Classics in the History of Psychology

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Christopher D. Green
York University, Toronto, Ontario

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The Kallikak Family:
A Study in the Heredity of Feeble-Mindedness

Henry Herbert Goddard (1913)

Director of the Research Laboratory of the Training School
at Vineland, New Jersey, for Feeble-minded Girls and Boys



No one interested in the progress of civilization can contemplate the facts presented in the previous chapters without having the question arise, Why isn't something done about this? It will be more to the point if we put the question, Why do we not do something about it? We are thus face to face with the problem in a practical way and we ask ourselves the next question, What can we do? For the low-grade idiot, the loathsome unfortunate that may be seen in our institutions, some have proposed the lethal chamber. But humanity is steadily tending away from the possibility of that method, and there is no probability that it will ever be practiced.

But in view of such conditions as are shown in the defective side of the Kallikak family, we begin to realize that the idiot is not our greatest problem. He is indeed loathsome; he is somewhat difficult to take care of; nevertheless, he lives his life and is done. He does not continue the race with a line of children like himself. [p. 102] Because of his very low-grade condition, he never becomes a parent.

It is the moron type that makes for us our great problem. And when we face the question, "What is to be done with them -- with such people as make up a large proportion of the bad side of the Kallikak family?" we realize that we have a huge problem.

The career of Martin Kallikak Sr. is a powerful sermon against sowing wild oats. Martin Kallikak did what unfortunately many a young man like him has done before and since, and which, still more unfortunately, society has too often winked at, as being merely a side step in accordance with a natural instinct, bearing no serious results. It is quite possible that Martin Kallikak himself never gave any serious thought to his act, or if he did, it may have been merely to realize that in his youth he had been indiscreet and had done that for which he was sorry. And being sorry he may have thought it was atoned for, as he never suffered from it any serious consequences.

Even the people of his generation, however much they may have known about the circumstances, could not have begun to realize the evil that had been done. Undoubtedly, it was only looked upon as a sin because it was a violation of the moral law. The real sin of [p. 103] peopling the world with a race of defective degenerates who would probably commit his sin a thousand times over, was doubtless not perceived or realized. It is only after the lapse of six generations that we are able to look back, count up and see the havoc that was wrought by that one thoughtless act.

Now that the facts are known, let the lesson be learned; let the sermons be preached; let it be impressed upon our young men of good family that they dare not step aside for even a moment. Let all possible use be made of these facts, and something will be accomplished.

But even so the real problem will not be solved. Had Martin Kallikak remained in the paths of virtue, there still remained the nameless feeble-minded girl, and there were other people, other young men, perhaps not of as good a family as Martin, perhaps feeble-minded like herself, capable of the same act and without Martin's respectability, so that the race would have come down even worse if possible than it was, because of having a worse father.

Others will look at the chart and say, "The difficulty began with the nameless feeble-minded girl; had she been taken care of, all of this trouble would have been avoided." This is largely true. Although feeble-[p.104]mindedness came into this family from other sources in two generations at least, yet nevertheless these sources were other feeble-minded persons. When we conclude that had the nameless girl been segregated in an institution, this defective family would not have existed, we of course do not mean that one single act of precaution, in that case, would have solved the problem, but we mean that all such cases, male and female, must be taken care of, before their propagation will cease. The instant we grasp this thought, we realize that we are facing a problem that presents two great difficulties; in the first place the difficulty of knowing who are the feeble-minded people; and, secondly, the difficulty of taking care of them when they are known.

A large proportion of those who are considered feeble-minded in this study are persons who would not be recognized as such by the untrained observer. They are not the imbeciles nor idiots who plainly show in their countenances the extent of their mental defect. They are people whom the community has tolerated and helped to support, at the same time that it has deplored their vices and their inefficiency. They are people who have won the pity rather than the blame of their neighbors, but no one has seemed to suspect the real cause [p. 105] of their delinquencies, which careful psychological tests have now determined to be feeble-mindedness.

