Mental Retardation and Behavior Problems

Mental retardation presents itself in so many forms, degrees, lifestyle, status symbol, and living conditions. It has many known and unknown causes, with so many questions unanswered. It is difficult to say clearly: these are the people who are retarded, and this is what they can do, and this what we can do for them, and this is how we can eliminate the problem.

To reach into the problem you must know what it is. To reach the people who have the problems. We must know who they are, how to understand them and how to help them. Who Are They? Mental retardation refers to significantly sub-average general intellectual functioning existing concurrently with deficits in adaptive behavior and manifested during the developmental period.

Mental Retardation Behavior Problems

Mental Retardation identifies with sub-normality in two behavioral dimensions intelligence and social adaptation occurring before the age of 18. This is a culmination of long debate and revision and may well be modified in the future. The severely retarded person has an obvious incapacity to exercise the expected controls of reason and of personal management necessary for normal living in any human culture.

Left to himself, anyone so impaired cannot easily survive. The great majority of severely retarded individuals also have physical characteristics that suggest a central nervous system defect as the basis of the developmentally retarded behavior. In many cases, no detectable physical pathology accompanies the deficiency of intelligence and adaptation. The limited ability to learn, reason and to use "common sense" is often unexplained.

Can undetected physical pathology be assumed? Further questions arise when milder degrees of the intellectual and adaptive deficit are commonly associated with particular families who have serious social and economic problems. Do poor living conditions produce mental retardation or is it the reverse?

Or does each condition compound the other? Still, further, members of certain minority groups tend to be highly represented among those identified as having intellectual and adaptive problems, especially in the school-age years.

Is such over-representation of certain groups a product of racial inferiority or of racial and ethnic discrimination and disadvantage? For a long time, mental retardation (or its earlier terms idiocy, feeble mindedness and the like), was thought to have much in common with insanity, epilepsy, pauperism, and social depravity, all of which were lumped together. And so, a concept of mental deficiency in terms of social deviance developed.

Then, as knowledge advanced, retardation was identified with congenital brain defect or damage and assigned to heredity. This approach led to redefining mental deficiency in medical terms as an organic defect producing inadequate behavior.

Mild forms of intellectual "weakness" became associated with forms of immoral behavior and social disturbance (the "moral imbecile"), and ascribed to more subtle defects of inherited character. Legal definitions in terms of social behavior began to appear.

Mental Retardation IQ

During the 19th and early 20th century what we now call "mild" retardation was not recognized except as associated with disturbed or delinquent behavior. There was no simple way of diagnosing the more mild or incipient forms of mental retardation until the development of psycho-metrics around 1910. Then the "IQ" rapidly became a universal means, not only of identifying a mental deficiency but also of measuring its severity.

In 1910, new techniques in the public schools discovered there were ten times as many feeble-minded as anyone had suspected, and promptly coined the term "moron" to cover them! Thus, a psycho-metric definition of retardation came into being.

The intelligence test measured behavioral performance on tasks assumed to be characteristic of the growth of children's ability at successive ages.  But it was interpreted as a measure of capacity for intellectual growth and therefore as a predictor of future mental status.

It was assumed to represent an inherent and usually inherited condition of the brain with a fixed developmental potential. The persistent debate over the nature and composition of intelligence finally led to an operational definition that it is "whatever an intelligence test measure".

Since intelligence measurements are scalar, and degrees on the scale were found to correlate rather well with other clinical and social evidence of mental proficiency, low IQ became virtually the sole basis for a diagnosis of mental retardation and for its classification at levels of severity from "borderline" to "idiot."

This measurement was especially important in schools, in fact, devised IQ tests became the standard means of determining school eligibility and classification. Intelligence tests also were used extensively as sole evidence for determining legal competency and institutional commitment, as well as the sub-classifications of institutional populations. But it is rejected a strictly psychometric definition, but it nevertheless became standard practice in diagnosis and classification.

The siblings and unrelated children had shown that general intelligence (i.e., measured IQ) is strongly inherited as a polygenic characteristic. However, following a normal Gaussian curve of frequency distribution in the general population. A slight negative skew was attributable to brain damage or genetic mutation. This deviation led to a theory of mental retardation which divided it into two major groups based on presumed causation. One group consisted of the more severely deficient type with brain damage or gross genetic anomaly characterized by various physical abnormalities and IQ generally of 55 or less.

