One obvious reason doctoral programs in psychology use the Graduate Record Examination.
Given that most doctoral programs in psychology have more applicants than openings, it is understandable that programs would focus on higher GRE scores which predict program completion better than lower scores.
Holmes
Cooper B
CB
Department of Psychology, Emporia State University, KS 66801-5087, USA.
D004500:Education, Graduate / Q000458:organization & administration*; D004521:Educational Measurement; D006801:Humans; D011237:Predictive Value of Tests; D011584:Psychology / Q000193:education*; D014481:United States