Cognitive processes

1. Engineering Psychology Cognitive processes perception – sensation – attention – thinking – imagination – memory – creativity – problem solving Jakub Jura Jakub.jura@fs.cvut.cz http://users.fs.cvut.cz/~jura/ing-psych/

2. What is Cognitive? • From latin cognoscere = getting to know • Distinguish emotional and rational • Descarte’s „Cogito ergo sum“. Mental processes mediate between stimulus and response.

3. Cognitive processes • Base Cognitive processes: • Perception • Sensation • Attention • Thinking • Imagination • Memory • Learning • Advanced Cognitive processes • Creativity • Problem solving

4. Sensation • Sensation is about sense organ and basic processes on this level. • Perception is about creating whole percept.

5. Sensation

6. Haptic sensibility • Tactile compasses • The brain – projection zone. • Skin surface and brain surface.

7. Sensation Delusions Lateral Inhibition Efect • Mach’s Strips

8. Blind spot • Close the right eye. Leave your head in the central position. • Look to the cross, by the left eye. • Approach your head to the paper. • The circle disappears in a given distance.

9. Negative afterimage

10. Perception • Perception is perception of diference. • Sensuals limits • Gestalt law • Multistable figures • Invariance in perception • Weber–Fechner law

11. Perception Delusionss Which of these circles is bigger?

12. Perception Delusionss • Effect of Contrast Lighter Darker

13. Perception Delusionss

15. Is anything here?

16. Gestalt Laws • Proximity • We tend to group nearby objects. • Similarity • We tend to group objects with similar properties • Closure • We are so accustomed to seeing closure that we sometimes close things that aren't.

17. Gestalt Laws • Good Continuation • We tend to assign objects to an entity that is defined by smooth lines or curves • Pregnantz • We tend to good shape

18. Experiment 2

19. Multistable perception • Mind separate figure and backgroun. • Unstably between two or more alternative interpretations. • Since you see both, you can’t see both. • Changing may be under control only partially.

20. Invariance in perception • Objects are recognized independent of rotation, translation, scale, elastic deformations, different lighting, and different component features.

21. Neisser's cycle of perceptionCognitive Ecology Actual world Object available information Samples Modify Schema of environment Exploration Locomotion and action Cognitive map Directs

22. Psychophysics • Ernest Heinrich Weber (1795–1878) • Gustav Theodor Fechner(1801–1887) • Stimulus Percept • Stimulus Sensation  Percept

23. Weber law • Ernest Heinrich Weber  (1795–1878) • Experiment with weight difference • Just noticeable difference (jnd) between two weights was approximately proportional to the mass of the weights • I = kw* I • I … Base intensity (Total weight) • I… Discrimination threshold (Weight difference) • kwConstatnt (Weber Fraction) • We can‘t perceive the intensity of stimulus directly, but in relation to the reference value.

24. Fechner law • Gustav Theodor Fechner (1801–1887) • Dependence of sense impression on the intensity of stimulus is logarithm. • P = k * ln (S) • P … percept • k … constant • S … stimulus

25. Experiment 1 • Dependence of sense impression on the intensity of stimulus • Sound • Light • Procedure: • Set intensity to basic level (L) • Increase intensity up to one degree (L+1) • Remember this degree and set intensity up to L+2, L+3, … L+n Impresion Sensum

26. Fechner law

27. Weber–Fechner Law • P = k * (S/S) • dP = k * dS/S, • P = k * ln (S/S0) • P … percept • k … constant • S … stimulus • S0 … lower possible stimulus

28. Weber-Fechner law • Weber-Fechner principle in the acoustics: • LI=10 log (I/I0) • Lp=20 log (pe/pe0) • L … Level of intensity • I … Intensity • P … Aacoustic pressure • I0, pe0 ... Minimal perceived value