Olfactory change detection

The human sense of smell is very sensitive and precise. For instance, humans are able to detect thousands of odors. However, we do not trust our olfactory abilities and rather rely on visual than on olfactory information when determining changes of the environment. Against this background, we developed a “one-back-change detection test” which allowed us to determine the human capacity to detect changes in the olfactory environment.

Participants received four odor conditions which were presented via a computer-controlled olfactometer (2 odor qualities in 2 concentrations each). The participants' task was to react as soon as they perceived a change of the odors. The odors were tested for iso-intensity and potential trigeminal activations in three pilot studies. A total of 83 healthy participants (aged 18 to 34 years, 50 women) were included and all of them were furthermore tested for selective attention, olfactory function, environmental sensitivity, subjective importance of the sense of smell and the ability to lateralize odors. The participants furthermore underwent the same 1-back-change-paradigm with visual stimuli.

Visual changes were detected reliably by all of the participants, olfactory changes however were reliably detected by a subgroup of only 18% of the participants. Those were characterized by high olfactory sensitivity, high scores in the importance of olfaction scale and low environmental sensitivity. Across all participants, changes of olfactory quality were detected more reliably than changes of olfactory concentration.

Publication History

Publication Date:
18 April 2018 (online)