Psychophysiology or physiological psychology is the branch of psychology that is responsible for studying the biological elements of behavior . It is a discipline related to the physiological basis of psychological processes and brain functioning.
Psychology is a broad science that, for example, is interested in knowing the reasons why certain people are afraid of spiders. On the other hand, psychophysiology is a more concrete discipline that would be interested in the mental and physiological processes responsible for the fear of spiders.
Psychophysiology is therefore a branch that developed out of psychology. In fact, the first text on scientific psychology written by the famous German psychologist Wilhem Wundt in the late 19th century bore the title Principles of Physiological Psychology.
In recent years, the large amount of information obtained in experimental biology and in scientific studies from other disciplines has contributed significantly to the investigation of human behavior.
Thus, psychophysiological studies are essential for the development of psychology as a science. Increasingly, there is more information about the functioning of the nervous system and brain structures.
In the modern history of the investigation of the physiology of human behavior, the experimental methods of psychology have been combined with those of physiology, giving rise to what is now known as psychophysiology.
History of psychophysiology
The branch of psychophysiology was started and developed by Wilhem Wundt at the end of the 19th century, through the publication of the book “Principles of physiological psychology”. constitute a research discipline.
In this sense, the most relevant historical aspects of psychophysiology are:
During the years 428 and 347 BC, the well-known philosopher postulated three different regions in human functioning: reason and perception located in the head, noble passions like courage or pride located in the heart, and base passions like greed and lust located in the liver and intestines.
Later, Aristotle postulated that the brain did not cause sensation and understood that the heart should be where sensations occur.
In the same way, Aristotle hypothesized a structure of the anima in three dimensions: vegetative, sensible and intellectual.
A contemporary of Aristotle, Herophilus dedicated himself to dissecting the bodies of animals and people to study the nervous system, tracing nerves from muscles and skin to regions of the spinal cord.
In the year 157 BC, Galen made an important assessment reporting that changes in gladiator behavior were caused by injuries to the head. For the first time, the brain begins to be associated with mental functioning.
In the year 400 AD, Nemesisus formulated a theory of location in the brain, elaborating the idea that cognition is in the ventricles.
During the 18th century, Thomas Willis provided valuable insight into how the brain works. He was the first author to place the functions in the cerebral cortex. Specifically, the author located sensation in the striatum, perception in the corpus callosum, and memory in the cortex.
Likewise, during the same period, La Peroynie placed intelligence in the corpus callosum, since a lesion in the hemisphere did not cause significant deficits.
At the beginning of the 19th century, Joseph Gall promoted the study of the location of the brain in different cognitive functions. Similarly, Flourens posited a theory antagonistic to Gall’s, arguing that mental processes depended on the overall functioning of the brain.
In the middle of the 19th century, the golden years of psychophysiology appear. Broca, a Swiss neurologist discovered the perforation area through the TAN-TAN case. 5 years later, Wernicke‘s area is discovered.
In the 60s of the last century, two authors stood out. Geshwind demonstrated the importance of connections in complex tasks and described the disconnection syndrome, referring to damage to connections between different areas of the brain.
Luria, on the other hand, devoted himself to studying World War II patients and described disorders located in the prefrontal cortex of the brain.
What does psychophysiology study? (study object)
Psychophysiology is responsible for analyzing the physiological bases of psychological processes. That is, it focuses on examining how psychological activities produce physiological responses.
Historically, most authors tend to examine physiological responses and organs innervated by the autonomic nervous system.
Instead, more recently, psychophysiologists have become interested in the central nervous system, exploring cortical and event-related potentials, brain waves, and functional neuroimaging.
In this sense, psychophysiology can investigate, for example, how exposure to a stressful situation produces a result in the cardiovascular system, such as a change in heart rhythm or ventricular vasodilation.
In general, the main aspects that psychophysiology focuses on are:
sensation and perception
The general principles of sensory information processing are one of the foundations of psychophysiology as a science.
The functioning of the mind, consciousness and perception are the main elements that research and examine this branch of psychology.
The functioning of the bodily senses and their integration with mental processes are also studied from the perspective of psychophysiology.
Somatic modalities, receptors, somatic pathways and transduction would be the main topics of interest. Likewise, psychophysiology examines pain and analgesia processes and the functioning of somatic information in the cerebral cortex.
