Sensation

1
Sensation
2
Sensation

• The process by which our sensory receptors and
  nervous system receive stimulus from the
  environment.

3
Perception

• The process of organizing and interpreting
  sensory information, enabling us to recognize
  meaningful objects and events.

4
Activity!

• I need two volunteers

5
Bottom-Up v. Top-DownProcessing
Bottom-Up See the shapes and figures first to
make up baseball players. You have no
preconceived notions going into the ball park.
Top-Down See the image as a whole and make
assumptions about it based on memory and
experience.
RED SOX WIN!
6
What if we could sense everything?
Life would hurt. So we can only take in a window
of what is out there. This is the study of
psychophysics relationship between physical
stimuli and our psychological experiences to them.
7
Absolute Threshold

• The minimum stimulation needed to detect a
  stimulus 50 of the time.

At what point can you recognize this man?
8
Absolute Threshold

• If something is OVER YOUR absolute threshold, you
  can sense it.
• If something is UNDER YOUR absolute threshold,
  you can not sense it.

9
The Mosquito Ring Tone!?!
10
Difference Threshold

• The minimum difference that a person can detect
  between two stimuli.
• Also known as Just Noticeable Difference

Can you see the difference between the images?
If you can the images are above your difference
threshold.
11
Webers Law

• The idea that, to perceive a difference between
  two stimuli, they must differ by a constant
  percentage not a constant amount.

I would notice if five pounds were added on the
dumbbells on the left, but I would not notice the
same five pounds on the bench press to the right.
12
Subliminal Stimulation

• Below ones absolute threshold for conscious
  awareness.

Does this work?

• Yes and No
• The effects are subtle and fleeting.

13
Popcorn
14
PAUL IS DEAD
15
In a childrens book???
16
Signal Detection Theory

• Predicts how we detect a stimulus amid other
  stimuli.
• Assumes that we do not have an absolute
  threshold.
• We detect stuff based on the situation.
• Examples

17
We do not perceive the world how it really is,
but as it is useful for us to perceive it.
18
Sensory Adaptation

• Diminished sensitivity as a result of constant
  stimulation.

Do you feel your socks or your underwear right
now?
19

• http//viscog.beckman.uiuc.edu/grafs/demos/15.html
  
• Left ½ of the room, count the number of times
  someone in a BLACK TEE SHIRT touches the ball.
• Right ½ of the room, count the number of times
  someone in a WHITE TEE SHIRT touches the ball.

20
Selective Attention

• The focusing of conscious awareness on a
  particular stimulus.

21
An example of selective attention is
Cocktail Part Effect ability to listen to one
voice among many.