Assessment Guide

Intelligence Tests for Different Age Groups and Intellectual Disability: A Brief Overview

Subodh Kumar, Divye Kartikey and Tara Singh

ABSTRACT

From an evolutionary point of view the one factor that helped humanity thrive and survive against all odds was the human’s ability to use their intelligence. Intelligence is what makes us unique among all the species in the world. The aim of this review paper was to discuss the role of intelligence tests in measuring intelligence of different age groups and diagnosing intellectual disability. The reviewed papers have revealed that measuring intelligence is not a construct that can only be measured for grown ups but it can also be measured for newborns. Although IQ tests are used prominently in judging school performance, job performance, intellectual disability and overall well-being, its measurement gets affected by emotions, genetics, cultural background and environmental factors. To improve the validity or accuracy of intelligence tests it is important to incorporate these factors.

Keywords: Intelligence, IQ, IQ tests, Intellectual Disability.

INTRODUCTION

Intelligence is the general cognitive ability to use attention and memory for learning and developing ideas to solve problems. Modern science defines intelligence as the ability to do abstract critical thinking, planning the strategy and solving the problem. However, intelligence is a wide concept and also includes the ability to comprehend complex ideas, Integrate the information, adapting oneself to situations, choosing appropriate response to stimuli, learning from experience, changing the environment and one’s own behaviour, overcome obstacles in life and many more. People differ in intelligence from one another and also in their ability to conduct cognitive tasks, which can be due to various reasons like genetic, personality or complexity of the task (Colom et al., 2010).

Journal of Psychosocial Research Vol. 16, No. 1, 2021, 199-209 DOI No. : https://doi.org/10.32381/JPR.2021.16.01.18

Corresponding author. Email : [email protected] ISSN 0973-5410 print/ISSN 0976-3937 online ©2021 Dr. H. L. Kaila http//www.printspublications.com

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Studying intelligence is important because it helps us understand the strengths, weaknesses, and unique abilities of an individual. Since intelligence is treated as a measurable quantity, currently there are many standardized tests in use which can measure intelligence with considerable accuracy, consistency and also predict future performance of individuals of all ages. The measured quantity of intelligence is called IQ or intelligence quotient and tests which measure IQ are called IQ tests. IQ can be calculated with the formula i.e. IQ = (intelligence age/actual age)x100.

Intelligence tests can be age scale or point scale. Age scale intelligence tests are based on the concept of calculating mental age for diagnosing intellectual disability. The Seguin Form Board test is an example of an age scale intelligence test. Point scale intelligence tests are based on the concept of calculating total points scored in the test to calculate intelligence. Most intelligence tests have both verbal and non-verbal questions. Separate scores are generated for both verbal and non-verbal, and combined score is the score after taking into account both the scores (APA Dictionary of Psychology, n.d.).

Classification of intelligence is expanding and new ways of analyzing it are coming forward. According to the traditional “investment” theory, intelligence can be classified into two main categories i.e. fluid and crystallized. Fluid intelligence is the ability to use reasoning to solve novel problems, in the absence of any prior specific knowledge. As we grow older fluid intelligence tends to decrease, especially in late twenties. It is also influenced by genetics. Crystallized intelligence is the ability to use previously learned knowledge to solve problems. As we grow older crystallized intelligence tends to increase. (Kaufman, 2013).

Intellectual disability: IQ tests are used not only to measure intelligence but also to diagnose intellectual disability. Intellectual disability is characterized by significant problems in cognitive functioning and social skills of an individual. In terms of IQ score, generally the score less than 70 and inability to carry out age specific day to day tasks amounts to intellectual disability. (American Psychiatric Association, n.d.; Schalock et al., 2010).

RESEARCH OBJECTIVES

The aim of this study is to discuss the role of intelligence tests in measuring intelligence of different age groups and diagnosing intellectual disability.

METHODOLOGY

Online databases (NCBI, PUBMED, PSYCINFO, PsycNET, Frontiers in Psychology, Google Scholar, Research gate) and websites were searched for papers published in

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English related to intelligence, intelligence tests and intellectual disability. Twenty seven articles (1994 - 2020) were identified and referred.

