Evolution Made Human Intelligence Almost Inevitable, NYU Neuroscientist Argues

In One Hand Clapping: Unraveling the Mystery of the Human Mind (Prometheus/Swift Press, 2025), New York University neuroscientist Nikolay Kukushkin builds a ground-up account of consciousness and contends that the arc of life on Earth set a near-inevitable path toward human-like minds. Kukushkin—who studies memory in non-brain biological systems, from human kidney cells to sea slugs—combines neuroscience, evolutionary biology and philosophy to trace how cellular innovation, social complexity and language shaped our minds.

What Kukushkin Means by Consciousness

Kukushkin contrasts two approaches. A top-down view treats consciousness as the private, first-person quality of experience: the way it feels to be you. From the bottom up, he defines consciousness as a particular pattern of causation in which neural activity continuously predicts and updates perceptions in a circular loop. This ongoing feedback—predictions shaping perception, and perception revising predictions—is, he argues, the dynamism we experience as awareness.

"There is a circular motion of causality that makes us constantly reevaluate our beliefs, including our beliefs about what we are and who we are," Kukushkin says. "That rolling motion is consciousness, in my definition."

How Humans Differ from Computers

Kukushkin highlights a hardware distinction. Most current computers separate memory from processing: models are formed and then used to infer. Biological systems, by contrast, often integrate memory and inference at once—perception and prediction occur continuously and shape one another. He suggests that replicating consciousness in machines would require architectures where memory and inference are deeply integrated so the system can train on its own inferences, not only on preexisting data.

Evolutionary Steps Toward Humanness

Kukushkin points to two complementary drivers of increased cognitive complexity. First is a gradual trend: primate cortex size correlates with social group size. Managing many social relationships—tracking intentions, emotions and second-order beliefs (what someone thinks about what another thinks)—creates exponential cognitive demand. This "social brain" dynamic favors larger, more capable brains.

Second is a categorical change: language. Human language is uniquely generative—capable of producing an open-ended range of expressions—and is culturally transmitted across generations. Kukushkin likens the coevolution of language and brain to flowers and pollinators: neither evolved alone, and each reinforced the other's development.

The Eukaryotic Turn

A pivotal moment in life's history, Kukushkin argues, was the emergence of eukaryotic cells—formed when bacterial and archaeal lineages merged and one lineage adopted internal symbionts such as mitochondria. Mitochondria provided a dramatic boost in available energy, enabling cells to become larger and more metabolically expensive. That energy surplus set off a cascade of complexity: specialized tissues, defense and offense strategies, nervous systems and, eventually, brains that learn rather than encoding every behavior genetically.

Implications and Takeaways

Kukushkin stresses continuity rather than mystique: human minds emerged from natural, traceable processes. Complexity brought vulnerability and thus stronger selection for mechanisms that anticipate and avoid danger—brains that learn, adapt and generate internal motivations independent of genetic scripts. While humans are remarkable, our origins follow the same kinds of transitions that distinguish eukaryotes from prokaryotes.

Interview Notes

The following highlights from an interview clarify Kukushkin's view: consciousness is a circular causal process in neural networks; social living and language drove cognitive expansion; and reproducing similar dynamics in machines likely requires rethinking hardware so memory and inference are intertwined.

About the author: Nikolay Kukushkin is a neuroscientist at New York University who researches memory in diverse biological systems and explores philosophical questions about the mind.

Editor’s note: This piece condenses and clarifies Kukushkin’s arguments and interview responses for readability and flow.