Do animals have consciousness?

Articles

Aug. 24

Historically, animal intelligence and sentience have been the subject of intense debate. Over the centuries, the question of whether nonhuman species are capable of feeling and thinking has evolved significantly, encompassing a range of philosophical and scientific perspectives.

In ancient times, philosophers such as Aristotle believed that animals lacked reason, and that this lack was the main difference between them and human beings. Centuries later, René Descartes compared animals to machines, arguing that they lacked the ability to feel pain, communicate, or experience emotions. In contrast, thinkers such as Voltaire maintained that animals bore great similarities to humans, both being capable of feeling pleasure, anxiety, or suffering. Along these same lines, Jeremy Bentham formulated the famous premise: “The question concerning animals is not whether they can reason, or whether they can speak, but whether they can suffer.” Later, Charles Darwin would reinforce this view by stating that “there is no fundamental difference between man and the higher mammals as regards their mental faculties… the mental difference between man and the higher animals… is certainly one of degree and not of kind.”

The Cambridge Declaration

Over time, a growing number of philosophers and scientists came to accept the idea that animals possess consciousness. This paradigm shift was officially cemented in July 2012 with the Cambridge Declaration on Consciousness. In this historic document, leading neuroscientists concluded the following: “The absence of a neocortex does not seem to imply that an organism does not experience affective states. Converging evidence indicates that nonhuman animals possess the neuroanatomical, neurochemical, and neurophysiological substrates of states of consciousness, along with the capacity to exhibit intentional behaviors. Consequently, the bulk of the evidence suggests that humans are not the only ones to possess the neurological basis that gives rise to consciousness. Nonhuman animals, including all mammals and birds, and many other creatures, including octopuses, also possess these neurological substrates.”

This decree was instrumental in establishing a scientific consensus that various species possess the anatomical, psychological, and functional characteristics necessary to be considered conscious beings. From that point on, the debate shifted: the question was no longer whether animals possess consciousness, but rather whether there are different degrees of consciousness among species.

Dimensions of Animal Consciousness

Although there is still no absolute consensus on all the implications of consciousness and its exact levels, experts highlight various dimensions of how animals perceive their environment and themselves:

Sensitivity: This is the ability to experience states such as pain, fear, anxiety, pleasure, or affection. Scientific evidence shows that, at least in vertebrates, these abilities exist and can be rigorously assessed through the study of their biological receptors.
Evaluation of experiences: This refers to the ability to process past experiences for learning and decision-making. A clear example can be seen in organisms that hide their food and are later able to recall its exact location, evaluating and adapting their behavior based on past experiences that were either negative or positive.
Self-awareness: This is one of the most complex dimensions and the one in which the greatest variations in scientific results are observed. To determine whether an animal possesses self-awareness, the standard assessment is the “mirror test.” This involves placing a visible mark on the animal’s body and positioning it in front of a reflective surface; if the animal attempts to touch the mark on its own body, rather than interacting with the reflection as if it were another individual, this is interpreted as a sign of self-awareness. Success in this test has been documented in species such as chimpanzees, dolphins, elephants, magpies, and even certain types of fish.

The study of animal cognition remains a highly active field of research. Advances to date suggest a gradual shift toward a deeper and more comprehensive understanding of other species, thereby promoting a more ethical and respectful treatment of all living beings with whom we share the planet.

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