In order to attain a top grade in Psychology, should I rote learn and memorise as many studies as possible?

An examiner will certainly expect you to engage with named research and studies within the academic field, as this is an easy way for you to support your own assertions and remain critical. However, you don't want to risk sounding like a textbook - try and remember a couple of key names and studies for each topic in order to engage fully with the question posed and to demonstrate that you have a firm grasp of the topic. Don't worry too much about rote learning. You can pick the areas that interest you as this will make them memorable, and referring to them will make your expression sound and assured as well as showing the examiner that you are able to critically engage with your material.