How the biological study of mental processes has contributed to the development of psychology as a discipline? To better answer the question, this essay will illustrate how the study of mental processes has evolved through three significant phases: before Biological studies, this “era” focuses on the early philosophical and introspective approaches; the Stimulus-reaction period, which is the “era” of behaviourism and early neurophysiological models, which characterised the brain as a stimulus-response machine; Predictive Processing, the current “era”, which provides a more integrated and dynamic understanding of mental processes as proactive, prediction-based processes.

Brain’s function and structure across time.

Before going into a detailed exploration of the study of mental processes across the history of psychology, it’s important to look at the evolution of understanding brain functions and structures across the mentioned periods; to see the profound changes in the conceptualisation of the brain in psychology and neuroscience.

Before Biological contribution: In the beginning mind and body were mostly studied by philosophers. The understanding of the brain function and structure, of that time, was rudimentary and relayed on philosophical speculations. The anatomical knowledge was as well limited and the brain’s importance was overlooked. Aristotle for instance thought that the heart has a more crucial role and is the primary organ of sensation (Aristotle, 350 BCE). Another example of when the brain’s fun actions were viewed through metaphysical concepts, is the Humoral theory, which suggests that bodily fluids influenced behaviour and temperament (Hippocrates, 400 BCE). Later in the 17th century, Descartes proposed a new theory “Mind-Body Dualism”, where he distinctly separates the nature of the mind and the nature of the body, arguing that one can exist without another. Although he assigns a function of consciousness and reason to the brain.

Stimulus-Reaction Era: shaped by the rise of behaviourism and early neuroscience, the understanding of the brain shifted towards more empirical and anatomical forms. Which led to a clearer understanding of the brain’s structure and functions. One of the most significant findings was Broca’s discovery of the speech production centre in the brain, known as Broca’s area, which linked specific brain areas to cognitive function (Broca, 1861). This was the beginning of a new field- neurophysiology. Later Wernickle (1874) developed even further the brain-behaviour relationship, by identifying the brain’s area responsible for language comprehension. During the same period, the brain’s function was understood as a stimulus-response mechanism, (where specific inputs led to certain outputs.) This era was dominated by the behaviourists’ perspective that all behaviours could be understood as reflexes conditioned by environmental stimuli (Watson, 1913; Pavlov 1927).

The predictive processing era views the brain as an active participant that doesn’t just passively respond to the external world but proactively simulates and predicts the environment. The distinction of understanding brain structure in this era is neuroimaging technologies such as fMRI and PET scans which allowed to examine hierarchical organisation of the brain, showing how different layers of neural circuits predict sensory inputs at various levels of abstraction (Friston, 2005). The brain’s function is understood as a continuous prediction process, to minimise the error between its predictions and sensory inputs and by adjusting its predictions, shapes cognitive functions. As well as, construct and maintain perceptual reality (Clark, 2013). Unlike earlier theories which often separated mind and body, the modern approach emphasises the inseparability of cognitive processes from their biological bases, aligning psychology more closely with biological science.

This section compares how mental processes were understood and studied across different eras, examining each historical period through various psychological fields.

Perception and Cognition.

First era: In the evolution of psychological theories, early introspective methods by Descartes (1637) and Locke (1690) gave subjective insights but lacked empirical accuracy. Associationism was introduced by Hume (1739) and experimental approaches by Ebbinghaus (1913) began to systematise the study of memory and learning, by observing how subjects recall and connect ideas. The biggest flaw of these methods was introspection’s subjectivity. Wundt challenged that drawback by stressing the importance of the use of experimental methods to increase precision (Wundt, 1910). Developing on the idea Titchener, (1896) founded structuralism but was criticized for missing psychological holistic aspects. Later, Wertheimer, (1923) developed Gestalt psychology and switched the focus onto the observable behaviours and perception of the whole, which showed more objective insight into cognitive processes. During the Stimulus-Reaction era, behaviourism was a dominant theory during which the emphasis was on observable behaviours. In comparison to the previous era, this era is characterised by a more objective framework, including controlled laboratory settings as the main setting for behavioural analysis. Main methods such as Pavlov’s (1927) classical conditioning and Skinner’s (1938) operant conditioning defined brain function as a direct stimulus-response mechanism. However, a strong focus solely on the behaviour part was criticised for neglecting the brain’s complex cognitive and neurological underpinnings. Later Lashley’s (1929) lesion studies and Thompson’s (1986) investigations into neural plasticity challenged this limitation. They have expanded the understanding of the brain’s role and revealed complex synaptic changes and neural pathways, which are critical in learning and memory processes.

