Would a burglar taken by surveillance camera be creating those circumstances ?
Clearly he's not involved in the monkey taking the pictures. He has no right to them.
I would define it as "exercising the most volition that leads to producing the outcome". Not sure how the law would actually define it.
EDIT - Thought experiment: If a photographer spends days constructing all the elements of a shot (including subject, lighting, and camera settings), and, seeing that he/she is about to hit the shutter button, a passerby sneaks up behind the photographer and taps the button before the photographer, would the photo's copyright go to the passerby? What if the photographer had intended to wait a few more seconds before hitting the button? You could argue that the photographer had no intention to take the picture right at that (early) moment, but clearly (to me anyway), the photographer is still the author of the photo because he/she brought together all the elements - not because they simply hit the shutter release button.
And of course, the act of taking the picture might conceivably constitute some other crime, such as criminal damage (if a film camera, you're rendering good film unusable) or computer misuse (if digital), so in general, this selfie-taking exercise would be even less of a smart move than usual.
The timing of the shot can be as important or more important than the composition itself.
So depending on the circumstances, I wouldn't dismiss the claim of the passerby right away.