Rhesus monkeys recognize themselves in mirrors

This video says about itself:

Monkeys May Be Able To Recognize Themselves In A Mirror With Training

8 January 2015

Researchers at the Chinese Academy of Sciences may have taught rhesus monkeys to recognize themselves in a mirror for the first time.

The team trained the monkeys to pass the “mark test”, considered to be the primary method of determining self-recognition.

For several weeks, training involved shining a laser light on seven monkeys in front of a mirror.

At the end of this period, they could touch the virtual mark by seeing it on a mirror image of themselves which was considered a passing of the mark test.

The monkeys also displayed self-directed behavior in the mirror to examine parts they couldn’t normally see like their mouths and genitals.

Previously, elephants, pigeons, dolphins, and apes were among the other animals which passed the test for self-recognition but not monkeys.

The monkeys that successfully passed the test retained the ability for one year.

However, they could not pass on the skill to their untrained peers.

Those that did not get trained by researchers failed to self-recognize.

Self-recognition is considered an important indicator of the brain’s capacity to empathize with others.

Despite the study’s success, Gordon Gallup Jr., developer of the mark test, blasts the results as “fundamentally flawed,” since they focus on training and do not prove an inherent understanding of behavior.

From Current Biology:

Mirror-Induced Self-Directed Behaviors in Rhesus Monkeys after Visual-Somatosensory Training

Liangtang Chang, Qin Fang, Shikun Zhang, Mu-ming Poo, Neng Gong

Highlights

•We developed a novel training strategy to study mirror self-recognition in monkeys
•Trained rhesus monkeys passed the conventional mark test in front of a mirror
•Trained rhesus monkeys exhibited spontaneous mirror-induced self-directed behaviors
•Rhesus monkeys may be useful for studying the origin of mirror self-recognition

Summary

Mirror self-recognition is a hallmark of higher intelligence in humans. Most children recognize themselves in the mirror by 2 years of age [ 1 ]. In contrast to human[s] and some great apes, monkeys have consistently failed the standard mark test for mirror self-recognition in all previous studies [ 2–10 ]. Here, we show that rhesus monkeys could acquire mirror-induced self-directed behaviors resembling mirror self-recognition following training with visual-somatosensory association. Monkeys were trained on a monkey chair in front of a mirror to touch a light spot on their faces produced by a laser light that elicited an irritant sensation.

After 2–5 weeks of training, monkeys had learned to touch a face area marked by a non-irritant light spot or odorless dye in front of a mirror and by a virtual face mark on the mirroring video image on a video screen. Furthermore, in the home cage, five out of seven trained monkeys showed typical mirror-induced self-directed behaviors, such as touching the mark on the face or ear and then looking at and/or smelling their fingers, as well as spontaneously using the mirror to explore normally unseen body parts. Four control monkeys of a similar age that went through mirror habituation but had no training of visual-somatosensory association did not pass any mark tests and did not exhibit mirror-induced self-directed behaviors.

These results shed light on the origin of mirror self-recognition and suggest a new approach to studying its neural mechanism.

Researchers experienced human raters with digital images of rhesus macaques of different ages and asked them to identify related individuals. They found that although infant rhesus macaque faces are individually distinguishable, only just before they reach puberty can offspring be matched correctly to the faces of their parents: here.

But scientists do not fully understand how the association between stress and health plays out at the cellular level. A new University of Washington-led study examines one key stress-inducing circumstance — the effects of social hierarchy — and how cells respond to the hormones that are released in response to that stress. They found that social status determined how individual [rhesus] macaques responded to a key stress hormone, glucocorticoid: here.

When it comes to being willing to explore more efficient options to solving a problem, monkeys exhibit more cognitive flexibility than humans, according to a study by Georgia State University psychology researchers: here.