Monkeys grasp sense of ‘me’

U. BUFFALO (US) — Monkeys possess enough self-awareness to recognize that their actions can cause certain outcomes.

The findings, published in the journal Biology Letters, could have implications for people with a variety of cognitive disabilities, including autism, schizophrenia, and Alzheimer’s disease.

Previous research has shown that rhesus monkeys, like apes and dolphins, have metacognition, or the ability to monitor their own mental states—but consistently fail to recognize themselves in a mirror.

“We know that in humans, the sense of self-agency is closely related to self-awareness,” says Justin Couchman, a PhD cognitive psychologist at the University at Buffalo. “That it results from monitoring the relationship between pieces of intentional, sensorimotor and perceptual information.

“Based on previous findings in comparative metacognition research, we thought that even though they fail the mirror test, rhesus monkeys might have some other form of self-awareness. In this study we looked at whether the monkeys have a sense of self agency, that is, the understanding that some actions are the consequence of their own intentions.”

For the study, 40 UB undergraduates and four male rhesus monkeys were trained to move a computer cursor with a joystick while a distractor cursor partially matched their movements.

After moving the cursor, both humans and monkeys were asked to identify the computer cursor that they controlled—the one that matched their movements and intentions.

Both species were able to select the cursor they controlled from an array of choices, including the distractor cursor, at greater than chance levels.

“This suggests that the monkeys, like humans, have some understanding of self agency,” says Couchman. “This awareness or implicit sense that it is ‘me’ who is presently executing a bodily movement or thinking thoughts is an important form of self-awareness.”

Because this is the first such demonstration of self-agency in a species that has not passed the mirror self-recognition test, the results may shed light on apparent self-awareness deficits in humans.

“Mirror self-recognition is developmentally delayed in autistic children and absent in many who are mentally retarded, have Alzheimer’s disease or are schizophrenic. It is not clear why this deficit occurs, but like rhesus monkeys,” Couchman says, “these groups may simply have biases against mirrors.

“If, when studied, such individuals attempted to distinguish self-generated actions from partially altered actions in the paradigm reported in this study,” Couchman says, “it might offer information as to whether the breakdown in their mirror self-recognition is due to a difficulty in processing certain kinds of perceptual or cognitive information.”

The concept of agency implies an active organism, one who desires, makes plans, and carries out actions. The sense of agency and its scientific study is significant in the study of social cognition, moral reasoning, and psychopathology because of its implications for intention, consciousness, responsibility, desire and development.

“Self agency also plays a pivotal role in cognitive development,” Couchman says. “It is linked to metacognition, the first stages of self-awareness and theory of mind (understanding the mental states of others). These abilities give humans the sense that they are entities separate from the external world, and allow them to interact with other agents and the environment in intelligent ways.

“If rhesus monkeys are able to recognize themselves as agents that cause certain actions, then they probably have a similar understanding that they are entities independent from the environment.”

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