1. Pattern recognition = perception Template theory  has problems Prototype theory  better Distinctive features theory  better

2. Structural theory Based on how your brain arranges features in the object your looking at Feature = part of a stimulus you are perceiving E.g., face  eyes, mouth, nose, eyebrows, etc. Further  eyes  circles, colors, etc.

3. More on structural theory Important thing = how the features relate to each other “T” = horizontal line + vertical line “L” = horizontal line + vertical line So, T and L have exactly same features So, important aspect = how the two features fit together

4. Geon theory Stands “geometrical ions” All objects made up of elementary particles (geons) Geometrical because they are basic shapes in 3 dimensions tube

5. More on geons We have in memory about 20-30 different geons Our mind divides objects into the geons that comprise it

6. Geon theory is structural We identify objects based on the relationships amongst the geons cup pail

7. Crux of the geon theory Point  arranging the two geons (cylinder and the rounded tube) in two different ways gives two completely different objects Arrangement that matters (structure) Geons can be stretched, pulled, rotated, etc.

8. Geon theory Biederman (1985) How do you know what a cup is? A cup is composed of two geons—a cylinder and the rounded tube—in a particular arrangement (knowledge in your memory) (look at examples on p.31)

9. What happens with incomplete objects? E.g., coffee cup with broken handle Biederman (1985): altered pictures of objects to make the objects incomplete or broken Easy to see cylinder Harder to See cylinder

10. Biederman (1985) Presented two types of objects (one broken where geons are still recognizable; other broken where geons not recognizable) (see p. 32) Flashed images on screen  people say out loud what the object was Results: geons visible  ~70% accurate Geons not easily visible  < 50% accuracy

11. Biederman experiment Conclusion: geons must be identifiable for you to perceive an object

12. Whole Report Procedure Viewed an array of objects in a very short period of time (~ 500 ms) Asking how many objects can you perceive in that short period of time? Write down what you saw (you “report” the “whole” display) In lab, average is about 4.5 out of 9

13. interpretation Obviously, whole report is a difficult task But, most people experience “seeing” all of the letters, but can’t write them down or report all of them Suggests that you CAN perceive or maybe partially perceive all, but can’t write them all down (maybe because you can’t remember them?)