The other group consisted of the lower portion of the negative tail on the normal curve of distribution of polygenic intelligence. This could explain the association of milder forms of low intelligence with low socio-economic status and its concomitants. In other words, the less competent tend to sink to the bottom of the social scale in a competitive society. The issue of cultural bias was raised immediately, however, with respect to racial and ethnic groups who scored consistently lower on the standard tests.

Evidence began to accumulate which generated a variety of additional controversial issues. The constancy of the IQ was questioned on both statistical and experimental grounds. The pioneering work had indicated that measured intelligence, as well as other observable behavior, could be substantially modified by drastic changes in the social environment of young children.

The quality of the infant's nurture was found to have enduring effects of intellectual functioning, especially in the absence of detectable brain pathology. Follow-up studies of persons released from institutional care and of those who had been identified in school as retarded showed high rates of social adaptation, up-ward mobility and even substantial in-creases in measured intelligence in adult years.

Epidemiological studies have consistently shown a "disappearance" of mildly retarded persons in the adult years. Explanations for these findings could be offered without abandoning previous assumptions: Improvement in low IQ scores over several repetitions simply exemplifies the statistical regression toward the mean, inherent in errors of measurement: those who improve with stimulation and environmental change were never "really" retarded, but exhibit "pseudo-retardation" which masks true capacity.

Eventually, evidence converged to show that measured intelligence is modifiable within limits, that it is not, in any case, a measure of fixed capacity, but of the continuity of a developing intellectual and social competence in which "nature" and "nurture" are inseparable components and individual "growth curves" may take a variety of forms and may be influenced by many factors.

A gradual trend developed toward the definition of mental retardation in functional rather than in structural terms and not tied either to a specific cause or to unchangeable status. There were those, however, who continued to find a dual view of retardation more credible than a single continuum. The measures of intelligence came to be recognized as primarily predictive of school performance of an academic or abstract nature requiring language skills, and less predictive of other nonverbal types of behavior.

Consequently, the need developed to measure other dimensions of behavior. The combined linguistic with the non-linguistic performance or quantitative elements and yielded a "profile" of distinguishable mental traits. Factor analysis of measures of intellectual behavior had demonstrated that "intelligence" is not a single trait but a composite of many distinguishable functions.

The measurement of adaptive behavior presented even greater difficulty. Such measures were extensively used but had an only limited validity. The Adaptive Behavior Scale all attempted to measure the nonintellectual dimensions of developmental adaptation, but they lacked the precision and reliability of the intelligence measures. Consequently, there has been a continuing reliance, especially in the schools, on measures of IQ alone as the criterion for mental retardation.

This practice is a better measure of adaptive behavior. In the meantime, the issue of cultural bias became an increasingly serious problem. All measures of either intelligence or of adaptive behavior reflect social learning, hence tend to be culture-bound. Their validity, therefore, is dependent on the cultural population on which the norms have been standardized. No one has succeeded in developing a universally applicable "culture-free" test of behavior.

Therefore, attempt to devise "culture-fair" tests which employ comparable but culturally different elements have as yet failed to yield valid bases of comparison. The extent to which cultural bias affects the frequency with which members of minority cultures are labeled "retarded" and assigned to special education classes. This is especially true when only measures of IQ are used. Social evaluations of such children show that a high proportion is not significantly impaired in their adaptation in non-school environments.

This discovery has led to the coining of the term "Six-Hour Retarded Child," meaning a child who is "retarded" during the hours in school, but otherwise functions adequately. Thus, it has called such persons who are identified in one or two contexts but not in others the "situationally retarded," in contrast to the "comprehensively retarded," who are identified as such in all the contexts in which they are evaluated.

Situational retardation occurs by far most frequently in school settings, and next most frequently in medical settings, and much less frequently in ratings by families or neighbors or in settings officially responsible for the comprehensively retarded. The situational retardate is primarily the product of the labeling process informal organizations in the community, especially the Public Schools.

The litigation and legislative action, limiting the use of IQ tests as the sole criterion for labeling and special class placement, on the ground that such practices systematically penalize minority groups and violate their rights to equal educational opportunity.

The present tendency is to accept the formulation which requires both an IQ of less than 70 and substantial failure on a measure of adaptive behavior. The requirement of the age of onset prior to 18 is more open to question and not always regarded as critical. This was an extremely important difference because it excluded the "borderline" category which accounted for about 35% of the school-age population! Mental retardation, by any of the proposed criteria, occurs with varying degrees of severity.

