the subject of 'to-infinitive'

Imagine that you are out in the country on a cold night, inadequately dressed for the torrential rain, your clothes soaked. A stinging cold wind completes your misery. As you wander around, you find a large rock that provides some shelter from the fury of the elements. The biologist Michel Cabanac would call the experience of that moment intensely pleasurable because it functions, as pleasure normally does, to indicate the direction of a biologically significant improvement of circumstances. The pleasant relief will not last very long, of course, and you will soon be shivering behind the rock again, driven by your renewed suffering to seek better shelter

My question is whether the sentence below is right

"The biologist Michel CAbanac would call the experience of that moment intensely pleasurable to indicate the direction of a biologically significant improvement of circumstances, because it functions, as pleasure normally does."

I want to know what is the subject of 'to indicate', the biologist Michel Cabanc? or the experience of that moment? Which one?

Pls give me some advice.