It's the Vocabulary, Stupid

As was noted in the comments of this post, teaching low-IQ kids is exceedingly difficult. The problem is that low-IQ kids learn more slowly than their smarter peers. Unless we accelerate the learning of these kids, they will fall further and further behind.

We know how to accelerate the learning of some, but not yet all, of the many important academic skills.

We know how to accelerate the learning of written word decoding (i.e., reading) by teaching forty sounds and by teaching how to blend those sounds rapidly together. Thus, a general case can be learned that will permit the reading of any regular-sound English word. And, in this way, a great efficiency in teaching is achieved when a relatively small set of building blocks can be recombined into a large set of applications. Almost all kids without a cognitive disability can be taught to decode in a timely manner.

Similarly, spelling can be efficiently taught by using a related process of spelling-by-sounds, which is an effective procedure for spelling words with regular letter-sound correspondences. The process also assists with the spelling of irregular words.

Elementary math can also be efficiently taught as several problem-solving skills that operate as general cases. These cases have more limited applications than decoding, however, and thus generate less net gain in accelerated learning.

Language skills, involving general cases of grammatical rules and word classifications, appear to have about the same level of potency as arithmetic. Thus, language skills are also teachable even to low IQ kids.

The performance of lower performers can be accelerated to national norms by the end of third grade in reading, math, spelling and grammar skills through careful instruction. And, it stands to reason, that the academic performance of higher performers can also be accelerated at least as dramatically.

What remains a problem, however, is the acquisition of vocabulary and underlying concepts, which is not nearly as amenable to general case learning. The learning of vocabulary is a "linear additive set" which is described as follows:

In a linear additive set, the learning of one element gives little advantage in learning a new element. To be sure, there are families of words that have common root meanings and common meanings of affixes, which permit some limited general cases to be generated. But, by and large, the learning of proper names, new concepts, and the learning of synonyms for concepts already known by another name, involve linear additive sets in which each new element must be taught. Knowledge of the English language, which is absolutely essential to oral and written comprehension, serves largely to define intelligent behavior (Miner, 1957). Teaching this language involves a task of the first magnitude.

Generally speaking, schools do not systematically build vocabulary-concept knowledge. Current programs are structured to teach middle-class children or children who, to a large extent, are taught oral-language comprehension at home. It is assumed that this form of language learning is then transferred to reading comprehension at school.

Most schools employ some sort of basal reading program until the third grade which utilize a controlled vocabulary for instruction. Typically, about 1,500 hundred words are covered at this time. And, the average student has a working oral vocabulary of two to three times this size.

After the third grade, vocabulary shifts to an increasingly uncontrolled adult vocabulary. It is estimated that, on the average, 5,000 words are learned after third grade. Since schools do not systematically build vocabulary knowledge, students with weak home training in English language skills are often in trouble by fourth grade, if not earlier. It is this vocabulary-concept knowledge deficit that plays a major role in reading comprehension problems.

It is the vocabulary deficit that remains the educational sticking point for lower performers, though some inroads have been made. Since low IQ kids do not learn as quickly as higher IQ kids, their vocabulary acquisition rate is significantly reduced. The problem is compounded because low IQ kids tend to have low IQ parents and the language used at home tends to be much lower than in higher IQ families:

In an important study, White et al. (1990) investigated reading vocabulary size and growth differences between students in grades 1 through 4 in two low socioeconomic status (SES) schools and one middle SES school. Reading vocabulary was defined as the number of printed words that were both decoded and understood. White et al. (1990) found that even in grade 1, there were important differences in the size of the reading vocabularies of students in the middle SES school (about 4,800 words out of 19,050) compared to students in the two low SES schools (about 3,500 and 2,500 words, respectively). Also, the differences between the number of words known by students at each grade level indicated that vocabulary increases may exceed the 3,000 words per year commonly referenced (e.g., Baumann & Kameenui, 1991; Beck & McKeown, 1991; Graves, 1986). A prevailing finding was that vocabulary growth appeared to differ on the basis of SES. The vocabulary size of the students in the middle SES school increased by about 5,200 words per year while that of the students in the two low SES schools increased by about 3,500 words per year.

