Nothing that you've written is new here, other than that William James quote.

Actually, WIlliam James quote in context refers to introspection.

Within the last few years, a psychologist went through a 'mindfulness of emotions' exercise. I cried.

So, I'm going to re-purpose your thread by explaining how rationalists can methodological try the following, evidence-based self-awareness technique/introspection which to the best of my research, hasn't been suggested elsewhere, anywhere:

...in 3 difficult steps: (oooh...applause lights)

*1. don't bother introspecting on attitudes

*2. introspect on your feelings

*3. recognise that conscious awareness alone of biases doesn't mitigate them

who should do this

This advice is particularly relevant to autistic Lesswrongers. Those on the autism spectrum have impaired self-awareness.

how can you do this

Self-awareness, according to the opening phrase of that Wikipedia article, is about introspection. Introspection , autists

why

If reducing feelings or attitudes makes one regret them more oftent than otherwise, it's evident that this kind of thinking, analysing one's first impressions, is the heart of rationaliation - a cardinal sin of rationality.