Many attempts were made in the past to classify differences of severity, usually based on social adaptation or academic learning criteria. Social adaptation criteria distinguished borderline feeble minded, moron, imbecile, and idiot. Academic Criteria distinguished slow learner, educable, trainable (with no term suggesting learning capability for the still lower category). It is proposed using neutral terms to indicate standard deviation units on the continuum of the IQ and any other scales employed. This is continued to categorize levels of intellectual functioning.

Also, it identified still another variable of a significant sociological nature. Most children who rated low on both IQ and adaptive measures technically "retarded," came from homes that did not conform to the prevailing cultural pattern of the community (socio-culturally nonmodal). This group appeared to be identified as retarded more because of a cultural difference than because of inadequate developmental adaptation.

Further evidence showed that members of this group who were identified as retarded children tended more than the socio-cultural modal group to "disappear" as identifiable retarded on leaving school. Mental retardation, as an inclusive concept, is currently defined in behavioral terms involving all essential components: intellectual functioning, adaptive behavior, and age of onset. The causes of retardation are irrelevant to the definition, whether they be organic, genetic, or environmental.

What is indicated is that at a given time a person is unable to conform to the intellectual and adaptive expectations which society sets for an individual in relation to his peers. In this sense, mental retardation reflects social perception aided by a variety of clinical and nonclinical techniques of identification. Within this broad functional definition, the deficits indicated in the diagnosis of mental retardation may or may not be permanent and irreversible.

They may or may not be responsive to intervention. They may persist only so long as the person remains in a culturally ambiguous situation, or at the other extreme, they may be of life-long duration. Or perhaps only their consequences may be ameliorated to a greater or lesser degree, not the condition itself. Consequently, it is difficult to estimate how frequently mental retardation occurs and how many retarded people there are.

Mental Retardation and Cerebral Palsy

Well, as time passes, the mental retardation can range from mild to severe. Because learning disabilities without mental retardation are also related to cerebral palsy. The hearing, speech, and vision complications (Strabismus) sometimes accompany Cerebral Palsy. That can make learning difficult and many patients have normal IQs and no learning disabilities and may have seizure disorders.

How Big is the Problem?

The incidence of a disorder refers to the frequency of occurrence within a given period. The purpose of determining incidence is to yield information as to the magnitude of the problem with a view to its prevention and to measure the success of preventive programs. The prevalence of a disorder refers to the number of cases existing at a specified time in a specified population and is usually expressed as a percentage of that population or number. Thus, the prevalence of diabetes mellitus in the United States might be expressed either as the percent or number of the total population known or estimated to have the disease in a designated year.

The prevalence of people crippled from poliomyelitis can be expressed as a gradually decreasing figure as the result of the greatly reduced incidence of the disease following the discovery of the vaccines. This shows that prevalence is derived from incidence but modified by the extent to which cases disappear by death, recovery or inaccessibility.

The value of prevalence rates is in determining the magnitude of the need for care, treatment, protection or other services. Incidence Mental retardation can be diagnosed only after birth when appropriate behavioral indices have developed sufficiently for measurement. During gestation the identification of certain conditions usually or invariably associated with mental retardation may be detected and potential retardation inferred.

From the examination of spontaneously aborted fetuses, it is estimated that probably 30 to 50 percent are developmentally abnormal and that if they had survived many would have been mentally deficient; but this information gives us only an incidence of fetal mortality and morbidity, with an estimate of some types of developmental deviation, not an incidence of mental retardation itself.

The mortality rates of the potential or retarded vary with the severity of the defect, which means that many development-tally impaired infants die before retardation has been, or even can be, determined. Since mental retardation manifests itself at different ages and under different conditions, there is no single time e.g., at birth or at one year of age when it can be determined of every child that he is or ever will be identified as mentally retarded.

Mildly mentally retarded persons are most frequently identified, if at all, during school years, and frequently disappear as recognizably retarded after leaving school. The methods of identifying retardation are still highly varied; consequently, surveys of incidence or prevalence are frequently not comparable. The degree of subnormality employed as a criterion for identification as retarded greatly affects the count of incidence.

Currently, however, in view of the problems of arriving at truly meaningful estimates of the incidence of mental retardation on a global basis, the emphasis for purposes of prevention is placed on the incidence from specific known causes. Unfortunately, these comprise only a small proportion of the total identified as retarded. The earliest success stories in the reduction of the incidence of mental retardation were in the case of endemic cretinism.