The second difficulty is that of caring for this large army of people. At the lowest estimates of the number needing care, we in the United States are at present caring for approximately one tenth of the estimated number of our mental defectives. Yet many of our States think that they are now being over-taxed for the care of these people, so that it is with great difficulty that legislatures can be induced to appropriate money enough to care for those already in institutions. It is impossible to entertain the thought of caring for ten times as many. Some other method must be devised for dealing with the difficulty.

Before considering any other method, the writer would insist that segregation and colonization is not by any means as hopeless a plan as it may seem to those who look only at the immediate increase in the tax rate. If such colonies were provided in sufficient number to take care of all the distinctly feeble-minded cases in the community, they would very largely take the place of our present almshouses and prisons, and they would greatly decrease the number in our insane hospitals. Such colonies would save an annual loss in property and life, due to the action of these irresponsible people, [p. 106] sufficient to nearly, or quite, offset the expense of the new plant. Besides, if these feeble-minded children were early selected and carefully trained, they would become more or less self-supporting in their institutions, so that the expense of their maintenance would be greatly reduced.

In addition to this, the number would be reduced, in a single generation, from 300,000 (the estimated number in the United States) to 100,000, at least, -- and probably even lower. (We have found the hereditary factor in 65 per cent of cases; while others place it as high as 80 per cent.)

This is not the place for arguing the question or producing the statistics to substantiate these statements. Suffice it to say that every institution in the land has a certain proportion of inmates who not only earn their own living, but some who could go out into the world and support themselves, were it not for the terrible danger of procreation, -- resulting in our having not one person merely, but several to be cared for at the expense of the State. These statements should be carefully considered and investigated before any one takes the stand that segregation in colonies and homes is impossible and unwise for the State.

The other method proposed of solving the problem [p. 107] is to take away from these people the power of procreation. The earlier method proposed was unsexing, asexualization, as it is sometimes called, or the removing, from the male and female, the necessary organs for procreation. The operation in the female is that of ovariectomy and in the male of castration.

There are two great practical difficulties in the way of carrying out this method on any large scale. The first is the strong opposition to this practice on the part of the public generally. It is regarded as mutilation of the human body and as such is opposed vigorously by many people. And while there is no rational basis for this, nevertheless we have, as practical reformers, to recognize the fact that the average man acts not upon reason, but upon sentiment and feeling; and as long as human sentiment and feeling are opposed to this practice, no amount of reasoning will avail. It may be shown over and over again that many a woman has had the operation of ovariectomy performed in order to improve her physical condition, and that it is just as important to improve the moral condition as the physical. Nevertheless, the argument does not convince, and there remains the opposition as stated.

In recent years surgeons have discovered another method which has many advantages. This is also [p. 108] sometimes incorrectly referred to as asexualization. It is more properly spoken of as sterilization, the distinction being that it does not have any effect on the sex qualities of the man or woman, but does artificially take away the power of procreation by rendering the person sterile. The operation itself is almost as simple in males as having a tooth pulled. In females it is not much more serious. The results are generally permanent and sure. Objection is urged that we do not know the consequences of this action upon the physical, mental, and moral nature of the individual. The claim is made that it is good in all of these. But it must be confessed that we are as yet ignorant of actual facts. It has been tried in many cases; no bad results have been reported, while many good results have been claimed.

A more serious objection to this last method comes from a consideration of the social consequences. What will be the effect upon the community in the spread of debauchery and disease through having within it a group of people who are thus free to gratify their instincts without fear of consequences in the form of children? The indications are that here also the evil consequences are more imaginary than real, since the feeble-minded seldom exercise restraint in any case. [p. 109]

Probably the most serious difficulty to be overcome before the practice of sterilization in any form could come into general use would be the determining of what persons were proper subjects to be operated upon.[1] This difficulty arises from the fact that we are still ignorant of the exact laws of inheritance. Just how mental characteristics are transmitted from parent to child is not yet definitely known. It therefore becomes a serious matter to decide beforehand that such and such a person who has mental defect would certainly transmit the same defect to his offspring and that consequently he ought not to be allowed to have off-spring.


