1. Upon entering the Odorama event space, the attendees were invited to judge which of the two vases (Scents Apparatus, by Margherita Soldati) fit best with the odour it contained. They were then asked to note their preferences along with their age and gender on a numbered slip of paper. Attendees were deliberately not told that there would be a later memory experiment, to stop them from trying to learn the smells (!).
2. During the talk given by Prof. Dr. E.P. Koster, the attendees received five odours on (the two they had smelled in the vases and three new smells) on numbered blotting cards. The participants were asked to indicate for each smell whether it was one they had smelled in the vases or not and to indicate how sure they were of their answer.
3. It was to be expected that the participants were better at detecting which smells they had not smelled before ('correct rejection'), than at detecting the ones they had smelled before in the vases ('hits').
The results of the experiment confirmed the above-mentioned theory. The percentage of 'correct rejections' (68.71%) was indeed higher than that of the 'hits' (62.24%), and people were on average more sure about their 'correct rejections' (average 4.25 on a five point scale from 1=not certain at all, to 5=extremely sure) than about their 'hits' (average 4.12).
The differences between the percentages of the 'hits' and 'correct rejections' and the differences between the certainty indications were smaller in this Odorama group than usual. It could be that this specific group had too much interest in olfaction! In this sense, the Odorama group is exceptional and this is also illustrated by the overall very high degree of certainty attached to answers (on average, above 4.12), whereas in 'regular' groups it is between 2 and 3.
Also worthy of note is that on average, the Odorama group had a slight tendency to overestimate its olfactory memory capacity. The average certainties with which people made mistakes (claiming that they had smelled one of the new smells in the vases) was at an average of 4.32, while total misses (claiming that they had not smelled the vase odour before) was at an average of 4.19. Amusingly, these were higher than the certainties for their corresponding correct answers (respectively, 4.25 for 'correct rejections' and 4.12 for 'hits').