The Creation of Intelligence Quotient

Intelligence Quotient (Or IQ as we all know it) was devised in the early part of the 20th century by German Psychologist William Stern. It came about when Stern was using the Stanford Binet Test (known prior to this as the Binet-Simon test). During this test, which was a test to determine the 'mental age' of school children using a series of tests which started with simple things (following a match) ranging to more complex things such as repeating random sets of numbers and making rhymes. Stern found that the use of this, thus ones mental age could be used as a test of not just the child's development but also an individuals general – not specific – intelligence.

The mathematics behind the IQ test are as follows: The calculation is as simple as (Mental age / by Chronological age) x100.

The average for an IQ test is 100, thus if one achieves the score of 100 they are of average intelligence for their age (or have reached the correct age. Simply put, if a seven year old achieves a score of 100, they have achieved their own expected chronological age intelligence) so if one scores above 100, they are classed as above average (or genius but 150) and one achieving below 100 is below average.

Yet the intelligence test as we know it now did not come around until the English researcher Spearman conducted studies in England. He tested on 100 local school children, many of whom were heading to top English public schools such as Eton and Harrow. (both of which have intelligence requirements for entry). Thus Spearman thought it useful to test this sample. He tested them on the basis of the IQ test (mental age / chronological age x 100). Spearmans tests varied, but focused mainly on memory. Thus testing ones intelligence. However, he concluded his study by suggesting that those individuals who scored higher on IQ tests would also score higher on intellectual tests.

For those who are unsure of the differences between intelligence and intellect, see below.

'Intelligence (noun): The ability to acquire and apply knowledge and skills'

'Intellect (noun): The faculty of reasoning and understanding objectively, especially with regard to abstract matters.'

Thus, we can conclude that Spearmans test was important for both of these functions for it tested both levels in testing memory; as it would seem memory is important for both of these functions. - Suggesting of course that those with better memories are indeed the more intelligent beings.

Spearman looked at specific intelligence also (things such as mathematical ability). He found that although specific intelligence was indeed important for some tasks, his positive correlations suggested that the underlying and most important factor was indeed the general intelligence mentioned earlier, this being the important – if not essential – matter for good performance in IQ tests, as these test only general intelligence (or as Spearman labelled it 'g')

When in the mid part of the 20th century David Weschler began his studies on intelligence, he was one to confront the idea of IQ mathematics. His reasoning for this was that prior to his work, IQ tests had been performed mainly on children unless otherwise commissioned by government bodies. As Weschler pointed out, though the method is highly effective on children due to their rapid gaining of intelligence, it is completely defective on adults as their intelligence level begins to level out, thus meaning the older the adult the less intelligent they will appear. Weschler changed the IQ mathematics from those seen above to the one listed below.

Actual Test Score /by Expected Test Score for Age x100 (however this test involved further levels of standardisation)

Simply put the Weschler test(s) were designed to test the deviation from the standard scores which was achieved by the individual. Working on the same theory the Raven tests were developed. Only these tests followed the same theories as those of the Weschler tests, yet used measures which were independent of the influence of both culture and language which before had quite heavily influenced the tests – thus placing certain minority individuals at a disadvantage.

Following this, along came Thurstrones theory of intelligence, one which worked from Spearmans 'g' theory. Thurstone suggested that 'g' resulted from the formation of seven key factors. Those are listed below are follows.

• Associative Memory – Ability for rote learning
• Number – Be able to carry out mathematical tasks
• Perceptual Speed – Revolves around the perceptual system
• Reasoning – Inductive and deductive reasoning ability
• Spatial Visualisation
• Verbal Comprehension
• Word Fluency

According to Thurstone a fluent and confident possession of all these abilities proved a higher level of 'g' than in their absence. It was until the emergence of the theories of a man called Cattell that we, in psychology, got a real understanding of intelligence. Once again, Spearmans 'g' is featured and not disputed. However, Cattell proposes two broad scopes to general intelligence. This being 'crystallised intelligence' (the things we are not consciously aware of acquiring and are harder to change – knowledge of culture and language.) and fluid intelligence (the easily used part, this referring to the ability to objectively analyse and use abstract thinking which is free of cultural influences). Cattell suggests that the fluid intelligence is present from birth, stabilising in adulthood, whereas crystallised intelligence is more formed in adulthood, thus this is why many adults have less changeable opinions and less ability to engage in new activities – the use of technologies.

In 1977 Guildford proposed the Structure of Intellect Theory, which in essence completely disagreed with Spearmans aging theory of 'g'. Guildford instead suggested there were 120 – 150 different factors which built intelligence. Below are just some of the suggested possessed abilities. They are split into numerous categories.

Operations (Mental Processing)

• Evaluation
• Convergent Production ('ability to bring more information to a single theme' – Maltby, Day, Macaskill, 2013)
• Divergent Production
• Memory
• Cognition

Contents

• Visual
• Auditory
• Symbolic
• Semantic
• Behavioural

Products

• Units (Ability to comprise information on something which is classed as a unit)
• Classes
• Relations
• Systems
• Transformation
• Implication

Yet it was the work of Vernon (1950) which really brought about more information. He suggested that 'g; was of key importance when talking about intelligence. Following this however he suggested more specific intelligence followed, primarily in the appearance of verbal/educational intelligence (v:ed) and spatial/mechanical abilities (k:m). These then subdivide in more specific – and subgroup – intelligence which is deemed least important. Vernons theory thus became known as the Hierarchy Theory of Intelligence.

To conclude, Gardner is a more recent theorist whom suggested that the sensory system had little or nothing to do with the individuals intelligence and thus, intelligence is not a sensory system and is almost completely independent of sensory systems in general.

References

Maltby, J., Day, L., & Macaskill, A. (2013) Personality, Individual Differences and Intelligence. (3rd Ed) Chapter 12. London: Pearson