The Effect of Intelligence on Religious Faith
Is it more logical to be a
Christian? Is religion the natural choice of a smart person familiar with more
of the evidence? Not according to a broad consensus of studies on IQ and
religiosity. These studies have consistently found that the lower the IQ score,
the more likely a person is to be religious.
To place these studies in
perspective, it is helpful to know the general religious attitudes of Americans
today. According to a February 1995 Gallup poll, 96 percent of all Americans
believe in God, and 88 percent affirm the importance of religion. However, the
degree of religiosity within this group varies considerably. Only 35 percent can
be classified as "religious," using a definition that requires them to consider
religion important and attend religious services at least once a week. And a
March 1994 Gallup poll found that only 20 percent of all Americans belong to
that politically active group known as "Christian conservatives."
following is a review of several studies of IQ and religiosity, paraphrased and
summarized from Burnham Beckwith's article, "The Effect of Intelligence on
Religious Faith," Free Inquiry, Spring 1986: (1)
1. Thomas Howells, 1927
Study of 461 students
showed religiously conservative students "are, in general, relatively inferior
in intellectual ability."
2. Hilding Carlsojn, 1933
215 students showed that "there is a tendency for the more intelligent
undergraduate to be sympathetic toward… atheism."
Confirming Howells and Carlson, tested 354 Jewish
children, aged 10-16. Found a negative correlation between religiosity and IQ as
measured by the Terman intelligence test.
4. Thomas Symington,
Tested 400 young people in colleges and church groups. He reported,
"There is a constant positive relation in all the groups between liberal
religious thinking and mental ability… There is also a constant positive
relation between liberal scores and intelligence…"
5. Vernon Jones,
Tested 381 students, concluding "a slight tendency for intelligence
and liberal attitudes to go together."
6. A. R. Gilliland,
At variance with all other studies, found "little or no relationship
between intelligence and attitude toward god."
7. Donald Gragg,
Reported an inverse correlation between 100 ACE freshman test scores
and Thurstone "reality of god" scores.
8. Brown and Love,
At the University of Denver, tested 613 male and female students.
The mean test scores of non-believers was 119 points, and for believers it was
100. The non-believers ranked in the 80th percentile, and believers in the 50th.
Their findings "strongly corroborate those of Howells."
Concluded that "although intelligent children grasp
religious concepts earlier, they are also the first to doubt the truth of
religion, and intelligent students are much less likely to accept orthodox
10. Jeffrey Hadden, 1963
Found no correlation between
intelligence and grades. This was an anomalous finding, since GPA corresponds
closely with intelligence. Other factors may have influenced the results at the
University of Wisconsin.
11. Young, Dustin and Holtzman,
Average religiosity decreased as GPA rose.
Polled 1400 college seniors. Found little difference, but
high-ability students in his sample group were over-represented.
C. Plant and E. Minium, 1967
The more intelligent students were less
religious, both before entering college and after 2 years of
14. Robert Wuthnow, 1978
Of 532 students, 37 percent
of Christians, 58 percent of apostates, and 53 percent of non-religious scored
above average on SATs.
15. Hastings and Hoge, 1967, 1974
200 college students and found no significant correlations.
Mean SATs for strongly anti-
religious (1148), moderately
anti-religious (1119), slightly anti-religious (1108), and religious
17. Wiebe and Fleck, 1980
Studied 158 male and female
Canadian university students. They reported "nonreligious S's tended to be
strongly intelligent" and "more intelligent than religious
STUDENT BODY COMPARISONS
1. Rose Goldsen,
Percentage of students who believe in a divine god: Harvard 30; UCLA
32; Dartmouth 35; Yale 36; Cornell 42; Wayne 43; Weslyan 43; Michigan 45; Fisk
60; Texas 62; North Carolina 68.
2. National Review Study,
Percentage of students who believe in a Spirit or Divine God: Reed
15; Brandeis 25; Sarah Lawrence 28; Williams 36; Stanford 41; Boston U. 41; Yale
42; Howard 47; Indiana 57; Davidson 59; S. Carolina 65; Marquette
3. Caplovitz and Sherrow, 1977
Apostasy rates rose
continuously from 5 percent in "low" ranked schools to 17 percent in "high"
4. Niemi, Ross, and Alexander, 1978
schools, organized religion was judged important by only 26 percent of their
students, compared with 44 percent of all students.
VERY-HIGH IQ GROUPS
1. Terman, 1959
Studied group with IQ's over
140. Of men, 10 percent held strong religious belief, of women 18 percent.
Sixty-two percent of men and 57 percent of women claimed "little religious
inclination" while 28 percent of the men and 23 percent of the women claimed it
was "not at all important."
