In this video I consider sex differences in IQ scores. While average male and female IQ scores are comparable, there are differences in performance on certain types of tasks including verbal fluency, spatial ability, math problem-solving, use of complex prose, and others. There is also a difference in the distribution of IQ scores for males and females, with males showing greater variance and greater representation at the extremes of both low and high scores. Interpreting the consequences of these IQ differences is difficult, as there are sex differences in genes, hormones, interests, personality traits, and sociocultural expectations and pressures, all of which could be influencing outcomes such as career choices.
Don’t forget to subscribe to the channel to see future videos! Have questions or topics you’d like to see covered in a future video? Let me know by commenting or sending me an email!
Halpern, D. F. (1997). Sex differences in intelligence: Implications for education. American Psychologist, 52(10), 1091–1102. https://doi.org/10.1037/0003-066X.52.10.1091
Intelligence: Knowns & Unknowns https://differentialclub.wdfiles.com/local–files/definitions-structure-and-measurement/Intelligence-Knowns-and-unknowns.pdf
Check out my book, Master Introductory Psychology, an alternative to a traditional textbook: http://amzn.to/2eTqm5s
Video Transcript
Hi, I’m Michael Corayer and this is Psych Exam Review. In this video we’re going to look at the sex differences in IQ. Now when we look at male and female IQ scores, their average scores are comparable so there’s not really any major difference between males and females in terms of their average IQ scores. Now occasionally you may see studies that find males slightly outperforming females or females slightly outperforming males and it might depend on whether we’re looking at children or adults but in general we can say that the average scores are pretty much the same.
But their performance is not exactly identical. So we do find that there are differences in performance on certain tasks. And when we think about this it makes sense, when we consider that IQ tests are designed to not be biased towards males or females. So we do have differences in task performance between males and females on certain types of tasks but we wouldn’t want to have a test where we only tested those types of tasks because then males would perform much better than females or females would perform much better than males. And so throughout the creation of IQ tests there’s been an attempt to sort of balance out these different types of skills in terms of their representation on IQ tests and that would be why the average scores would be comparable.
So what are these differences in task performance? Well if we look at the ability of males and females on these tasks again we’re looking at the overall population, we’re not talking about individuals here, we find that females tend to be better on tasks involving things like complex prose verbal fluency and some types of fine motor skills and males tend to do slightly better on tasks involving things like spatial ability; so mentally rotating or transforming objects. They tend to do slightly better on tasks involving fluid reasoning and on certain types of math problem-solving.
Now, again, it’s important to remember that we’re talking about averages here, not individuals. So it’s not telling us anything, it’s not saying at all that any male is, any particular male is going to be better at spatial ability than any particular female. We’re not saying that at all. We’re just saying if we look at the averages overall between males and females we find some slight differences in these different tasks. Ok, we also find a difference in IQ when we look at the distribution of IQ for males and females.
So this is something approximating a normal curve and I made a video already, hopefully you’ve watched, on the normal curve related to IQ and so we saw that the average IQ is about 100 and we have standard deviation about 15 and we get this normal curve where we have most people near the center, near the average, and then this sort of symmetrical decrease in the frequency of scores as we get higher and higher and as we get lower and lower. But what I didn’t mention in that video is that there’s a slight difference in the curves if we look at the normal curve, or the Gaussian curve, for male performance and female performance. So if we assume this line here is the male performance then what would the female curve look like? Well it would look something like this.
So what we see is that the female curve for IQ is tighter, it’s closer together, there’s less variance. Males tend to show more variance in their IQ scores; they’re more spread out. But when we look at this, the average is still going to be here. The mean, the median, and the mode for both of these curves is going to be here in the center and they’re still symmetrically distributed. So we still have an average score of about 100 for both males and females but they’re distributed slightly differently. So what does this mean?
Well, it means that males are going to be over-represented at the extremes. So we’re gonna have more males at these extremes. So males are more likely to be found at the extreme scores. Now this means we’re going to have more males with disability, there’s more males than females over here at the very low end, but we’re also going to have more males at the higher end more males with intellectual giftedness, very high IQ. Now we can see this if we look at things like dyslexia, intellectual disability, autism, ADHD, males tend to be over-represented in those problems but they also are overrepresented in terms of very high IQ.
Ok, so again this is remember, about individuals; I’m sorry not about individuals, this is about groups. So just knowing that someone is male or female doesn’t really tell you anything about their IQ, right? Because a female could be anywhere on this line and a male could be anywhere on this line. So you can obviously have females here who are, you know, have higher IQs than the vast majority of males and similarly you can have females over here with with lower IQ who are going to have lower IQs than most males or most other females in that case. And again these lines are symmetrical meaning that basically half of males and half of females are gonna have IQs below average and half are gonna be on the other side above average. Ok, so what does this all mean? Why might this be? Why might it be that these curves are different? And then what does it mean?
