The study of race differences in intelligence is an acid test case for psychology. Can behavioral scientists research this subject with the same freedom, objectivity, thoroughness, and scientific integrity with which they go about investigating other psychological phenomena? In short, can psychology be scientific when it confronts an issue that is steeped in social ideologies? In my attempts at self- analysis this question seems to me to be one of the most basic motivating elements in my involvement with research on the nature of the observed psychological differences among racial groups. In a recent article (Jensen, 1985b) I stated:<p>I make no apology for my choice of research topics. I think that my own nominal fields of expertise (educational and differential psychology) would be remiss if they shunned efforts to describe and understand more accurately one of the most perplexing and critical of current problems. Of all the myriad subjects being investigated in the behavioral and social sciences, it seems to me that one of the most easily justified is the black- white statistical disparity in cognitive abilities, with its far reaching educational, economic, and social consequences. Should we not apply the tools of our science to such socially important issues as best we can? The success of such efforts will demonstrate that psychology can actually behave as a science in dealing with socially sensitive issues, rather than merely rationalize popular prejudice and social ideology. (p. 258)

"Most people cannot stand being alone for long. They are always seeking groups to belong to, and if one group dissolves, they look for another. We are group animals still, and there is nothing wrong with that. But what is dangerous is not the belonging to a group, or groups, but not understanding the social laws that govern groups and govern us.
When we're in a group, we tend to think as that group does: we may even have joined the group to find "like-minded" people. But we also find our thinking changing because we belong to a group. It is the hardest thing in the world to maintain an individual dissent opinion, as a member of a group.
It seems to me that this is something we have all experienced - something we take for granted, may never have thought about. But a great deal of experiment has gone on among psychologists and sociologists on this very theme. If I describe an experiment or two, then anyone listening who may be a sociologist or psychologist will groan, oh God not again - for they have heard of these classic experiments far too often. My guess is that the rest of the people will never have had these ideas presented to them. If my guess is true, then it aptly illustrates general thesis, and the general idea behind these essays, that we (the human race) are now in possession of a great deal of hard information about ourselves, but we do not use it to improve our institutions and therefore our lives.
A typical test, or experiment, on this theme goes like this. A group of people are taken into the researcher's confidence. A minority of one or two are left in the dark. Some situation demanding measurement or assessment is chosen. For instance, comparing lengths of wood that differ only a little from each other, but enough to be perceptible, or shapes that are almost the same size. The majority in the group - according to instruction- will assert stubbornly that these two shapes or lengths are the same length, or size, while the solitary individual, or the co

The theory that each race of men has some special faculty, some peculiar gift or quality of mind or heart, needed to the perfection and happiness of the whole is a broad and beneficent theory, and, besides its beneficence, has, in its support, the voice of experience. Nobody doubts this theory when applied to animals or plants, and no one can show that it is not equally true when applied to races. All great qualities are never found in any one man or in any one race. The whole of humanity, like the whole of everything else, is ever greater than a part. Men only know themselves by knowing others, and contact is essential to this knowledge. In one race we perceive the predominance of imagination; in another, like the Chinese, we remark its almost total absence. In one people we have the reasoning faculty; in another the genius for music; in another exists courage, in another great physical vigor, and so on through the whole list of human qualities. All are needed to temper, modify, round and complete the whole man and the whole nation.

The scientific method liberates us to pursue truth regardless of who we are. Similarly, evolutionary psychology, a discipline viscerally despised by many progressives, is expressly anti-racist in that it recognizes that underneath many of our surface differences, human minds were borne of the same evolutionary forces irrespective of our racial or ethnic backgrounds. Environmental forces (or culture) do affect our thinking styles, reasoning, and decision making, but these effects are not immutable elements of one’s race or ethnicity. There is no “black mind” or “white mind,” no “white male way of knowing” or “indigenous way of knowing,” there is only one truth, and we find it through the scientific method.

