Will future explorers on Mars be able to overcome the cognitive problems associated with the long journey under weightless conditions? Image via Nicolas Lobos / Unsplash.
Astronauts on long space missions may experience a cognitive decline that makes them slower to read the emotions on other people’s faces and more likely to perceive facial expressions as angry. According to a new study by scientists at the University of Pennsylvania and the German Aerospace Center (DLR), published March 17, 2021 in the peer-reviewed journal Frontiers in physiology.
In their study, scientists subjected people to simulated weightlessness for two months and tested their cognitive skills, such as finding the only element that does not belong to a group of objects or memorizing 10 shapes. In these cognitive tests, participants showed an initial decrease in speed, but then remained unchanged over time. The exception was recognizing emotions, or being able to describe the emotion on someone’s face in a photo, which continued to deteriorate. According to researchers, the decline in such skills could have serious consequences for the well-being of a crew on a long mission to Mars, due to the essential need for teamwork and harmony in such a precarious mission.
The study details experiments performed to test cognitive functioning on a long mission to Mars. The study caused 24 subjects to spend 60 days confined to bed with their heads tilted down 6 degrees to simulate a weightless environment. Some of the participants also underwent 30 minutes a day in a centrifuge to simulate short periods of gravity, a method that could be used in space to help counteract the effects of weightlessness.
Resting the bed down with a slight 6-degree angle is the standard way to simulate the effects of microgravity on Earth. Image using DLR.
Test subjects in the centrifuge are spun to experience artificial gravity. Image using DLR.
In this long-exposure photograph, the striped lights show the movement of the rotating centrifuge. Image using DLR.
Participants completed cognitive tests along with a brief alert and mood survey before, during, and after periods of bed rest tilted down. At first, subjects showed signs of a slowdown in cognitive function, but only one tested experienced factor (emotion recognition performance) continued to decline throughout the study period. The more time participants spent in the reclining position of the bed tilted down, the later they recognized facial emotions. They also reported seeing more negative emotions on their faces during and after the study than before starting antigravity simulations.
He Emotion recognition task measures the extent to which the participant recognizes emotions from facial expressions. Study participants would look at photographs of professional actors depicting various emotions on their face. Participants then labeled the expressions as happy, sad, angry, fearful, or neutral. An in-depth analysis showed that participants were significantly less likely to rate faces as happy or neutral and more likely to rate them as angry with the increase in time spent on antigravity simulation.
Being able to work together in space will be key to the success of any mission. Misreading emotional cues has all the hallmarks of a dramatic space opera. But the threat is real. As Mathias Basner of the University of Pennsylvania, lead author of the study of cognition and antigravity, said:
The ability of astronauts to correctly “read” the emotional expressions of others will be of paramount importance for effective teamwork and mission success. Our findings suggest that their ability to do so may be affected over time.
Mathias Basner, of the University of Pennsylvania, was the lead author of the study that looked at the cognitive effects astronauts might experience on a mission to Mars. Image through the University of Pennsylvania.
In order for space astronauts to feel the effects of gravity, and perhaps combat some of the cognitive impairment that might be associated with it, the spacecraft or the astronauts themselves should be rotated to induce artificial gravity. None of these methods have yet been used in practice in space. But the 30 minutes daily in a centrifuge to simulate artificial gravity had no positive effect on participants in this test.
The results of the study of harmful effects on the cognition of astronauts under weightless conditions raise questions about astronauts who are already in space for long periods of time. EarthSky asked Basner, “Is this an effect that space station astronauts currently have to deal with?” He replied:
We do not know. Astronauts spend more time on the International Space Station (ISS) than subjects were exposed to bed rest in our study. However, the ISS is currently the size of a 4-bedroom house and there are many ways for astronauts to connect with loved ones on the ground. We have some data on emotion recognition testing in a very limited number of ISS astronauts, but we will need to increase the number of astronauts over the next few years.
EarthSky also asked Basner about the difference between a long mission to Mars and astronauts who have spent a year or two on space on the International Space Station. He said:
There are only 4 astronauts who have spent more than a year in a row on the ISS! Mars’ mission will be much longer (~ 3 years), the spacecraft much smaller, the crew smaller (probably 3 or 4), no chance of rescue, radiation exposure is a much bigger problem and delays in communication. Therefore, Mars ’mission will be much more stressful.
The effects of microgravity environments on astronauts ’cognitive emotional responses are an area that still needs further study. Alexander Stahn, of the University of Pennsylvania, was one of the scientists in the study. Stahn said:
We cannot say whether the effects observed in the emotion recognition test were induced by simulated microgravity or by the confinement and isolation inherent in the study, with separate rooms and sporadic contact with the study team. Future studies will have to undo these effects.
But the possible connection between weightlessness and decreased ability to read someone’s emotions is important and has yet to be addressed. The study stated:
The relevance of space flight from an impairment of emotional processing with increasing time on the mission cannot be overstated, especially for space exploration missions, where astronauts will be limited to a small space with a small group of companions during a period of up to 3 years.
Summary: A study has shown that people undergoing 60 days of simulated weightlessness had a slow ability to read the emotions on people’s faces, often seeing anger in them compared to before starting testing.
Source: Continuous and intermittent artificial gravity as a countermeasure to the cognitive effects of 60 days of bed rest tilted down