This condition occurred rather frequently in certain localities, notably some of the Swiss alpine valleys. The problem was attacked in the second half of the 19th century and the start of the 20^th century. The first step was to identify the condition with the occurrence of goiter, an enlargement of the thyroid gland. The next step was to relate this condition to the people's diet and finally to the absence of trace iodine in the soil and water supply.

Iodine was found to be necessary to the functioning of the thyroid gland in its production of the hormone thyroxin, the absence of which can cause cretinism. The addition of iodine to table salt resulted in reducing mental retardation caused by endemic cretinism to near zero. It also led to the preventive and therapeutic use of the extract of thyroxin in the treatment of myxoedema or hypothyroidism from other causes.

An example of incidence is more problematic, but nevertheless significant. The mild retardation is more frequently found in families of low socioeconomic status, especially in families in which the mother is mildly retarded. The retardation in such families can be reduced by early intervention in providing stimulation to the child and home assistance to the mother.

This illustrates the values of pursuing the study of incidence to identifiable causes or correlative conditions as a means of identifying preventive measures. Prevalence The principal problems of obtaining reliable prevalence estimates relate to definitions, criteria, and administrative procedures on the one hand, and to the absence of uniform and centralized data collection, on the other.

The former problems are gradually becoming resolved. The latter requires vigorous and sustained efforts to establish an effective data bank. Prevalence is a product of cumulative incidence modified by loss. Loss may be the result of death or cure or unaccounted disappearance. Whereas measures of incidence are important to the problem of prevention, measures of prevalence are important to the provision of service resources.

As prevention requires differential classification by identifiable cause, service provision requires differential classification by types of need. Overall estimates of the prevalence of mental retardation have been made by two methods: by empirical surveys and by a selection of a cut-off point curve for the distribution of intelligence scores. The mental retardation does not represent a simple portion of the lower tail, It is far from being normally distributed, varying widely by age, by socio-economic and ethnic factors.

the diagnosis of mental retardation is based essentially on an IQ and mental retardation is identified in infancy. The diagnosis does not change, and d) the mortality of retarded individuals is similar to that of the general population." The first assumption ignores the adaptive behavior component; the second holds only for a small portion, nearly always organically and severely impaired; the third holds only as a generality for those of IQ below 55, and the fourth holds only for the mildly retarded.

The potential incidence, probably quite conservative in estimating that infants who survive birth will at some time in their lives be identified as mentally retarded in some context most probably in the public schools. The moderate, severe and profound levels or IQ below 50%. The rate among lower-class nonwhites is higher than among middle-class whites, but the differences are not so striking as is the case in mild retardation levels.

Higher rates of prematurity, higher health risk, and inferior maternal and child health care could account for the difference at the more severe levels. In any case, the presumption of the actual prevalence of the severe forms of defect predictive of mental retardation would be highest at birth, declining rapidly by mortality to a relatively low rate in adult life. Prevalence rates of the severely retarded have been affected by several tendencies in the past 20 years. On the one hand, modern medicine has made enormous strides in its ability to preserve life.

Infant mortality rates have fallen markedly; survival of premature at progressively younger ages has become possible, with correspondingly increased risk of developmental damage; recovery from infectious diseases by use of antibiotics has become commonplace. Consequently, along with other infants and young children, severely and profoundly retarded children now have a better chance of prolonged survival.

On the other hand, improved health care, especially for mothers at risk, immunization, protection from radiation exposure, improved obstetrics, control of Rh isoimmunization and other measures have prevented the occurrence of some abnormalities and reduced the complications which formerly added to the incidence and prevalence of retardation. New hazards appear, however, in environmental toxic substances, strains of microorganisms more resistant to antibiotics, new addictive and nonaddictive drugs, new sources of radiation, environmental stress, all of which are potential producers of biological damage and mental retardation.

On balance, it is possible that the incidence of severe retardation is falling while prevalence is continuing to rise. The high birth rate of the post-World War II period produced a record number of severely retarded children who are surviving longer than ever before. The future, envisioning more control of the causes with a lower birth rate more limited to optimal conditions of reproduction may in time yield lower prevalence rates of the moderate, severely and profoundly retarded.

The prevalence of mild retardation is quite a different matter. Where the severely retarded show a declining prevalence by age, based wholly on mortality, the mildly retarded show a sharply peaked prevalence in the school years (6-19) and a rapid falling off in the adult years. This phenomenon cannot be a product of mortality, because the mildly retarded have shown longevity very nearly that of the general population.

