Evidence for conscious awareness and nonconscious perception in rhesus monkeys

What is it about?

Many animals perform complex intelligent behaviors, but the question of whether animals are aware while doing so remains a long debated but unanswered question. Here, we develop a new approach to assess whether non-human animals have awareness by utilizing a well-known double dissociation of visual awareness – cases where people behave in completely opposite ways when stimuli are processed consciously versus non-consciously. Using this method, we found that a non-human species –the rhesus monkey— exhibits the very same behavioral signature of both non-conscious and conscious processing. This opposite double dissociation of awareness firstly allows striping away the long inherent ambiguity when interpreting the processes governing animal behavior. Collectively, it thus provides robust support for two distinct awareness modes in non-human animals.

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Photo by Andre Mouton on Unsplash

Photo by Andre Mouton on Unsplash

Why is it important?

Scholars have long debated whether animals are consciously aware, yet since many complex human behaviors and high-level functions can be performed outside of conscious awareness, it was long considered unfeasible to untangle if animals displaying impressive intelligent behaviors are conscious rather than conditionally or non-consciously performing. Here, we develop a completely novel empirical approach to this question: We harness well established crossover double dissociations that occur between non-conscious and conscious processing in humans— cases where people perform completely oppositely when stimuli are perceived consciously versus non-consciously. To date, no one has explored whether similar performance dissociations exist in a non-human species. In a series of seven experiments, we first establish these signatures in humans in two different non-verbal double dissociation tasks, and then reveal identical signatures in non-human primates. Given this crossover (opposite predictions) approach for distinct modes of awareness, our new study is able to override the most persistent problems that have prevented scholars from unambiguously inferring animal consciousness in previous studies. In other words, we successfully disentangle conscious from non-conscious perception in a non-human species, a previously considered unattainable issue that was deemed necessary in order to inform the question of animal consciousness.

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