A type of intelligence test would be solving many problems in a very short time. Most of the problems have to do with seeing things, or telling what a rotated shape would look like. Some are also related to mathematics: for example to tell what number would come next in a row. Other tests have to do with words or the understanding of language. After giving such a test to a person, a number would be calculated to give an approximation of the Intelligence Quotient (IQ). Intelligent machines Computer engineers try to build machines that act as if they were intelligent. This is related to computer science and is called Artificial intelligence (man-made "intelligence"). Artificial intelligence uses logic, and often combines it with machine learning. This means that similar to living organisms, the machine has to be trained to solve a problem. After training, it will solve the problem faster. Intelligence in animals and plants Intelligence is not limited to humans. Many animals also show signs of intelligence: animals also need to solve problems, and remembering how a problem is solved is useful to them. Many animals use tools to solve problems. Intelligence () has been defined in many ways: the capacity for abstraction, logic, understanding, self-awareness, learning, emotional knowledge, reasoning, planning, creativity, critical thinking, and problem-solving. It can be described as the ability to perceive or infer information and to retain it as knowledge to be applied to adaptive behaviors within an environment or context. The term rose to prominence during the early 1900s. Most psychologists believe that intelligence can be divided into various domains or competencies. Intelligence has been long-studied in humans, and across numerous disciplines. It has also been observed in the cognition of non-human animals. Prominent among these are the various Intelligence Quotient (IQ) tests, which were first developed in the early 20th century to screen children for intellectual disability. Over time, IQ tests became more pervasive, being used to screen immigrants, military recruits, and job applicants. As the tests became more popular, belief that IQ tests measure a fundamental and unchanging attribute that all humans possess became widespread. An influential theory that promoted the idea that IQ measures a fundamental quality possessed by every person is the theory of General Intelligence, or g factor. It is sometimes derided as being merely "book knowledge", and having it is being "book smart". In contrast, knowledge acquired through direct experience and apprenticeship is called "street knowledge", and having it is being "street smart". == Nonhuman animal == Although humans have been the primary focus of intelligence researchers, scientists have also attempted to investigate animal intelligence, or more broadly, animal cognition. These researchers are interested in studying both mental ability in a particular species, and comparing abilities between species. They study various measures of problem solving, as well as numerical and verbal reasoning abilities. Some challenges include defining intelligence so it has the same meaning across species, and operationalizing a measure that accurately compares mental ability across species and contexts. Wolfgang Köhler's research on the intelligence of apes is an example of research in this area, as is Stanley Coren's book, The Intelligence of Dogs. Non-human animals particularly noted and studied for their intelligence include chimpanzees, bonobos (notably the language-using Kanzi) and other great apes, dolphins, elephants and to some extent parrots, rats and ravens. Cephalopod intelligence provides an important comparative study. Cephalopods 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 have shown a fairly high degree of intellect that varies according to each species. The same is true with arthropods. === g factor in non-humans === Evidence of a general factor of intelligence has been observed in non-human animals. First described in humans, the g factor has since been identified in a number of non-human species. Cognitive ability and intelligence cannot be measured using the same, largely verbally dependent, scales developed for humans. Instead, intelligence is measured using a variety of interactive and observational tools focusing on innovation, habit reversal, social learning, and responses to novelty. Studies have shown that g is responsible for 47% of the individual variance in cognitive ability measures in primates and between 55% and 60% of the variance in mice (Locurto, Locurto). These values are similar to the accepted variance in IQ explained by g in humans (40–50%). Some of these definitions are meant to be general enough to encompass human and other animal intelligence as well. An intelligent agent can be defined as a system that perceives its environment and takes actions which maximize its chances of success. Kaplan and Haenlein define artificial intelligence as "a system's ability to correctly interpret external data, to learn from such data, and to use those learnings to achieve specific goals and tasks through flexible adaptation". Progress in artificial intelligence can be demonstrated in benchmarks ranging from games to practical tasks such as protein folding. Existing AI lags humans in terms of general intelligence, which is sometimes defined as the "capacity to learn how to carry out a huge range of tasks". Mathematician Olle Häggström defines intelligence in terms of "optimization power", an agent's capacity for efficient cross-domain The Limits of Intelligence: The laws of physics may well prevent the human brain from evolving into an ever more powerful thinking machine. By Douglas Fox in Scientific American, 14 June 2011. A Collection of Definitions of Intelligence