Department of Physics, Chemistry and Biology (IFM)

250 human females and 250 human males between 18 and 40 years of age agreed to participate in this study. This age group has been shown to be homogenous in their olfactory performance.

The three odorants that were used were as previously stated Bourgeonal, Helional and N-pentyl acetate. For each of these three odorants a dilution series in twelve steps was prepared using the solvent diethyl phtalate or DEP. Additionally 24 bottles that only contained the solvent with the same total volume of fluid was prepared, these are the blank control bottles.

The subjects' task was to discriminate a given bottle from the dilution series from two blank control bottles by smell alone. If they succeded in one dilution step of an odorant i would present less and less concentrated solutions, i.e. more diluted solutions, of the odorant until they failed at finding the correct bottle. On the other hand if they failed at finding the first bottle with the odorant, i would present more and more concentrated solutions, i.e. less diluted solutions,  until they correctly identified the bottle with the odorant. The lowest concentration of each odorant that the subject was able to detect was taken as the detection threshold for that odorant for that subject. I then compared the data between the males and females for all three odorants.