Despite the main focus of this era being on observable behaviour, it sets the groundwork for the cognitive-behaviour revolution. Clinicians started to recognise that to change or understand behaviours they need to take into consideration cognitive processes which co-occur with behaviours. This realisation led to the foundation of cognitive-behavioural therapy (CBT) (Beck, 1976).

Predictive Processing Era: This era has transformed the understanding of perception and cognition. For instance, Karl Friston (2005) and his influential research “The Free Energy Principle” showed how the brain simultaneously reduces surprises making predictions based on internal models and updating them using sensory input, thus giving the brain an active role in the perception processes. Additionally, his development of dynamic causal modelling shows the transition from previous approaches to connectivity, by using an explicit generative model which measures brain responses in their non-linear causal architecture (Friston et al., 2003). Moreover, he brought sophisticated statistical tools to neuroscience, enabling a detailed examination of how the brain minimises prediction errors. It could require more careful and resourceful interpretation to avoid misrepresenting complex brain functions. Nonetheless, he fundamentally challenged traditional stimulus-response models. (Friston, 2009). Studies like those by Rauss and Pourtois (2013) utilize fMRI and EEG to observe how top-down predictions influence sensory processing, showcasing the application of predictive models in real-time brain activity analysis. Andy Clark’s integration of Bayesian inference into psychological theory (Clark, 2013) offers a robust framework for understanding perception as an active, inference-driven process, in comparison to the past passive role in linear perception systems. While these methodologies provide profound insights into the brain’s predictive mechanisms, they also demand high computational resources and sophisticated data analysis skills, which can be a barrier to broader application. Additionally, the reliance on statistical modelling to infer neural processes requires assumptions that may oversimplify the underlying biological realities.

Clinical psychology.

First era: The Dominating theory of this period was Freudian psychoanalysis, which emphasised internal conflicts, childhood experiences, and the unconscious mind as determinants of psychopathology (Freud, 1923). Freud introduced talk therapy and psychoanalytical techniques in clinical settings (Freud, 1900). The methodology of that time included mostly theoretical and qualitative case studies, which lacked empirical factors and were hard to generalise.

Stimulus-reaction era: One of the main shifts was the application of behaviourist principles in clinical settings. For example, Wolpe (1958) developed a systematic desensitisation method, using classical conditioning to treat anxiety disorders. By his method, participants would practice relaxation techniques while being gradually exposed to fear- inducing stimuli. The method aims to recondition the patient’s response. Another notable example of the development of behaviour modification therapies is: that techniques such as token economies and contingency management were used in various settings, including hospitals and schools, to modify behaviours by manipulating reinforcements and punishments (Ayllon & Azrin, 1968).

This era also is signified by research on brain lesions, which provided a deeper understanding of the neural mechanisms underlying behaviour. For instance, studies by Milner et al., (1968) on patient H.M. demonstrated the role of the medial temporal lobe in memory formation, which changed clinical approaches to amnesia and other cognitive deficits. Additionally, studies on animals with induced lesions revealed critical brain areas involved in emotional responses, such as the amygdala and prefrontal cortex (Murray et al., 2022).

Another crucial contribution to clinical psychology was the discovery of neurotransmitters and their roles in mood and behaviour. For example, the identification of serotonin’s role in depression led to the development of selective serotonin reuptake inhibitors (SSRIs), revolutionizing the treatment of mood disorders (Wong et al., 2005). This biological perspective integrated pharmacological treatments with behavioural therapies, offering a more holistic approach to mental health.

