People often wonder how smart they are, and this curiosity dates back "nearly 4,000 years when China used written tests to rate applicants for civil service," according to AllPsych Online. Today, two common ways to judge ability are intelligence and aptitude testing. Though linked, these two tests have different purposes and reasons for implementation.

Intelligence

A person's intelligence quotient (IQ) is widely believed to explain how smart a person is, but what really is intelligence? Intelligence is a term used to define a person's ability, but unlike aptitude, this is seen as a single trait. Typically, intelligence is a more vague term, meant to suggest an overall sense of smartness. An intelligent person doesn't necessarily have more knowledge than someone who tests lower. The term refers to the person's ability to gain and use knowledge, not what knowledge they already have.

Aptitude

An aptitude is linked to intelligence, but is commonly thought to be a specific set of skills where intelligence is a broad generalization. According to AboutIntelligence, you could compare an aptitude to a competency, which can be mental or physical. People can have aptitudes in music, sewing, people skills and more, and these skills can directly help a person in school and work. Career aptitude tests are a common type of test because aptitudes directly link to work.

Intelligence Tests

The most common type of intelligence test is the Intelligence Quotient, or IQ. This test does not test specific knowledge. Instead, the questions are very generic and meant to gain an understanding of the person's ability to learn. Subjects are asked to answer questions and complete tasks. The tests are a ratio of ability to chronological age, with 100 being normal. The results are used often in education, commonly when students need to be placed for special services. Occasionally, employers might use these tests as well.

Aptitude Tests

Aptitude tests differ from IQ tests because though they are testing ability, they are testing specific abilities in specific areas. According to Psychometric Success, there are over 5,000 different aptitude tests on the market. Some test only one specific skill set and some test a variety. Aptitude tests look for strengths in numbers, verbal strengths, mechanics and other areas. These tests are often timed, and used for a more specific purpose, like job placement or college admission. The SAT and ACT would be considered aptitude tests.

Controversy

Aptitude and Intelligence testing have come under scrutiny. Aptitude tests like the SAT require students to answer questions that some believe to be culturally biased or biased by income. Another argument against the SAT and ACT is that the tests are irrelevant and do not really predict success as a student. IQ tests have had similar complaints, though most of the controversy surrounding the IQ tests are that these tests primarily test logic, and many believe that there is more to intelligence than just logic.