In our rapidly developing world, people often need to create words to name new concepts. The process of creating a new word is actually very complex and consists of a number of stages that are mostly carried out at the subconscious level. People need to understand the role of a newly encountered phenomenon in the world around them and how that phenomenon will be classified within the framework of the already familiar categories. Another problem is the choice of the outer (phonetic) form of the newly created word, which is mainly based on the categorization process of the new phenomenon encountered by a person. This paper is aimed at studying the role of morphemes of Ancient Greek and Latin origin in the process of coining neologisms in the field of psychology. Psychology is a rapidly developing branch of science, and consequently new words need to be coined frequently. In the paper, we tried to reveal what kind of categorization processes take place when creating new words, and how these processes affect the external phonetic composition of given neologisms, and in particular, why Ancient Greek or Latin morphemes are chosen for coining neologisms in the field of psychology.