5 Interesting Things About IQ Self-Estimates

After my post last week about what goes wrong when students self-report their grades, the Assistant Village Idiot left a comment wondering about how this would look if we changed the topic to IQ. He wondered specifically about Quora, a question asking/answering website that has managed to spawn its own meta-genre of questions asking “why is this website so obsessed with IQ?“.

Unsurprisingly, there is no particular research done on specific websites and IQ self-reporting, but there is actually some interesting literature on people’s ability to estimate their own IQ and that of those around them. Most of this research comes from a British researcher from the University College London, Adrian Fuhrman.  Studying how well people actually know themselves kinda sounds like a dream job to me, so kudos to you Adrian. Anyway, ready for the highlights?

  1. IQ self estimates are iffy at best One of the first things that surprised me about IQ self-estimates vs actual IQ was how weak the correlation was. One study found an r=.3, another r=.19.  This data was gathered from people who first took a test, then were asked to estimate their results prior to actually getting them. In both cases, it appears that people are sort of on the right track, but not terrific at pinpointing how smart they are. One wonders if this is part of the reason for the IQ test obsession….we’re rightfully insecure about our ability to figure this out on our own.
  2. There’s a gender difference in predictions Across cultures, men tend to rank their own IQ higher than women do, and both genders consistently rank their male relatives (fathers, grandfathers and sons) as smarter than their female relatives (mothers, grandmothers and daughters). This often gets reported as male hubris vs female humility (indeed, that’s the title of the paper), but I note they didn’t actually compare it to results. Given that many of these studies are conducted on psych undergrad volunteers, is it possible that men are more likely to self select when they know IQ will be measured? Some of these studies had average IQ guesses of 120 (for women) and 127 (for men)….that’s not even remotely an average group, and I’d caution against extrapolation.
  3. Education may be a confounding factor for how we assess others One of the other interesting findings in the “rate your family member” game is that people rank previous generations as half a standard deviation less intelligent than they rank themselves. This could be due to the Flynn effect, but the other suggestion is that it’s hard to rank IQ accurately when educational achievement is discordant. Within a cohort, education achievement is actually pretty strongly correlated with IQ, so re-calibrating for other generations could be tricky.  In other words, if you got a master’s degree and your grandmother only graduated high school, you may think your IQ is further apart than it really is. To somewhat support this theory, as time has progressed, the gap between self rankings and grandparent rankings has closed. Interesting to think how this could also effect some of the gender effects seen in #2, particularly for prior generations.
  4. Being smart may not be the same as avoiding stupidity One of the more interesting studies I read looked at the correlation between IQ self-report and personality traits, and found that some traits made your more likely to think you had a high IQ. One of these traits was stability, which confused me because you don’t normally think of stable people as being overly high on themselves. When I thought about it for a bit though, I wonder if stable people were defining being “smart” as “not doing stupid things”.  Given that many stupid actions are probably more highly correlated with impulsiveness (as opposed to low IQ), this could explain the difference. I don’t have proof, but I suspect a stable person A with an IQ of 115 will mostly do better than an unstable person B with an IQ of 115, but person A may attribute this difference to intelligence rather than impulse control. It’s an academic distinction more than a practical one, but it could be confusing things a bit.
  5. Disagreeableness is associate with higher IQs, and self-perception of higher IQs  Here’s an interesting chicken and egg question for you: does having a high IQ make you more disagreeable or does being disagreeable make you think you have a higher IQ? Alternative explanation: is some underlying factor driving both? It turns out having a high IQ is associate both with being disagreeable and being disagreeable is associated with ranking your IQ as higher than others. This probably effects some of the IQ discussions to a certain degree….the “here’s my high IQ now let’s talk about it” crowd probably really is not as agreeable as those who want to talk about sports or exchange recipes.

So there you have it! My overall impression from reading this is that IQ is one of those things where people don’t appreciate or want to acknowledge small differences. In looking at some of the studies of where people ranking their parents against each other, I was surprised how many were pointing to a 15 point gap between parents, or a 10 point gap between siblings. Additionally, it’s interesting that we appear to have a pretty uneasy relationship with IQ tests in general. Women in the US for example are more likely to take IQ tests than men are but less likely to trust their validity. To confuse things further, they are also more likely to believe they are useful in educational settings. Huh? I’d be interested to see a self-estimated IQ compared to an actual understanding of what IQ is/is not, and then compare that to an actual scored IQ test. That might flesh out where some of these conflicting feelings were coming from.

