to become a registered psychologist you need to complete honours in psychology, which you can do via an arts degree, a science degree, or a specialised psych degree. so the answer to your question is yes. however - entry to psych honours is fairly competitive, and the advantage of doing one of the specialised psych degrees is that you're guaranteed an honours place if you keep your marks above a certain level. people doing psych majors in generic degrees then have to compete for however many honours places are left after the people in the specialised degrees have all been enrolled.