Introduction to Psychology

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Introduction to Psychology Suzy Scherf Lecture
8 How Do We Know? Sensation and Perception
Early Memory
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What are Our Senses For?
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What are Our Senses For?
All the senses designed to -
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Transduction by Design
1. Eyes designed to transduce
2. Auditory apparatus designed to transduce
3. Tongue and Olfactory apparatus designed to
transduce
4. Sensory receptor in the skin, organs, joints,
bones all designed to transduce
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Transduction by Design
If we thought that a sixth sense existed, we
would have to figure out -
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What are Our Senses For?

• Our senses have evolved to -

• Our senses provide the necessary information -

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Vision

• Processes electromagnetic energy

• Electromagnetic energy travels -

• Vision is a -

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Visual Spectrum of Light

• Includes wavelengths of light that -

• Includes wavelengths of light that -

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Anatomy of the Eye
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Photoreceptors in the Retina
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Visual Pathway
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Visual Pathway
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Audition

• Objects produce vibrations that -

• Auditory systems detect -

• Analysis of these sound waves -

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Ear Apparatus for Hearing
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Auditory Receptors
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Spectrum of Audible Sound Waves

• Provide a source of info -

• Low freq. waves travel ________ than short freq.
  waves

• A consequence of natural selection

• Elephants vs. Insects

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Chemical Senses

• Seen in all animals and are likely to be most
  important of the senses and the first to evolve

• Animals that live in the sea -

• Smell evolved when -

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Taste

• Only a contact sense -

• Provides animals with -

• Not only via the tongue -

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Taste
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Taste
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Taste

• Salty

2. Sweet
3. Sour
4. Bitter
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Smell

• ________ sense

• discerning chemical composition of substances -

• provides animals with an ability to detect

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Smell and Taste
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Sensory Apparatus for Smelling
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Sensory Apparatus for Smelling
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Somatosensory

• Detects -

• Specialized response to extremes -

• Pain

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Somatosensory Receptors
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Vestibular

• Sensitive to -

• Provides info about -

• Liquid in ear canals -

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Ear Apparatus for Vestibular Sense
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Human Vestibular Cortex and Out-of-Body
Experiences
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Elements of all Sensory Systems
1. Specialized sensory receptors that are
designed specifically to transduce a particular
kind of physical energy.
2. Specialized neural circuits that channel the
sensory information through the Thalamus to the
relevant Primary Sensory Cortical Areas
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Elements of all Sensory Systems
3. Maps at all levels of the brain hardware that
represent and organize the sensory information so
that it will mirror the physical world

• Including

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What is Perception For?

• ____________ sensory information

• Perception reflects the real world -

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What is Perception For?

• Designed to -

• Tight link with memory -

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Perception Designed to Guide Action

• Example How do we avoid bumping into things?

Possible answers
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Perception Designed to Guide Action

• Example How do we avoid bumping into things?

Actual answer
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Perception Designed to Guide Action

• Example How do we avoid bumping into things?

Size of image on retina (mm)
Distance from eye (meters)
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Perception

• Most of the time perception leads animals to -

• Perceptual mechanisms have evolved to -

• Even though perceptions are derived in large part
  from transduced info that has been re-represented
  in the brain.

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Sensory and Perceptual Systems are Modularized

• They are specialized to -

• Most of these systems have -

• Early deprivation of activity -

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Sensory and Perceptual Systems are Modularized

• Then passed on to higher-order regions of the
  brain -

• Parietal Lobe
• Temporal Lobe
• Frontal Lobe

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Dorsal Pathway -
Ventral Pathway -
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Integrating Perceptual Info

• When info processed and sent onto other systems
  for analysis - things can go awry.

• The case of Synesthesia

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Synesthesia

• Syn ___________ aisthesis ___________

• Means joined sensation -

• Music that looks like shards of glass

• Involuntary, but triggered by stimulus -

• Can be temporarily induced by -

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Synesthesia

• Tends to run in families, more women than men,
  and left-handed

• Excellent memory but poor spatial and
  mathematical skills

• Prone to unusual experiences like those of
  temporal-lobe epileptics - déjà vu, clairvoyance

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Synesthesia - Neural Basis
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Synesthesia

• May reflect a holistic process of perception that
  is not usually available to consciousness - but
  is totally normal - some evidence in kids

• Clearly demonstrates how sensation, perception,
  emotion, and memory working together to interpret
  our environment

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What do We do with Perceptual Info after We
Integrate and Act?

• Keep track of it for future use?

gt
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Memory - Whats it for?
Why dont we remember everything about all our
past experiences?
1.
2.
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Memory - Whats it for?
Why dont we remember everything about all our
past experiences?
3.
4.
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Memory - Whats it for?
For our memory systems to function efficiently we
have to forget much of our experience or ignore
it all together (ie. never encode it).
Example Change Blindness
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Change Blindness - Whats Important for Us to
Remember?