Intelligence

• 1. Introduction

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  Intelligence has been defined in at least two dozen ways, and when two dozen prominent theorists were once asked to define it, they gave two dozen different answers. Some called it the capacity for abstraction and logic. Others pointed to self-awareness, emotional knowledge, planning, creativity, or problem-solving. One researcher reduced it to a single equation. Another insisted there may be no meaningful way to define it at all, aside from just pointing to ourselves. The word itself rose to prominence in the early 1900s, yet the thing it names has been studied across many disciplines for far longer. This documentary asks what intelligence actually is, why the experts cannot agree, and why the search has expanded far beyond the human mind. It reaches into apes and dolphins, into mice and cephalopods, even into plants and machines. The story begins with a word that early philosophers tried hard to avoid.

• 2. A Banished Word

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  The Latin verb intelligere meant to comprehend or perceive, and from it grew the nouns intelligentia and intellēctus. In the Middle Ages the word intellectus became the scholarly term for understanding, serving as a translation for the Greek philosophical term nous. That term carried heavy cargo. It was tied to the metaphysical and cosmological theories of teleological scholasticism, including the immortality of the soul and the concept of the active intellect, also called the active intelligence. Early modern philosophers wanted no part of that baggage. Francis Bacon, Thomas Hobbes, John Locke, and David Hume all preferred the plainer word understanding in their English works. Hobbes made the point with a joke. In his Latin De Corpore he used the phrase intellectus intelligit, rendered in English as the understanding understandeth, and offered it as a typical example of a logical absurdity. So intelligence faded from English-language philosophy. It would return later, scholastic theories and all, when contemporary psychology took it up again.

• 3. Two Dozen Definitions

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  Alfred Binet called intelligence judgment, otherwise known as good sense, practical sense, initiative, and the faculty of adapting one's self to circumstances. David Wechsler framed it as the aggregate or global capacity to act purposefully, to think rationally, and to deal effectively with one's environment. Lloyd Humphreys described a process of acquiring, storing, retrieving, combining, comparing, and using information in new contexts. Howard Gardner tied it to solving genuine problems and creating effective products, while also finding or creating new problems to learn from. Robert Sternberg and William Salter offered just three words: goal-directed adaptive behavior. Reuven Feuerstein's theory of Structural Cognitive Modifiability cast intelligence as the unique propensity of human beings to change the structure of their own cognitive functioning. Shane Legg and Marcus Hutter distilled more than 70 definitions into one mathematically formalized line: intelligence measures an agent's ability to achieve goals in a wide range of environments. Alexander Wissner-Gross went further still. He reduced intelligence to a force, written F equals T times the gradient of S, a force that acts to keep options open and maximize future freedom of action. In his words, intelligence doesn't like to get trapped. Behind all this variety sits a 1995 consensus report from the Board of Scientific Affairs of the American Psychological Association, titled Intelligence: Knowns and Unknowns. It conceded that no single conceptualization had answered all the important questions, and that none commanded universal assent.

• 4. Measuring The Mind

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  Intelligence Quotient tests were first developed in the early 20th century with a narrow purpose: to screen children for intellectual disability. Their reach kept growing. Over time IQ tests were used to screen immigrants, military recruits, and job applicants, and as they spread, so did the belief that they measured a fundamental and unchanging attribute every human possesses. The idea found theoretical support in the g factor, or General Intelligence, a construct that summarizes the correlations observed between a person's scores across a range of cognitive tests. Today most psychologists agree that IQ captures at least some aspects of human intelligence, particularly the ability to thrive in an academic context. Many still question whether such tests can measure intelligence as a whole. Debate also surrounds the heritability of IQ, meaning how much of the difference between individuals comes from genetic versus environmental factors. On one point the scientific consensus is firm: genetics does not explain average differences in IQ test performance between racial groups. The distinction worth holding onto is that intelligence is not the same as learning. Learning is retaining facts and recalling them later. Intelligence is the cognitive ability to carry out that and other processes.

