Alice wants to stop treating her beliefs as binary and start treating them probabilistically—that is, she wants to update herself incrementally. So she's hoping to work on the skill of raising her credence a little bit when she encounters weak evidence against her beliefs, instead of entirely disregarding anything that doesn't completely "change her mind". What should she do?
Obvious plan is obvious: If she encounters weak contrary evidence, then she should update slightly away from the hypothesis.
But obvious plan is not best plan. Why not?
Let's assume that Alice already knows exactly what she means by "update slightly away from the hypothesis" and knows exactly how to do it. (So the first problem is that in real life, she might not know either of those things.) The problem I want to focus on in this post is that "encounter weak contrary evidence" is a shitty trigger no matter how good the action you plan to take when the trigger happens.
Imagine one of those fake duck ponds you see at carnivals, the ones with the kiddie pool and the yellow rubber ducks. A current is pushing the floating ducks in circles around the edge of the pool. There are nine ducks with their bellies painted red, and one duck with its belly painted purple. To win the prize, you have to grab the purple-bellied duck when it floats by.
Now imagine the same duck pond, but instead of their bellies being painted, it's their backs. There are nine red-backed ducks and one purple-backed duck, and to win the prize, you have to grab the purple-backed duck when it floats by.
The second game's a lot easier, right? Why is that?
The mere fact that the purple duck is in front of you is an insufficient trigger. When you play the second game and win, you're not just grabbing the duck in front of you when it's purple. You're grabbing the duck in front of you when you see that it is purple. You notice a purple experience happening in your mind, and that's how you know to grab the duck. In the first game, you lose, because there's nothing to notice. Even though the ducks are in fact different, they all look the same from your vantage point.
Back to Alice.
The game she's playing is "update slightly when I encounter weak contrary evidence". The duck pond is the world, the current is time, and the ducks are events. Most of the ducks are red, and the purple ducks are "weak contrary evidence". "When I encounter weak contrary evidence" is a bad trigger in exactly the same way that "when the purple duck is in front of me" is a bad trigger. It doesn't pick out a subjective experience that distinguishes the attempted trigger from everything else. There's nothing to notice.
To make a good training plan, Alice needs an analogue to an experience of purpleness. She needs to know exactly what it feels like to encounter weak contrary evidence. Once she has that, then she has a reliable trigger.
So how can Alice find out what subjective experience is a function of weak contrary evidence? First of all, she's got to know what weak contrary evidence is. Not just what it feels like, but what it means. Let's assume she knows that already. So what's left is to identify the corresponding subjective experience.
Here's how I do it.
- I guess. I remember or imagine a few specific instances of encountering weak contrary evidence (such as when I thought my friend wasn't attracted to me, but when I made eye contact with him across the room at a party he smiled widely). On the basis of those simulations, I make a prediction about what it will feel like, in terms of immediate subjective experience, to encounter weak contrary evidence in the future. The prediction is a tentative trigger. For me, this would be "I feel a sort of matching up with one of my beliefs, there's a bit of dissonance, a tiny bit of fear, and maybe a small impulse to direct my attention away from these sensations and away from thoughts about the observation causing all of this".
- I test my guess. I keep a search going on in the background for anything in the neighborhood of the experience I predicted. Odds are good I'll miss several instances of weak contrary evidence, but as soon as I realize I've encountered one, I go into reflective attention so I'm aware of as many details of my immediate subjective experience as possible. I pay attention to what's going on in my mind right now, and also what's still looping in my very short-term memory of a few moments before I noticed. Then I compare those results to my prediction, noting anything I got wrong, and I feed that information into a new prediction for next time. (I might have gotten something wrong that caused the trigger to go off at the wrong time, which probably means I need to narrow my prediction.) The new prediction is the new trigger.
- I repeat the test until my trigger seems to be accurate and precise. Now I've got a good trigger to match a good action.
If I were Alice, I'd take one more step toward noticing every instance of weak contrary evidence. A precise and accurate trigger is necessary, but it's not always sufficient. This kind of skill takes practice.
I have a knitting counter, which I bought for $7.13 on Amazon. Knitting counters are very simple: You press a button, and it advances the count by one. When I'm training myself to notice a trigger, I carry the knitting counter in my pocket. Every time I notice the trigger, I push the button. I reset the counter to zero at the end of the day, and the next day I try to beat my highest score.
(There are plenty of substitutes for the knitting counter, of course, such as keeping track in your head. But it does make a highly satisfying cliking sound.)
I keep doing this until my score levels out. Then, I swap out the action of pressing the button for whatever other action I think is useful. In this case, it would be "update slightly away from the hypothesis".
Usually, the leveling out process runs into the action-swapping process, so for a while I'm responding with the action while I'm still getting better at noticing the trigger. But if the action is any more complicated than pressing a button, I hold off on taking it and train noticing specifically until I'm feeling pretty comfortable with the noticing itself.
So in short, here's how to train noticing: Identify a subjective experience you want to notice, predict what the experience will be like, test your prediction, repeat 'til you've got it right, and gamify your practice.