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. For example, food will be more pleasant when hungry compared to when an organism is satiated. The sensation aroused therefore depends not only on the quality or on the intensity of the stimulus, but also on the internal state of the organism as sensed by internal receptors. The relationship between the perceptual system and physiology is subjective and studied by psychophysics.