Final answer:
A psychologist from an existential or humanistic background would most agree with considering individuals' dealings with life's meaning and their value in living when looking at abnormality development.
Step-by-step explanation:
A psychologist who agrees with the statement that when establishing how abnormality develops, one should consider how individuals deal with the meaning of life and the value they find in living, is most likely to come from an existential or humanistic background. Psychologists from these backgrounds focus heavily on self-actualization, personal growth, and the potential for good that is innate to all humans. Abraham Maslow and Carl Rogers are notable psychologists in this field, emphasizing free will, self-determination, and the endeavor of each individual to become the best person they can become.