Alliesthesia (from Ancient Greek: ἀλλοῖος, romanized: alloios – be changed, and αἴσθησις (aísthēsis) – sensation, perception; thus "changed sensation"; French: alliesthésie, German: Alliästhesie) is a psychophysiological phenomenon (not to be confused with the pathologic symptom of allesthesia) that describes the dependence of perceived pleasure or displeasure of stimuli[1] on the internal state of an organism.
The internal state of an organism is in constant change, and any stimulus that can help to correct an error or to satisfy a need will be pleasantly perceived.
The relationship between the perceptual system and physiology is subjective and studied by psychophysics.
[5] The term alliesthesia was first mentioned in the annex of Physiological Role of Pleasure and was further elaborated in collaboration with the coauthor Stylianos Nicolaïdis.
Originally, alliesthesia was demonstrated in experiments with human subjects, and later confirmed in rats (Rattus norvegicus).