Intelligence is difficult to operationalise, as the definition varies according to different culture. Thus there is no single unified universal definition of intelligence. However, Sternberg and Kaufrman, (1998) define intelligence as the quality to form relationships, solve problems, learn and adapt to situations. This leads to success and fulfilment in a specific culture and time.
Number of theories have been conducted to identify the nature of intelligence, Spearman (1904) highlights that intelligence is a general cognitive ability, that can be measured though IQ and psychometric tests. In relation to this, Thurstone (1938) rejected the ‘g’ factor as it is too simplistic and developed multi-factor theory, in which different ability counts as intelligence. In support of this theory Sternberg developed Triarchic theory, highlighting that general ability is limited and intelligence is an umbrella terms, covering a verity of related mental abilities (LeBoutillier, 2012).
Like other psychological variables, IQ test is useful if it is accurate. Binet test, WAIS and WISC have a high reliability of +.9; also the results of the second test matched their first score (Mayer 2012). This demonstrates the consistence of IQ test. Although, practice reduces reliability, due to the practice individuals receive and the improvement in test results. This has been verified in the research by Bosso et al. (2002) where results of second IQ test, increased by three and eleven points. Thus, suggesting IQ measurement is not reliable over a period of time. Moreover, IQ test have lack of external validity, due to culture bias, as the definition of intelligences varies within cultures. For instance, individualist cultures define intelligence as an individual’s quality, whereas collectivist cultures define intelligence as a shared knowledge between the individual and the society (Flanagan, 2011). Harkness and Super (1992), a intelligent child is the one who is respectful, trust worthy and obedient. Moreover, IQ tests have never claimed to measure all forms of intelligence such as social, verbal, musical etc. However, IQ test attempt to measure specific forms of intelligence. Hence, the measurement of intelligence is not valid, as it does not examine what it claims to measure.
In psychology, intelligence has been a greater debate, to whether it is determined by nature or nurture. Bouchard and McGue (1981), found that Monozygotic twins reared apart have similar IQ results. Thus, suggesting that intelligence is genetically determined, also identical twins display similar talents such as music, sport (Vinkhuyzen et al.2009). The influence of nature and nurture has been identified in adoption study by Horn et al. (1979), emphasising that the influence of environment declines with age while the impact of genes increases. The correlation highlights that genetic contribution is closer to parents. However, if individual’s intelligence is affected by nurture during infancy and childhood then intelligence is shaped.
One the other hand, research by Voracek and Haubner (2008) compared IQ results of twins and non-twins and found that singleton scored lower then twins, because twins are treated similarly (same friends and share time) then same sex individual. Thus, intelligence is determined by interaction with the environment. Similarly, children living in high social economical status scores ten times higher in IQ test then in low social economical status, due to access to resources which enhances cognitive and intellectual development. Hence, technology such as video games, films, computer, internet and TV have an enormous impact on intelligence.
Furthermore, Binet and Simon developed the first IQ test to identify children with special education needs in France. In addition, Simon and Binet, designed IQ to advance education opportunities. Unfortunately, it has been misused to create tension in the society. For instance, Terman (1918) assessed human traits and only intelligent people were encouraged to reproduce, in order to create a better human race, also Nazi’s adopted idea, where inferior humans, especially ‘Jews’ had to be destroyed . Furthermore, Immigrations were required to pass the IQ test in order to cross the border of the USA. In addition, the IQ test must not be used in education system, because teachers may treat students according to IQ results. Thus, children may feel degraded, the IQ results and feedback from teachers and students may lead to self-felling prophase. Hence, this may lead to under achievement. However, others argue that IQ test helps to identify learning disabilities, thus, those that require help needs to be identified. On the other hand, the IQ results and tests do not indicate any learning methods that may help individuals learn. Therefore, the behaviour of individuals at home and in the class is a better indicator of individual’s ability, rather than an IQ test.
In conclusion, if there is no single unified definition of intelligence, then how could intelligence be measured? Thus, the measurement of intelligence is problematic. Hence, this rise questions concerning the validity and reliability of the results and the IQ test. In addition, many researches fail to explain whether intelligence of ‘gifted learners’ is determined by nature or nurture. Moreover, IQ test should be used in education, this will provide information about children and adolescents about problem solving and to express themselves. Furthermore, information from the IQ test can be used to design tasks for children with learning difficulties or those gifted in academic areas.