INTELLIGENCE TESTS

APGAR (Appearance, Pulse, Grimace, Activity, and Respiration)

APGAR test is a rapid test to evaluate the physiological condition of neonates at the time of birth to know the level of medical attention needed in case of resuscitation. The test evaluates a newborn on five parameters i.e. appearance, pulse, grimace, activity and respiration.

Low scores of 1 or 0 on each category are given if the newborn has pale or blue appearance, heart rate less than 100 beats per minute or no heart beats, no grimace, cough and crying on stimulation, less muscle activity or no muscle activity and Slow, irregular respiration or no respiration.

High scores of 2 on each category are given if newborn have, mostly pink appearance, heart rate more than 100 beats per minute, grimace, crying and coughing on stimulation, active muscle activity, healthy and normal breathing

The final score out of 10 is recorded at 1 minute and 5 minute after the birth. Scores less than 6 are considered as low whereas scores like 7 or more than 7 are considered as good scores (Simon, 2021).

APGAR is not only the indication of health of newborns during birth but also can predict the IQ in the later stages of life. A study in the UK found that infants having low APGAR scores during their birth seems to have a higher risk of having low IQ by the age of 18 (Odd, 2008).

Stanford Binet Intelligence test (SB)

The Stanford Binet intelligence scale is used to measure both the intelligence and intellectual disability. Currently its 5th edition is under use which can be administered to people in the age range of 2 to 89. cognitive abilities like Fluid reasoning, Knowledge, Quantitative reasoning, visual/spatial reasoning and working memory are measured in both verbal and non verbal format. In total there are 10 tests, for every cognitive ability there is a verbal and a nonverbal test. (Marom, 2018).

Wechsler Test for Preschool and Primary scale of Intelligence (WPPSI)

Currently the fourth edition of the test is under use i.e. WPPSI-IV. There are 14 subtests in it which are administered on children. For children who are in the age range of 2 years 6 months to 3 years 11 months, the subtests which are given include: block design

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(constructing model with coloured blocks), information (to answer general questions), object assembly (to fix pieces of puzzle into a standard arrangement), picture naming (to name a picture shown), receptive vocabulary (child points out the correct picture based on the vocabulary spoken aloud).

For children who are in the age range of 4 years to 7 years 7 months are administered the 5 above subtests along with subtests like animal coding, comprehension, matrix reasoning, Picture completion, picture concepts, word reasoning, vocabulary, symbol search and similarities (Slattery, 2015).

Wechsler Intelligence Scale for Children (WISC)

Currently the 5th edition of WISC is under use i.e. WISC-V. It measures 5 things that are as follows: visual and spatial index measures the ability of a child to process visual and spatial information like geometrical figures, fluid reasoning index, working memory index, processing speed index and verbal comprehension index. The individual scores from all the above indexes are combined to form a full scale intelligence quotient (Flanagan et al., 2010).

Kaufman Assessment Battery for children (K-ABC)

The Kaufman intelligence test was developed in 1983, by Alan S. Kaufman and Nadeen L. Kaufman. The test was based on Laria’s neuropsychological theory of sequential and simultaneous cognitive processing and contains four scales- (1) Sequential processing scale, (2) Simultaneous processing scale, (3) Achievement scale and (4) mental processing scale. Sequential processing scale measures short term memory through problem solving related to sequential or order placement. Simultaneous processing scale measures ability to solve problems by processing several information simultaneously. Achievement scale measures application of learned skills on practical problems, and mental processing scale measures the ability to solve problems by using both sequential and simultaneous processing (Marom, 2021).

Kaufman Adolescent and Adult intelligence test (KAIT)

This test measures fluid intelligence and crystallized intelligence. It can be administered on people from age 11 to 85. KAIT has a core battery and an extended battery. The core battery has six subtests, total time is 65 minutes, which measure parameters like crystallized intelligence(Gc), fluid intelligence(Gf) and composite intelligence. The extended battery has four additional subtests in addition to the subtests of the core battery and takes 90 minutes to complete (Fahmy, 2021).

Wechsler Adult Intelligence Scale (WAIS)

Currently the 4th edition of WAIS is under use i.e. WAIS-IV. In this test 4 major components of intelligence are measured.

