A key consideration when selecting for latent mental traits is whether a common pathway model holds for the latent variable under selection. In an ideal common pathway model, all covariance between indicators is mediated by a single underlying construct.
When this model fails, selecting for one trait can lead to unintended consequences. For instance, attempting to select for Openness might not reliably increase open-mindedness or creativity. Instead, such selection could inadvertently target specific parts of whatever went into the measurement, like liberal political values, aesthetic preferences, or being the kind of person with an inflated view of yourself.
Unlike personality factors, which demonstrate mixed evidence for a coherent latent structure, IQ has been more consistently modeled using a common pathway approach.
TL;DR: Selecting for IQ good. Will get smarter children. Selecting for personality risky. Might get child that likes filling in the rightmost bubble on tests.
Sources:
https://psycnet.apa.org/record/2013-24385-001
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7839945/
You’re missing the point. While I agree that we don’t want to select too hard for personality traits, the bigger problem is that we’re not able to robustly select for personality traits the way we’re able to select for IQ. If you try to select for Extraversion, you may end up selecting for people particularly prone to social desirability bias. This isn’t a Goodhart thing; the way our personality tests are currently constructed means that all the personality traits have fairly large correlations with social desirability, which is not what you want to select for. Also, the specific personality traits our tests measure don’t seem real in the same way IQ is real (that’s what testing for a common pathway model tells us).
The key distinction is that IQ demonstrates a robust common pathway structure—different cognitive tests correlate with each other because they’re all tapping into a genuine underlying cognitive ability. In contrast, personality measures often fail common pathway tests, suggesting that the correlations between different personality indicators might arise from multiple distinct sources rather than a single underlying trait. This makes genetic selection for personality traits fundamentally different from selecting for IQ—not just in terms of optimal selection strength, but in terms of whether we can meaningfully select for the intended trait at all.
The problem isn’t just about avoiding extreme personalities—it’s about whether our measurement and selection tools can reliably target the personality constructs we actually care about, rather than accidentally selecting for measurement artifacts or superficial behavioral patterns that don’t reflect genuine underlying traits.