Further compounding the problem is that schools are increasing downplaying the need to learn facts, i.e., vocabulary and underlying concepts, in favor of higher order thinking and other constructivist laden nonsense. The logical processes involved in reading comprehension are general case sets which can be taught with some efficiency. Research has shown that when "poor readers" understand and are familiar with the concepts presented in a written passage their reading comprehension is at least as good as "better readers" who are not familiar with the concepts.

For example, in one study (Recht and Leslie, 1988), the researchers tested junior high school students who were either good or poor readers (as measured by a standard reading test) and who were also knowledgeable or not about the game of baseball (as measured by a test created for the study by three semi-professional baseball players). The children read a passage written at an early 5th-grade reading level that described a half inning of a baseball game. The passage was divided into five parts, and after each part the student was asked to use a replica of a baseball field and players to reenact and describe what they read. The researchers found that baseball knowledge had a big impact on performance: Poor readers with a high knowledge of baseball displayed better comprehension than good readers with a low knowledge of baseball.

If you've been reading this blog for the past few weeks and caught my series on how the brain works, you might be able to adduce what's going on here.

[T]he students with a lot of knowledge of baseball were able to read a series of actions and chunk them. (For example, if some of the text described the shortstop throwing the ball to the second baseman and the second baseman throwing the ball to the first baseman resulting in two runners being out, the students with baseball knowledge would chunk those actions by recognizing them as a double play--but the students without baseball knowledge would have to try to remember the whole series of actions.) Second, because they were able to chunk, the students with baseball knowledge had free space in their working memory that they could devote to using the replica to reenact the play as well as providing a coherent verbal explanation. Without being able to chunk, the students with little baseball knowledge simply didn't have enough free space in their working memory to simultaneously remember all of the actions, keep track of their order, do the reenactment, and describe the reenactment.

It is possible that low IQ kids may lack the cognitive abilities required to perform higher order abstract thinking, such as theoretical mathematics and the like. But, it is unlikely that such skills are required at the K-12 level. So, such a shortcoming is likely not a limiting factor for learning at this level. The problem is much simpler than that. The problem is that these lower IQ kids are simply not learning oral comprehension as quickly as their smarter peers and such learning is not as amenable to acceleration of learning through optimized instruction.

Currently schools are mostly structured to teach middle-class children or children who, to a large extent, are taught oral-language comprehension at home. This is why IQ correlates so well with general language ability. Smarter kids learn faster, are exposed to more vocabulary at home, read more, and, as a result, learn more of what's taught at school. Slower kids learn slower, are exposed to less vocabulary at home, read less, and as a result learn less at school.

Becker recognized this problem 30 years ago in his analysis of the Project Follow Through data.

Children coming from home backgrounds that fail to provide adequate training for the continuous growth of vocabulary and concepts are likely to continue to fall behind in public schools. Even after four years of intensive effort, children taught in the Direct Instruction Model are far short of an average high-school senior's vocabulary--a vocabulary that is presumed by most fourth-grade tests.

The data on our fifth and sixth graders strongly imply that the schools fail to build skills toward this goal. One might conclude that this is simply more evidence of the failure of compensatory education. When viewed from a different perspective, however, the data point to a failure of school programs to accomplish their assigned roles.

Advocates of compensatory education assumed that all learning problems would be solved by finding the critical stage where some magic could be applied to fertilize cognition. The Follow Through data suggest that a magical solution is unlikely.

Massive restructuring of school systems is required. As schools are presently constituted, there is no way that low-performing children can be adequately prepared for the vocabulary they will encounter by the fourth grade. Clearly, the first step toward improving this situation is to recognize that language learning does not end by the third grade. Once this is understood, programs can then be engineered to teach vocabulary-concept knowledge in a systematic way throughout the school years.

Much has been learned in the intervening years and the teaching of vocabulary has improved so that lower performing students at least up to the fifth grade level can continue to perform at national norm levels in reading comprehension. But, in most schools it is still business as usual with vocabulary acquisition still being downplayed or ignored all too frequently.