1. Confusing contours & pieces of glass Rob van Lier, Tessa C.J. de Wit, Arno Koning Presented by Nick van der Poel

2. Contents Introduction Experiment 1 Results 1 Experiment 2 Results 2 Conclusion & Discussion

3. Introduction Albert Michotte (1964) Kanisza square

5. Experiment 1 12 participants (students)

7. Experiment 1 12 participants (students) ‘Are the grey bars straight or indented?’ 256 trials per participant

8. Results 1

9. Experiment 2 17 participants (students) Same stimuli and procedure as in Exp 1 ‘What is the (possible) direction of shift?’

10. Results 2

12. Conclusion & Discussion Proportion incorrect judgements higher for the illusory surfaces Control group had many incorrect judgements Ramachandran’s checkboard illusion Attention and fixation