In 1866 an Austrian monk by the name of Gregor Mendel discovered and published a law of inheritance in certain plants, which, after lying practically unknown for nearly forty years, was rediscovered in 1900 and since then has been tested with regard to a great many plants and animals.

Mendel found that there were certain peculiarities in plants which he termed "unit characters" that were [p. 110] transmitted from parent to offspring in a definite way. His classical work was on the propagation of the ordinary garden pea, in which case he found that a quality like tallness, as contrasted with dwarfness, was transmitted as follows:--

If tall and dwarf peas were crossed, he found in the first generation nothing but tall peas. But if these peas were allowed to grow and fertilize themselves, in the next generation he got tall and dwarf peas in the ratio of three to one. The dwarf peas in this case bred true, i.e. when they were planted by themselves and self-fertilized there was never anything but dwarf peas, no matter how many generations were tested. On the other hand, the tall peas were divisible by experiment into two groups; first, those that always bred true, viz. always tall peas; and secondly, another group that bred tall and dwarf in the same ratio of three to one; and from these the same cycle was repeated. Mendel called the character, which did not appear in the first generation (dwarfness), "recessive"; the other (tallness) he called "dominant." The recessive factor is now generally considered to be due to the absence of something which, if present, would give the dominant factor. According to this view, dwarfness is simply the absence of tallness. [p. 111]

This law has been found to hold true for many unit characters in many plants and animals. Since study in human heredity has been taken up, it has been a natural question, Does this same law apply to human beings? It has been found that it does apply in the case of many qualities, like color of hair, albinism, brachydactylism, and other peculiarities. Investigation has of late been extended to mental conditions. Rosanoff has shown pretty clearly that the law applies in the case of insanity, while Davenport and Weeks have shown evidence that it applies in cases of epilepsy.

Our own studies lead us to believe that it also applies in the case of feeble-mindedness, but this will be taken up in a later work to which we have already referred. We do not know that feeble-mindedness is a "unit character." Indeed, there are many reasons for thinking that it cannot be. But assuming for the sake of simplifying our illustration that it is a "unit character," then we have something like the following conditions.

If two feeble-minded people marry, then we have the same unit character in both, and all of the offspring will be feeble-minded; and if these offspring select feeble-minded mates, then the same thing will continue. But what will happen if a feeble-minded person takes a normal mate? If feeble-mindedness is recessive (due [p. 112] to the absence of something that would make for normality), we would expect in the first generation from such a union all normal children, and if these children marry persons like themselves, i.e. the offspring of one normal and one defective parent, then the offspring would be normal and defective in the ratio of three to one. Of the normal children, one third would breed true and we would have a normal line of descent.

Without following the illustration further, we see already that it is questionable whether we ought to say that the original feeble-minded individual should have been sterilized because he was feeble-minded. We see that in the first generation all of his children were normal and in the next generation one fourth of them were normal and bred true. We should not forget, however, that one fourth of his grandchildren would be feeble-minded and that two other fourths had the power of begetting feeble-minded children. We must not forget, either, that these are averages, and that for the full carrying out of these figures there must be a large enough number of offspring to give the law of averages room to have full play. In other words, any marriage which, according to the Mendelian principle, would give normals and defectives in the ratio of three to one might result in only one child. That child might hap-[p. 113]pen to be one of the feeble-minded ones, and so there is propagated nothing but the feeble-minded type. It is equally true that it might be the normal child, with a consequent normal line of descendants; or still again, it might be one of the intermediate ones that are capable of reproducing again the ratio of three normal to one defective, so that the chance is only one in four of such offspring starting a normal line.

