A/HRC/43/49 guilt, often exacerbated by anxiety about social exclusion, self-hatred and suicidal tendencies. As with other methods, therefore, it is the intentionality and purposefulness of degrading treatment, and the powerlessness of the victim, which are decisive for its categorization as either torture or other ill-treatment.40 4. Environmental orientation (sensory manipulation) 53. Sensory stimuli and environmental control are a basic human need. Deliberate sensory manipulation and disorientation through sensory deprivation or hyperstimulation involves both the sensory organs and the cognitive processing of sensory perception. Sensory hyperstimulation, in particular, is thus at the very interface between physical and psychological torture. 54. While short-term sensory deprivation alone can trigger extreme mental torment, prolonged deprivation generally produces apathy, followed by progressively severe disorientation, confusion and, ultimately, delusional, hallucinatory and psychotic symptoms. Accordingly, the Body of Principles for Protection of All Persons under Any Form of Detention or Imprisonment explicitly prohibits holding a detainee “in conditions which deprive him, temporarily or permanently, of the use of any of his natural senses, such as sight or hearing, or of his awareness of place and the passing of time”.41 In practice, such deprivation involves the partial or complete elimination of sensory stimulation through an accumulation of measures such as: • Suppression of oral communication with the victim • Constant monotonous light • Visually sterile environment • Sound-proof insulation of the cell • Hooding • Blindfolding • Use of gloves • Use of facial masks • Use of earmuffs 55. Sensory hyperstimulation below the threshold of physical pain, such as through constant bright light, loud music, bad odours, uncomfortable temperatures or intrusive white noise, induces progressively severe mental stress and anxiety, inability to think clearly, followed by increasing irritability, outbursts of anger and, ultimately, total exhaustion and despair. Extreme sensory hyperstimulation which, immediately or with the passage of time, causes actual physical pain or injury should be regarded as physical torture. This may include, for example, blinding victims with extremely bright light, or exposing them to extremely loud noise or music, or to extreme temperatures causing burns or hypothermia. 5. Social and emotional rapport (isolation, exclusion, betrayal) 56. A routine method of psychological torture is to attack the victim’s need for social and emotional rapport, through isolation, social exclusion, mobbing and betrayal. Persons deprived of meaningful social contact and subjected to emotional manipulation can quickly become deeply destabilized and debilitated. 57. The predominant method of isolation and social exclusion is solitary confinement, which is defined as “the confinement of prisoners for 22 hours or more a day without meaningful human contact”.42 Under international law, solitary confinement may be 40 41 42 See also, Cakal, “Debility, dependency and dread”, pp. 23–24. General Assembly resolution 43/173, annex. The Nelson Mandela Rules, rule 44. 15