Snakes and the Brain

Snakes On the Brain: Are Primates Hard-Wired to Recognize Snakes?

Oct. 28, 2013 — Was the evolution of high-quality vision in our ancestors driven by the threat of snakes? Work by neuroscientists in Japan and Brazil is supporting the theory originally put forward by Lynne Isbell, professor of anthropology at the University of California, Davis.

The snake-sensitive neurons were more numerous, and responded more strongly and rapidly, than other nerve cells that fired in response to images of macaque faces or hands, or to geometric shapes. Isbell said she was surprised that more neurons responded to snakes than to faces, given that primates are highly social animals.

“We’re finding results consistent with the idea that snakes have exerted strong selective pressure on primates,” Isbell said.

Isbell originally published her hypothesis in 2006, following up with a book, “The Fruit, the Tree and the Serpent” (Harvard University Press, 2009) in which she argued that our primate ancestors evolved good, close-range vision primarily to spot and avoid dangerous snakes.

Modern mammals and snakes big enough to eat them evolved at about the same time, 100 million years ago. Venomous snakes are thought to have appeared about 60 million years ago — “ambush predators” that have shared the trees and grasslands with primates.

Nishijo’s laboratory studies the neural mechanisms responsible for emotion and fear in rhesus macaque monkeys, especially instinctive responses that occur without learning or memory. Previous researchers have used snakes to provoke fear in monkeys, he noted. When Nishijo heard of Isbell’s theory, he thought it might explain why monkeys are so afraid of snakes.

“The results show that the brain has special neural circuits to detect snakes, and this suggests that the neural circuits to detect snakes have been genetically encoded,” Nishijo said.

The monkeys tested in the experiment were reared in a walled colony and neither had previously encountered a real snake.

“I don’t see another way to explain the sensitivity of these neurons to snakes except through an evolutionary path,” Isbell said.

Isbell said she’s pleased to be able to collaborate with neuroscientists.

“I don’t do neuroscience and they don’t do evolution, but we can put our brains together and I think it brings a wider perspective to neuroscience and new insights for evolution,” she said.

Read More Here…


Key Terms…
  • Hard-Wired ↔ inata (sinais via cabo–>ligação direta a cabo)
  • driven by ↔ impulsionado pela
  • threat ↔ ameaça
  • supporting the theory ↔ apoiando a teoria
  • put forward by ↔ apresentada por
  • geometric shapes ↔ formas geométricas
  • following up with ↔ … em seguida
  • she argued that ↔ ela argumentou que
  • close-range vision ↔ visão de curto alcance
  • spot ↔ detetar, notar, perceber, destacar
  • ambush ↔ emboscada
  • shared ↔ compartilhado
  • grasslands ↔ pastagens
  • reared ↔ criados
  • walled colony ↔ colônia murada
  • real snake ↔ cobra de verdade
  • except through an ↔ exceto por meio de um
  • pleased ↔ satisfeito
  • insights ↔ percepções, entendimento, discernimento, compreensão


Hard-Wired inata (sinais via cabo–>ligação direta a cabo)
(Psychology) (of human behaviour) innate; not learned; humans have a hard-wired ability for acquiring language
Scared of snakes? Primates are hard-wired to notice them more than other types of predators
Are we secretly scared of snakes? Primate brains are hard-wired to notice snakes before we even know we’ve seen them
Did hard-wired fear of snakes drive evolution of human vision?
Did you know our brains are hard-wired for making us feel good when we give? It’s a fact! Ask a scientist!
Jealousy: Is it in Our Genes? To what degree is jealousy hard-wired into our DNA? And what can we do to control…
driven by impulsionado pela
Nosso impressionante recorde de crescimento deve-se à inovação constante. ↔Our record of impressive growth is driven by a constant stream of innovation.
A economia continuará a ser fortemente suportada pelo consumo e investimento. ↔The economy will continue to be strongly driven by consumption and investment.
put forward by apresentada por
Dos oito candidatos apresentados pelo Conselho só um era mulher. ↔Of the eight candidates put forward by the Council only one was a woman.
she argued that ela argumentou que
E a esposa argumentou que ela ainda tinha pecado em seu coração. ↔And the wife argued that she still had sin in her heart.
A população local alegou que o gasoduto deveria ser colocado no mar. ↔Local people argued that the pipeline should be laid out to sea.
Os ministros defenderam que a política ambiental faz parte da solução para resolver a crise actual. ↔Ministers argued that environmental policy is part of the solution to tackle the current crisis.
ambush emboscada
If your attack is going too well, youre walking into an ambush.
He was caught in an ambush. ↔Ele foi pego numa emboscada.
Tom explained how the ambush would work. ↔Tom explicou como seria a emboscada.
reared criados
I rear cattle. ↔Eu crio gado.
Trata-se dos animais criados pela carne, como os animais para abate e as aves de capoeira. ↔These include animals reared for their meat such as animals for slaughter and poultry.
insights percepções, entendimento, discernimento, compreensão
▪ He is a leader of great insight.
▪ The author analyzes the problem with remarkable insight.
▪ We need to gain insight into the politics of the region.
▪ Her book provides us with fresh new insights into this behavior.
Do you have any insight into the company’s direction?
o projeto realmente precisa de aprofundamentos em questões pontuais ↔the project really needs insights into timely issues
His insight into the human mind was fascinating. ↔Seu entendimento sobre a mente humana era fascinante.


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