anchoring for coordination

post by sark · 2011-04-22T10:42:32.743Z · LW · GW · Legacy · 11 comments

Reading Schelling's the Strategy of Conflict, a useful social purpose for anchoring occurred to me.

First some background.

You and your husband/wife lose each other in the mall. The two of you have not before this agreed on a place to meet in case you lose each other. Still, there is a good chance both of you would decide to meet up at some salient/prominent place, say the main information desk. This is coordination without communication and with aligned interests.

You and your partner/rival are independently given the choice of "Heads" or "Tails". Neither knows the choice of the other. If both of you choose "Heads" you'll get $1 and your opponent $3. If both of you choose "Tails", you'll get $3 and your opponent $1. Otherwise neither of you gets anything. Most pairs would coordinate on "Heads" (again because of convention/salience), with the Tails player not insisting on Tails because she has no way to coordinate (arrange for compensation, say) with the Heads player on this. This is coordination without communication and with some conflict of interest. But not total conflict, as they would rather coordinate than get no payment at all.

Schelling then goes on to consider explicit bargaining situations where there is of course actual communication between the parties deciding on a mutually acceptable outcome. But he notes that even here, "focal points" seem to exert a huge influence. Furthermore, these focal points are often quite partial towards the interests of a certain party. Yet often, the 'losing' party still accepts this less than stellar bargaining outcome. For example, a nation conceding some territory because the only prominent landmark permitting a stable division was some river partial to the interests of the other nation.

He then proceeds to show how explicit bargaining is not so different from the Heads/Tails coordination game. In a bargaining situation, both sides would rather reach agreement than none at all. And there is a range of possible points of agreement, where the 'losing' party would rather concede than forfeit any agreement. But how to decide among these points of potential agreement? A stable point of agreement for an outcome of the bargaining would be one in which neither expects the other to make further concessions. But a party decides if they would concede based on their expectations of the other party's likelihood of conceding. And so it goes back and forth. Hence, Schelling argues, even in explicit bargaining, focal points play an important role in coordinating expectations, and in ensuring that an agreement is reached, to the mutual (if lopsided) benefit of both parties.

This is where anchoring comes in. The proposal is that, sure, by letting yourself be influenced by a subpar anchor, you are forgoing a much better bargaining outcome for yourself. But this is better than no agreement at all! If you accepted a price from a merchant who proposed high price to set an anchor, it was only because this was a price you were willing to accept before you started bargaining. And if instead the lowest price the merchant would allow was too high, you would simply have rejected the transaction, and perhaps found a better offer from his competitors.

Anchoring is of course, not limited to such explicit bargaining situations. But then so is the principle of 'focal points'! In many situations throughout life, there are situations where participants share some interests and diverge on others, and where bargaining is not entirely explicit. To coordinate on these at all we require the ability to respond to anchors. Of course, this would only create an incentive to manipulate anchors, and subsequently an incentive to be resistant to such manipulation. But resistance is not total non-susceptibility! If one does not respond to anchors at all, one would be unnecessarily forgoing many mutually beneficial bargaining outcomes, to one's own detriment.

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comment by CuSithBell · 2011-04-22T17:28:02.153Z · LW(p) · GW(p)

You and your partner/rival are independently given the choice of "Heads" or "Tails". Neither knows the choice of the other. If both of you choose "Heads" you'll get $1 and your opponent $3. If both of you choose "Tails", you'll get $3 and your opponent $1. Otherwise neither of you gets anything. Most pairs would coordinate on "Heads" (again because of convention/salience), with the Tails player not insisting on Tails because she has no way to coordinate (arrange for compensation, say) with the Heads player on this. This is coordination without communication and with some conflict of interest. But not total conflict, as they would rather coordinate than get no payment at all.

I don't understand. Is the situation:

A and B are playing. If both pick "heads", A gets $1 and B gets $3. If both pick "tails", A gets $3 and B gets $1.

?

If so, they seem to be in symmetrical positions, so why would they both gravitate to "heads"?

Edit: Is it just that "heads" is a more obvious default answer than "tails"?

