“Humans, chimpanzees, elephants, magpies and bottle-nosed dolphins can recognize themselves in a mirror, according to scientific reports, although as any human past age 50 knows, that first glance in the morning may yield ambiguous results.
Not to worry. Scientists are talking about species-wide abilities, not the fact that one’s father or mother makes unpredictable appearances in the looking glass.
Mirror self-recognition, at least after noon, is often taken as a measure of a kind of intelligence and self-awareness, although not all scientists agree. And researchers have wondered not only about which species display this ability, but about when it emerges during early development.
Children start showing signs of self-recognition at about 12 months at the earliest and chimpanzees at two years old. But dolphins, researchers reported Wednesday, start mugging for the mirror as early as seven months, earlier than humans.
Diana Reiss a psychologist at Hunter College, and Rachel Morrison, then a graduate student working with Reiss, studied two young dolphins over three years at the National Aquarium in Baltimore.
Dr. Reiss first reported self-recognition in dolphins in 2001 with Lori Marino, now the head of The Kimmela Center for Animal Advocacy. She and Dr. Morrison, now an assistant professor in the psychology department at the University of North Carolina Pembroke collaborated on the study and published their findings in the journal PLoS One.
Dr. Reiss said the timing of the emergence of self-recognition is significant, because in human children the ability has been tied to other milestones of physical and social development. Since dolphins develop earlier than humans in those areas, the researchers predicted that dolphins should show self-awareness earlier.
Seven months was when Bayley, a female, started showing self-directed behavior, like twirling and taking unusual poses.
Dr. Reiss said dolphins “may put their eye right up against the mirror and look in silence. They may look at the insides of their mouths and wiggle their tongues.”
Foster, the male, was almost 14 months when the study started. He had a particular fondness for turning upside down and blowing bubbles in front of the one-way mirror in the aquarium wall through which the researchers observed and recorded what the dolphins were doing.
The animals also passed a test in which the researchers drew a mark on some part of the dolphin’s body it could not see without a mirror. In this so-called mark test, the animal must notice and pay attention to the mark. Animals with hands point at the mark and may touch it.
The dolphins passed that test at 24 months, which was the earliest researchers were allowed to draw on the young animals. Rules for animal care prohibited the test at an earlier age because of a desire to have the animals develop unimpeded. During testing, the young animals were always with the group of adults they live with, and only approached a one-way mirror in the aquarium wall when they felt like it.
Rules for drawing on human children are apparently less strict, and they pass the mark test at 18-24 months.
Frans de Waal, of Emory University, who studies cognition in apes and other animals and is the author of “Are We Smart Enough to Know How Smart Animals Are?” , said in an email, “Great study.”
Dr. de Waal worked with Dr. Reiss on an earlier study of self-recognition in elephants but was not involved in the dolphin research.
He said the study has value because science needs to go beyond asking whether species display mirror self-recognition (MSR) to ask “whether the emergence of MSR correlates, as it does in humans, with other milestones of development.” Connecting the ability to the rest of development can help researchers “begin to answer the question of what MSR means.”
A small side note that doesn’t have any apparent scientific significance is that Foster, the male, visited the mirror many more times than Bayley, the female.
“He clearly was interested in viewing himself,” Dr. Reiss said.