Astronauts in long space missions may experience a cognitive decline that will make them slower to read emotions on other people’s faces and more likely to experience facial expressions angrily. This is according to a new study by scientists from the University of Pennsylvania and the German Space Center (DLR), published on March 17, 2021 in a peer-reviewed journal Limits in physiology.
In their study, the scientists subjected people to a simulated weightlessness for two months and tested their cognitive skills, such as finding objects that do not belong to a group of objects or memorizing 10 shapes. In these cognitive tests, participants showed an initial decrease in speed, but remained unchanged over time. The exception was the recognition of emotions or the possibility of describing emotions on the face of someone in a photograph, which continued to worsen. The decline in these types of capabilities, the researchers say, could have serious consequences for the well-being of the crew on a long mission to Mars due to the essential need for teamwork and harmony in such an uncertain mission.
The study describes in detail the experiments conducted to test cognitive functioning on the long Mars mission. The study had 24 subjects who spent 60 days locked in a bed with their heads tilted down by 6 degrees to simulate a weightless environment. Some of the participants also spent 30 minutes a day in a centrifuge to simulate short periods of gravity, a method that can be used in space to help suppress the effects of weightlessness.
Participants completed cognitive tests, along with a brief study of wakefulness and mood before, during, and after a period of reclining bed rest. Early on, subjects showed signs of slowing cognitive function, but only one factor of the experimenter tested — emotion recognition performance — continued to decline during the study period. The longer participants spent in a reclining position to rest in bed, the longer it took them to recognize facial emotions. They also reported seeing more negative emotions on faces during and after the study than before the start of antigravity simulations.
The The task of recognizing emotions measures how well the participant recognizes emotions from facial expressions. Study participants would look at photos of professional actors showing the various feelings on their faces. Participants then labeled the expressions as happy, sad, angry, timid, or neutral. In-depth analysis showed that participants were significantly less likely to rate faces as happy or neutral and more likely to be furious about the increasing time spent in the antigravity simulation.
The ability to work together in space will be the key to the success of any mission. Misreading emotional hints 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 properly “read” emotional expressions to each other will be crucial to effective teamwork and mission success. Our findings suggest that their ability to do so could be diminished over time.
In order for astronauts in space to be able to feel the effects of gravity and perhaps fight some cognitive decline that could be related, whether the spacecraft or the astronauts themselves would have to rotate to cause artificial gravity. None of these methods have yet been used in space practice. But 30 minutes a day in a centrifuge to simulate artificial gravity had no positive effect on participants in this test.
The results of a study of the detrimental effects on the cognition of astronauts in weightless conditions raise questions about astronauts who have been in space for a long time. EarthSky asked Basner, “Is this an effect that astronauts on the space station currently have to deal with?” He replied:
We don’t know that. Astronauts on the International Space Station (ISS) spend longer than the subjects were exposed to bed rest in our study. However, the ISS currently has the size of a 4-bedroom house, and astronauts have plenty of ways to connect with loved ones on earth. We have some data on emotion recognition tests on a very limited number of ISS astronauts, but the number of astronauts will need to increase over the next few years.
EarthSky also asked Basner about the difference between a long mission to Mars compared to astronauts who spent a year or two in space on the International Space Station. He said:
There are only 4 astronauts who have spent more than one year in a row on the ISS! The Mars mission will be much longer (~ 3 years), the spacecraft much smaller, the crew smaller (probably 3 or 4), there is no rescue option, radiation exposure is a much bigger problem and communication delays. So the mission to Mars will be much more stressful.
The effects of the microgravity environment on the cognitive emotional responses of astronauts is an area that remains to be studied. Alexander Stahn of the University of Pennsylvania was one of the scientists in the study. Stahn said:
We cannot say whether the effects observed on the emotion recognition test were caused by simulated microgravity or the closure and isolation inherent in the study, with separate bedrooms and sporadic contact with the study team. Future studies will need to separate these effects.
But a possible link between weightlessness and a declining ability to read someone’s emotions is an important one that still needs to be addressed. The study stated:
The relevance of space flight due to the deterioration of emotional processing with increasing time in the mission cannot be overestimated, especially for space exploration missions, where astronauts will be limited to a small space with a small group of peers for up to 3 years.
Conclusion: One study found that people who were exposed to 60 days of simulated weightless activity had a slower ability to read emotions on people’s faces, often seeing anger there compared to before testing began.
Source: Continuous and occasional artificial gravity as a countermeasure to the cognitive effects of 60 days of reclining bed rest