Babies can tell how badly do you want something

Ten-month-old infants can assess how much someone values a particular goal by observing how hard they are willing to work to achieve it, a study has found.
This ability requires integrating information about both the costs of obtaining a goal and the benefit gained by the person seeking it, suggesting that babies acquire very early an intuition about how people make decisions, according to the study published in the journal Science.
"Infants are far from experiencing the world as a 'blooming, buzzing confusion,'" said lead author Shari Liu, from the Harvard University in the US.
"They interpret people's actions in terms of hidden variables, including the effort people expend in producing those actions, and also the value of the goals those actions achieve," Liu said.

The researchers showed infants animated videos in which an "agent," a cartoon character shaped like a bouncing ball, tries to reach another cartoon character.
In one of the videos, the agent has to leap over walls of varying height to reach the goal.

First, the babies saw the agent jump over a low wall and then refuse to jump over a medium-height wall. Next, the agent jumped over the medium-height wall to reach a different goal, but refused to jump over a high wall to reach that goal.
The babies were then shown a scene in which the agent could choose between the two goals, with no obstacles in the way.

An adult or older child would assume the agent would choose the second goal, because the agent had worked harder to reach that goal in the video seen earlier.
The researchers said when the agent was shown choosing the first goal, infants looked at the scene longer, indicating that they were surprised by that outcome.
"Across our experiments, we found that babies looked longer when the agent chose the thing it had exerted less effort for, showing that they infer the amount of value that agents place on goals from the amount of effort that they take toward these goals," Liu said.

The findings suggest that infants are able to calculate how much another person values something based on how much effort they put into getting it.