1. Unit 4 Sensation and Perception
Module 16 The Basic Principles of Sensation and Perception

2. How well did you read?!
Sensation is to _____________ as perception is to ________________.
a) Recognizing a stimulus; interpreting a stimulus
b) Detecting a stimulus; recognizing a stimulus
c) Interpreting a stimulus; detecting a stimulus
d) Seeing; hearing

3. What sensory information is available in this image?

4. When we look at the image first for sensory information, what type of processing are we using?
In this situation we are using bottom-up processing. (aka. Stimulus driven processing)
sensory analysis that starts at the entry level, with the actual stimulus around us

5. Bottom-up Processing begins with Sensation.
Sensation is the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment

6. What do you see in the image?

7. Now looking at this image as a whole, drawing on your own experiences and expectations, what type of processing are you using?
This is Top-Down processing. (aka. Conceptually driven processing )
In this process we construct perceptions based on our past experiences and expectations.

8. Top-Down Processing begins with Perception.
Perception is the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events

9. I cdnuolt blveiee taht I cluod aulaclty uesdnatnrd waht I was rdanieg
I cdnuolt blveiee taht I cluod aulaclty uesdnatnrd waht I was rdanieg. The phaonmneal pweor of the hmuan mnid, aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it dseno't mtaetr in waht oerdr the ltteres in a wrod are, the olny iproamtnt tihng is taht the frsit and lsat ltteer be in the rghit pclae. The rset can be a taotl mses and you can sitll raed it whotuit a pboerlm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe.

10. Selective Attention/Inattention
Selective Attention: Focus on a particular stimuli
Cocktail party effect
Inattentional blindness: failing to “see” visible stimuli when attention is elsewhere
Change blindness
Choice Blindness:
food choice example

11. Transduction Convert 1 form of energy to another
Receive sensory information using receptor cells
Transfer stimuli into neural impulses
Deliver neural info to the brain
Psychophysics: study of the relationship between physical characteristics of stimuli such as intensity and our psychological experiences of them

12. Absolute Threshold
The minimum stimulation necessary to detect a particular stimulus 50% of the time
Are you surprised by any of these thresholds?

13. How Well Can you Smell?
Why could some of you sense the smell before others?
What biases could be in play?
Absolute threshold varies from one person to another and according to signal detection theory can also vary within a person depending on his or her psychological state.

14. Signal Detection Theory
a soldier on duty is more like to hear an otherwise unnoticeable sound during wartime than peace.
Exhausted parents of a newborn will notice a faint whimper from their child but fail to notice louder unimportant sounds.

15. Difference Threshold
Does anyone remember from your reading what difference threshold is?
The minimum difference a person can detect between two stimuli.
What is another name for it?
Just Noticeable Difference or JND

16. Weber’s Law
The principle that says that the difference threshold is not a constant amount but some constant proportion of the stimulus.
What does this mean?
Weight of quarters example

17. Sensory Adaptation
If exposed to a stimuli that doesn’t change, we become less aware of it.
Nerve cells actually fire less frequently
Except eyes….why?