2. Warren and Heist, 1960
differences among National Merit Scholars. Results may have been effected by the
fact that NM scholars are not selected on the basis of intelligence or grades
alone, but also on "leadership" and such like.
3. Southern and Plant,
Studied 42 male and 30 female members of Mensa. Mensa members were
much less religious in belief than the typical American college alumnus or
STUDIES Of SCIENTISTS
1. William S. Ament,
C. C. Little, president of the University of Michigan, checked
persons listed in Who's Who in America: "Unitarians, Episcopalians,
Congregationalists, Universalists, and Presbyterians [who are less religious]
are… far more numerous in Who's Who than would be expected on the basis
of the population which they form. Baptists, Methodists, and Catholics are
distinctly less numerous."
Ament confirmed Little's conclusion. He noted
that Unitarians, the least religious, were more than 40 times as numerous in
Who's Who as in the U.S. population.
2. Lehman and Witty,
Identified 1189 scientists found in both Who's Who (1927) and
American Men of Science (1927). Only 25 percent of those listed in the
latter and 50 percent of those in the former reported their religious
denomination, despite the specific request to do so, under the heading of
"religious denomination (if any)." Well over 90 percent of the general
population claims religious affiliation. The figure of 25 percent suggests far
less religiosity among scientists.
Unitarians were 81.4 times as numerous
among eminent scientists as non-Unitarians.
3. Kelley and Fisk,
Found a negative (-.39) correlation between the strength of
religious values and research competence. [How these were measured is
4. Ann Roe, 1953
Interviewed 64 "eminent scientists,
nearly all members of the prestigious National Academy of Sciences or the
American Philosophical Society. She reported that, while nearly all of them had
religious parents and had attended Sunday school, 'now only three of these men
are seriously active in church. A few others attend upon occasion, or even give
some financial support to a church which they do not attend… All the others have
long since dismissed religion as any guide to them, and the church plays no part
in their lives… A few are militantly atheistic, but most are just not
5. Francis Bello, 1954
questionnaired 107 nonindustrial scientists under the age of 40 judged by senior
colleagues to be outstanding. Of the 87 responses, 45 percent claimed to be
"agnostic or atheistic" and an additional 22 percent claimed no religious
affiliation. For 20 most eminent, "the proportion who are now a-religious is
considerably higher than in the entire survey group."
Questionnaired 740 US psychologists and chemists. He
reported, "The highly creative men… significantly more often show either no
preference for a particular religion or little or no interest in religion."
Found that the most eminent psychologists showed 40 percent no preference, 16
percent for the most eminent chemists.
7. Vaughan, Smith, and Sjoberg,
Polled 850 US physicists, zoologists, chemical engineers, and
geologists listed in American Men of Science (1955) on church membership,
and attendance patterns, and belief in afterlife. Of the 642 replies, 38.5
percent did not believe in an afterlife, whereas 31.8 percent did. Belief in
immortality was less common among major university staff than among those
employed by business, government, or minor universities. The Gallup poll taken
about this time showed that two-thirds of the U.S. population believed in an
afterlife, so scientists were far less religious than the typical
The consensus here is clear: more
intelligent people tend not to believe in religion. And this observation is
given added force when you consider that the above studies span a broad range of
time, subjects and methodologies, and yet arrive at the same conclusion.
This is the result even when the researchers are Christian conservatives
themselves. One such researcher is George Gallup. Here are the results of a Fall
1995 Gallup poll:
Percentage of respondents who agreed with the following statements:
Religion is Religion can
"very important "answer all or most
Respondents in their life" of today's problems"
Attended college 53 percent 58 percent
No college 63 65
Income over $50,000 48 56
$30,000 - $50,000 56 62
$20,000 - $30,000 56 60
Under $20,000 66 66
Why does this correlation exist? The first answer that comes to mind is that
religious beliefs tend to be more illogical or incoherent than secular beliefs,
and intelligent people tend to recognize that more quickly. But this explanation
will surely be rejected by religious people, who will seek other explanations
A possible counter-argument is that intelligent
people tend to be more successful than others. The lure of worldly success and
materialism draws many of these intellectually gifted individuals away from God.
After all, who needs God when you (apparently) are making it on your
However, this argument does not withstand closer scrutiny. Most of
the studies outlined above describe the religious attitudes of students, who
have yet to enter the working world, much less succeed in it. Some might then
argue that the most intelligent students are nonetheless succeeding in school.
But "success" in school (for those who may have forgotten!) is more measured in
terms of popularity, sports, physical attractiveness, personality, clothes, etc.
Grades are but one of many measures of success in a young person's life -- one
that is increasingly becoming less important, as many social critics point
The simplest and most parsimonious explanation is that religion is a
set of logical and factual claims, and those with the most logic and facts at
their disposal are rejecting it largely on those grounds.