone, capacity is limited in some way. Initially used to account for individual differences in reading comprehension ability in a person’s first language, the theory also accounts for a wide range of seemingly unrelated phenomena, such as why people remember certain sequences of numbers and not others, why they recall certain words that have been heard, why people vary on what parts of sentences they remember best, why certain stimuli are ignored and others attended to, and why some students are good note takers and others are not. A theory of working memory, then, allows psychologists to unify a variety of behaviors and outcomes that on the surface level do not necessarily appear to be related. There are even attempts to apply the theory of SLA to explain why some people learn faster and better than others.

Let’s take a final example, this time from language. In one theory of syntax (sentence structure), a grammar can allow movement of elements in the sentence. This is how we get two sentences that essentially mean the same thing, as in the following:

• (1) Mary said what?
• (2) What did Mary say?

In this particular theory, the what is said to have moved from its position as an object of the verb said to occupy a place in a different part of the sentence. At the same time, this theory also says that when something moves, it leaves a hidden trace. Thus, the syntactician would write (2) like (3):

• (3) What_i did Mary say t_i?

In (3) the t stands for the empty spot that the what left and the i simply shows that the what and the t are “co-indexed”; that is, if there happens to be more than one thing that moves, you can tell which trace it left behind.

To add to the picture, the theory also says that t s, although hidden, are psychologically real and occupy the spot left behind. Thus, nothing can move into that spot and no contractions can occur across it. Armed with this, the syntactician can make a variety of predictions about grammatical and ungrammatical sentences in English. We might predict, for example, that (4) is a good sentence but (5) is bad and not allowed by English grammar:

• (4) Should I have done it?
• (5) Should I’ve done it?

The reason for this is that should has moved from its original spot and left a t behind, as illustrated in (6):

• (6) I should have done it. → Should_i I t_i have done it?

At the same time, the syntactician would predict restrictions on the contraction of want to to wanna. Thus, (7) is fine because there is no trace intervening where a contraction wants to happen:

• (7) Who_i do you want to invite t_i to dinner? → Who do you wanna invite to dinner?

All English speakers would agree, however, that (8) is awful:

• (8) *Who do you wanna take Susie to the prom next month?

You could probably work this out yourself, but the reason (8) sounds bad is that the who has moved and has left behind a t that blocks a possible contraction. Compare (7) and (8) redone here as (9) and (10):

• (9) Who_i do you want to invite t_i to dinner? → Who do you wanna invite to dinner?
• (10) Who _i do you want t_i to take Susie to the prom next month? → *Who do you wanna take Susie to the prom next month?

Be careful not to pronounce wanna like want tuh; want tuh is not a contraction and is merely the schwawing of the vowel sound in to. Want tuh sounds OK in sentence (8) precisely because it is not a contraction.

Thus, the theory unifies constraints on contractions with modals (should, would, will, may, might), with auxiliaries (do, have), with copular verbs (be), with the verb want, and with pronouns (I, you, he, and so on). It makes predictions about good and bad sentences that perhaps we have never seen or heard, some of which—like silkworms and beer—don’t seem to have much in common.

To summarize so far, a theory ought to account for and explain observed phenomena and also make predictions about what is possible and what is not. In addition, most theories—good ones, that is—when accounting for and predicting things, also tend to unify a series of generalizations about the world or unify a series of observations about the world. In the brief view we had of syntactic theory, the few generalizations made about how syntax works unify a variety of observations about contractions and not just contractions with should. All contractions conform to the generalizations.

For SLA, then, we will want a theory that acts like a theory should. We will want it to account for observable phenomena (something to which we turn our attention later in this chapter). We want it to make predictions. And, ideally, we want it to unify the generalizations we make as part of the theory. In other words, we want a single theory to bring all of the observed phenomena under one umbrella. Whether this is possible at this time has yet to be determined and is something that this book will explore.

What Is a Model?

Many people confuse theories and models. A model describes processes or sets of processes of a phenomenon. A model may also show how different components of a phenomenon interact. The important word here is how. A model does not need to explain why. Whereas a theory can make predictions based on generalizations, this is not required of a model. The problem is that in the real world—and in SLA as a research discipline—this distinction is not always maintained. You will find as you read further in the field that researchers often use model and theory interchangeably. Thus, although in principle it would be a good idea to distinguish between these two terms as they do in the natural sciences, in practice many of us in SLA do not do so.

What Is a Hypothesis?

Distinct from a theory, a hypothesis does not unify various phenomena; it is usually an idea about a single phenomenon. Some people use theory and hypothesis interchangeably, but in fact, they are distinct and should be kept separate. In science, we would say that a theory can generate hypotheses that can then be tested by experimentation or observation. In psychology, for example, there are theories regarding memory. You may recall the theory about working memory and capacity discussed earlier. The theory says (among many other things) that working memory is limited in capacity. This means that people can pay attention to only so much information at a given time before working memory is overloaded. The theory also says that there are individual differences in working memory and how people use what they have. Some people have X amount of working memory capacity as they attend to incoming information, whereas others have more or less. A hypothesis that falls out of this, then, is that working memory differences among individuals should affect reading comprehension: Those with greater working memory capacity should be faster readers or should comprehend more. This is a testable hypothesis. We ought to add here that the only valuable hypotheses for a theory are those that are testable, meaning some kind of experiment can be run or some kinds of data can be examined to see if the hypothesis holds up. Another example of a hypothesis comes from SLA: the Critical Period Hypothesis. This is a theory in neurolinguistics that states that at an early age, the brain begins to specialize; specific brain functions become increasingly associated with specific areas of the brain. In addition, some functions may be developmentally controlled; that is, they turn on and, more important for language learning, turn off at specific points in development. The Critical Period Hypothesis is a direct consequence of this theory. It states that the ability to attain native-like proficiency in a language is related to the initial age of exposure. If language learning begins after a certain age (and there is a considerable controversy over what this age is as well as whether there even is a critical period—see the various papers in Birdsong, 1999), the learners will never reach a level of proficiency or competence comparable to a native speaker’s. A corollary to this hypothesis is that language learning ability declines with age after this point. Again, both of these are testable hypotheses. Recall that earlier we said we wanted a theory to make predictions. Predictions are actually hypotheses. When we make a prediction based on a theory, we are in effect making a hypothesis.

These definitions about theories, models, and hypotheses are important because in everyday speech, we may use the term theory in a way not intended in science. For example, one might hear in a disparaging tone that something is “just a theory.” In science, the phrase “just a theory” makes no sense, as all work is theoretically driven. What is more, the term theory has often been politicized to denigrate particular theories (e.g., evolution) so that “just a theory” becomes a way of dismissing something that has scientific rigor but runs against some other set of beliefs. Finally, in movies and other nonscientific situations, one often hears the term theory used to mean...