The main criticisms of Wundt's introspection method centred around its subjective nature. Critics argued that the introspective reports, being based on personal experiences, were inherently subjective and could not be reliably measured or replicated across different individuals. This criticism led to significant shifts in psychological research methodologies. The biggest impact was the rise of behaviourism, which emerged as a reaction to the perceived limitations of introspection. Behaviourism focused on observable and measurable behaviours, rather than the internal conscious experience. This shift was crucial as it led to a greater emphasis on empirical evidence and the development of more objective research methods in psychology. The transition also underscored the importance of verifiability in psychological research, paving the way for more rigorous scientific approaches in the study of human behaviour and mental processes.

Wundt's work was instrumental in advancing the understanding of consciousness in psychology. Through his method of introspection, Wundt aimed to dissect the conscious experience into its fundamental components, such as sensations, feelings, and thoughts. This approach was groundbreaking as it moved the study of consciousness from a philosophical concept to a subject of empirical research. Wundt's focus on the structured analysis of conscious experience helped establish consciousness as a central topic in psychology. His work laid the foundation for subsequent theories and research on cognitive processes, such as perception, attention, and memory. While the method of introspection itself has been largely replaced, its emphasis on the systematic study of consciousness has had a lasting impact on how psychologists approach and understand the human mind.

Wundt's laboratory at the University of Leipzig was a landmark development in the field of psychology. It was the first facility dedicated solely to psychological research, signifying the separation of psychology from philosophy and its establishment as a distinct scientific discipline. The laboratory provided a structured environment for conducting controlled experiments, which was a novel approach in the study of mental processes at the time. This emphasis on empirical research and experimentation set new standards for psychological research. The laboratory also became a training ground for many of the next generation of psychologists, who spread Wundt's ideas and methods internationally. Consequently, the laboratory's influence extended beyond its own research output, playing a key role in shaping the development of psychology as an academic and scientific discipline.

Voluntarism, a concept introduced by Wundt, played a central role in his psychological theory. It proposed that the mind actively organizes and structures sensory experiences, rather than passively receiving them. This theory was in contrast to the dominant associative psychology of the time, which viewed mental processes as automatic and passive. Voluntarism emphasised the active, willful nature of mental processes, including attention, perception, and apperception (the process by which new experiences are integrated with existing knowledge). This approach was significant as it highlighted the complexity and dynamism of the human mind, suggesting that consciousness is more than just a sum of sensory inputs. Wundt's emphasis on the active role of the mind in organizing experiences laid the groundwork for later developments in cognitive psychology and gestalt psychology, which similarly focused on the holistic and structured nature of mental processes.

Wundt's approach to psychological research had a profound influence on the methodology of modern psychology. He championed the use of scientific methods in the study of the mind, including controlled experimentation, empirical observation, and measurement. This emphasis on scientific rigor and empirical evidence was a significant departure from the philosophical and introspective methods that had previously dominated the field. Wundt's approach laid the foundation for the development of experimental psychology, which focuses on conducting experiments under controlled conditions to understand psychological phenomena. His insistence on methodological precision and replicability in research has permeated modern psychological research, leading to more sophisticated experimental designs, data analysis techniques, and a greater emphasis on empirical validation. Consequently, Wundt's influence is evident in the rigorous scientific methods that characterize contemporary psychological research.