Let us now turn to the facts as we have them in the Kallikak family. The only offspring from Martin Kallikak Sr., and the nameless feeble-minded girl was a son who proved to be feeble-minded. He married a normal woman and had five feeble-minded children and two normal ones. This is in accordance with Mendelian expectation; that is to say, there should have been part normal and part defective, half and half, if there had been children enough to give the law of averages a chance to assert itself. The question, then, comes right there. Should Martin Jr. have been sterilized! We would thus have saved five feeble-minded individuals and their horrible progeny, but we would also have deprived society of two normal individuals; and, as the results show, these two normals married normal people and became the first of a series of generations of normal people. [p. 114]

Taking this family as a whole, we have the following figures:--

There were 41 matings where both parents were feeble-minded. They had 222 feeble-minded children, with two others that were considered normal. These two are apparent exceptions to the law that two feeble-minded parents do not have anything but feeble-minded children. We may account for these two exceptions in one of several ways. Either there is a mistake in calling them normal, or a mistake in calling the parents feeble-minded; or else there was illegitimacy somewhere and these two children aid not have the same father as the others of the family. Or we may turn to the Mendelian law and we discover that according to that law there might be in rare instances such a combination of circumstances that a normal child might be born from two parents that function as feeble-minded. For practical purposes it is, of course, pretty clear that it is safe to assume that two feeble-minded parents will never have anything but feeble-minded children.

Again, we find that there were eight cases where the father was feeble-minded and the mother normal, and there were ten normal children and ten defective.

There were twelve cases where the father was normal and the mother feeble-minded, with seven feeble-minded [p. 115] children and ten normal. Both of these are in accordance with Mendelian expectations.

We further find that in the cases where one parent was feeble-minded and the other undetermined, the children were nearly all feeble-minded, from which we might infer that the probabilities are great that the unknown parent was also feeble-minded.

We shall not go further into this matter in the present paper, but leave the detailed study of this family from the Mendelian standpoint for further consideration, when we take up the large amount of data which we have on three hundred other families. Enough is here given to show the possibility that the Mendelian law applies to human heredity. If it does, then the necessity follows of our understanding the exact mental condition of the ancestors of any person upon whom we may propose to practice sterilization.

From all of this the one caution follows. At best, sterilization is not likely to be a final solution of this problem. We may, and indeed I believe must, use it as a help, as something that will contribute toward the solution, until we can get segregation thoroughly established. But in using it, we must realize that the first necessity is the careful study of the whole subject, to the end that we may know more both about the [p. 116] laws of inheritance and the ultimate effect of the operation.


The Kallikak family presents a natural experiment in heredity. A young man of good family becomes through two different women the ancestor of two Iines of descendants, -- the one characterized by thoroughly good, respectable, normal citizenship, with almost no exceptions; the other being equally characterized by mental defect in every generation. This defect was transmitted through the father in the first generation. In later generations, more defect was brought in from other families through marriage. In the last generation it was transmitted through the mother, so that we have here all combinations of transmission, which again proves the truly hereditary character of the defect.

We find on the good side of the family prominent people in all walks of life and nearly all of the 496 descendants owners of land or proprietors. On the bad side we find paupers, criminals, prostitutes, drunkards, and examples of all forms of social pest with which modern society is burdened.

From this we conclude that feeble-mindedness is largely responsible for these social sores. [p. 117]

Feeble-mindedness is hereditary and transmitted as surely as any other character. We cannot successfully cope with these conditions until we recognize feeble-mindedness and its hereditary nature, recognize it early, and take care of it.

In considering the question of care, segregation through colonization seems in the present state of our knowledge to be the ideal and perfectly satisfactory method. Sterilization may be accepted as a makeshift, as a help to solve this problem because the conditions have become so intolerable. But this must at present be regarded only as a makeshift and temporary, for before it can be extensively practiced, a great deal must be learned about the effects of the operation and about the laws of human inheritance.


[1] At present eight states have laws authorizing some form of asexualization or sterilization. But in all these cases the practice is carefully restricted to a few inmates of various specified institutions.