Now this reminds me of back in 2005 when I was a student at Harvard and at the time there was a big controversy over some comments that were made by then-president of Harvard Larry Summers because he was speaking about the representation of males and females in math and the sciences in higher positions in academia. And he suggested that part of the explanation might be biological differences between males and females and this caused this uproar, which in my opinion was blown out of proportion by the press, but what, what do these things mean when we think about differences between males and females? How should we interpret them especially when it comes to applying them to these types of issues?
Well one thing we can say is when we think about biological differences between the sexes we can say, well what’s going to be the result of, you know, if somebody’s male or female? Well there’s going to be different genes, right? Males and females are going to have different genes and maybe that’s gonna influence some things. And it’s going be the case also that they’re gonna have different hormones. Ok, so maybe different levels of hormones are going to have influences on their intellectual development. And we also see differences in other traits. So we see differences in things like risk-taking. Males tend to be more risk-taking than females and it’s also the case that males tend to be more competitive. And we could think about this through sort of an evolutionary lens and think about the fact that often males are competing for access to mates and this means males are competing with each other and maybe that’s going to have some influence on certain traits that they develop.
And then we can think about well, there’s also differences in interests, right? So we can find differences in interests between males and females and we can actually find this in other species as well. So, for instance you can give toys to vervet monkeys and you’ll find that male and female vervet monkeys actually show different preferences in which toys they prefer to play with, And these are toys they’ve never played with before. And, you know, we don’t have some sort of societal structure that that’s giving them all sorts of advertising and experience with these different stereotypes regarding these toys. So that suggests that maybe there are innate differences in interests and so when we think about something like representation of males and females in certain fields, maybe it has to do more with interests and maybe there’s some biological basis to that. And when we look at things like career interests, it might be the case that just men are more interested in things like objects and women are more interested in people.
And that seems to be the case. It seems to be that males show greater interest in objects and females show greater interest in people and we also see this in careers that people choose. Women are more likely to be in careers focused on other people and men are more likely to be in careers focused on objects. And so this difference in career interest might be related to differences in biology between the sexes. And different career interest is actually one of the best predictors of the careers that people are in. People have different interests and that sort of determines their career path and maybe biology is playing a role in that.
Now, of course the big thing that I haven’t mentioned yet is well maybe there’s some socio-cultural explanations for this, you know, maybe society is responsible for these differences between males and females. Now some people take this to the extreme and they suggest that it’s all about socio-cultural forces. That any of the differences between males and females arise purely because of societal expectations and pressures but I think it’s more likely and more reasonable to suggest that this is only going to be part of the explanation. Just like we shouldn’t say that genes are going to be everything and they’re going to be deterministic for everything you do, we probably shouldn’t say the same for culture.
This is the nature-nurture debate we’ve talked about already. So it’s probably going to be part of the explanation but not the whole explanation. So when we go back to look at something like this curve and we ask this question of, well why is it, why do we have these differences? We have all these other possible factors that might be related. Now some people might look at this and say well it’s purely socio-cultural, you know, they might say well there’s the, you know, oppressive nature of patriarchal society that’s holding women down and that’s why women are going to be underrepresented in certain fields or males are going to be over-represented. And it’s because men are holding women down and it’s this, you know, patriarchal society or something.
Now often people apply that type of explanation when they’re looking out here at areas of very high performance. Why are males over-represented in these very high positions or something? And they give this socio-cultural explanation but the problem with this explanation is that you don’t often see it used at the other end of the distribution. You don’t see many people saying well, why is it that men have higher rates of intellectual disability and dyslexia and ADHD and autism? Why is that the case and you’re probably not going to see some somebody saying “well it’s the patriarchal oppressive nature of society” because, well, that explanation doesn’t seem to make much sense for why males would be over-represented at these extremes of disability.
And so it’s not really reasonable to say that well it’s biology people say “well it’s probably biology in that case but it’s not reasonable to say well it’s biology for this half of the curve” and then when we get over here it’s only culture. So again it’s probably going to be an interaction of both but we can’t deny that there are going to be the potential for biological differences between the sexes that might be playing a role in these types of situations.
Ok, but that’s a little bit more complex than we probably would get to in an introductory course. So maybe that’s something I can make more videos on in the future but for now we’ll move on. And in the next video we’ll take a look at some differences in IQ scores amongst races, which is, again, another controversial topic. So I hope you found this helpful, if so, please like the video and subscribe to the channel for more. Thanks for watching!
