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Human scent is on par with animals, Rutgers professor reports

John McGann, an associate professor in the Department of Psychology, researches how human smell compares to that of animals. – Photo by

On Friday, the Center for Human Evolutionary Studies hosted a presentation on the sense of smell and how human smelling power compares to that of other animals.

John McGann, an associate professor in the Department of Psychology, who specializes in behavioral neuroscience, focused on how the human sense of smell compares to that of other animals, particularly rodents. After a brief introduction to the history of odor-reception research, he discussed the meaning of his findings.

In his lab, McGann works with rodents in an attempt to understand the biological systems behind the sense of smell and how the brain differentiates and adapts to different odors, he said. His study centers around the olfactory bulb, an organ located in the front of the brain, that plays a major role in an animal's ability to smell. 

McGann said that signals are sent from special cells in the nose and travel to the olfactory bulb, where they are then transferred to other parts of the brain. 

“We are interested in understanding how the brain learns about the world and uses that information to interpret incoming sensory stimuli," he said. "We use the olfactory system, the sense of smell, as a model to allow us to see how the brain changes with odor-dependent learning and if an odor means something to an animal.” 

Despite marked size differences, the bulbs of different species have a relatively equal amount of cells in them, McGann said. The ability to pick up on more smells and identify them better relies on the amount of specific chemical receptors that animals have in their special sensory neurons. 

Humans who have less receptors than animals — such as mice or dogs — are traditionally thought to have great senses of smell. They are on par, or sometimes even better, at detecting smells than other animals, he said. Studies show that humans are able to sense certain smells at consistently lower concentrations than other animals. This remains true across many different chemicals and substances humans have the capacity to detect.

“Humans have an excellent and impactful sense of smell," McGann said. "We can smell lots of things, and they really do influence our lives, and that means that losing your sense of smell is a real loss, and if they teach you in Intro to Bio that humans have a bad sense of smell compared to other animals, they’re incorrect.” 

He said the issue occurs when humans come into contact with smells they do not have receptors for and therefore cannot detect. Though they cannot detect as many different odors as other mammals, humans still rely on their smelling capabilities, which play a big part in neurological processes.  

Along with understanding how humans smell, McGann said he seeks to discover how this sense affects various experiences and interactions with the world. 

McGann said he is interested in the emotions people associate with certain odors, what people expect certain substances and situations to smell like and how people adapt to the world through their olfactory system. A key part of his work is comprehending how the brain reacts to and processes the things it senses, something called sensory cognition.

The center's mission is to promote innovative faculty and student research, grounded in evolutionary theory that explores what it means to be human, according to its website.

McGann said he actively studies human and mammalian hearing with a team of researchers at his lab, where he is always looking for talented and driven assistants and the occasional test subject. 

“Communicating your discoveries to the scientific community is a key part of doing research," McGann said. "If no one knows you did it, it doesn't really help. And it's an opportunity to talk about data that isn't published yet so you can get feedback on it while you're still doing it.”

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