The concept of intelligence is not generally considered controversial. However, it is an idea that can be very difficult to define. Different psychologists have developed different theories to answer the question "What is intelligence?" and, although they overlap, there is no universally accepted definition. Furthermore, since it is difficult to measure intelligence quantitatively, the connotation of the word “intelligence” must be taken into account in the definition. One possible definition of intelligence is "the ability to excel in a certain area involving rational thinking". Since excellence is subjective, it is important to note that this definition requires the use of a comparison. For example, an intelligent person is someone who excels above the norm in a certain topic or area involving rational thinking. A dolphin is very intelligent in the realm of other animals, but a specific dolphin may not be intelligent compared to other dolphins. The question of how to define intelligence is not new. Psychologists have worked for years to determine a way to classify, measure, and define intelligence, and there are several theories that have stood out. The first widely known theory was developed by British psychologist Charles Spearman, born in 1863. After conducting tests to measure subjects' mental abilities, he "concluded that intelligence is a general cognitive ability that can be measured and expressed numerically" (Cherry ). His theory is known as general intelligence. "dictionary.com" definitions of intelligence include the "capacity for learning, reasoning, understanding, and similar forms of mental activity; aptitude for grasping truths, relationships, facts,... middle of paper..." .00 in language signs, and refers to himself as “Orangutan Person,” while other less sophisticated orangutans receive the label “orange dog” (Antotta, 2005). This demonstrates linguistic (verbal) intelligence and introspective intelligence significantly exceeding the currently known capabilities of most animals. To determine whether or not Chantek is intelligent compared to other orangutans, research should be done to test the cognitive abilities of several other apes. Works Cited http://www.orionmagazine. org/index.php/articles/article/6474/http://www.orionmagazine.org/index.php/articles/article/152/http://www.aboutintelligence.co.uk/the-theory-multiple- intelligences.htmlhttp://psychology.about.com/od/cognitivepsychology/p/intelligence.htmdictionary.comhttp://psychology.about.com/od/psychologicaltesting/a/int-history.htm