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- Johansson, B., et al.
(author)
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Detection thresholds : Effect of stimulus presentation order and addition of blanks I. Odor of pentanal and hexanol
- 1973
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In: Lebensmittel-Wissenschaft + Technologie. - 0023-6438 .- 1096-1127. ; 6:4, s. 115-122
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Journal article (peer-reviewed)abstract
- Detection thresholds for the odor of pentanal and hexanol were determined using a method of constant stimuli with single sample presentations. The effects of addition of blanks and of order of sample presentation (ascending, descending, randomized) were studied for grouped threshold values. Moreover, differences between groups of subjects with different frequencies of false alarm, and between males and females were studied. Preceding blanks, added to the ascending series, but unknown to the subjects, caused a significant decrease in threshold values for all groups of subjects. The decrease was probably mainly an anticipation effect caused by the information to the subjects. For pentanal, the ascending concentration order gave a significantly lower threshold value than the descending or randomized orders, between which there was no significant difference. For hexanol, in general, the differences among presentation orders were not significant. A sufficient explanation for this unexpected difference between the two compounds cannot be given. For each compound, subjects with lower frequencies of false alarm had, in all experimental series, significantly higher threshold values than subjects with higher frequencies. Females had significantly lower threshold values than males. © 1973 Forster-Verlag AG, Zürich.
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