Complex sentence: He returned to school in his thirties, studying cognitive psychology/cognitive science first at Stanford University (he received his B.A. in 1992 with honors and highest university distinction) and then the University of Oregon where he received his M.Sc.
Split into simpler sentences: He returned to school in his thirties, studying cognitive psychology/cognitive science at Stanford University (he received his B.A. in 1992 with honors and highest university distinction). He attended the University of Oregon where he received his M.Sc.