7 thoughts on “5 Interesting Things About IQ Self-Estimates

  1. I don’t deal in self-estimates. I saw my IQ score on my 7th grade teacher’s desk. The “bad boy” of the class and I took a look before school when the teacher was out of the room. I have looked at some online converters of SAT scores and IQ. My take on the Merit, when I took it, that my Merit score was pretty close to my my IQ score- 3 points away. (Back then the Merit test was different from the PSAT)

    Following is my opinion of how these converters did on my IQ score.
    Converting between IQ and SAT scores Its IQ estimate (pre-1996) was too low
    How to estimate your IQ based on your GRE or SAT scores IQ estimate way too high

    Convert SAT and GRE Test Scores to IQ IQ based on SAT, fairly accurate- incidentally the same score I got on the Merit.
    IQ based on GRE- too high- for both of my GRE scores. The first time I took the GRE, I scored within 25 of my SAT score. The second time I took the GRE, my GRE score was 90 points above my SAT.

    My sister and I got about the same IQ score but I scored better on the SAT and GRE than she did.


  2. Gringo – for fun. There is a limited increase in many tests given to children on a retest a year later. Some of this seems to be related to being a year older, but this is factored in on tests like the WISC. It isn’t on the SAT’s. Having test experience is also part of it, but this curve flattens quickly.
    BTW, this natural increase is a lot of how SAT-improvement course stay in business. They don’t tell you that.

    As for IQ self-estimate, I’m thinking your explanation under #3 is likely, and I found #4 quite intriguing. “Not doing stupid things” is one good definition of “smart,” though that’s not quite the same as intelligent in the school, learning, and cleverness sense.


    • AVI:
      1. When I was in high school, there were four main opportunities to take the SAT or an SAT precursor;
      a) Spring of sophomore year: Pre-PSAT. I didn’t take it
      b) Fall of junior year: PSAT. I took it.
      c) Spring of junior year: SAT. I didn’t take it
      d) Fall of senior year: SAT. I took it.
      Out of four main opportunities to take the SAT, I used only two, which suggests to me that for me, retesting didn’t increase my scores. (I was told that SAT scores would be 5/50 points each better than the PSAT scores- which was a fairly accurate predictor.)
      2) GRE retesting: While there was a 70 point jump between the first and second time I took the GRE, there was also a 17 year gap, so any retesting advantage was irrelevant.
      3) I am reminded of the columnist Bob Greene, who wrote a column on retaking the SAT decades after high school. His verbal score jumped- a consequence of his being in a reading and writing profession. His math score fell- as he didn’t use math very much in his job.

      Perceived generational difference in IQ. I am reminded of my grandmother with the 8th grade education. At one time I considered her not as bright as her better educated descendants. ( I ignored how, in conversations with people with graduate degrees, she always held her own. In fact, she was more intimidating than intimidated.) In later years I changed my mind, for a number of reasons. Even in her 80s, her dry wit was as good as or better than that of her descendants. I also note that both my father’s and mother’s families used a lot of dry wit- as did aunts and uncles who married into the families. In her 80s, I recorded my grandmother talking about the old days. In going over the recordings, I was impressed at how well she expressed herself. No ums or ahs, for example: her recordings flowed. I also realized what a good judge of character she was. After two hours with my sister’s boyfriend, she concluded that he wasn’t treating her with sufficient respect. It took my sister 7 years to reach the same conclusion.


      • I am impressed with your ability to recount this history. My personal scores tend to stick (though I don’t have an exact IQ number), but I think I’d trip up on when exactly I took them. I had over a decade between the SAT and GRE though, but I actually scored pretty similarly. Both times I was 10 points higher on the verbal than the quantitative, which always makes me laugh.


  3. I was never under any illusions with my Swedish grandmother. My mother played tournament bridge and always asserted that her own mother was a much better player. Nanna did crosswords continually, and when I was home sick in grammar school, would watch her out-answer the contestants on Jeopardy. 8th grade education, because she had to go to work when her father died.


  4. Your fourth point is very interesting. I have read numerous comments about how smart Bill Clinton is, and discounted them because he did so many stupid things. Maybe that is not completely inconsistent. Well, there are probably numerous ways to quantify “smartness,” and IQ is only one of them. For example, I think there is a difference between “smart” and “clever.” If you pinned me down, I could not define them, but I have known people who were not smart in the academic sense, but were very clever.


    • Yeah, that point interested me too. I think there’s something in there about what we call “common sense”, but it’s definitely hard to define exactly.


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