What Is the Smartest Thing in the World? What the Evidence Shows

Nothing holds a measured title as the smartest thing in the world, because no test ranks people, animals and machines on one scale. Each yardstick has its own leader. On ARC-AGI-3, the best standard AI score was 62.7% on 7 November 2026. The African elephant has the most neurons (257 billion). The long-finned pilot whale has the most in the cortex (37.2 billion). On neuron counts, humans lead neither list.

The new finding is how fast one of those leaders moved. In March 2026 the first frontier models scored about 0.5% on ARC-AGI-3, a game test built so that people can solve every environment. By 7 November the best standard score was 62.7%, about 120 times higher. Below: every yardstick we could check, what each one measures, and why none of them is an IQ.

What is the smartest thing in the world?

What is the smartest thing in the world? No one can say, because "smartest" needs a yardstick and the available yardsticks disagree. We checked six. Each names a different leader, and each has a catch that stops it being a ranking of everything.

• IQ tests, people against people: no one holds the top spot. The scale has a mean of 100 and a standard deviation (SD) of 15, and standard tests stop near 160. Catch: most people have never been tested. See who is the smartest person living
• ARC-AGI-3, a game test that people can solve: GPT-6 Astra leads the standard leaderboard at 62.7% (ARC Prize Foundation, 7 November 2026). Catch: the same model scored 99.9% when run in its developer's own harness, so the set-up changes the result
• Artificial Analysis Intelligence Index, a composite of nine AI evaluations (version 5.0.1, 7 November 2026): Gemini 4 Carbon first at about 60 out of 100, Claude Opus 5.5 at about 59. Catch: it ranks AI models only, and its version changed between our 14 October reading (v4.3.2) and this one
• Neurons in the whole brain: African elephant, 257 billion, against 86.1 billion for the human brain (Herculano-Houzel and colleagues, 2014; Azevedo and colleagues, 2009). Catch: 97.5% of the elephant's neurons sit in the cerebellum
• Neurons in the cerebral cortex: long-finned pilot whale, about 37.2 billion, against about 16 billion for humans (Mortensen and colleagues, 2014). Catch: the authors say the higher count comes from a larger brain, not a denser one
• A self-control test given to many species: ravens and chimpanzees both scored 100% on the cylinder task, dogs 79% (our smartest animals study). Catch: it tests one skill, and 5 chimpanzees took part

Read down the list. Six yardsticks give six different answers, and not one of them gives an animal or a machine an IQ.

Is AI the smartest thing in the world now?

Not on the one test that sets AI against people. ARC-AGI-3 is designed to be solvable by people, and the best standard AI score is 62.7%, still short of the ceiling.

ARC Prize describes ARC-AGI-3 as made of 100% human-solvable environments. It says a score of 100% would mean an AI agent beats every game as efficiently as humans. Its leaderboard (read 7 November 2026) has GPT-6 Astra first at 62.7%, then GPT-6.1 Sol at 52.7% and Gemini 4 Argon at 49.8%. Claude Opus 5 stands at 30.2% and Claude Sonnet 5.5 at 24.3%.

The jump is recent. The earliest scored entries on the same board were 0.1% to 0.5%. Our report on the March launch gives the first headline figure, 0.51% for AI against 100% for people. That is the "about 120 times" rise above: 62.7 divided by 0.51 is 123 (our arithmetic).

Set-up matters too. Our article on the two ARC-AGI-3 harnesses shows how GPT-6 Astra reached 62.7% under the neutral harness and 99.9% under one supplied by OpenAI. A benchmark percentage is also not an IQ. It counts tasks completed. An IQ is a position inside a reference group, and no reference group exists for machines. Our guide to whether AI is smarter than humans covers the wider benchmark picture, and our report on the most intelligent AI model shows how rankings disagree.

Is the human brain the smartest thing in the world?

Only on a scale built for people. The human brain has about 86.1 billion neurons on average (plus or minus 8.1 billion), but it holds neither the whole-brain record nor the cortex record.

Azevedo and colleagues (Journal of Comparative Neurology, 2009) counted adult male brains and put about 19% of the neurons in the cerebral cortex, roughly 16 billion. The elephant study found 257 billion neurons in the whole brain, three times the human figure. But 251 billion of them are in the cerebellum, and the elephant cortex holds 5.6 billion, about a third of the human cortex.

The pilot whale study found about 37.2 billion neurons in the neocortex, almost twice the human figure. The range across individual whales was 29.1 to 46.3 billion. The two papers read their counts in opposite ways. The elephant authors say their result supports a link between human cortical neurons and human cognition. The whale authors conclude that the number of neurons in the human neocortex does not by itself explain it.

Inside our own species the link is weak too. Our report on brain size and IQ explains what a correlation of 0.24 means.

Which animal is the smartest thing on Earth?

What is the smartest thing on Earth among animals? No animal is the smartest thing on Earth, because the top animal changes with the measure. In our study of 222 species with published neuron counts, the elephant has the most neurons and the pilot whale the most cortical neurons. Humans have the largest brain for their body size (an EQ of 8.3).

Tests tell a similar story. MacLean and colleagues (PNAS, 2014) gave two self-control tasks to 567 animals from 36 species. They found that absolute brain volume best predicted performance across species. On the cylinder task, ravens and chimpanzees tied at 100%.

For single groups, read our companion articles on the smartest primate and the smartest fish in the world. The species pages cover chimpanzees and dolphins.

Why can't one score name the smartest thing?

Because an IQ is a position inside a reference group, and no test has a reference group that spans people, animals and machines. An IQ test compares your score with a norm sample of people your age. The scale has a mean of 100 and an SD of 15.

Take an IQ of 130. It sits at the 97.7th percentile, so about 2 in 100 people score higher. Our IQ percentile calculator converts any score on this scale. A benchmark percentage, a neuron count and a cylinder-task score each use a different unit with no norms behind them. You cannot convert one into another.

To see where your own reasoning sits on a scale built for people, take the IQ Metrics IQ test.

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