1. Pattern Recognition Nick Lund Attention and Pattern Recognition

2. Introduction Pattern recognition has been defined as ‘the ability to abstract and integrate certain elements of a stimulus into an organised scheme for memory storage and retrieval’ (Solso,1998).

3. Features of pattern recognition Five principles(Solso,1998): 1.Quickly and accurately. 2.Recognise and classify unfamiliar objects. 3.Accurately recognise shapes and objects from different angles.

4. Features of pattern recognition 4.Identify patterns and objects even when partly hidden. 5.Recognise patterns quickly,with ease,and with automaticity.

5. Features of pattern recognition Template matching theories Feature analysis Prototype theories

6. Top-down and bottom-up processing An examination of the theories of pattern recognition raises the question of whether pattern recognition involves top-down or bottom-up processing.

7. Bottom- up process Template matching theory Geons (Structural- description theory) Feature theory Prototype theory

8. Template matching theory External stumuli matches internal template Vast numbers of templates are stored Templates are created by experience E.x.: visit Russia

9. A A A A Problems: 1) Only occurs when there’s a one-to-one match Payne and Wenger (1998)

10. 2) Where are all these templates stored? 3) Slow process Ex.: recognize 1000-1500 letters a minute 4) To recognize new variations of a pattern (Solso, 1998)

11. Geons (Structural- description theory) Biederman (1987) Limited number (24) of simple geometric shapes , or geons for us to analyse patterns. Ex.: mug v.s. bucket

12. Geons

13. Advantage: Recognize pattern from different angles Disadvantage: Can’t explain why we recognize a particular chair. Ex.: My face v.s. my friend’s face

14. Feature theory Patterns are recognized by analysis of the individual features of the pattern. Ex.: MANGO M A

15. Four stages of pattern recognition Image demons: record the image and pass it Feature demons: analyse the image for specific feature Ex.: Pandemonium model (Selfridge, 1959)

17. Cognitive demons: detect the present feature and shout Decision demons: pick up the loudest feature

18. Advantage: More flexible than template theory Ex.: A , regardless of size, shape or orientation Neisser: M -> N H M V -> longer RT (more distracter) M -> O M Q G -> shorter RT

19. Disadvantage: Fail to account for the effects of context and expectations Ex.: Two experiments which can’t explain feature theory Fail to detect “t” in “the” (Healy) Teacup, eyebrow -> cup, eye ; eac, ebr (Inhoff and Topolski)

21. Disadvantage: Some questioned the existence of hypercomlex cells How specialized they need to be? Run out of cells

23. Disadvantage: can’t explain the effect of context (Eysenck, 1993) old woman v.s. young lady B, R, P have similar prototype

24. Top-down processing Word superiority effect Rat-Man demonstration

25. Rat-Man demonstration

26. Rat-Man demonstration

27. Rat-Man demonstration

28. The effect of context

29. Summary Pattern Recognition Theories Template matching Feature analysis Prototype Central-tendency Attribute- frequency

30. Summary Word superiority effect Rat-Man demonstration Pandemonium model Geons Top-down processing Bottom- up processing

31. THE END