Predictive Processing Era: This era significantly expanded the current understanding of various psychological disorders and their manifestation in the brain structure and function. One notable example is how Predictive Processing theories can explain the mechanisms behind delusions and hallucinations in schizophrenia. According to this, the symptoms appear due to impaired prediction error signalling within the brain, leading to an inability to distinguish between internally generated and external stimuli (Corlett et al. 2007). This has led to new approaches in psychosocial interventions that focus on enhancing the brain’s ability to form accurate predictions.

Another key contribution is in the treatment of Depression and Anxiety. Ramos-Grille et al. (2021) demonstrate a new outlook on the understanding of mood disorders. By using the Predictive Processing framework, he was able to examine in patients with depression how maladaptive predictive models could lead to persistent negative biases. Moreover, to correct cognitive distortions, he reinterpreted cognitive-behavioural treatment strategies as methods for updating those distorted brain predictions.

A similar approach was suggested for OCD interventions. Studies by Voon and colleagues (2015) in that area have shown that repetitive behaviours in OCD may stem from an over-reliance on prediction error minimisation strategies that inaccurately signal a need for corrective action. This approach makes it possible to recalibrate the brain’s predictive models to reduce compulsive behaviours.

Another groundbreaking discovery in clinical settings using the Predictive Processing model was explaining the perceptual peculiarities, such as hypersensitivities and attention to detail in Autism Spectrum Disorders (ASD). Pellicano and Burr’s (2012) research has shown that overwhelming sensory experiences in ASD are the result of the atypical predictive processes where sensory input is under-predicted. This led to the development of a therapeutic approach which modulates sensory prediction mechanisms. The integration of Predictive Processing into clinical psychology further developed neuroimaging tools to assess how therapy influences brain predictions. Such techniques as real-time fMRI and EEG neuro-feedback help clinicians to observe how therapeutic interventions influence brain activity patterns, and to choose more effective treatment (Zotev et al., 2014; Perronnet et al., 2017). These techniques not only help with a better understanding of undergoing processes of the brain predictions but also integrate advanced theories into everyday clinical practice.

Conclusion.

The biological study of mental processes had a great impact on the development and structuring of the field of psychology. It significantly changed the understanding of the brain-behaviour relationship and provided a robust empirical foundation. During the pre-biological era, psychological theories were mostly speculative and philosophical. Moreover, the scientists of that time were relying on introspective methods that lacked empirical foundation. This changed significantly during biological study development at the beginning of the stimulus-reaction era. Pioneering work by researchers like Ivan Pavlov and B.F. Skinner introduced systematic experimental methods to study behaviour, while neurophysiological discoveries by scientists such as Paul Broca and Karl Wernicke linked specific brain areas to cognitive functions, thus laying the groundwork for neuropsychology. Neuropsychology’s rapid development started with the predictive processing era. During this scientists further developed the understanding of mental processes. According to a new model the brain doesn’t have a passive role anymore as it was viewed in previous eras, it has an active role in predicting and interpreting sensory inputs and at the same time maintaining a complex framework of reality. One of the biggest contributions in the field was Karl Friston’s Free Energy Principle and advancements in neuroimaging technologies, such as fMRI and EEG, revolutionised an outlook on the brain’s hierarchical organisation and its predictive mechanisms. What is more, this era has also seen significant developments in clinical psychology, where predictive models have been applied to understand and treat various mental disorders. Indeed, the gap between theoretical models and clinical practice has been minimised by implementing real-time neuroimaging techniques in clinical settings. This allowed clinicians to be more accurate in assessing various disorders like schizophrenia, depression, OCD, and ASD. As well as it helped to tailor therapeutic interventions to the individual neurological needs of patients.

In conclusion, modern psychology has come a long way from speculative science to science grounded in empirical research. It would not be possible without biological study. This assay shows how intertwined the two fields are. The development of biological research has deepened the understanding of the connection between the human brain, its functions, structure, emotions, behaviours and reactions. Another important aspect is the significant development in the efficiency of therapeutic interventions and methodology. This highlights the inseparable nature of psychology and neuroscience. The future advancement in biological psychology will enrich the field and improve mental health care practices even more.

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