Feigning beliefs for approval is something I suppose I've engaged in a time or two, and to the best of my recollection, quickly felt the need for a shower
I agree - there is rarely conscious feigning of belief for want of benefits. People who do this are actually "evil" mutants. A neurotical human would feel guilty, even neurotypical humans who don't actually care about truth feel guilty when they lie.
in the rare cases where I keep quiet and don't express opposing beliefs, I feel horrible. However I do think this is a huge issue for the rest of the world
The rest of the world are not evil mutants - see here. They behave as if they are, but they are operating using similar cognitive machinery as yourself. So here are some alternative explanations for the behavior:
1) There is often withholding beliefs for fear of social repercussions. Lies by omission are less guilt inducing.
2) There is often being sincerely convinced (or sincerely uncertain about something you would be certain about) for the wrong reason - because your social group believes it. This is most common for beliefs that have no practical consequences, or beliefs for which the practical consequences are non-obvious.
3) There is often belief-in-belief (thinking that you believe in accordance with your social group, but then not acting that way and failing to see the contradiction.) Basically self-deception: there is an instinctive imperative not to lie, it doesn't matter if we make that an explicit norm.
It's hard to actually notice when you are doing these things.
But I think you're still correct that changing the social incentive structures would change the behavior.
The rest of the world are not evil mutants
I disagree. Oh, they're not so evil, but they may as well be a different species.
You know how Haidt has different moral modalities, with different people putting consistently different weights to those modalities? I think the same thing occurs with truth modalities. For some people, the truth is whatever is socially useful. To such a creature, values that I hold dear such as honesty and knowledge are simply alien and irrelevant issues. To me, they are Clippy, looking to turn me into a paperclip. And the bad news for me is that on this planet, I'm the weirdo alien from another planet, not them.
One major issue for group rationality is signaling with dishonest beliefs. Beliefs are used as a signal to preserve your reputation or to show membership in a group. It happens subconsciously, and I believe it is the cause of most of the issues of both religions and political parties. It also happens on Less Wrong, most commonly though not sharing beliefs that you think people will disagree with.
First, let's identify the problem. This is mostly from the viewpoint of ideal agents as opposed to actual humans. You are part of a community of rationalists. You discuss lots of issues, and you become familiar with the other members of your community. As a result, you start to learn which members of the community are the smartest. Of course, your measure of the intelligence of the members is biased towards people who say things that you agree with. The members who say things that you agree with build up more reputation in your mind. This reputation makes you more likely to trust other things that this person says. I am also a member of this community. I have opinions on many things, but there is one issue that I think really does not matter at all. On this issue, most of the community believes X, but I believe not X. By signaling belief in X, I increase my reputation in the community, and will cause other people to take more seriously my views on other issues I think are more important. Therefore, I choose to signal belief in X.
What is happening here is that:
(A) People are assigning reputation based on claims, and judging claims based partially on other beliefs signaled by the same person.
(B) People want their claims are taken seriously, and so take actions which will preserve and improve their reputation.
Therefore,
(C) People take signal beliefs that they believe are false because they are shared by the community.
Signaling honest beliefs is kind of like cooperating in a prisoners dilemma. It helps the community push towards reaching what you believe are valid conclusions, at the cost of your own reputation. It is possible for us to decide as a community that we want to cooperate, especially with tools such as anti-kibitzer. However, there is more than one way to do that. I think there are three options. I think they are all theoretically possible, but I think they are all bad.
(1) We can agree to stop assigning reputation based on beliefs.
This option is bad because there is a loss of information. People who made the right choice on one issue are more likely to make the right choice on other issues, and we are ignoring this correlation.
(2) We can agree to always report honest beliefs even though we know it will cost us reputation.
This option is bad because it encourages self-deception. If you commit to honestly report beliefs, and you can gain more reputation by reporting belief in X, you may trick yourself into thinking that you believe X.
(3) We can allow dishonest reporting of beliefs to continue.
This option is bad because it causes a bias. The community will get a source of evidence biased towards their current beliefs.
Which option do you prefer? Am I missing a fourth option? Is one of the choices obviously the best or obviously the worst? Should we combine them somehow? Am I modeling the problem entirely wrong?