Sensation and perception.

Knowledge is developed through interaction with the material and cultural environments. As we noted the initial processes are mediated by receptor cells for the basic five senses of hearing, vision, smell, touch and taste. All sensation is initiated by some environmental stimulus that carries sufficient energy to excite the nervous system. What we call sensation is the conversion of stimulus energy into neurophysiological processes that create a psychological experience. You taste food from a foreign culture and the sensation may be pleasant or unpleasant dependent on individual preferences and previous sensory experience. However, not all energy that impacts our bodies is brought to our attention. For example some wavelengths are not experienced at all. Our hearing is also limited, whereas dogs possess more acute hearing and smell. The minimum energy required to create a sensation is called the absolute threshold. However, a difference threshold is the minimum change of stimulation required to determine a change in sensation. It is believed that cognition begins with these basic sensory processes.

As we experience the sensory world we gradually build up experience as a reference point for new sensations. Perception involves the organization of association areas in the cortex thereby integrating previous knowledge. Without experience all sensations would be experienced as new and the individual could produce no meaningful pattern from sensory input. Importantly experience creates priming effects as we expect certain feelings associated with past stimuli. Cross-cultural comparisons in the basic areas of sensation and perception show remarkable universal outcomes in various societies pointing to the similarity of the computers we have inherited (Yaroshevski, 1996).

Date: 2015-01-11; view: 923