Man’s best friend is socially smarter than previously thought, scientists say citing new research which found that a dog knows if someone is not trustworthy.

When a dog owner points to the location of anything be it a toy, food, or ball the dog will run towards the area the person is pointing to.

Recent dog research been found that dogs can also easily figure out if these gestures are misleading. Once a dog has decided a person is unreliable, it stops following the cues they give, Japanese scientists say.

In a study published in the journal Animal Cognition, Akiko Takaoka of Kyoto University and her team put 34 dogs through three rounds of pointing.

In the first round, a researcher pointed to where food was hidden in a container, and in the second round, he pointed to an empty container.

In the third round food was once again placed in the container, but when the research pointed the dogs did not respond to the cue.

The dogs’ reactions suggest that they use their experience of the human to assess whether they were a reliable guide, the BBC quoted Takaoka as saying.

The next part of the experiment was to substitute the pointer. Another human did exactly the same thing as the first had done. The dogs, once again, followed the new person with interest.

Takaoka says she was surprised that the dogs “devalued the reliability of a human” so quickly.

“Dogs have more sophisticated social intelligence than we thought. This social intelligence evolved selectively in their long life history with humans,” she said.

Several studies in the past have shown that dogs can sense human emotions. In fact, recent research found that they can tell the difference between happy and angry faces. Takaoka’s study takes it one step further.