Mice Pass Mirror Test, Indicating Potential Self-Awareness

Neuroscientists discover specific neurons activate when mice recognize themselves, raising questions about animal self-awareness.

Mice may be self-aware as they have passed the mirror test, a psychological milestone previously only achieved by a few animals such as humans, apes, dolphins, and some birds.
Scientists marked the foreheads of black-furred lab mice with a spot of white ink, and the animals spent more time grooming their heads in front of the mirror, seemingly to try to wash away the ink spot.
The mice only showed self-recognition-like behaviour under certain circumstances: they needed to be already accustomed to mirrors, had socialised with other mice that looked like them, and the ink spot needed to be relatively large.
Scientists discovered that certain neurons in the brains of mice activated when they “recognised” themselves in the mirror. When these neurons were not functioning, the mice no longer groomed themselves in the mirror when the ink dot was placed on their heads.
The research raises the possibility that many more animals than previously thought are self-aware.