PSYC105 Lecture Notes - Lecture 6: Saccule, Middle Ear, Semicircular Canals
1 Jun 2018
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Perception:
How many senses do we have?
• Sight (visual, eyes)
• Hearing (auditory, ears)
• Smell (olfactory, nose)
• Taste (gustatory, tongue)
• Touch (tactile/haptic, skin)
• A few more:
o Balance (equilibrioception, vestibular system)
o Body awareness (proprioception, joints)
o Heat (thermoception, skin/internal)
• Think of it as:
o Vision
o Audition
o The Chemical senses (gustation, olfaction)
o The body senses (somatosensation, haptics, proprioception,
equilibrioception)
• ESP (extra sensory perception) → makes no sense, no evidence that exists
Perception:
• We need to understand how we process the information from our senses
• It is the study of how we get information about our environment
• The only way we get information about our environment
• We can only directly perceive a small amount of the information in our
environment
Sensation vs. Perception –
• Sensation → detection of physical energy by the sense organs
• Perception → the brain’s interpretation of the sensory inputs
• BUT – more sensible to think of the whole sequence of events as the process
of perception (or of perceiving)
Sensory Integration?
• Sometimes information from 2 or more senses is ‘integrated’ by our brains
Outline and Objectives:
• Overview of perception
• Learn about senses we have
• Learn about how they work
Psychophysics –
• This refers to the scientific study of the subjective experience of perception
• The relationship between physical stimuli and psychology
• Psychophysics techniques enable researchers to take reliable measurement of
what people see, hear, feel etc. when exposed to particular stimuli
• Our understanding of perception depends on these techniques
find more resources at oneclass.com
find more resources at oneclass.com
Touch (Somatosensation):
• The various layers of skin contain a bewildering array of receptors with an
astonishing range of sizes and shapes
• We know very little about what they do
• Convey information about touch, temperature and ‘pain’
• Skin sensors – pain?
o Receptors in your skin which convert pressure into neural signals (and
therefore signal touch)
o Others convert heat energy into neural signals (and therefore signal
temperature)
o But there cannot possibly be receptors in your skin that respond to pain
because there is no pain ‘out there’ in the world for them to respond to
o Any stimulation if intense enough can cause pain
• Somatosensory cortex:
o Touch information is conveyed to the somatosensory cortex
o At the top of the brain
o It sits just behind the motor cortex
o More important parts of the body (in terms of processing touch
information) have larger parts of the somatosensory cortex devoted to
them
Taste (gustation):
• Taste receptors are in clumps – taste buds located on small projections on the
tongue called papillae
• Respond to chemicals dissolved in saliva
• Chemical specific
• So far only 5 different sorts have been confirmed in humans: salt, sweet, sour
and bitter and umami (savoury)
• Tongue maps:
o Traditionally, students have been taught that receptors responding best
to these four tastes are located in certain regions of the tongue
o This has been known to be WRONG since at least 1974, but for some
reason this misinformation survives in many textbooks
Smell (olfaction):
• Much of what we call flavour is due to the simultaneous activation of our
senses of taste and smell
• Sensory integration
• As in taste, only dissolved chemicals (in the mucus in the nose) can activate
the smell receptors
• Also as in taste, it seems as if certain smell receptors respond to particular
chemicals, and that all the smells we experience are some combination of the
activations of these primary smells
• There are at least seven primary smell receptors
• Many were discovered by investigating specific anosmias – smell blindnesses
• Odours activate receptors in the olfactory epithelium, at the top of nasal cavity
• These receptors synapse directly onto the olfactory bulb – a specialized part of
the brain for processing smells
find more resources at oneclass.com
find more resources at oneclass.com
