The ancient Greeks explained human behavior using the myth of..

Using the myth of the Gods of Olympus.

Explanation:

The ancient Greeks used mythology to explain everything possible such as the origin of the universe, life, death, human birth, the phenomena of nature, and even human behavior.

The myth used to explain human behavior was the myth of the Olympian gods. Each of these gods had a personality that was the true representation of the psychological aspects of human beings that govern their behavior.

Psyche

Explanation:

The ancient Greek, used mythology of Psyche to explain human behavior, from the story of Psyche, a beautiful woman, whose beauty was said to rival that of goddess Aphrodite. Hence, Aphrodite while being jealous, sent her son, Eros, to make Psyche fall in love with the ugliest man in the world.

However, in the cause of achieving the task, Eros fell greatly in love with Psyche, and took her to his palace while showering her with gifts,  with the promise that, she could never see his face.

Later, Psyche's sisters made Psyche to demand for to see the face of Eros, which eventually made Eros to abandon her as she betrayed his trust and promise in her.

However, Psyche appealed to Aphrodite to reunite her with Eros, in which Aphrodite gave her various difficult tasks to complete. Psyhe did complete all of these trials; ultimately, her perseverance paid off as she was reunited with Eros and was ultimately transformed into a goddess herself.

Therefore, Psyche tends to depicts human soul’s victory over the misfortunes of life in the pursuit of true happiness, which explains the study of human mind and  behavior.