Sensation and Perception

1
Sensation and Perception

• Unit 3

2
Definitions

• Sensation what occurs when a stimulus activates
  a receptor
• Perception -how we select, organize, and
  interpret this information
• Sensation provides the raw information that
  perception constructs into our experiences
• Receptor cells are activated by energy to send
  messages to the brain
• Transduction is the process of converting energy
  into a chemical code

3
Fact or Falsehood?

• On a clear, dark night we can see a candle flame
  30 miles away.
• Advertisers are able to shape our buying habits
  through subliminal messages
• Constant eye movements prevent our vision from
  being seriously disrupted
• The retina of the eye is actually a piece of the
  brain that migrates to the eye during early fetal
  development

4

• If we stare at a green square for a while and
  then look at a white sheet of paper, we see red.
• People who live in noisy environments are more
  likely to suffer from high blood pressure,
  anxiety, and feelings of helplessness.
• Touching adjacent cold and pressure spots
  triggers a sense of wetness
• People who are born without the ability to feel
  pain usually die by early childhood.
• If we close our eyes and hold our nose, we cannot
  taste the difference between an apple and a raw
  potato.
• Pleasant scents can boost workers performance.

5
Absolute Threshold

• Absolute threshold is the minimum level at which
  we recognize the energy/stimulation. It can very
  based on level of stimulation.
• Vision a candle flame seen from 30 mi on a
  clear, dark night
• Hearing The tick of a watch from 20 ft. in very
  quiet conditions
• Taste 1 g (.0356 oz) of table salt in 500 L (529
  quarts) of water
• Smell 1 drop of perfume diffused throughout a
  three-room apartment
• Touch The wing of a bee falling on the cheek
  from a height of 1 cm

6
Adaptation

• Adaptation is the adjustment in our senses to the
  average level of stimulation
• Vision staring at the sun/getting up in the
  morning
• Hearing air condititioner
• Taste salty peanuts
• Smell Bath Body Works
• Touch Mosh pit
• Think of the similarity to what you learned about
  neurons and action potentials

7
Difference Threshold

• Difference threshold is the smallest change in
  stimulation that is detected
• Add 1 lb to 5 lbs
• Add 1 lb to 100 lbs
• Webers law states that the difference threshold
  is always a fraction/proportion of the original
  stimulus
• .3 change in sound
• 20 change in taste
• 2 change in weight

8
Subliminal Perception

• Events occur below our level of awareness
• Experiments
• Competitive vs. neutral messages before a sports
  competition
• Honesty vs. hostility before neutral situation
  read to the group
• http//www.ciadvertising.org/student_account/sprin
  g_01/adv391k/hjy/adv382j/1st/application.html

9
Extrasensory Perception

• Ability to perceive or acquire information beyond
  the normal senses
• Clairvoyance awareness of an unknown object or
  event
• Telepathy knowledge of someone elses thoughts
  or feelings
• Precognition foreknowledge of future events
• Currently no scientific support