Notes on Perception
General principles
o Our perception of the world is direct, immediate and effortless and to
ourselves there is no hint of any intervening operations taking place in the
brain.
o Perception is seen as simple however, the apparent simplicity is reinforced by
the fact that our perceptions are almost always accurate
o Mistakes are rarely made when a face or voice needs to be identified, or in
judging the temperature of a cup of tea or navigating a flight of steps.
o Our perceptions nearly always agree with those of other people. Sounds,
sights and smells seem to be “out there” in the world, not constructed in our
head.
The chemical senses
o Chemical senses are known as senses of smell and taste because they extract
info from the environment by means of direct chemical interactions.
o Molecules from external substances interact with receptor molecules in the
nose and mouth, resulting in generation of neural signals
o Olfactory chemoreceptors in the nose detect chemical molecules by
atmospheric currents, so the stimulating substance itself can be quite remote
from the perceiver.
o Taste, however, is a contact sense and so molecules must be in a solution
that makes direct contact with chemoreceptors
The body senses
o Body senses provide info about surfaces touching the skin (somatosensation),
about the position and movement of body parts (proprioception and
kinesthesis), about pain (nociception) and about position and movement of
body itself relative the external world (vestibular sense)
o All the above sensation and perceptions share significant aspects of neural
processing in terms of receptors pathways so they will be discussed together
in this chapter in the section on the somatosensory system, though argthey
are different sensory modalities.
o The vestibular senses is distinctively different from the other body senses in
terms of its neural processing, so will be discussed in a separate section.
o The sensory modality providing info about the position of body parts, served
by mechanoreceptors in the muscoskeletal system.
o Kinesthesis: the sensory modality providing info about the movement of body
parts, served by mechanoreceptors in the muscoskeletal system
Visual physiology
o When light strike the network of cells that line the inside surface of the eye it
initiates a chain of neural events in the visual system that leads, 100
milliseconds or so later, to a conscious visual experience.
o All the neurons responsible for seeing comprise the visual system, which can
be divided into three major component: the retina, the visual pathway and
the visual cortex
General principles
o Our perception of the world is direct, immediate and effortless and to
ourselves there is no hint of any intervening operations taking place in the
brain.
o Perception is seen as simple however, the apparent simplicity is reinforced by
the fact that our perceptions are almost always accurate
o Mistakes are rarely made when a face or voice needs to be identified, or in
judging the temperature of a cup of tea or navigating a flight of steps.
o Our perceptions nearly always agree with those of other people. Sounds,
sights and smells seem to be “out there” in the world, not constructed in our
head.
The chemical senses
o Chemical senses are known as senses of smell and taste because they extract
info from the environment by means of direct chemical interactions.
o Molecules from external substances interact with receptor molecules in the
nose and mouth, resulting in generation of neural signals
o Olfactory chemoreceptors in the nose detect chemical molecules by
atmospheric currents, so the stimulating substance itself can be quite remote
from the perceiver.
o Taste, however, is a contact sense and so molecules must be in a solution
that makes direct contact with chemoreceptors
The body senses
o Body senses provide info about surfaces touching the skin (somatosensation),
about the position and movement of body parts (proprioception and
kinesthesis), about pain (nociception) and about position and movement of
body itself relative the external world (vestibular sense)
o All the above sensation and perceptions share significant aspects of neural
processing in terms of receptors pathways so they will be discussed together
in this chapter in the section on the somatosensory system, though argthey
are different sensory modalities.
o The vestibular senses is distinctively different from the other body senses in
terms of its neural processing, so will be discussed in a separate section.
o The sensory modality providing info about the position of body parts, served
by mechanoreceptors in the muscoskeletal system.
o Kinesthesis: the sensory modality providing info about the movement of body
parts, served by mechanoreceptors in the muscoskeletal system
Visual physiology
o When light strike the network of cells that line the inside surface of the eye it
initiates a chain of neural events in the visual system that leads, 100
milliseconds or so later, to a conscious visual experience.
o All the neurons responsible for seeing comprise the visual system, which can
be divided into three major component: the retina, the visual pathway and
the visual cortex
