In your sentence, the following expressions can be used interchangeably with no difference in meaning: "perceive", "recognize", "realize", "come to understand", "become aware of". Even though they mean the same in your sentence, "perceive" and "realize" have slightly different meanings. If you look at the history of "perceive", you will find that it comes from an Indo-European (very very old) root that means "capture" or "take in". To perceive something means to take it in THROUGH ("per-") your senses (hearing, feeling, touch, sight, and taste). It is similar to "realize" except that "realize" makes no mention of the senses. "Realization" is a purely cognitive synthesis that you can accomplish even while you lie on your back with your eyes closed. The words are so close though that people will often use them interchangeably. "Knowledge" is something else entirely.

If it is in a work relating to psychology--a book on child development, perhaps--it might be using the word in a psychological sense. Some psychologists sometimes draw a distinction between "sensation" and "perception." Sensation means simple awareness of light or sound or touch. Perception means organizing and recognizing sensations and interpreting them as objects in the world. It's the difference between "I see light" and "I see the moon," or "I hear a sound" and "I hear my mother's voice." Perception doesn't feel like conscious thought. It happens quickly and automatically. You don't say "Oh, that's a circular patch of light, let me think, it must be the moon," you just say "Oh, that's the moon." Without knowing more about the source, I can't tell if "perception" is just being used as a synonym for "know" or "learn," or whether it has overtones of perception in the psychological sense.

Thinking about it a little longer. I am wondering how the youngster can know through by or via any of his or her senses --> the relationship between success and effort. The writing struck me as a little odd immediately, and it still does.

The three words have different meanings so, of course, you would expect a good English speaker to use the correct one to convey a precise meaning. But, to be honest, ‘perceive’ sounds borderline wrong here. It’s too complicated a connection to be ‘perceived’, especially for a youngster. As is almost always the case, you need to look at the context to see what the author is saying. With any of the words, the sentence is ambiguous because of ‘must’. Are we talking about a conclusion that the writer is drawer or an obligation that the writer is imposing?

This is another classic case of not supplying the preceding or surrounding context. i.e the full paragraph from which the sentence came from. Yes all three words can be interchanged but to use the word "perceive" here seems odd to me. I'm inclined to go along with Dan Smith the sentence may could come from a psychological perspective or writing about that subject.