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Prehistoric disorder on land has resulted in larger, more intelligent human brains

CNN – The way our ancestors got used to inconsistent landscapes full of obstacles that, according to researchers at Northwestern University, “jet fueled” the evolution of the brain of animals and early human ancestors.

The combination of improved eyesight and higher intelligence to survive in this complex rural environment is “the reason why we can eat seafood but seafood is not for us,” said Malcolm MacIver, professor of biomedicine and mechanical engineering at the northwest McCormick School of Engineering the University.

Maciver and his colleagues use computer simulations to study aspects of evolution. Earlier, they found that 380 million years ago, just before animals moved out of the sea to live on land, their eyes tripled, he told CNN.

This increase in vision does not offer a great advantage in water. Instead, surviving in open water is a speed game in which the prey has to outwit its predators.

However, their research indicated that these animals were more like crocodiles because they lived in the water but raised their eyes above the surface, “which allowed them to see hundreds more times than is possible in water because of water quickly absorbed and scattered. ”

; Light, “said Maciver, who is also a professor of neurobiology at the Weinberg College of Arts and Sciences in the northwest.

These animals probably chased insects that lived on land and staggered out of the water to nibble on. Over time, they evolved to move more on land, and their increased eyesight provided important information about their surroundings.

MacIver and his colleagues were curious. “How could seeing things so far change the way we try to get the things we need to live like food and companions while avoiding things like predators?”

In their latest simulation, published this week in the journal Nature Communications, the researchers used existing computational models that show how animals interact with their landscapes. They adapted these models to show whether living on land favored planning or habit-based action.

“We ask the question: How hard does the prey have to think to survive as we vary the complexity of the environment?” MacIver said.

The model is essentially a 15 x 15 chess board with open and closed squares. The closed squares represent obstacles. Loot must navigate through these fields to reach a goal. In the meantime, a predator moves through this landscape after the prey.

Their simulations showed that in an inconsistent landscape, a mixture of grasslands with trees, bushes, boulders and hills, the survivability was significantly improved by planning. MacIver said this was “a pronounced brain capacity that appears to have developed in mammals and birds.” and appears to be particularly well developed in our own species. “

Strategic thinking or planning in a completely open or completely closed environment like open water or dense jungle had no advantage.

But in a patchy landscape, any movement could help hide or reveal the location of the prey from a predator. Therefore, various options for navigating in space need to be considered.

“You need quite a bit of brain power to work through this tactic,” said MacIver. “If you look further away, you have time and space to think further away.”

With old people, who, unlike their chimpanzee relatives, stood upright on all fours on all fours, as predators they were able to overlook the inconsistent landscape and also had to think like prey to avoid everything that was after them, like saber-toothed cats.

“Incidentally, our brain has almost quadrupled after we split off from our next ancestor, the chimpanzee,” said MacIver. “This increase in brain size could be related to how much brain power is required to be strategic in these areas, but more research will be needed to know for sure.”

MacIver and his colleagues turned their simulation into an online game and, as prey, navigated different landscapes to see if you could reach your destination before a predator caught you.

It’s hard to imagine what life would have been like if it had stayed strictly in the water, but MacIver was ready to speculate.

“There would be no special relativity theory. There would be no SpaceX. There would be no 747,” said MacIver.

“Although these things are only about people and their ingenuity, the cognitive force that drives them has a neural basis that we can see in other land-based animals such as mammals and birds.”

The distribution of cognitive power is completely uneven between animals living on land and those living under water, MacIver said.

Dolphins and whales are the exception because they actually evolved on land and have returned to the water. Other exceptions are squid and squid infested with land animals, dolphins and whales. They could have evolved to avoid them.

MacIver and his colleagues next want to observe how real animals behave in the laboratory, and use robotic predators and prey.

“My greatest hope is that this work will eventually give scientists a clear understanding of how we plan to know how to manipulate this ability in our own brains, perhaps through some kind of cognitive prosthesis,” said MacIver.

“This may make it less difficult to plan remote threats or opportunities than we currently find as a species.”

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