The fact that a reasonable hypothesis has not been rigorously proved does not mean that it should be summarily dismissed. It only means that we need more appropriate research for putting it to the test. I believe such definitive research is entirely possible but has not yet been done. So all we are left with are various lines of evidence, no one of which is definitive alone, but which, viewed all to­gether, make it a not unreasonable hypothesis that genetic factors are strongly implicated in the average Negro-white intelligence difference. The preponderance of the evidence is, in my opinion, less consistent with a strictly environmental hypothesis than with a genetic hypothesis, which, of course, does not exclude the influence of environment or its interaction with genetic factors.

[Jensen] does not believe that [heritability] estimates alone can decide the issue of genetic versus environmental hypotheses. However, he argues that the probability of a genetic hypothesis will be much enhanced if, in addition to evidencing high [heritability], we find we can falsify literally every plausible environmental hypothesis one by one. He challenges social scientists who believe in an environmental explanation of the IQ gap between the races to bring their hypotheses forward. Given his competence and the present state of the social sciences, the result is something of a massacre.... Far too many of Jensen's critics have not taken up the challenge to refute him in any serious way, rather they have elected for various forms of escape, the most popular of which has been to seize on an argument put forward by the distinguished Harvard geneticist Richard C. Lewontin.

The study of inbreeding depression seems to me especially important in the study of human abilities, because inbreeding depression indicates genetic dominance, and the presence and degree of dominance are related to natural selection for the trait in the course of its biological evolution. It was of great interest to me to discover, for example, that of the several ability factors that can be extracted from the various subtests of the Wechsler Intelligence Scale for Children, the one that shows the greatest susceptibility to inbreeding depression is the g factor (Jensen, 1983b). This finding indicates that one of our most widely used standard psychometric tests of intelligence yields scores that reflect some part of the variance in the biological intelligence that has developed in the course of human evolution.

Isn’t the social scientist’s use of the null hypothesis simply the application of Popperian (or Bayesian) thinking in contexts in which probability plays such a big role? ... since an output variable such as adult IQ, or academic achievement, or effectiveness at communication, or whatever, will always, in the social sciences, be a function of a sizable but finite number of factors... Putting it crudely, if you have enough cases and your measures are not to-tally unreliable, the null hypothesis will always be falsified, regardless of the truth of the substantive theory.

As is well-known (and not disputed by Popper), when we spell out in detail the logical structure of what purports to be an observational test of a theoretical conjecture T, we normally find that we cannot get to an observational statement from T alone. We require further a set of often complex and problematic auxiliaries A, plus the empirical realization of certain conditions describing the experimental particulars C [but] in social science the auxiliaries A and the initial and boundary conditions of the system C are frequently as problematic as the theory T itself.

I have tried to show that psychiatric research can be empirical and experimental, controlled, and operational and not dependent on inferences, analogies, or anecdotes. Hypotheses can be derived which are testable. Theory is a different matter. At the present we rely heavily on psychoanalytic theory or on still poorly formulated and defined general systems theory, information theory, or transactional theory. To explain the depth and variety of the interrelationship of somatopsychosocial facets of the totality of human behavior in process requires a unified theory of human behavior which we have not yet even approached. Integration or synthesis of biological, psychological, and social theory is not enough.

Recently, researchers captured an unbelievable picture of a small group of photons as waves and another group behaving as particles at the same time.14 Although the idea of complementarity is now established in physics, it is not widely seen as a possible foundational idea for thinking about the mind/brain explanatory gap. I think it should be, and first want to look at how physics came to accept its seemingly puzzling reality. Following its acceptance in physics, the idea of complementarity may prove itself to be key to thinking about biology, and about the mind/brain gap in particular.

Our empirical criterion for a series of theories is that it should produce new facts. The idea of growth and the concept of empirical character are soldered into one.

I scarcely believe that in psychology data are present which can be mathematically evaluated. But one cannot know this with certainty, without having made the experiment. God alone is in possession of the mathematical bases of psychic phenomena.

The Mismeasure of Man treats one particular form of quantified claim about the ranking of human groups: the argument that intelligence can be meaningfully abstracted as a single number capable of ranking all people on a linear scale of intrinsic and unalterable mental worth. Fortunately — and I made my decision on purpose — this limited subject embodies the deepest (and most common) philosophical error, with the most fundamental and far-ranging social impact, for the entire troubling subject of nature and nurture, or the genetic contribution to human social organization.