Psychophysiology

Psychophysiology is the branch of psychology that studies the relationship between physiological processes and psychological phenomena. It seeks to understand how bodily systems such as the nervous, endocrine, cardiovascular, and autonomic systems reflect, support, or influence cognition, emotion, perception, and behavior. Researchers examine how mental states are associated with measurable physiological signals and how these signals change under different tasks or states.

Common methods include central measures like electroencephalography (EEG) and event-related potentials (ERPs), which track brain activity with high temporal resolution, and peripheral measures such as heart rate and heart rate variability, skin conductance (galvanic skin response), respiration, pupil diameter, and facial electromyography to infer emotional expressions. Modern psychophysiology also uses imaging and noninvasive techniques such as functional MRI and optical methods. Data are analyzed in relation to task conditions, stimuli, or subjective reports, and can be used in experimental, clinical, or developmental contexts.

Historically, psychophysiology emerged from late 19th and early 20th century interest in linking physiology to mental processes, with early demonstrations of physiological responses to psychological states. The development of EEG in the 1920s by Hans Berger and the subsequent growth of autonomic measures expanded the field. The term now covers research across laboratories worldwide and is closely integrated with cognitive neuroscience and behavioral medicine.

Applications span cognitive science, emotion research, sleep, psychopharmacology, and clinical assessment. While psychophysiology offers objective measures, it faces challenges such as measurement artifacts, interindividual variability, and the difficulty of inferring causality from correlational findings. Multimodal approaches and careful experimental control are common practical solutions.