[1] While psychophysiology was a general broad field of research in the 1960s and 1970s, it has now become quite specialized, based on methods, topic of studies and scientific traditions.
[4] A psychophysiologist may look at how exposure to a stressful situation will produce a result in the cardiovascular system such as a change in heart rate (HR), vasodilation/vasoconstriction, myocardial contractility, or stroke volume.
[citation needed] Overlaps in areas of interest between psychophysiologists and physiological psychologist may consist of observing how one cardiovascular event may influence another cardiovascular or endocrine event; or how activation of one neural brain structure exerts excitatory activity in another neural structure which then induces an inhibitory effect in some other system.
[citation needed] Often, physiological psychologists examine the effects that they study in infrahuman subjects using surgical or invasive techniques and processes.
[citation needed] Psychophysiology is closely related to the field of neuroscience, which primarily concerns itself with relationships between psychological events and brain processes.
[5] Evaluative reports involve participant introspection and self-ratings of internal psychological states or physiological sensations, such as self-report of arousal levels on the self-assessment manikin,[6] or measures of interoceptive visceral awareness such as heartbeat detection.
[8] Physiological responses also can be measured via instruments that read bodily events such as heart rate change, electrodermal activity (EDA), muscle tension, and cardiac output.
[9] Many indices are part of modern psychophysiology, including brain waves (electroencephalography, EEG), fMRI (functional magnetic resonance imaging), electrodermal activity (a standardized term encompassing skin conductance response, SCR, and galvanic skin response, GSR), cardiovascular measures (heart rate, HR; beats per minute, BPM; heart rate variability, HRV; vasomotor activity), muscle activity (electromyography, EMG), electrogastrogram (EGG) changes in pupil diameter with thought and emotion (pupillometry), eye movements, recorded via the electro-oculogram (EOG) and direction-of-gaze methods, cardiodynamics, recorded via impedance cardiography, and grip force.
[5] Psychophysiological measures are often used to study emotion and attention responses to stimuli, during exertion, and increasingly, to better understand cognitive processes.
[17] Some of these differences can be attributed to variables like induction technique, context of the study, or classification of stimuli, which can alter a perceived scenario or emotional response.
The approach is to enable implicit and symmetrical human-computer communication by granting the software access to a representation of the user's psychological status.
The advantages of using psychophysiological indices are that their changes are continuous, measures are covert and implicit, and only available data source when the user interacts with the computer without any explicit communication or input device.