Final answer:
E. Thayer Gaston believed that music therapy should have a scientific basis and that music provided a means of promoting psychological well-being and enhancing communication and self-expression.
Step-by-step explanation:
E. Thayer Gaston believed that music therapy (MT) should have a scientific basis. He emphasized the importance of research and empirical evidence in the field of MT. Gaston believed that music provided a means of facilitating and promoting psychological and emotional well-being in individuals, as well as enhancing communication and self-expression.