1. Perception https://www.youtube.com/watch?v=QNeewhvw3bM

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

18. Auditory Illusions
If the sounds do not work click here for link.

19. Absolute Threshold
The smallest amount of a stimuli we can detect about half of the time.

20. Subliminal Messages Stimuli below our absolute threshold. Backmasking
Do you hear "Now he uses marijuana.“?
Stimuli below our absolute threshold.
Backmasking
25th frame
Do Subliminal Messages work?
Probably a placebo effect
Do you hear Pass the gun now. It kills the love, the love is cold”?
Do you hear “Ah, see me. I'm not too young”?
Do you hear"Play backwards. Hear words sung.“?

21. (Just Notable Difference) Difference Threshold
The smallest amount of change needed to detect in a stimulus before we detect a change.

22. Weber’s Law Computes the Just Noticeable Difference.
The change needed is proportional to the original intensity of the stimulus.
The more intense the stimulus the more change is needed to notice the difference.
8% for vision.

23. Perceptual Ideas

24. Signal Detection theory
Absolute thresholds are not really absolute.
Things like motivation or physical state can effect what we sense.
False Positives
False Negatives
My wife could sleep through a war, but if one of our sons even whimpers, she is up!!!

25. Top-Down Processing We perceive by filling the gaps in what we sense.
I _ant ch_co_ate ic_ cr_am.
Based on our experiences and schemas.
If you see many old men in glasses, you are more apt to process a picture of an old man (even when you may be in error).

26. Bottom-Up Processing Also called feature analysis.
We use the features on the object itself to build a perception.
Takes longer that top-down but is more accurate.
Click to see an example of bottom –up processing.

27. Figure Ground Relationship
Our first perceptual decision is what is the image is the figure and what is the background.

28. Gestalt Psychology
Gestalt psychologists focused on how we GROUP objects together.
We innately look at things in groups and not as isolated elements.
Proximity (group objects that are close together as being part of same group)
Similarity (objects similar in appearance are perceived as being part of same group)
Continuity (objects that form a continuous form are perceived as same group)
Closure (like top-down processing…we fill gaps in if we can recognize it)

29. Constancy
Objects change in our eyes constantly as we or they move….but we are able to maintain content perception
Shape Constancy
Size Constancy
Brightness Constancy

30. Perceived Motion Stroboscopic effect (flip book effect) Phi phenomenon
Autokinetic Effect (if people stare at a white spotlight in a dark room, it appears to move.)

31. Depth Cues Eleanor Gibson and her Visual Cliff Experiment.
If you are old enough to crawl, you are old enough to see depth perception.
We see depth by using two cues that researchers have put in two categories:
Monocular Cues
Binocular Cues

32. Monocular Cues
You really only need one eye to use these (used in art classes to show depth).
Linear Perspective
Interposition
Relative size
Texture gradient
Shadowing

33. Binocular Cues We need both of our eyes to use these cues.
Retinal Disparity (as an object comes closer to us, the differences in images between our eyes becomes greater.
Convergence (as an object comes closer our eyes have to come together to keep focused on the object).