Mirror test in Japanese study suggests self-awareness in fish, raising questions about animal intelligence

WASHINGTON - A small tropical reef fish was able to recognize itself in a mirror, scientists said Thursday, in a finding that raises provocative questions about assessing self-awareness and cognitive abilities in animals. The study involved experiments in which the bluestreak cleaner wrasse was given a mirror self-recognition test, a technique developed in 1970 for gauging animal self-awareness. In aquarium experiments at Osaka City University, researchers applied a brown-colored mark on the fish's body in a place that could be seen only in a mirror reflection. The fish tried to remove the marks by scraping their bodies on hard surfaces after watching themselves in a mirror, but never tried to remove them without a mirror present, indicating they understood the reflection was of them, the researchers said. When a transparent, rather than brown, mark was applied, the fish never tried to remove it.