The brain impulse that makes us quit is found
No matter what you are doing, there comes a point when it’s time to call it a day.
小編注：call it a day，意為“到此為止、收工”。
例句：I worked on my term paper until about ten o'clock last night, but got so sleepy I decided to call it a day. （昨晚我寫我的期末論文一直寫到十點，但后來太困了所以決定不寫了。）
And scientists believe they have discovered the precise part of the brain which tells you when that time has arrived.
Researchers say evidence of an in-built instinct to quit has been witnessed throughout the ages.
The impulse which told ancient foragers to give up on one pasture and move on to more fertile hunting grounds is the same as that which urges us to try a different internet site if our initial choice is taking too long to appear on screen, the experts believe.
Scientists found that a section of the brain called the dorsal anterior cingulate cortex (ACC) appears to be responsible for weighing up reward against cost in any given situation.
When a certain threshold is reached, the brain gives a signal to throw in the towel.
小編注：throw in the towel，字面意思是“扔毛巾”，引申為“認輸”的意思。
例句：He vowed he would never throw in the towel. （他發(fā)誓絕不認輸。）
U.S. researchers from Duke University in North Carolina studied rhesus macaques.
They observed whether the monkeys decided to stay with a food source giving ever smaller squirts of fruit juice or move to a newer and potentially better supply.
小編注：ever smaller，越來越小的。ever 以后跟形容詞比較級，代表“越來越……”。
The scientists studied a set of neurons within the animals’ ACCs, which showed increasing activity as time passed. Once it reached a certain threshold the monkeys immediately moved on.
Professor Michael Platt said: ‘It is as if there is a threshold for deciding it’s time to leave set in the brain.’
Researchers also factored in the time it would take to travel to the next food source – and when this was increased, it took longer for the ‘quit’ threshold to be reached.
Professor Platt said that the findings tallied with a 1976 evolutionary theory, the Marginal Value Theorem, which stated that foragers would stay longer at a blackberry bush as the distance between bushes became greater.
The idea has been shown to hold true across the animal kingdom in worms, bees, fish and seals.
Professor Platt said: ‘This is a really fundamental solution to a fundamental problem.’ He added that the same was true when it came to our use of modern technology.
‘In the case of internet users, the cost of travel time translates to download speed. The faster the downloads, the quicker browsers are willing to forage elsewhere,’ he said.
