People with superior sense of smell are better navigators, study reveals

Follow your nose all the way home.

People with superior sense of smell are better navigators, study reveals
A Star Is Born, Warner Bros Pictures
  • It has to do with two parts of the brain, both of which are thicker in those with better smell and spacial recognition.
  • Your nose can detect about 1 trillion smells.
  • While your nose isn't a full GPS, it can help you pick out a general direction.

Smell is a funny thing. Some people—like actor Jason Sudekis—have no sense of smell at all. This might seem like a good thing until you realize just how important smell is to not only your sense of taste but your sense of memory, too. Turns out that a keen sense of smell is also good for something else: your sense of direction.

Screenshots of the virtual town (left), graph indicating the positions of participants between the two tests (right).

McGill University

According to a study done by McGill University out of Montreal, and recently published recently in Nature, your sense of smell and your sense of direction are actually linked. It had been thought they were before (the 'olfactory spatial hypothesis' goes back to at least 1971), but no conclusive study had been done until now.

57 participants were asked to navigate a virtual town. They were given 20 minutes to familiarize themselves with it, essentially build a cognitive map, and then quizzed on how to get from one virtual landmark to another.

Scented markers: Part of any good scientific toolkit.

In another part of the test, the 57 participants were asked to smell 40 unlabeled scented markers and to guess which smell was which.

Turns out, those who had the better sense of smell were also the best navigators.

The tests, while seemingly unrelated, actually trigger overlapping brain areas. It has to do with the mOFC, or medial orbitofrontal cortex, and the hippocampus. The thicker the left side of the mOFC, the better the person is at spatial memory and the thicker the right side of the hippocampus, the better the peron's sense of smell. As the study puts it, "greater mOFC cortical thickness is associated with both fewer errors during spatial learning and better olfactory identification."

To follow up their findings, the research team also conducted a brain lesion study on a small sample of people whose spacial memory and sense of smell is impaired by frontal lobe damage that affects the mOFC brain group, comparing them against a control group.

The authors write: "... we showed for the first time that mOFC damage affects performance on both olfactory identification and spatial memory tasks. These deficits were not explained by general cognitive impairment, as patients with mOFC damage performed similarly to control participants on standard neuropsychological tests."

ABC Photo Archives/ABC via Getty Images

The study suggests this could go back to the days of our earliest ancestors, when catching a faint whiff of wild animal meant that dinner or danger was nearby.

"Our findings reveal an intrinsic relationship between olfaction and spatial memory that is supported by a shared reliance on the hippocampus and medial orbitofrontal cortex. This relationship may find its roots in the parallel evolution of the olfactory and hippocampal systems."

So maybe there's some truth to the Toucan Sam adage, "follow your nose". Bonus fact: Did you know your nose can actually detect about 1 trillion different types of smells?


This is what aliens would 'hear' if they flew by Earth

A Mercury-bound spacecraft's noisy flyby of our home planet.

Image source: sdecoret on Shutterstock/ESA/Big Think
Surprising Science
  • There is no sound in space, but if there was, this is what it might sound like passing by Earth.
  • A spacecraft bound for Mercury recorded data while swinging around our planet, and that data was converted into sound.
  • Yes, in space no one can hear you scream, but this is still some chill stuff.

First off, let's be clear what we mean by "hear" here. (Here, here!)

Sound, as we know it, requires air. What our ears capture is actually oscillating waves of fluctuating air pressure. Cilia, fibers in our ears, respond to these fluctuations by firing off corresponding clusters of tones at different pitches to our brains. This is what we perceive as sound.

All of which is to say, sound requires air, and space is notoriously void of that. So, in terms of human-perceivable sound, it's silent out there. Nonetheless, there can be cyclical events in space — such as oscillating values in streams of captured data — that can be mapped to pitches, and thus made audible.

BepiColombo

Image source: European Space Agency

The European Space Agency's BepiColombo spacecraft took off from Kourou, French Guyana on October 20, 2019, on its way to Mercury. To reduce its speed for the proper trajectory to Mercury, BepiColombo executed a "gravity-assist flyby," slinging itself around the Earth before leaving home. Over the course of its 34-minute flyby, its two data recorders captured five data sets that Italy's National Institute for Astrophysics (INAF) enhanced and converted into sound waves.

Into and out of Earth's shadow

In April, BepiColombo began its closest approach to Earth, ranging from 256,393 kilometers (159,315 miles) to 129,488 kilometers (80,460 miles) away. The audio above starts as BepiColombo begins to sneak into the Earth's shadow facing away from the sun.

The data was captured by BepiColombo's Italian Spring Accelerometer (ISA) instrument. Says Carmelo Magnafico of the ISA team, "When the spacecraft enters the shadow and the force of the Sun disappears, we can hear a slight vibration. The solar panels, previously flexed by the Sun, then find a new balance. Upon exiting the shadow, we can hear the effect again."

In addition to making for some cool sounds, the phenomenon allowed the ISA team to confirm just how sensitive their instrument is. "This is an extraordinary situation," says Carmelo. "Since we started the cruise, we have only been in direct sunshine, so we did not have the possibility to check effectively whether our instrument is measuring the variations of the force of the sunlight."

When the craft arrives at Mercury, the ISA will be tasked with studying the planets gravity.

Magentosphere melody

The second clip is derived from data captured by BepiColombo's MPO-MAG magnetometer, AKA MERMAG, as the craft traveled through Earth's magnetosphere, the area surrounding the planet that's determined by the its magnetic field.

BepiColombo eventually entered the hellish mangentosheath, the region battered by cosmic plasma from the sun before the craft passed into the relatively peaceful magentopause that marks the transition between the magnetosphere and Earth's own magnetic field.

MERMAG will map Mercury's magnetosphere, as well as the magnetic state of the planet's interior. As a secondary objective, it will assess the interaction of the solar wind, Mercury's magnetic field, and the planet, analyzing the dynamics of the magnetosphere and its interaction with Mercury.

Recording session over, BepiColombo is now slipping through space silently with its arrival at Mercury planned for 2025.

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