Trace the historical trends that led to the development of Watsonian behaviourism.

1. Introduction:
Watsonian behaviorism, named after its founder John B. Watson, emerged as a dominant school of thought in psychology during the early 20th century. This approach emphasized the study of observable behavior and rejected the study of mental processes, marking a significant departure from the introspective methods of structuralism and functionalism.

2. Rise of Experimental Psychology:
The development of Watsonian behaviorism was influenced by several historical trends in psychology. One key factor was the rise of experimental psychology in the late 19th and early 20th centuries. Psychologists such as Wilhelm Wundt and Edward Titchener established laboratories dedicated to the scientific study of mental processes, laying the groundwork for empirical research in psychology.

3. Critique of Introspection:
Another important trend that contributed to the development of behaviorism was the critique of introspection as a valid method for studying mental processes. Critics argued that introspection was subjective, unreliable, and lacked scientific rigor, leading psychologists to search for alternative methods for studying behavior.

4. Behaviorist Precursors:
Prior to Watson, several psychologists laid the groundwork for behaviorism by emphasizing the importance of observable behavior in psychological research. Ivan Pavlov's work on classical conditioning demonstrated how reflexive behaviors could be systematically studied and understood through controlled experimentation. Edward Thorndike's research on instrumental conditioning also contributed to the behaviorist perspective by highlighting the role of reinforcement in shaping behavior.

5. Watson's Behaviorism:
John B. Watson's seminal paper "Psychology as the Behaviorist Views It" (1913) marked the official beginning of behaviorism as a distinct school of thought in psychology. In this paper, Watson argued that psychology should focus exclusively on observable behavior and abandon the study of mental states altogether. He proposed that behavior could be understood as a response to environmental stimuli, and that all behavior could be explained through the principles of conditioning.

6. Influence of Pavlovian Conditioning:
Watson was heavily influenced by the work of Ivan Pavlov and his experiments on classical conditioning with dogs. Watson extended Pavlov's principles to human behavior, demonstrating how conditioned responses could be elicited and modified through systematic manipulation of environmental stimuli. This focus on stimulus-response relationships became a hallmark of Watsonian behaviorism.

7. Impact of Watson's Behaviorism:
Watsonian behaviorism had a profound impact on the field of psychology, shaping the direction of research and influencing subsequent developments in psychological theory and practice. Behaviorism dominated American psychology for much of the first half of the 20th century, leading to significant advancements in areas such as learning theory, behavior therapy, and animal research.

Conclusion:
The development of Watsonian behaviorism was influenced by historical trends in psychology, including the rise of experimental methods, the critique of introspection, and the work of behaviorist precursors such as Pavlov and Thorndike. Watson's emphasis on observable behavior and rejection of mentalistic concepts laid the foundation for a new approach to psychology that would dominate the field for decades to come. Despite later critiques and challenges to behaviorism, Watson's legacy continues to shape contemporary psychological thought and practice.