There are two possible alternatives, both of which may be the case. Large numbers remain retarded but cease to be the objects of attention, or they, in fact, cease to be retarded. In any case, no survey has yet found prevalence rates of mild retardation remotely approaching a constant across ages, such as would be expected on the assumption of unchanged relative mental status.

The prevalence and social distribution of mild mental retardation differed markedly according to the definition and methods of identification employed. The "social system" definition ("mental retardate" is achieved status, and mental retardation is the role associated with the status with a "clinical" definition (mental retardation is an individual pathology with characteristic symptoms which can be identified by standard diagnostic procedures).

Furthermore, when higher criteria for IQ and adaptive behavior were used, the disadvantage to both Blacks and Mexican-Americans. The social distribution of mild mental retardation has been found by all investigators to be inversely related to socioeconomic status. It is, more prevalent among poor than among middle and upper-income groups and found most frequently among rural, isolated or ghetto populations.

Controversy persists concerning the contribution of constitutional and social learning factors to this distribution, but it is a question of the relative weight rather than an exclusive alternative. No one doubts the multiple effects of environmental deprivation on both physical and psychological development. Nor is there much doubt that social learning enables the great majority of those with mild intellectual limitations to assume normal social roles in adult life.

It is evident that what might appear to be a manifestation of the normal distribution of polygenic general intelligence is really a complex product in which the genetic component is only one among many factors yielding varying degrees and rates of retarded behavior, among varying populations at varying ages. There is little point, then, in arguing who is "really" retarded.

There is a great point in determining who needs developmental and supportive assistance in achieving a reasonably adequate adult life, in determining the relationships between identifiable characteristics and the kinds of services that will be profitable, and in employing terminology that will aid rather than obscure these relationships.

Mental Retardation Types

A critical issue is a degree to which cultural pluralism is reflected in the educational process. The classification involves a four-dimensional matrix in which potentially handicapping conditions, including mental retardation defined in either "clinical" or "social system" terms, maybe identified:

1. The dimension of intellectual functioning, measurable on a continuous scale represented by IQ. On this scale, an IQ of 69 or less is regarded as potentially handicap-ping and is one clinically defining characteristic of mental retardation. The person with only this dimension of disability as quasi-retarded. Ordinarily, this will be reflected in learning difficulties in the school setting and justifies individually prescriptive educational assistance.
2. The dimension of adaptive behavior, measurable on a developmental scale of behavioral controls accommodating the person to his environment. On this dimension, a person falling substantially below age norms is regarded as potentially handicapped. The person who has only this dimension of disability as behaviorally maladjusted, but she identifies the person with a disability in both 1) and 2) as clinically mentally retarded, requiring services in both school and non-school settings.
3. The dimension of physical constitution, describable in terms of the health or pathology of the various organ systems of the body. While not a defining characteristic of mental retardation, the physical impairment may be potentially handicapping and may be the cause of or magnify the handicapping limitations of 1) and 2). The probability of organic impairments being present increases with the severity of mental retardation at severe and profound levels. Individuals characterized by only 3) may be termed generically as physically impaired and in combination with 1) and 2) as organic mentally retarded. The term "multiply handicapped" is commonly used, but this would apply equally to persons with more than one substantial physical impairment.
4. Sociocultural modality is a fourth dimension that is distinguishable from the other three. It refers to the extent to which sociocultural variables of family background conform or do not conform to the modal culture in which the individual is assessed. When the family background is substantially nonmodal, in this sense, the individual may be potentially handicapped in relation to the prevailing cultural expectations because of a lack of opportunity for the appropriate learning. Such a person may be termed culturally disadvantaged.

The non-modality yielded effects which, to the dominant culture, appeared as low IQ, low adaptive behavior, or both when measured by the norms of the dominant culture. Utilizing a pluralistic model of mental retardation, sensitive to socio-cultural differences, a substantial reduction in the prevalence of mental retardation in the Mexican-Ameri-can as compared to the Anglo population of Riverside.

They need for much more highly refined procedures in the definition and epidemiology of mental retardation as a basis for the adequate and appropriate delivery of developmental and supportive services where they are needed.

There is complete agreement that it is impossible, at our present state of knowledge, to determine accurately either the incidence or the prevalence of mental retardation. There is far less agreement on what we can do to remedy this situation. The two-dimensional deficit in the level of behavioral performance unquestionably is responsive to many problems arising from older definitions. But several issues remain.

