possessive referring to behavior of multiple actors

Question

In "Alice and Bob's contrary behavior served to" vs "Alice's and Bob's contrary behavior served to"

Usually the choice between the two forms hinges on whether the two actors possess the subject in common. And usually behavior cannot be jointly owned. So my intuition is that this choice hinges on whether Bob and Alice are treated as a group or as individuals. Is that correct, or are there other considerations?

So I might use the first form if Alice and Bob are acting united relative to a third party or the second form if they are behaving contrary to each other or to many other parties separately.

This question is distinct from Third-Person Possessive Pronouns in Dual Possessives because behavior is an uncountable noun that cannot usually be co-owned and because this question does not involve pronouns. The linked question does not answer this one.

Answer 1

"Alice and Bob's contrary behavior served to" vs "Alice's and Bob's contrary behavior served to"

The problem you have is common to a lot of questions. The answer is that English is very dependent upon context.

The possibilities are that

(i) Alice behaved well, and Bob behaved badly - this would mean that A’s behaviour was contrary to B’s or

(ii) they both behaved badly/well and this was contrary to some other standard. This would mean that A’s and B’s behaviour was contrary to that standard.

You need context here.

Once you have context, then the standard

"Alice's and Bob's contrary behavior served to..." is applicable.

And usually behavior cannot be jointly owned.

I would take issue with this: "The children's behaviour was shocking", or consider any joint venture.