“Distributions of Ability of Students Specializing in Different Fields”, Dael Wolfle, Toby Oxtoby1952-09-26 (IQ)⁠:

…Table 1 gives test scores, converted to the Army General Classification Test scale, of students in each of a number of fields of specialization. On the AGCT scale the average person in the total population earns a score of 100. The standard deviation of the scale is 20 points [warning: not 15!], which means that 68% of the total population makes scores between 80 (100 minus 20) and 120 (100 plus 20).

…The average person earning a bachelor’s degree scores about 126 on the AGCT scale [ie. 119 IQ]. About 10 per cent of the total population earns a score this high. The average graduate student gets a score of around 129 [122 IQ]. About 7% of the total population does as well. The average PhD in the sciences makes a score of ~138 [128 IQ]. Only about 2 per cent of the total population makes a score that high.

…Yet there are consistent differences among the fields. In order, from top to bottom in terms of the median scores, students earning bachelor’s degrees line up as follows: physical sciences (except chemistry), chemistry, engineering, law, English, foreign languages, psychology, economics, geology and the earth sciences, biological sciences, fine arts, nursing (nurses with AB degrees), history, agriculture, business and commerce, humanities (except English and the foreign languages), social sciences (except history and economics), education, home economics, and physical education. Students of physical sciences other than chemistry average two points higher than students of chemistry, the next field in line; and students of home economics and physical education are 5 and 6 points below students of education. In no other case is the difference between adjoining fields more than one point on the AGCT scale. The exact ranks, therefore, are not to be taken too seriously. Repetition of the study on a different group of students might well change some of the ranks, but it is unlikely that the changes would be very great. Standard deviations of the medians vary, but almost all of them are less than one.

…In conclusion, those fields which have reputations of requiring abstract and rigorous thinking (eg. physics, chemistry, law) attract students who are, on the average, superior to those who major in traditionally “easier” subjects (eg. business and commerce or education). But the distributions all overlap; every field attracts some of the mediocre students; every field attracts some of the brightest.