1. Poggendorf Lab Visual Perception and Visual Illusions Relates to other vision labs, Stroop and RPS –Prism goggle lab was an optical illusion, different than a visual illusion (eye/mind distinction)

2. Two Different Views of Visual Perception and Psychology in General Look for organizational principles Perception is an organized whole Whole (does not equal) Sum of Parts Bottom Up: StructuralistsTop Down: Gestaltists Look for the “building blocks” of a given phenomenon The “building blocks” of perception are sensations Whole = Sum of Parts

3. The Gestaltists Used Illusions to Show that Perception was Organized Subjective Contours The Zollner Illusion The Necker Cube The Poggendorff Illusion

4. The length and width of these two tables is actually the same!

5. The black dots are phantom

6. Can you see the Dalmatian?

7. These Monsters are the same size… Illusion of converging lines toward the horizon

8. Mueller-Lyer Illusion: The lines are all the same length

9. Café Wall Illusion: The color and dis-alignment of the bricks causes the lines to look wavy. They are actually parallel.

13. Align the “upper half” of a Poggendorff illusion line with bottom half so that there appears to be one continuous line through the box Deviation from the “actual” straight line is the Dependent Variable -measured by points Your Task: The Width of the Box, The Angle of the Line, and Practice are the Independent Variables Width Angle Deviation

14. Some Results (from a previous class)

15. And the ever present Practice Effect In HOT PINK!