What is it that causes the human person to recognize beauty?
I think its safe to say that everyone, to some extent, has experience some sort of perception of transcendent beauty. This recognition of beauty could be an encounter with the music of Johann Sebastian Bach, or a breathtaking sunset, or an extremely attractive person. This innate attraction to beauty is not instinctual. It is absolutely unnecessary for survival. Where within the human person does this comes from?
Humans and other animals need to recognize favorable conditions and partners distinct from immediate prospects for obtaining a reward. It is likely that a sense of beauty is what accomplishes this. Although there are many cases of nonfunctional beauty, as long as they don't distract us too heavily, we will end up with partners who are less likely to be unable to help provide food etc. or be heavily burdened by parasites, and will be in an area where animal and plant foods are relatively abundant.
Here, for instance, is a relatively lengthy essay on the topic: Welsch, "Animal Aesthetics". In Contemporary Aesthetics volume 2 (2004).
Although I do not agree with everything in the article (e.g. it is far too focused on Darwin) it seems to be a pretty good introduction to how one should think of beauty from an evolutionary perspective.
Can you support your contention that a perception of beauty is unnecessary for survival? The beauty of a thing often is intimately related to its intrinsic characteristics. The fact that we cannot draw a direct line between between an object's attractiveness and its objective desirability in all cases does not mean that the ability to perceive beauty is not doing functional work in the larger context of our collective progression through life.
What is it that causes the human person to recognize beauty?
With every other creature on this planet, nature drew a lower and an upper limit. A lion can kill any creature in the jungle, but hard as it tries, cannot fly. More importantly it does not even want to fly. If a lion satisfies its hunger it is content.
Humans are unique in that nature did not specify an upper limit. Once we eat, a hundred other problems crop up. No matter who you are, every human dreams of being something more that what he/she is right now. Why does this longing exist? To understand this you need to understand the question "Why are you asking why the desire exists?".
This longing is infinite. To fulfill it even for a moment is to experience beauty. It cannot be put into words. Words are the domain of thought. And thought, no matter how vast, is physical and hence finite. If you could describe beauty in words, a person could read about the apollo of belvedere and be mesmerized by it.
To put it succinctly, there is reality outside you and reality as is projected in the firmament of your mind. If you get to experience reality as is you find it beautiful. To experience reality as is, you need to halt the distortions of your perceptions. When you find a sunrise beautiful, you don't want to ask why, you don't want to sleep with it, you don't want to eat it. You want to be in it. In other words, you are it. In that moment, when what you want and what is unite, you realize it as beauty.
An interesting conversation that follows the concept of beauty. https://www.brainpickings.org/2012/04/27/when-einstein-met-tagore/