The two dimensions are not independent, but are, in fact, highly correlated, the degree of correlation being related to the severity of deficit, the distinction of intellectual and adaptive measures have not been sufficiently refined. In practice, more reliance is frequently placed on IQ measures than on measures of adaptation or other bases of clinical judgment.

The cultural contamination of standardized tests used makes their findings suspect. They require a corrective for the cultural insensitivity of the instruments employed. The use of a global IQ measure which may be adequate for epidemiological purposes obscures the complexity of intellectual functioning and the variability of individual profiles which is the basis of service provision. Global IQ measures are rapidly losing favor among professional providers of service but are maintained for administrative convenience and ease of determination.

The differences in the conditions associated with mild retardation as compared to the more severe forms in terms of organicity, comprehensiveness of impairment, resistance to modification, relatedness to cultural norms, etc., that the two types are sufficiently different as to require separate classification, probably based on organic (or presumed organic) versus psychosocial etiology.

Since the instruments for the measurement of intelligence and adaptive behavior are scalar, with a continuous variation on both sides of central norms, the relationship between a specific level of deficit and the need for specific types of service and treatment may be highly artificial. This appears to be the central question underlying the controversy over the criterion level now excludes persons with IQs from 70 to 85 who formerly were included.

The fact that relatively few scorings above 69 IQ manifest significant deficits in adaptive behavior may miss the point. Adaptive behavior may be quite specific and situational, especially where culture modality may also be in question. The real issue is to determine individual needs, which cannot be derived from IQ or adaptive behavior.

This issue has been exacerbated by legislation which re-quires categorical classification as a condition of eligibility for service. Titles are necessary for any scientific system of classification and may be useful for certain administrative purposes, but their use in human service systems is a different matter. The attachment of a label to a species of plant or a type of rock makes no difference to the plant or the rock.

The label assigned to classify a human being does make a difference. To label a person mentally retarded has consequences of a psychological nature if the person is cognizant of it and can assign a meaning to it; it has consequences of a social nature insofar as other persons as-sign meaning and responds in terms of that meaning. This is especially the case with the label of "mentally retarded" because all terms associated with deficiency of intelligence are, in our culture, highly charged with negative values.

There have been many attempts to use systems of intellect classification as a means of adapting school and other programs to individual differences without making those differences appear invidious. These have not been entirely successful because value systems, even for children, tend to filter through the most subtle of euphemistic terminology.

This is a difficult issue to resolve. Success is possible only if a

1. a) classification for epidemiological purposes is entirely separated from need evaluation for purposes of social grouping and prescriptive treatment.
2. b) all treatment is person-centered rather than system-centered.
3. c) cultural value systems are recognized and respected.
4. d) eligibility for categorical assistance is based, not on global statistical criteria, but on the individual's need.

Obviously, the best database for the epidemiologist would be a computerized data bank including all information on every case. This has, in effect, been advocated since Samuel Howe's first attempt to catalog the "idiotic" population of Massachusetts in 1848, long before modern systems of information storage and retrieval were dreamed of.

However, rights of privacy and confidentiality have become a critical issue. The problem is one of reconciling the needs of the service delivery system and the individual recipient so that he will neither be "lost" as an anonymous number nor stigmatized for having his needs recognized.

Negativism

The nature of retardation lends itself to definition and assessment in the negative terms of the deficit from desirable norms. The individual person, however, is not made up of deficits but of asset characteristics, however meager or distorted some of them maybe. All treatment rests on the positive capacity of the person to respond, whether physiologically or psychologically.

The issue of negatively versus positively defined traits and classifications is a basic one between the purposes of epidemiology and the purposes of service assistance. Who are the people who are mentally retarded? They are individuals whose assets for effective living in their cultural and physical environments are insufficient without assistance.

The screen by which they are brought into view to be identified and counted is composed of a mesh of intellectual and adaptive behavior norms. But the screen is a somewhat crude and abrasive instrument and requires be refining and softening by concern for the individuals it exposes. How many mentally retarded people are there?

The loss of potential for normal development and even survival affects a high proportion of those who are conceived, and those who survive birth. In addition to those hundreds of thousands who are not well-born, there are millions who are not well-nurtured by the world in which they live.

How we sort out these millions, how many will be called "mentally retarded" will depend on our definitions and our perceptions of need. The roots of these needs are not yet under control, nor have we sufficiently provided for their engagement.