SENSATION AND PERCEPTION

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SENSATION AND PERCEPTION

• MCGONIGLE
• INTRO TO PSYCHOLOGY

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Example of Determining Factor

• Sentry at wartime
• Sentry at peacetime
• Who will be more likely to sense danger?

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Sensory Adaptation

• Imagine yourself at a bonfire, marshmallow roast,
  what happens to the faces in the background after
  a while?
• What animals see better in the night time as
  opposed to day? Why do you think this is true?

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Absolute Threshold

• Weakest amount of a stimulus that can be sensed.
• Dogs can hear certain whistles that we can not
  hear.
• Biological Psychological factors determine
  different thresholds.

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Difference Threshold

• The minimum amount of difference that can be
  detected between two stimuli is known as the
  difference threshold.
• Dark blue/ Navy blue could you tell the
  difference? Stang baseball hats- maroon?

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Signal Detection Theory

• Method of distinguishing sensory stimuli that
  takes into account not only their strengths, but
  
• Setting
• Physical state
• Mood
• Attitudes

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Eye
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Sensory Adaptation

• We become more sensitive to weak stimuli such as
  the faces around the fire.
• We become less aware of the heat of the fire or
  the sound of the wood burning or the smell of the
  marshmallows.
• Attleboro apartment near commuter rail

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Threshold Receptors

• Vision Rods and cones in the retina.
• Hearing Hair cells of the inner ear.
• Smell Receptor cells in the nose.
• Taste Taste buds on the tongue.
• Touch Nerve endings on the skin.

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Light

• Think of a rainbow/ prism
• What colors are most brilliant to you?
• Main colors of spectrum (Roy G Biv)
• Red, Orange, Yellow, Green, Blue, Indigo, Violet.
• Not visible - Infrared and ultraviolet.

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Eye

• Amount of light that enters the eye is determined
  by the size in the opening in the colored part of
  the eye. (pupil)
• Pupil dilation discussion
• Lens adjusts to the distance of objects by
  changing its thickness.
• FST why do people squint? Eye glasses/ contac
  lens..

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Human Eye (contd)

• Retina sensitive surface in the eye that acts
  like film in a camera. Made up of neurons not
  film.
• Photoreceptors once the light hits the
  photoreceptors, a nerve carries the visual input
  to the brain.
• Blind spot Where optic nerve leaves the eye 4-3.
  

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Eye ( last slide)

• Rods and Cones Rods are sensitive only to the
  brightness of light.
• Rods allow us to see in black and white
• Cones allow us to see in color.

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Visual Acuity

• Sharpness of vision is called visual acuity.
• Snellen Vision Chart 20/20
• Nearsighted, Farsighted. (Myopia, Hyperopia)

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Snellen Chart

• T E
• P V L

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Snellen Chart

• H C O E
• H P D N L Z A

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Snellen Chart

• D V H T L U
• E V O C U C
• P C Y L H N

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Snellen Last

• P C Y L h D v
• Dont squint!!!!!!

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Color Circle

• Each color has a complementary partner
• Discussion of Traffic Lights
• Why are school buses yellow??

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Afterimage/ Color Blindness

• Afterimage Of a color is its complementary
  color. ( USA Flag)
• Color blind unable to distinguish color due to
  an absence of or malfunction in the cones.
• Total Color blindness is very rare..
• Socks Black socks / Navy blue hard for men.

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Hearing

• Pitch How high or low a sound is depends on its
  frequency or of cycles per second.
• AI term used often..
• More cycles per second, the higher the pitch.
• Womens voices higher pitch than men, shorter
  vocal cords.

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Loudness

• Loudness determined by the height, or amplitude
  , of sound waves.
• Higher the amplitude the louder the sound.
• Loudness is measured in decibels. ( 0 watch
  ticking 20 away in a quiet room)

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Ear

• Shaped to capture sound waves, the outer ear is
  what we see.
• Eardrum thin membrane that vibrates when sound
  hits it.
• Transmits sound to the three bones in the ear. (
  hammer, anvil, and stirrup)

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Cochlea

• Latin for Snail ( Its shape) in the inner ear.
• Contains fluids neurons that move in response
  to vibrations of the fluids.
• Movement - Generates neural impulses that are
  transmitted to the brain.
• Auditory nerve transmits this message.

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Deafness

• Conductive Deafness Occurs because of damage to
  the middle ear.
• Sensorineural deafness Caused by damage to the
  inner ear. Neurons in cochlea are destroyed or
  damage to auditory nerve.
• What occupations would experience sensorineural
  deafness?

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Other Senses Smell Taste

• Dogs incredible sense of smell..
• Helen Keller ( 90)
• Onion/ Apple w/out smell???
• Odors are detected by neurons in each nostril.
• Receptors send info to the brain via the
  olfactory nerve.

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Taste

• 5 Taste Buds
• Sweetness, Sourness, Saltiness, Bitterness, Umami
• Without a sense of smell, our sense of taste can
  be compromised..

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Skin Senses

• Some are more sensitive than others
• P.91
• Fingertips
• Lips
• Cheeks

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Less sensitive to touch

• Shoulders
• Thighs
• Calves

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Temperature

• 98.6
• Neurons beneath the skin
• Hot day- receptors for warmth fire
• Cold day- receptors for cold fire
• Adjustment cold water after a while
• NE Patriot fan vs. Miami Dolphin fan !!!

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Pain

• Not all areas are equally sensitive to pain.
• Pain point of contact 1st.
• Pain - sent to the spinal cord 2nd.
• Pain now enters the thalamus in the brain.
• Pain ends in the cerebral cortex.

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Gate Theory

• Gate Limit
• Only a certain amount of info can be processed at
  one time.
• Rubbing the area can transmit sensations to the
  brain that compete w/ pain.
• Western Movies Bite the bullet

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Body Senses

• Vestibular sense Tells you whether you are
  physically upright w/out using your eyes. (
  gymnasts) - role of ears!
• Kinesthesis sense that informs people about the
  position and motion of their bodies.
  (kinesiology)

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Perception

• Closure Figure 4-10- Tendency to perceive a
  complete or whole figure even when there are gaps
  in what your senses tell you.
• Figure-Ground Perception Vase vs. 2 faces. Is
  the perception of figures against a background

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Perception ( Contd)

• Proximity ( 6 lines)
• Similarity ( xs os)
• Continuity ( wavy lines)
• Common fate ( people running together)

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Stroboscopic Motion

• Page 95- give illusion of motion (cat)
• Illusion of motion produced by showing the
  rapid progression of images or objects that are
  not moving at all.
• Little picture books- flipped to look like motion
  pictures.

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Visual Illusions

• Muller- Lyer illusions- which line is longer?
• Ponzo illusion lines appear to be coming
  together.
• Rule of size constancy. ( looking at people from
  a plane)

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Quiz Thursday

• Taste Buds
• Roy G Biv
• Rods Cones
• Lens Retina
• Absolute Threshold
• Difference Threshold
• Types of Deafness
• Bones in the Ear
• Decibel levels