Why We Should Assume That Even the Most Basic Animals Are Conscious

Do dogs possess their own thoughts and emotions? What about pigeons, honeybees, earthworms, or jellyfish? Your answer likely reveals a human tendency to attribute consciousness to familiar creatures, while skeptically viewing “simpler” beings like invertebrates.

In truth, we can never be fully sure that other beings possess awareness. “The subjective nature of experience means absolute certainty is unattainable. You can’t even be 100% certain about other humans,” says Jonathan Burch, an author at the London School of Economics, in his work The edge of the senses.

Despite this uncertainty, evidence can be gathered. We must first clarify what consciousness entails. Philosopher Herbert Feigle’s framework divides consciousness into three layers.

The most basic layer involves raw sensations of the present, including external perceptions and internal emotions such as pain, joy, excitement, and boredom. The second layer, “sapiens,” allows for reflection on our experiences, such as “This is the worst pain I’ve ever felt.” The final layer encompasses our sense of self, recognizing our existence through past and future.

Research into animal consciousness primarily centers on sensation. “Much of this research focuses on pain, but there is a trend toward exploring positive emotions like joy,” says Christine Andrews from York University, Toronto. For instance, fish in pain may swim toward an area of a tank infused with painkillers.

Social behavior provides evidence for the second type of sensation. “Animals acquire much of their knowledge and skills socially,” Andrews states. Even insects exhibit this behavior. For example, fruit flies learn about mating by observing other fruit flies.

Some remarkable findings have revealed that certain animals recognize cultural contexts, such as recent studies showing mice providing “first aid” to unconscious companions. Researchers are also investigating episodic memory—the capacity to reflect on past experiences—and have found it in various mammals, including rats and chimpanzees, as well as birds like scrub jays.

Although we are gathering substantial evidence about sensation, the neurobiological foundations of consciousness remain unclear. “However, these findings may not universally apply to other species with distinct neural structures,” Andrews notes, referencing various studies on mammals that discuss involved brain regions. For example, while insects do not possess a human-like brain, there is strong evidence that they can experience pain, confirming a sensory component.

Last year, Andrews, Burch, and colleagues issued the New York Declaration on Animal Consciousness, acknowledging the “realistic possibility of conscious experiences” in numerous invertebrates. Andrews goes further, asserting that we should begin by assuming all animals are conscious.

This challenges the prevailing assumptions of many biologists, but may not be a significant leap for the general public. The notion of animals as intricate automata represents “an anomaly in Western science,” explains Burch. “Non-Western cultures, and indeed many individuals in the West outside academia, have consistently regarded animals as sentient beings.”