Doctoral Thesis: Psychological Sciences Would Benefit From A General Theory

From the start of my undergraduate studies all the way to my doctoral research, I was guided by one question: What is the psyche and how can it be studied? Finding an answer to this question proved very difficult. Instead of clarity, my lectures provided varying and often contradictory explanations of the human psyche, which in no way helped to form a holistic understanding.
 
At one point, I "discovered" that the problem wasn’t with the courses, but rather with the field of psychology itself. Psychology as a field is fragmented and divided into sub-fields that operate in isolation. My discovery raised further questions: How can we understand the human psyche by drawing from a variety of theoretical approaches, and how can we determine the right theory?

This dilemma introduces the topic of my doctoral thesis. Fragmentation in psychology has been a significant issue for at least a century. For example, Lev Vygotsky already demonstrated long ago that the development of any (!) scientific field is characterised by such fragmentation. As science evolves, distinct and often isolated sub-fields emerge, focusing on specific, narrow topics. However, as these sub-fields evolve, they reach a point where the questions raised can no longer be answered without integrating knowledge from other scientific fields. At this stage, the need arises to develop a general theory – a system of common principles and laws. 

Modern psychology is still in a stage of fragmentation, but the main issue is that the need for a general theory is often ignored or deemed irrelevant. The prevailing view is that a general theory in psychology is neither possible nor necessary. In my doctoral thesis, I aimed to challenge this perspective. In the first article, I analysed research on the use of gestures, highlighting how different theoretical positions describe the same gesture in terms of its purpose and nature in different ways. This inconsistency poses several problems. For example, current knowledge does not allow for gestures to be effectively used in speech therapy, even though the potential is there.

The first article thus underscored a serious problem in scientific research. Indeed, while researchers emphasise the need to synthesise different theories in order to advance their fields, they are faced with seemingly insurmountable challenges. The root of the problem is that attempts to unify psychology often come from one of the narrow sub-fields. What is needed, however, are theories that transcend the boundaries of the individual fields and provide a holistic framework.

This is why my doctoral thesis explored a different approach. Namely, instead of bottom-up integration – attempting to explain the entire discipline using knowledge from one sub-field – I propose a top-down process. This approach involves selecting a holistic theory and testing whether its principles can explain knowledge systems of sub-fields. In my thesis, I chose a concept that addresses a unique feature of human thought: the development of the structure of verbal concepts. In two articles, I demonstrated that the principles of this theoretical construct can be applied to link different sub-fields in psychology. Specifically, I investigated the relationship between forms of conceptual thinking and visuospatial perception and memory. Through my work, I showed that one way to unify the sub-fields in psychology is to adopt a theory that inherently describes the psyche as a whole.

Tallinn Univeristy School of Natural Sciences and Health doctoral student Valeri Murnikov defended the doctoral dissertation „Toward overcoming fragmentation in psychology theory: explorative studies on the relationship between word meaning structure, visuospatial perception, and recall accuracy“ on 16 December. Thesis supervisors were Aaro Toomela, Professor at Tallinn University and Kristjan Kask, Associate Professor at Tallinn University, opponents were Jana Uher, Associate Professor at the University of Greenwich and Kaja Mädamürk, Associate Professor at Tallinn University