FA7P42 - Reading notes on 'The Brain Book' by Peter Russell (1979)
Russell explains that the brain analyses and digests “other visual data” in addition to reading facial expressions as well as “data from the other senses” “such as sounds and smells, to help identify the face (6).” An example of sound being used to identify someone’s face is that particular person’s voice and the smell could be a perfume or an aftershave they are wearing.
The nose is able to “detect one molecule of gas, while a cell in the retina of the eye is sensitive to a single photon of light (6).” If the ear were to be more sensitive than the nose or the eye “it would pick up the sound of the random vibrations of its own molecules (6).” This shows how sensitive these parts of the human body can be in terms of responding to smells, sights and sounds.
Although “the normal brain appears to limit its awareness, filtering out a large part of its sensory input” as a way of coping “with the problems of day-by-day survival,” the full sensitivity of the brain “is sometimes revealed in pathological cases (6).” Twenty-four hours before a man died from a blood clot that “was found on the right side of his optic prominence” he could identify “tiny objects from great distances” as a result of the clot (6).
Russell claims “Schizophrenics show abnormal sensory acuity (6 - 7).” More specifically people with schizophrenia have hallucinations that involve all five senses such as hearing, seeing, feeling, smelling and tasting things that are not actually there (HelpGuide.org). The most common hallucinations in schizophrenics are those when they hear voices that are not really there although visual hallucinations are also common (HelpGuide.org)
On page 18 there is a map of the brain (see Fig. 1) and the only part of the brain that specifically represents a sense is the one that is marked with ‘food taste’ although some could represent sight such as ‘time,’ ‘number’ and ‘creativity’ because people can see the time on a watch, numbers on a receipt in terms of the costs of each item and they can see things they create such as clay pots.
Figure 1 (Figure 3 in book): A map of the brain
Sensory memory is when people remember sights, sounds and tastes (82), for example “several thousand faces,” “favourite pieces of music, or the smell of some tasty dish.”
The lens of the eye focuses light onto the retina (189). There are tiny cells in the retina, the lining of the eye, that are “responsive to light” and the number of cells equates “to the population of the U.S.A. squeezed onto a postage stamp” in 1979. The optic nerve connects the retina to the brain and it sends images from the eye to the brain.
Figure 2: Diagram of the inside of the eye
The eye actually “takes short gulps of information” because the fovea, the part of the eye “where vision is most acute (189),” “sees less than one forty-thousandth of the total visual field (190).” For example if a person is reading some text then the fovea can only see about three words of the portion of text the person its reading, which is why “the eye must move along the text” so the person can read the whole text effectively (190).”
In 1908, Edmund Huey published a “pioneering work” called The psychology and Pedagogy of Reading. In this work “Huey found that the eye takes about a quarter of a second to move from one point of fixation to the next. (191),” therefore the eye can only make four fixations per second. The parts between fixations are called saccades. The diagram on page 192 (see Fig. 3) illustrates this.
Figure 3: Diagram showing fixations of eye movements
References
Book
Russell, P. (1979). The Brain Book. London: Routledge and Kegan Paul Ltd.
Website
Helpguide.org (No date). Schizophrenia: Symptoms, Types, Causes, and Early Warning Signs [Online]. Available at: http://www.helpguide.org/articles/schizophrenia/schizophrenia-signs-types-and-causes.htm (Accessed 26th July 2016).
