The unimportance of experimenter-bias in sensory deprivation research.

3 graduate student experimenters' expectations about the stress reaction of 24 subjects to sensory deprivation or to an ambulatory control condition were factorially manipulated. No significant differences were found for experimenters' expectation, directly or through interaction. Results were interpreted as a refutation ofthe assumed pervasiveness of experimenter-bias effects.     

Chiasm and hyperdialectic: re-conceptualizing sensory deprivation in infancy

The literature on sensory processing disorders in institutionalized infants highlights the impact of early deprivation on infant perception. Through a Merleau-Pontian, hyperdialectic analysis of the extraordinary development of infant perception under circumstances of severe deprivation the intimate link between environmental affordances and perceptual systems becomes apparent. This paper offers an updated reading of Merleau-Ponty’s late work as a philosophy of systems (“structures”, “forms”, “gestalts”, as he called them) and outlines some fertile philosophical concepts and methods developed by Merleau-Ponty in The visible and the Invisible. Merleau-Ponty’s concept of the chiasm, understood from a systems perspective, and his method of the hyperdialectic are applied in a child case study of an infant who suffered severe neglect in a Romanian orphanage.     

A qualitative analysis of sensory phenomena induced by perceptual deprivation

Previous studies have shown that misperceptions and illusory experiences can occur if sensory stimulation is withdrawn or becomes invariant even for short periods of time. Using a perceptual deprivation paradigm, we created a monotonous audiovisual environment and asked participants to verbally report any auditory, visual or body-related phenomena they experienced. The data (analysed using a variant of interpretative phenomenological analysis) revealed two main themes: (1) reported sensory phenomena have different spatial characteristics ranging from simple percepts to the feeling of immersion in a complex multisensory environment and (2) the active contribution of the perceiver where participants report engaging in exploratory processes even when there is nothing to find. Detailed analysis of the qualitative data further showed that participants who reported more perceptual phenomena were more likely to report internal bodily sensations, move more during the experiment and score higher on the Revised Hallucination Scale than those reporting fewer percepts explicitly linking perceptual deprivation to somatic phenomena. The results demonstrate how the variety of sensory experiences induced by perceptual deprivation can give further insight into the factors mediating conscious awareness and may suggest ways in which the brain imposes meaning on the environment under invariant sensory conditions.     

EEG alpha activity and hallucinatory experience during sensory deprivation.

The relationship between hallucinatory experiences under sensory deprivation and EEG alpha activities was studied. Each of seven male students lived alone in an air conditioned, soundproof dark room for 72 hours. When hallucinatory experiences occurred, the students pressed a button at once. If they could not press the button during the experience, they were required to press it two times when the hallucinatory experience was finished. Spectral analysis was performed on the consecutive EEG samples from just before button-presses to 10 min. before them, and the average alpha band amplitudes were obtained for the four epochs (0-.5, .5-2, 2-5, 5-10 min.). For the single button-presses, the amplitude of alpha band increased 2 min. before the button-presses. Right-hemisphere EEG activation was observed in the occipital area for the double button-presses. The results suggest an association between the hallucinatory experiences under sensory deprivation and the amount of EEG alpha activity.