Specifically, the functioning of the visual sense is one of the topics of special interest in psychophysiology. The particularities of the eye, retina and optical pathways are examined, as well as the transduction and encoding of visual information.
In addition, psychophysiology is responsible for analyzing visual information in the striate cortex and association cortex of the brain.
hearing and balance
As with the visual sense, the auditory sense is another aspect of research in psychophysiology.
To determine the peculiarities of the ear, the organ of corti and the auditory pathways are activities carried out in this branch of psychology. In addition, the transduction, encoding, and analysis of auditory information in brain regions is examined.
Psychophysiology is responsible for investigating the organization of sensorimotor function, effector systems, control of reflex responses and brain control of movements.
sleep and wake
On the other hand, psychophysiology is the discipline responsible for investigating circadian rhythms and their regulation, behavioral and physiological characteristics of sleep and wakefulness, as well as their neuronal mechanisms and functions.
The biological and physiological nature of motivational systems are also aspects of study in psychophysiology. The substrate of nervous reinforcement, incentive motivation and dependence would be the elements of special interest.
Hungry and thirsty
Digestion and metabolism are physiological aspects that are also of interest to psychophysiology. This branch of psychology focuses on examining the mechanisms of peripheral regulation of intake, neural control of hunger, and water balance.
With regard to sexual behavior, psychophysiology studies the organizing and activating effects of sex hormones, the neural control of sexual behavior, and the functioning of pheromones.
Emotional processes are probably the elements most related to psychophysiology today.
The nature of emotions and feelings, neuronal functions and systems of emotions, aggression and violence behaviors and the physiological stress response would be the main aspects.
Learning and memory
Finally, recently, psychophysiology has gained importance in the study of higher cognitive processes.
The nature of learning and memory, synaptic plasticity, basic forms of learning and implicit memory, relational learning and the neuronal functioning of working memory are elements studied by psychophysiology.
The objective of scientific research is based on the explanation of the studied phenomena. In psychophysiology, reduction is generally used. In this way, attempts are made to explain complex phenomena in terms of more specific phenomena.
However, psychophysiology is not just focused on providing reductionist responses. That is, it is not just based on observing behavior and correlating it with physiological events.
Thus, psychophysiology uses both generalization and reductionism. Reduction refers to explaining phenomena in terms of more basic physical processes. In contrast, in generalization, psychophysiology uses the traditional methods of psychology.
In this sense, reduction focuses on explaining behaviors in terms of physiological events in the organism, specifically in the nervous system, and generalization focuses on relating this information to the psychological processes studied.
More specifically, several authors conclude that the main goals of psychophysiology are:
- Analyze the nervous processes involved in transforming physical stimulation of the sensory organs.
- To study the influence exerted by biological changes in the formation of certain psychological manifestations.
Differences between psychophysiology and physiological psychology
Although they are two concepts often used interchangeably, psychophysiology and physiological psychology do not constitute the same branch of psychology.
Both disciplines focus on the study of the physiological functioning of the organism and its relationship with psychological processes. However, they differ in their way of working.
Psychophysiology focuses on analyzing how psychological activities produce physiological responses. Instead, physiological psychology focuses on analyzing the physiological mechanisms that lead to psychological activity.
The study components of the two subjects are generally the same. However, they are distinguished by the point of view from which they are investigated and analyzed.
For example, physiological psychology focuses on studying which physiological processes are responsible for producing the sensation of thirst, while psychophysiology would focus on examining which changes in physiological functioning cause the sensation of thirst.
Likewise, psychophysiology can play an important role in improving the conceptualization of cognitive processes. Indeed, some psychophysiological sensors have already been used to detect emotions in schools and to develop intelligent guidance systems.
Psychophysiological study requires the use of electronic mechanisms, and modern psychophysiology uses many different types of signals.
The most used are evoked potentials, potentials related to events and brain waves (electroencephalography).
Similarly, other types of signals are also used, such as functional magnetic resonance imaging (fMRI), skin conductivity measurements, galvanic skin response, cardiovascular system measurements, heart rate measurements, and HRV Heart Rate variability signals.
Finally, eye movements recorded by electrooculograms (EOG), gaze monitoring methods or changes in pupil diameter are other signals commonly used in psychophysiology.