Sensory Perception or Deception?
Norman MacCaig, in ‘As I remember’, describes how, “...into my, and your, five ports of knowledge come many cargoes and we should unship the lot.” (MacCaig, 1979, p84) While we have five senses and they bring us everything we know of the world, they can also prove unreliable and deceptive. Our contact with the world is solely through sensory perception; however, our brains can play “tricks” on us, send conflicting messages, and can misunderstand or misinterpret what the senses pass to them. I plan to examine how we can mistake sensory perception and the effects this has on our understanding and appreciation of the world which surrounds us and which sends these remarkable ‘cargoes’.
It is widely thought that the illusion of depth in illustration was first developed in the Renaissance when it is believed one of the first uses of perspective was in Giotto’s ‘Jesus Before the Caïf’. However; Lascaux, a complex of caves in France, demonstrates through its cave-paintings that its unknown, prehistoric artists had their own grasp on perspective: they even used the natural curving and jutting of the cave walls to convey depth and movement. Artists have, then been ‘tricking’ our visual perception for thousands of years, from the times of the so-called primitive Neanderthals to the present day. And we seem to like it, as the popularity of, for example, Escher’s visual conundrums testify.
Sight is obviously one of our strongest senses, in use every minute of the day until we fall asleep (but even our dreams operate in a visual world); however, it can be demonstrated that the senses of touch, hearing, smell and taste are equally capable of being deceived.
Despite all of these, arguably, “deficit” sensations, can new developments in sensory perception be used to enrich our lives?
The day to day tricks and illusions created by our brains and senses are very powerful. So what must it be like to be sensorily impaired or deprived? In understanding autism, it is difficult to grasp sensory perception and the depth and pervasiveness of sensory dysfunction. We were all taught the five senses from an early age and have a basic understanding of how these work. People with autism have far more complex senses, they interact and react differently, and there are an extra two. Proprioception refers to the way your body communicates with your joints, tendons and muscles. The vestibular sense refers to a person’s sense of balance and movement. To complicate matters, people on the autistic spectrum can be hypersensitive (over active) or hyposensitive (under active) to the senses, or both.
ADHD (attention deficit hyperactivity disorder) and sometimes cerebral palsy can cause similar challenges, people with these conditions can have trouble regulating and focusing their attention. Feurstein’s, ‘Tactile Instrumental Enrichment’ program uses cognitive or key thinking processes, one of which being, using our senses to gather information in an aim to teaching intelligence, which has proved particularly successful with children with ADHD. It forces them to regulate their attention to one sense.
Feurstein’s program has now been developed to be used with blind children. Initially, pencil and paper were used to teach this new way of learning but, in order to make this accessible to the blind, different shaped tokens were developed and symbols used. It is widely believed that people who lose one sensation compensate with the enhancement of another sensation. With visual perceptual difficulties it is argued that you can compensate for this cognitively. For example, the chef, Jamie Oliver is colour blind but he 'knows' what looks good on a plate and has compensated for his difficulty cognitively by learning what works. We learn to compensate for missing senses but the mind struggles to cope with complete sensory deprivation.
Sensory deprivation is a controversial subject, with allegations the technique has been used at Guantanamo Bay as an interrogation tactic. Thousands of prisoners around the world are kept in solitary confinement, often with a level of sensory deprivation. It is thought that sensory deprivation can make people much more suggestible. During experiments in this area most subjects would give up after 72 hours as the boredom and oppression of the conditions became overpowering. There have been many experiments of extreme isolated situations (such as living in the arctic and during space travel). The European Space Agency started Mars500 in 2010, six ‘astronauts’ boarded an artificial spaceship near Moscow to find out what two years in an isolation facility would do. How someone will cope with isolation may depend on your personality type. Results from experiments are that there are increased rates of disturbances of mood, psychiatric disorder, tension between captives, and a disruption of sleep rhythms. Short-term sessions of sensory deprivation are described as relaxing and encourage meditation, however, extended or forced sensory deprivation can result in extreme anxiety, hallucinations, bizarre thoughts and depression. In unusual circumstances our brains and senses can play dangerous tricks on us.
Trauma can cause our senses to act irregularly and send mixed messages to our brains. A phantom limb is the sensation that an amputated or missing limb is still there and is moving as normal. Approximately 60 to 80% of people with an amputation experience phantom sensations in their amputated limb, and the majority of the sensations are painful. In the early 1990s, Tim Pons, at the National Institutes of Health, showed that the brain can reorganize if sensory input is cut off. Various forms of treatment have been experimented with; such as drugs, vibration therapy, and acupuncture to name but a few. A team of researchers at the University of Manchester experimented with a technology of "immersive virtual reality" to combat the discomfort caused by phantom limb syndrome. The researchers reported that phantom limb pain could be relieved by attaching the sufferer's real limb to an interface that allows them to see two limbs moving in a computer-generated simulation.
Virtual reality as a form of therapy began in the early 1990s. Developed by Dr. Ralph Lamson, a now retired clinical psychologist, virtual reality was used to solve his own fear of heights. It is now widely used to treat post traumatic stress disorder, especially in soldiers. In 1996, Dr. Hunter Hoffman of the University of Washington’s Human Interface Technology Laboratory and Dr. David Patterson of Seattle’s Harborview Hospital Burn Centre devised a new psychological pain control technique which relied on diverting attention using virtual reality. Diverting attention is particularly useful in burn pain as pain perception is largely psychological. Snow World is a virtual reality system that lets users walk through wintry environments and throw snowballs at targets. The cool imagery and immersive game-play proved to be an alternative to strong drugs which tend to leave patients dazed and disconnected.
Our senses, however deceptive, can bring us great pleasure but when they malfunction the result can be traumatic. New developments in sensory perception allow us to intercept our senses and take back, a little, control.