Edit: Okay, I understand now :)

Replies from: bentarm, sark, ArisKatsaris
comment by bentarm · 2011-04-22T20:41:42.349Z · LW(p) · GW(p)

This is perhaps not the best example to illustrate the phenomenon. Consider, instead, the following game, also taken from Schelling:

A, B and C are given the labels A, B and C, and told to pick an ordering of the letters A, B and C. If they agree on the ordering, then the person whose letter is ranked first wins $4, the person whose letter is ranked second wins $2 and the person whose letter is third wins $1. Otherwise, no-one wins anything. The players are not allowed to communicate amongst themselves - what ordering should they pick?

Here, I think it is obvious that ABC is massively more salient than any other ordering. It is not completely obvious to me that "heads" is more obvious than "tails" in the OP.

Replies from: CuSithBell
comment by CuSithBell · 2011-04-22T21:33:25.664Z · LW(p) · GW(p)

That's a very good example.

comment by sark · 2011-04-22T19:29:58.532Z · LW(p) · GW(p)

Apologies for not being clear.

Yes, heads is supposed to be obvious/prominent/conventional/canonical.

Schelling actually did a small scale experiment (though with $2 instead of $1). His results: 16 out of 22 A's and 15 out of 22 B's chose heads.

If heads vs. tails seems too balanced to you, try this (from the book verbatim):

You and your two partners or rivals each have one of the letters A, B, and C. Each of you is to write these three letters. A, B, and C, in any order. If the order is the same on all three of your lists, you get prizes totaling $6, of which $3 goes to the one whose letter is first on all three lists, $2 to the one whose letter is second, and $1 to the person whose letter is third. If the letters are not in identical order on all three lists, none of you gets anything. Your letter is A/B/C.

Results:

9 out of 12 A's, 10 out of 12 B's, and 14 out of 16 C's, successfully co-ordinating on ABC.

Replies from: Normal_Anomaly, CuSithBell
comment by Normal_Anomaly · 2011-04-24T18:03:49.862Z · LW(p) · GW(p)

9 out of 12 A's, 10 out of 12 B's, and 14 out of 16 C's, successfully co-ordinating on ABC.

That's 3/4ths of As, 5/6ths of Bs, and 7/8ths of C's. I'm mildly (pleasantly) surprised that more people coordinated into giving themselves small prizes than coordinated into giving themselves larger prizes.

comment by CuSithBell · 2011-04-22T21:39:08.123Z · LW(p) · GW(p)

Yeah, I think that example is more clear - but it's nice to see that the prediction worked in the heads/tails case!

I guess I didn't hit on the "point" immediately, though I got it after rereading due to confusion. If I'm not an outlier it might help to hammer on it a little more - some choices are more 'obvious' 'landmarks' and for no other reason are attractors.

comment by ArisKatsaris · 2011-04-22T18:01:59.125Z · LW(p) · GW(p)

Okay, I understand now :)

But I still don't understand, so please explain your understanding.

Replies from: CuSithBell
comment by CuSithBell · 2011-04-22T18:05:35.209Z · LW(p) · GW(p)

I think the idea is: they both pick "heads" because it's more obvious than "tails", it's the most salient "landmark" in the territory (like the information desk).

I'd expect this to be a weak effect if the study were actually done between strangers, and I'd expect most people to spend most of their effort trying to simulate the other player rather than looking for landmarks, but that's the logic as I understand it.

Replies from: None
comment by [deleted] · 2011-04-22T19:40:59.064Z · LW(p) · GW(p)

I think the idea is: they both pick "heads" because it's more obvious than "tails", it's the most salient "landmark" in the territory (like the information desk).

I wonder: is heads a "landmark" all around the world, or is tails an equally obvious choice in some cultures? (It seems like the kind of thing that could be arbitrary.)

Replies from: CuSithBell
comment by CuSithBell · 2011-04-22T21:35:22.622Z · LW(p) · GW(p)

Hmmm... I'd guess whatever they call the "main" side is what we'd translate as "heads" (or "obverse")

; )

comment by Armok_GoB · 2011-04-22T15:34:45.213Z · LW(p) · GW(p)

Great observation, now we need to find a way to make our brains treat less things as bargaining situations to reduce this bias, if this is correct.