The Wheel Theory of Love is a developmental stage model that conceptualizes courtship, relationship development, and mate selection as an ongoing progression. The circular and sequential process consists of four interrelated phases understood as the spokes of a wheel: rapport, self-revelation, mutual dependency, and intimacy need fulfillment. Each of the four integrated processes is influenced by cultural role conceptions which serve to define perceptions, expressions, and expectations within a loving relationship. The theory was developed by Ira Reiss and was one of the first models to conceptualize the progression of love as an ongoing process. The theory suggests that "personality-need-fulfillment" is the key to falling in and out of love.