• 5. Beyond The Academic

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  Emotional intelligence is the ability to convey emotion to others in an understandable way and to read the emotions of others accurately. Some theories suggest it also speeds the generating and processing of emotions, not just their accuracy, and that it helps people manage emotions in ways that aid problem-solving. It ties closely to mental health and to social intelligence. Social intelligence is the ability to understand the social cues and motivations of others and oneself in social situations. It is thought to be distinct from other types of intelligence, though related to the emotional kind, and scholars debate whether the two belong to the same theory or to two different schools of thought. Moral intelligence stands apart as the capacity to understand right from wrong and to act on the value believed to be right, independent of both emotional and cognitive intelligence. Then there is the everyday contrast between book smarts and street smarts. One person gains knowledge through academic study but may lack the experience to apply it sensibly. Another gains knowledge through practical experience but may lack the accurate information that study provides. Artificial intelligence researcher Hector Levesque noted how dismissive we tend to be of learning through text. It is sometimes derided as merely book knowledge, he observed, while knowledge from direct experience and apprenticeship earns the prouder name of street knowledge.

• 6. Minds Without Words

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  Kanzi the bonobo learned to use language, and stands among the non-human animals most noted for intelligence. The list runs further: chimpanzees and other great apes, dolphins, elephants, and to some extent parrots, rats, and ravens. Wolfgang Köhler studied the intelligence of apes, and Stanley Coren wrote a book titled The Intelligence of Dogs. Researchers in this field study both the mental ability within a single species and the comparison of abilities between species, measuring problem solving alongside numerical and verbal reasoning. The challenges are steep. Intelligence must be defined so it means the same thing across species, and a measure must somehow compare mental ability fairly across very different contexts. Cephalopods make the puzzle sharper. They appear to exhibit characteristics of significant intelligence, yet their nervous systems differ radically from those of backboned animals. Vertebrates such as mammals, birds, reptiles, and fish show varying degrees of intellect, as do arthropods. The g factor itself, first described in humans, has since been identified in a number of non-human species. Because verbally dependent human scales cannot apply, intelligence in animals is measured through tools focused on innovation, habit reversal, social learning, and responses to novelty. Studies have shown that g accounts for 47% of the individual variance in cognitive ability among primates, and between 55% and 60% of the variance in mice, figures close to the 40 to 50% that g explains in humans.

• 7. The Disputed Edges

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  Plants have been proposed as intelligent on the grounds that they sense and model their external and internal environments, then adjust their morphology, physiology, and phenotype to preserve and reproduce themselves. The counterargument holds that real intelligence requires the creation and use of persistent memories, not mere computation without learning. By that standard, the machine learning of robots qualifies, while purely autonomic sense-reaction responses do not. Yet defenders argue plants are not limited to automated responses. They can discriminate positive from negative experiences, register memories from their past, communicate, run sophisticated cost-benefit analysis, and take controlled actions against environmental stress. Machines occupy the same contested ground. An intelligent agent can be defined as a system that perceives its environment and takes actions to maximize its chances of success. Kaplan and Haenlein define artificial intelligence as a system's ability to interpret external data, learn from it, and use those learnings to achieve goals through flexible adaptation. Mathematician Olle Häggström framed intelligence as optimization power, the capacity to steer the future into regions of possibility ranked high in a preference ordering. Deep Blue, he noted, steered a chessboard's future into a subspace it labeled winning, despite Garry Kasparov's attempts to steer it elsewhere. Existing AI still lags humans in general intelligence, sometimes defined as the capacity to learn how to carry out a huge range of tasks. Cognitive ability might even be pictured not as a single number but as a hypersurface in a multidimensional space, a way to compare systems good at different things. And some skeptics circle back to where this story began, insisting there is no meaningful way to define intelligence at all, aside from just pointing to ourselves.