A quiet revolution is brewing in the science of the mind, revealing that cognition is not a privilege reserved for creatures with brains, but a biological birthright shared by all living things.
For decades, the study of cognition—the processes of thinking, learning, and remembering—has been dominated by the image of the human brain, a complex computer processing information in the dark of our skulls. But what if the roots of thinking are far older, more widespread, and more fundamental to life itself? Emerging research suggests that cognition is not a privilege reserved for creatures with brains, but a biological birthright shared by all living things, from the humble bacterium to the towering elephant.
This new perspective, known as biological cognition or basal cognition, proposes that the ability to sense, learn, remember, and make decisions evolved first in the simplest organisms 5 . It reframes our most cherished mental capacities as basic biological functions that originated billions of years ago.
By getting down to biological basics, scientists are beginning to answer a profound question: How did life first begin to know its world, and what does that mean for our understanding of our own minds?
The traditional view of cognition, heavily influenced by the computer age, sees the mind as an information-processing machine. Input comes in from the senses, the brain's software processes it, and behavior is the output 8 . This approach has been incredibly productive for understanding human psychology, but it has limits. It largely ignores the question of where these cognitive capacities came from and why they evolved in the first place.
The biological approach shifts the focus. It argues that cognition is, first and foremost, a natural biological phenomenon 9 . Its primary role is not abstract thought, but to help an organism—any organism—regulate its body and navigate challenges and opportunities to survive and thrive 1 . This isn't just a philosophical point; it's a practical research program.
By studying simpler organisms, scientists can identify the core "toolkit" of cognitive capacities:
| Cognitive Capacity | Function | Example in Nature |
|---|---|---|
| Sensing & Perception | Gathering information about the internal state and external environment | A bacterium detecting chemical gradients 2 |
| Memory | Retaining information about past experiences for future use | A slime mold recalling a food location 5 |
| Valence | Assigning a "value" (good/bad) to stimuli | The preference for nutrients and avoidance of toxins 7 |
| Learning | Adapting behavior based on experience | A plant learning to associate a cue with light 5 |
| Decision Making | Selecting an action from alternatives | Bacteria deciding to sporulate under stress 2 |
| Communication | Sharing information with other cells or organisms | Bacterial communities using quorum sensing 2 |
Perhaps nowhere is the case for basal cognition more startlingly made than in research on bacteria. The idea that a single-celled organism could exhibit a capacity reminiscent of memory challenges our deepest assumptions about where cognition begins.
A crucial experiment in this field comes from the lab of Gürol Süel, who studies Bacillus subtilis, a common soil bacterium. Süel's team discovered that these bacteria, when living in structured communities called biofilms, use a sophisticated form of electrical communication to survive starvation 2 .
They grew structured biofilms of Bacillus subtilis in the lab, creating a miniature "city" of bacteria.
They subjected the biofilm to a metabolic stressor—specifically, they limited the supply of glutamate, a critical nutrient.
Using advanced imaging and fluorescent dyes sensitive to electrical charge, the team monitored the membrane potential of the bacteria in real-time.
They focused on the flow of potassium ions (K+), a charged particle known to be crucial for electrical signaling in neurons.
The researchers created controlled biofilms to study bacterial communication under stress conditions.
The results were astonishing. The team observed a wave of potassium ions traveling from the nutrient-starved cells in the interior of the biofilm to the well-fed cells on the periphery 2 .
| Metric | Observation | Biological Significance |
|---|---|---|
| Signal Type | A traveling wave of potassium ions (K+) | Uses the same mechanism as neural electrical signaling |
| Signal Trigger | Metabolic stress (glutamate starvation) | A response to a life-threatening challenge |
| Signal Effect | Peripheral cells stop growing | Allows nutrients to diffuse to the struggling interior cells |
| Community Outcome | Collective survival through metabolic co-dependence | Akin to altruistic behavior in complex societies |
This was more than just a chemical leak; it was a deliberate, information-rich signal. The distressed interior cells were effectively "telling" the peripheral cells to stop consuming all the food. This electrical coordination allowed the entire community to enter a state of collective dormancy, weathering the famine together 2 .
Even more remarkably, Süel's team later found that separate biofilms could synchronize their growth oscillations through these potassium signals, taking turns feeding to share scarce resources—a remarkable example of ecosystem-level decision-making 2 .
The importance of this experiment cannot be overstated. It demonstrates that the core biophysical machinery for long-distance communication and collective decision-making—a fundamental form of cognition—existed for billions of years before neurons ever evolved. The same type of ion channel that allows our own brains to think is being used by bacteria to run their societies 2 .
How do researchers uncover cognitive abilities in organisms without brains? The field relies on a diverse and innovative set of tools that bridge biology, physics, and computational modeling.
Proteins that allow charged particles to cross cell membranes; the fundamental unit of bioelectrical communication.
Example: Studying potassium channels in bacteria to understand the evolution of neural signaling 2 .
A technology for precisely modifying an organism's genome.
Example: Used to "knock out" genes suspected to be involved in cognitive processes to test their function 2 .
Molecules that glow under specific wavelengths of light, used to tag and visualize cellular activity.
Example: Visualizing calcium or voltage changes in cells to track "decision-making" in real-time 2 .
Mathematical and computational frameworks that simulate complex biological systems.
Example: Modeling how simple rules in individual cells lead to intelligent group behavior in slime molds or ant colonies 4 .
The reframing of cognition as a biological fundamental suggests that intelligence is not a singular phenomenon that appeared suddenly with the human brain, but a spectrum of capacities deeply embedded in the fabric of life 5 7 .
This perspective bridges long-separated scientific fields, from microbiology to neuroscience, and challenges us to reconsider the very definition of what it means to be a thinking being.
This new foundation opens up breathtaking possibilities in medicine and technology:
As we look to the future, the vision is one of integration and continuity. The BRAIN Initiative, a major U.S. research program, envisions a "comprehensive, mechanistic understanding of mental function" that spans from molecules to behavior 4 . The study of basal cognition provides the essential, deep-time evolutionary context for this vision, connecting the decision-making of a bacterium to the soaring creativity of the human mind. By getting down to biological basics, we are not reducing our humanity; we are finally beginning to understand our place in the grand, intelligent tapestry of life.