Explainer

A scuba diver using a light in deep water

Eighteen recreational divers entered a chamber simulating 40 meters below the surface and the brain signal tied to attention and target detection stayed slower even after the pressure eased, suggesting that nitrogen narcosis can leave information processing lagging beyond the deepest phase of a dive

Eighteen trained recreational divers sat inside a dry hyperbaric chamber, breathed compressed air at pressure equal to about 40 meters of seawater and then took a simple listening test while their brain activity was recorded. The striking part of the result was not only that performance slipped during the simulated deep dive. Some of the…

Hand holding creative glowing polygonal brain on blue background. AI and future concept

Humans Explainer

Fourteen men endured three two-hour immersions in 20°C water and their memory began adapting to the cold, while nitrous oxide used to simulate inert-gas narcosis continued to impair cognition throughout the day

Three scuba divers working together underwater

Humans Explainer

Firefighter divers spent five minutes at a simulated 50-meter depth and made more balance errors after surfacing, while an oxygen stop preserved improvement on a bead test, suggesting nitrogen narcosis can briefly linger after pressure returns to normal

Two scuba divers capturing the vibrant marine life near an underwater wreck in crystal clear waters

Humans Explainer

Twenty-eight Navy divers descended to a simulated 220 feet and experience showed up not in reported fear but in cortisol, heart-rate variability and steadier recovery during decompression

The Mir space station photographed from Space Shuttle Atlantis in 1997

Humans Explainer

Weekly mood surveys from 71 Shuttle-Mir astronauts, cosmonauts and controllers showed crews directing frustration toward Mission Control and controllers passing it upward toward NASA managers

A mesmerizing view of Earth as seen from a space station with solar panels and satellite modules

Space Explainer

Ten astronauts kept private journals through six-month ISS expeditions and their own words pointed to a third-quarter morale dip while also showing how meaningful work, family contact and the habit of writing helped them preserve perspective far from home

Researchers floating inside an aircraft during a parabolic microgravity flight

Humans Explainer

Two drone operators flew a virtual cave mission during 20 parabolas and became more confident during 30-second bursts of microgravity even though their accuracy did not improve, suggesting weightlessness can separate self-belief from actual performance

A participant resting in a hospital bed during a prolonged bed-rest setting

Humans Explainer

Twenty-four volunteers spent 60 days tilted head-down to mimic microgravity and by the end they took longer to read faces, leaned toward angry interpretations and saw no clear protection from daily artificial gravity sessions meant to help future crews

Twenty-four healthy adults agreed to spend two straight months in beds tipped six degrees head-down, a position used to mimic some of the body changes seen in orbit. By the end of the study, the most striking psychological shift was not a collapse in memory or attention. It was a slower response when reading facial…

Concept of human intelligence with human brain on blue background

Humans Explainer

Six volunteers spent 30 days inside a sealed spacecraft simulator and their EEG signals showed growing strain in the brain’s attention-control system before standard task scores fully captured how isolation was affecting focus

Six volunteers sealed inside a spacecraft simulator for 30 days showed one of the warning signs mission planners worry about most: the brain began working harder to manage attention before routine task scores showed the full size of the problem. The result points to a gap between how people seem to perform on the surface…

A spacecraft docked at the International Space Station above Earth

Humans Explainer

A 50-second delay between the International Space Station and Mission Control raised stress and frustration during a 166-day mission with three astronauts and 18 support staff, showing how a pause can unsettle the partnership that keeps crews and ground teams aligned

Fifty seconds is a small slice of time on Earth. A person can ask a question, glance at a screen, or take two breaths and keep moving. In orbit, during a demanding task, that same pause can feel much larger. A study tied to work aboard the International Space Station found that a 50-second one-way…

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