Heuristics in Heuristics and Biases are only descriptive. [...] Heuristics in Heuristics and biases are defined as having negative side effects.

If your claim is that heuristics are defined by H&B theorists as being explicitly not prescriptive, in the sense of never being "good" or "useful," this is simply not the case.

No, no, that's not what I'm saying. The claim that heuristics have negative side effects does not entail a claim that negative side effects are the only characteristics they have. The 'side effect' terminology might be taken to imply that there is a main effect which is not necessarily negative.

They have always claimed that heuristics are right most of the time. But they wouldn't recommend you purposefully try to "use" them. They only propose heuristics that could theoretically explain empirically observed biases. F&F heuristics do not necessarily need to explain biases. A F&F heuristic might only explain when you get something right that you otherwise shouldn't. I'm not even sure that an F&F heuristic need explain anything empirically observed but rather could be a decision strategy that they modelled as being effective that everyone should learn (what I clumsily meant by 'prescriptive'). And they have published ways to teach use of some of their heuristics.

Representativeness, one of the earliest examples of a heuristic given by the H&B program, is certainly used in a conscious and deliberate way. When asked, subjects routinely report relying on representativeness to make frequency or probability judgments, and they generally see nothing wrong or even really remarkable about this fact.

I don't recall introspective interviews with subjects taking place in H&B research, though I may apparently be wrong about that. What I had in mind when I wrote that was that I seem to recall K & T and Gigerenzer sparring over the validity of doing that.

Except.... now that I think of it I seem to recall something like that in the really early K & T papers... maybe as I understood it, which may be obsolete, is that introspection could be useful to help generate empirical theories but could not be used to validate them whereas I seem to recall Gigerenzer arguing that they could provide validity. Maybe the camps have converged on that, or my memory continues to be faulty.

[irrelevant digression: representativeness was the absolute earliest, and by a large margin if you include "the law of small numbers" as the germ of representativeness. But if you count the law of small numbers as a heuristic and separately then it was the first.]

Nick Epley's work also strongly suggests that people very deliberately rely on anchoring-and-adjustment strategies when making some common judgments (e.g., "When was George Washington elected president?" "Hmm, well it was obviously some time shortly after the Declaration of Independence, which was in 1776... so maybe 1786?").

It implies that anchoring-and-adjustment is consciously available as a strategy at least some of the time.

When it theoretically appears in the anchoring bias ("Are there more or less than 60 nations in the UN from Africa?") it's virtually impossible to debias, suggesting it's outside of conscious control in that case.

So it does force the concession that it's not always true, though.

Fast and Frugal heuristics, however, you can learn and use intentionally.

One can certainly learn to use any heuristic strategy, but for some heuristics proposed by the F&F camp, such as the so-called fluency heuristic (Hertwig et al., 2008), it is not at all obvious that in practice they are utilized in any intentional way, or even that subjects are aware of using them. ...

Wasn't aware of that one. I haven't kept up with the literature since 2005 or so. If there are some F&F heuristics that are outside of conscious awareness and some H&B heuristics that are within awareness then conscious awareness is eliminated as a possible distinction.

There are some F&F heuristics that they argue we should use more than we already would. I'm not sure if there are any H&B heuristics for which that would be true.

Descriptive F&F heuristics aren't evolutionary quirks.

I'm not sure what you mean here. If an "evolutionary quirk" is a locally optimal solution that falls short of a global maximum...

I mean like a dead-end local maxima that we could be "stuck" in but doesn't hurt us that much. We would have better vision if we didn't all have a little blind spot. There's no reason for it being there, invertebrates that have highly developed eyes don't have it. But we're stuck with it since it goes back to the way the first vertebrates. I don't think an H&B theorist would object to the idea of evolutionary "mistakes" as an explanation whereas I think an F&F theorist very well might. Maybe that's not a very good a distinction.

I do not think that F&F theorists think that their heuristics are globally optimal, something that was globally optimal would no longer be a heuristic of any stripe.

[edit: I think I see where I was going wrong here. H&B theorists study biases that are not necessarily theoretically caused by heuristics. For instance, prospect theory isn't a heuristic. Or, framing isn't caused by any heuristic that I can think of. But it's orthogonal to their definition of what a heuristic is.]

...besides the obvious that Fast and Frugal heuristics are "good" while heuristics as in Heuristics and biases are "bad".

This impression is entirely due to differences in the framing and emphasis employed by the two camps. It does not represent anything like a fundamental distinction between how they each view the nature or role of heuristics in judgment and decision making.

I meant those as scare quotes, meaning I don't necessarily endorse them. I agree that framing and emphasis is a very large part of the difference between the camps. I'm not 100% convinced it is entirely the difference.

I think there may be still the issue that a heuristic in F&F can be something that they modelled which is not empirically used, or at least not empirically seen as much as it should be optimally, but it would be good if we could be taught to use it whereas I don't think that an H&B heuristic would ever have that set of characteristics. though perhaps you could convince me otherwise.