With all the truth-seeking that goes around here it's easy to forget that knowledge is not the ultimate value agreed upon by everyone and used as foundation for every other value. Not even close, and for good reasons.
Knowledge is not the goal behind most things we do. Yes, studying and research happen. Lots of other, not knowledge-focused activities happen aswell.
Knowledge is the byproduct of practically any activity. Whatever you do, it's hard to avoid gaining some knowledge in the process. And that is precisely why "I'll have more knowledge" is not a good argument to justify any activity. Picture the worst immoral action you can think of. If you perform it, you will be more knowledgeable about the world (probably in more ways that you can currently imagine).
But, reversed familiarity with outgroup stuff isn't familarity with ingroup stuff, or vice versa, similar to how reversed stupidity is not intelligence (https://www.lesswrong.com/posts/qNZM3EGoE5ZeMdCRt/reversed-stupidity-is-not-intelligence).
"Reversed stupidity is not intelligence" is an idea that needed to be stated because it is counter-intuitive. We naturally tend to look for 2 matching opposite ideas that can be mapped onto "good-bad" intensity scale. Pick any pair of antonyms for simple example, or any pair of virtues and sins for example more relevant to this particular discussion. Because whatever is associated with an outgroup feels like sin and whatever is associated with ingroup feels like virtue.
It's mainly about associations.
The outgroup is bad. There are beliefs and behaviors associated with the outgroup.
Therefore these beliefs and behaviors are bad. If I show any of these beliefs and behaviors people might think I'm bad.
Yes this is flawed logic, but it's not something people think about logically in the first place. That's just how we normally feel.
And it's important to remember that there can be consequences for signalling or lack of signalling.
And people tend to care about these consequences way more than they care about abstract knowledge.
But of course your examples of it being harmful are valid
Some examples are cases where people in groups renowned for or labelled for some trait (e.g., jocks, supermodels) are stereotyped as "unintellectual" as part of their identity and thus hide or cut off their intellectual interests.
The opposite is also true, I've known some people who seriously neglected their health because they associated exercise with not-so-bright folks. Notice how it has the same process behind it, but it's not related to knowledge the same way your example was. And I do agree that this is not a good basis for decision-making.
It's just it's not always quite as simple as in these examples.
Maybe not. Maybe some people can transcend all the arbitrary norms, and avoid forming their own arbitrary norms, and find a way to interact with everyone else without signalling, and not end up practically exiled, but I'm not hopeful.
It's something fairly difficult to do in practice and I'm yet to see examples of people succeeding at it long term.
"Knowledge is a byproduct" is insightful. It's a better mental model than "we don't care about knowledge at all, it's all social status." And knowledge does feedback into the system. People do make scientific progress, or think and question their in-group and steer their in-group or leave it, or read a banned book out of intellectual curiosity and leave their tribe. I might say knowledge is a tributary role.
Here's a phenomenon I was thinking about.
In many situations, knowledgeable people don't just go out of their way to show off how much they're familiar with things that raise their clout with the ingroup -- for example, an artsy person rattling off names of obscure artists to his artsy friends, or a very patriotic person singing her country's historic folk songs or preparing its national foods.
It's also the case that many will go out of their way to deny or signal lack of knowledge about things that are either associated with outsiders or non-ingroup, if not necessarily outgroup, members.
For instance, a patriotic person bragging about how little he knows about foreign customs, foods, or languages that are not well-known in his own country. Or a proudly nerdy or "indie" kid claiming to not watch a popular TV show, and bragging she knows nothing about the local sports team or latest celebrity gossip, in contrast to her narrower ingroup's own niche interests.
What I find interesting is this:
There seems to be a social "penalty" of sorts in many groups for knowing too much outsider stuff, regardless of if it really comes at the expense of insider stuff.
Imagine you have some people.
Person A: Is very knowledgeable about ingroup stuff. Knows very little about outsider stuff.
Person B: Is as equally knowledgeable as person A on ingroup stuff but on top of that also knows a lot of outsider stuff. So, knowing what A knows and then something else.
Person C: Is more knowledgeable than person A and B about ingroup stuff AND outside stuff alike. So is more knowledgeable than A and B across the board.
It's interesting that people will sometimes see person A as higher status, more proud, loyal, patriotic or whatever, towards the ingroup, than person B or C, even if the latter two have already what A has in terms of ingroup stuff or even added more. In fact, person B or C may be labelled even less like-one-of-our-ingroup than say, another less knowledgeable across-the-board person D, who knows even less than A, B or C about either ingroup or non-ingroup stuff, but happens to know just-a-little-bit of ingroup stuff but no outgroup stuff. Maybe in some scenarios, it's the ratio of familarity with ingroup stuff than non-ingroup or outgroup stuff that matters, not absolute familiarity with ingroup stuff.
There could be a number of causes for this I imagine, even setting aside the very adversarial cases that knowledge, familiarity, or interest in outsider stuff may signal you may want to help an outgroup with vested interests to harm your ingroup (such as showing interest in learning the foreign language or customs of an adversary in a political conflict such as war). Maybe people perceive ingroup and non-ingroup stuff as competing or zero sum in time, effort or cost and thus not spending more time on ingroup stuff is seen as disloyal even if the outgroup stuff isn't seen as bad per se (e.g. why are you less patriotic for spending or showing interest travelling and learning about foreign places, even after you've travelled locally enough? You could be spending even more time and effort on local stuff, maybe.).
People constantly drop, hide or otherwise pretend to lack knowledge or skill with outsider stuff to try and fit into ingroups, even though it's not like dropping the extra non-ingroup knowledge adds to their ingroup knowledge.
But, reversed familiarity with outgroup stuff isn't familarity with ingroup stuff, or vice versa, similar to how reversed stupidity is not intelligence (https://www.lesswrong.com/posts/qNZM3EGoE5ZeMdCRt/reversed-stupidity-is-not-intelligence).
Should we treat this state-of-affairs as a good thing? For those who value pursuit of knowledge, skill and openness for its own sake (if it's not harmful to others at least), there's a lot of wasted potential (and squandered opportunity for self-actualization) in people not pursuing their full goals because learning new things is bad for ingroup identity.
Some examples are cases where people in groups renowned for or labelled for some trait (e.g., jocks, supermodels) are stereotyped as "unintellectual" as part of their identity and thus hide or cut off their intellectual interests. Having a PhD in astrophysics, or joining a very academic book club to read about medieval French history doesn't make the strong person weaker or the supermodel less physically attractive but it's possibly associated with people like effete intellectuals or unseemly dorks who are not in the athlete or beauty queen's ingroup.
Children of culturally-distinctive immigrants (or ethnocultural minorities that are distinctively non-mainstream in culture) can feel pressure to drop knowledge or familiarity with minority-culture stuff to be seen as more assimilated than someone who's never jettisoned minority-culture stuff at all, but just added enough mainstream-culture-stuff to match the other mainstream-culture members.
Men can refrain from honing or pursuing their skill in feminine hobbies or activities, or women in masculine ones, even if they already have excellent skills in more gender-conventional ones, and the newer ones would not detract or be in opposition to them. And there are many more examples like this.