People are often exposed to complex scents rather than a single scent in their daily lives. Under normal circumstance, humans can distinguish scents out of two scents relatively well, but they have limitations in recognizing each single scent in the mixture of three or more scents. We here studied characteristics of human olfactory behaviors upon stimulations with either a single odorant or odorant mixtures containing the specific odorant. We examined whether elements of the olfactory behavior characteristics of the single odorant would be comparable to those of odorant mixtures containing the specific odorant. Since the odorant is detected by the odorant receptors (ORs), we chose three narrowly tuned ORs (i.e. highly specific to particular odorant(s)) and made an odorant mixture repertoire consisting of one to three odorants recognized by the specific odorant receptors. An evaluation of the scent of 50 human subjects was evaluated via a survey consisting of 146 descriptors responsive to olfactory behaviors. We built and analyzed a database based on results from the survey and found that there are significant olfactory cognitive differences between a single odorant and its odorant mixtures. Our finding will provide critical backgrounds for many applications in the fragrance industries.