INDIVIDUAL DIFFERENCES IN INTELLIGENCE CONTENTS

1.0 INTRODUCTION

Individuals differ in different ways. There are many theories about individual differences. In this unit, the various reasons that may account for differences in intelligence are examined. The unit also examines the concept of intelligent quotient (I.Q.) and its dynamics.

2.0 OBJECTIVES

By the end of this unit, you should be able to:

1.   explain what is meant by normal distribution; 
2. identify different forms in which intelligence comes into play; and state the defect in IQ. 

3.0 MAIN CONTENT

3.1 Intellectual Performance

Globally, people differ greatly in intelligence, aptitudes, physical strength, manual dexterity, knowledge, skill, interests, personality traits, motivation, threshold of tolerance, and many other attributes which potentially influence behavior and productivity.


Of a group of exceptionally intelligent persons, one may be an artist, another writer, a third a mathematician, a fourth a historian, and so on.
Their high intelligence comprises a high general factor plus one or more specific factors. This theory helps to explain why some bright pupils may be outstanding in certain subjects and only mediocre in others. We all know a pupil who is clever at mathematics and dull in languages or vice-versa. Gardener suggests that intelligence comes in at least the following forms: (a) Musical Intelligence or Sensitivity to pitch, melody, rhythm, and tone.

1.  Linguistic intelligence, or sensitivity to the meaning and order of words and varied uses of languages. 
2.  Logical-mathematical intelligence or the ability to handle long chains of reasoning and to recognize patterns and order in the world. (d) Spatial intelligence or the ability to perceive the visual world accurately and to recreate, transform, or modify aspects of that world based on one's perceptions. (e) Interpersonal intelligence or access to one’s own ‘feeling of life’. We will now consider two styles of reasoning. ‘Convergent and divergent’. We will describe the boys as convergers and divergers. 

The converger is the boy who is substantially better at the intelligence tests than he is at the open-ended tests; the diverger is the reverse. By open- ended tests, we mean objective/multiple-choice test. In addition to this categorisation, there are the all-rounders, the boys who are more or less equally good (or bad) on both types of text. It may well be that 30% are divergers, and the remaining 40% could be in the middle as all-rounders. In a typical classroom, we may find extreme divergers (10%); moderate divergers (20%): all-rounders (40%); moderate convergers (20%); extreme convergers (10%).
Let us go on with our discussion.

3.2 Mental Ability

As it has been argued elsewhere (Alhassan, 1989), the most important element in all of education is the element of individual differences. If there is anyone characteristic of people which is universally valid and important, it is that they differ. To say that all persons are created equal is a statement of human rights under the law. It communicates nothing at all about human nature.

SELF-ASSESSMENT EXERCISE 1

Five attributes which influence behaviour are:

3.3 Normal Probability Curve

Let us continue our discussion by looking at figure 1 which is generated by graphically plotting the distribution of IQ scores we discussed in unit 6. Fig. 1: A Normal Distribution Curve of Intelligent Quotient (IQ) Figure 1 suggests that mental ability essentially follows a normal probability or bell shaped curve. The figure looks simple, but it is significant that most people are jus average and, therefore, cannot be expected to perform well on many jobs that demand the complex mental process required, for example in most scientific and professional positions. It is important for you to note that an individual’s IQ, would be equal to 100 if his mental age exactly matched his chronological age. Thus, IQ’s greater that 100 reflect advanced or accelerated intellectual development, while those below 100 reflect some degree of intellectual slowness or backwardness. It is to be noted that any plan for Universal Basic Education in Nigeria must provide for the intellectual diversity of children. It is clearly undesirable to educate children to take an examination which they are unlikely to pass. A secondary school which concentrates on getting as many senior secondary school students as possible to the university would provide a poor education for children of low IQ.

3.4 Defects in I.Q.

Although the intelligence quotient reflects the extent to which a child is mentally advanced or backward for his/her age, this particular index of intelligence has a weakness: while mental age must necessarily stop increasing at some point during an individual’s life, chronological age, alas, does not. Referring to this major weakness in the IQ, Baron et. al. (19-70) argues that scores determined in this simple manner begin to decrease as maturity is attained. As students of Developmental Psychology, we know that mental development seems to reach a maximum in the late teens or early twenties. 

I am sure you feel something should be done to remove the weakness in IQ.
Let us go on with our discussion. It is not surprising, therefore, that in the face of this serious weakness; IQ scores based on the concept of mental age were replaced some years ago by another measure called deviation IQ.

Remember that scores derived by this new measure represent an individual’s performance on the test relative to those of other persons of his/her age. Thus, the average performance of all such persons is arbitrarily set equal to 100, and the individual's IQ then expresses the extent to which his/her own performance departs (that is deviates) from this level. You must note that a major advantage of such scores is that they are statistically adjusted in such a manner that it is possible to tell, from appropriate mathematical tables, precisely what proportion of others taking the test score higher or lower than a given individual.

SELF-ASSESSMENT EXERCISE 2

Complete the following sentence:…………………….essentially follows………………………………….probability curve.

4.0 CONCLUSION

In this unit, you have learnt that the most important element in all of education is the element of individual differences. You have therefore learnt that universally, people 100 if differ greatly in intelligence, aptitudes, manual dexterity, and personality traits, amongst others.

5.0 SUMMARY

1. What you have learnt in this unit concerns differences in intelligence.
2. You also learnt that mental ability essentially follows a normal probability curve
3. You equally learnt that IQ is defective and the concept of deviation
IQ was explained and understood.

6.0 TUTOR-MARKED ASSIGNMENT

1. a. State the most important element in all of education.
b. State attributes which may influence behaviour and productivity

 c. Describe the importance of the normal probability curve
d. Who is a converger?