This two works together, you can not talk about emotions with out mentioning the psychological state of the person because their emotions are usually affected their psychology, when they have a good psychological state their emotions too will be very balanced so i do see it like a complementary thing, if you have a good psychology that keeps you to sticking to your discipline, most definitely you are going to have your emotions under control as you going to have a really good money management skill that will inform your trades such that you are going to be really confident on your trades to the point you will not be stressed emotionally unlike others.

placing a Trade with a very calculated risk management strategy such that you know how much is at stake in every trade and so if it goes against you, you are going to be sure of how much you are loosing because your risk management has already informed you what is at stake and its such at hat you can handle should in case things go south and so even your emotions will not be troubled at that point because you are actually aware of what is at stake and its such that you are very comfortable with because you are thinking in a very good probability and not very high expectations and emotions. conclusively both psychology and emotions got a very vital role to play Trading but then Psychology influences the other the most but then working on both together is very essential.