1. Chapter Five
Sensation and Perception

2. Sensation vs. Perception
Sensation –What comes
into our body through our
sensory organs
Perception –What our brain
does with that information

3. A Little Test
• Unscramble the words Activity

4. The Expectancy Effect
• Our expectations (i.e.,
preconceptions about
what we are supposed to
perceive) can influence
our perception.
• We just proved this
through our
experiment!
• (80-90% of students)

5. How Do We Study Sensation?
Psychophysics
• Study of the
relationship between a
physical stimulus and
your perception of it.
• Concerned mostly
with physical
attributes of the
stimulus (e.g., amp &
loudness).
Gustav FechnerGustav Fechner
Father of Psychophysics

6. In other words…
Psychophysics: The point
• To learn about our senses by
pushing them to the limits
Example: the auditory system
• – Play a sound very quietly
• – Eventually it’ll be so quiet, you may not be
able to hear it
• – Absolute threshold: the loudness that people
say they can hear the sound 50% of the time

7. Sensory Adaptation
• Do you feel your clothes if they are still?
• How about hearing a sound that hums in
the background consistently?

8. How do we know that we share the
same reality?
• Color blindness
• Blindness
• Deafness
• Schizophrenia
“There is no reality.
There is only
perception.”

9. Sensory ProcessesSensory Processes
 Visual information processingVisual information processing
• Feature detectionFeature detection
• Parallel processingParallel processing
 Color visionColor vision
• HueHue
• SaturationSaturation
• BrightnessBrightness
• Color constancyColor constancy
p. 74p. 74

10. Sensory ProcessesSensory Processes
 Hearing (audition)Hearing (audition)
• Sound wavesSound waves
 AmplitudeAmplitude
O decibels – absolute thresholdO decibels – absolute threshold
85+ - produce hearing loss85+ - produce hearing loss
140+ - rock bands140+ - rock bands
• Locating soundsLocating sounds
 Sound shadowSound shadow
 EcholocationEcholocation
A demonstrationA demonstration

11. Sensory ProcessesSensory Processes
 Smell (olfaction)Smell (olfaction)
• Age and sex differencesAge and sex differences
 Taste (gustation)Taste (gustation)
• Taste budsTaste buds
• MicrovilliMicrovilli

12. What’s that Smell Activity???

13. Flavor Activity

14. Attention and PerceptionAttention and Perception
**Unattended stimuli and pop-out stimuli**Unattended stimuli and pop-out stimuli
• Cocktail party effectCocktail party effect
• Pop-out stimuliPop-out stimuli
**Multi-tasking**Multi-tasking
• http://http://youtu.be/xO_oEGHWSMUyoutu.be/xO_oEGHWSMU

15. Theories of PerceptionTheories of Perception

16. Theories of PerceptionTheories of Perception

17. Sensation and Perception - intro.ppt © 2001 Laura Snodgrass, Ph.D.

18. Homework
• Read Chapter Six
• See you Thursday!