Vidna kognicija IV

1. Vidna kognicija IV Danko Nikolić

2. Sinestezija

3. Sinestezija Grčki:(syn)ujedinjenje + (aesthesis)osjeti “Ujedinjenje osjetila”

4. Ramachandran & Hubbard, 2003.

8. Osnovne karakteristike sinestezije • Osjetna iskustva izazvana neuobičajenim podražajem • Živo i detaljno perceptivno iskustvo • Automatska asociacija; Nema voljne kontrole • Od ranog djetinjstva (“otkad znaju za sebe”) • Asocijacije se (uglavnom) ne mijenjaju vremenom

9. Poznate osobe sinestete • Wassily Kandinsky • Vladimir Nabokov • Franz Liszt • Nikolai Rimsky-Korsakov • Nikola Tesla • Richard Feynman

11. Induktor Dodatno iskustvo Sensorno iskustvo Sensorno iskustvo

12. Induktor Semantička reprezent. Dodatno iskustvo Drugačiji model Sensorno iskustvo Sensorno iskustvo

16. Test for eccentricities: 1 Report that Synaesthesia disappeared at higer eccentricities: An indication for a perceptual aspect of synaesthesia We retested our synaesthetes: none showed a dissapearence of synaesthesia at high eccentricities • All our synaesthetes reported, that letters and digits do change color depending on their • meaning, e.g, O and 0. • So we tested our synaesthetes with • 3 Homographs: • Montage (Installation)/Montage (Wochentage) • Collagen (Plural von Collage)/Collagen (Bindemittel) • Heroin (Suchtmittel)/Heroin (Heldin)

17. Dixon et al 2000 -one synaesthete vs. control -arithmetic test, where the concept of a digit can induce synaesthesia

18. Rich an Mattingley 2003 Ambiguous stimuli • 14 synaesthetes vs. 14 controls • first, a stroop test was performed • next, they asked the subjects to attend to either the global • or the local stimuli only • => the interference effect was significantly reduced, compared • to the first experiment

22. Palmeri et al., PNAS, 2002 However, Edquist et al. (2006) could not replicate these results on a larger group of synaesthetes. [Oben sehen Sie eine Studie aus dem Jahr 2002. Hier war die Aufgabe, in dem schwarz-weiss Bild das Ziel, in diesem Fall die zwei, zu finden. Da der Proband das Ziel farbig sah (rechtes Bild) war er schneller, als die Vergleichsgruppe (sog. “pop out” Effekt). Dieses Ergebnis konnte allerdings 2006 nicht wiederholt werden.]

23. Serial search Time Pop out Set size Serial visual search

24. Shape search task • same 2 synaesthestes • 40 controls • Display: 5´s scattered randomly on a white screen, among • these 2´s forming a global shape like a triangle (4 shapes) • - each stimulus was presented for 1 s Result: The synaesthetes were significantly (81.25%) better than the control (59,4%)

26. A crowding study

29. Stroop zadatak Zelena Zelena kongruentna nije kongruentna Stroop, 1935

30. Result: Naming the congruent colour is faster than naming the incongruent colour • Indicates automatic and involuntary processing • No effect with words without a colour meaning: CAR CAR

31. Stroop task: Grün, Rot, Blau, Gelb vs. Grün, Rot, Blau, Gelb Conclusion: reading is an automatic process

32. Stroop u sinesteziji • Zadatak: “Imenuj stvarnu boju slova.” • Resultat: Sinestete imenuju pravu boju slova brže ako ta boja odgovara sinestetskoj boji (kongruentne boje) nego ako se te dvije boje razlikuju (ne kongruentne) (e.g.,Odgaard et al., 1999).

33. Result: Synaesthetes are faster in naming the true color if this color is the same as (congruent to) synaesthetic than if these colors are different (incongruent) (e.g.,Odgaard et al., 1999).

34. Međutim: • Tipični Stroop zadatak ne dokazuje da synaesthesia proizvodi stvarna perceptualna iskustva. • Npr. Stroop efekt se može očekivati čak i za obične asociacije, “Znam da je limun žute boje”.

35. Studija I: Priroda dodatnih iskustava Induktor Dodatno iskustvo Sensorno iskustvo Sensorno iskustvo

36. Colour-opponency in synaesthetic experiences

37. Activation in colour-specific areas • fMRI provided evidence for an activation of the colour specific areas V4/V8 of the visual cortex during synaesthetic color experience. (e.g., Hubbard et al., 2005; Sperling et al., 2006) • This suggests the involvement of early stages of visualprocessing

38. Colour opponency Theory • First stage: Receptor stage consists of the three photopigments (blue, green and red cones). • Second stage: neural processing stage where the colour opponency occurs.

40. Krug boja: Sinestetska boja Nezavisna boja Oponentna boja

41. + + - or - Color-opponency in synesthesia • Test color opponency in synaestetic experiences by Stroop task • Stroop effect can occur for non-synaesthetic associations. For example, “I know that lemon has yellow color”. • Typical Stroop task is not a direct proof that synaesthesia produces a real perceptual-like experience.

42. Isteboje Oponentne boje Ne oponentne boje + Oponentneboje Ne oponentneboje + Syn. Real Syn. Real Syn. Real - - - - - - Sem. Real Sem. Real Hipoteze • Grafem-boja sinestezija • Semantičke asociacije (npr. žuti limun)

43. Dizajn:

44. Design • 6 synaesthetes: 2 projectors, 4 associators • 5 graphemes per participant, presented in three colours plus baseline condition • Each grapheme was presented 10 times; a total of 200 trials • 2 control participants per synaesthete, matched by gender and age

45. Six synaesthetes:

46. Distribution of colors

47. Synaesthetes (n=6) Results Control subjects (n=12) p=0.89 p=0.005

48. Individual synaesthete subjects

49. Individual graphemes for one subject

50. Conclusions • Reaction times for incongruent colours were overall slower than the congruent condition • Reaction times for the congruent colour showed a facilitation • Strong indication that synaesthesia arises within colour-opponency