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1) Verbal Comprehension Index- subtests include similarities, Vocabulary, Information, Comprehension.

2) Perceptual Reasoning Index- subtests include Block design, Matrix, Reasoning, Visual puzzles, Pictures completion, Figure weights.

3) Working Memory Index- subtests include Digit span, Arithmetic, Letter-numbering sequencing.

4) Processing Speed Index- subtests include symbol search, coding, cancellation.

The scores from all the subtests of all the indexes gives the full scale IQ score. Whereas the scores of similarities, vocabulary and information subtests from verbal comprehension index, and scores of block design, matrix reasoning and visual puzzles subtests from perceptual reasoning index gives the score on general ability index (Cherry, 2020).

Woodcock-Johnson Test of Cognitive abilities

The Woodcock-Johnson test of cognitive abilities was developed in 1977 by Richard Woodcock and Mary E. Bonner Johnson. Currently it’s 4th version is under use. It can be administered from a child of age two to an adult of age 90. The test is based on Cattell-Horn-Caroll’s theory of intelligence which focuses on nine main cognitive abilities like comprehensive knowledge, fluid reasoning, quantitative knowledge, reading and writing ability, short term memory, long term storage and retrieval, visual processing, auditory processing and processing speed (Hamour et al., 2012).

Raven’s Progressive matrices test

Raven’s progressive matrices test was developed by John C Raven in 1939. It is designed to measure the reasoning ability of individuals who are in the age range of 5.5 years to 11.5 years, adults and senior citizens. The questions are in the form of matrices in which pattern has to be figured to answer about the missing element in a matrix. The difficulty level increases as the test progresses. There are three types of Raven progressive matrices test: Standard Raven’s progressive test, Coloured Raven’s progressive test and Advanced Raven’s progressive test. Questions are presented in black and white pattern. It is suitable for adults who have high intelligence (Thiel, 2020).

Bhatia Battery of Performance test of intelligence

This test was developed by C.M. Bhatia in 1955. The battery is applicable to the illiterate as well as the literate groups with separate norms provided for each group. While the

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test was originally developed for the 11-16 years age group, the use of this test on adults beyond 16 years of age is based on the assumption that intelligence does not increase beyond 16 years of age which was set as the upper limit of the test (Barnabas & Rao, 1994). The test contains five subtests: Koh’s block design test, Alexander pass along test, pattern drawing test, immediate memory test and picture construction test (Roopesh, 2020).

Binet Kamat test of intelligence

This test is the indian adaptation of the Stanford binet intelligence test developed by Kamat for the age group of 3 years to 22 years. It is used widely in diagnosing intellectual disability. This test is administered by increasing the difficulty level of questions until a child fails to solve the questions. Questions below the child’s chronological age are also asked until a child solves all of them successfully. The test contains questions related to vocabulary, language, analogies, social reasoning, similarities and differences, and visual motor ability (Roopesh, 2020).

Seguin form board test

The Seguin form board test was developed by Seguin in 1856 for the age group 3 years to 15 years. The test measures the parameters like visual ability, eye and hand coordination, non-verbal ability, psychomotor ability and spatial ability. There is a form board which has 10 slots of different shapes and a participant has to place every block in the right slot within the best possible time. The time needed for the administration of the test is usually 10 minutes. A participant gets three trials and the best time among them is noted to calculate the mental age (Koshy, 2017).

DISCUSSION

IQ tests and overall well being: Studies have pointed that there are gaps in interpretation of IQ results. IQ tests focus only on selected mental abilities which are useful only for school admission, college admission and job roles. Research has found a weak correlation of IQ tests with overall individual well being. The solution is not to limit the importance of IQ tests but rather define intelligence in an inclusive way and also not to inflate the interpretation of IQ tests (Ganuthula, 2019).

IQ tests and emotions: Many studies have shown that motivation and emotions decides the performance of an individual in an IQ test. Motivation of a test taker gets affected by positive and negative emotions. Positive emotions like curiosity, resilience and courage boosts the performance of the test taker. Whereas negative emotions like fear and test anxiety negatively affect the performance in the IQ test. (Ganuthula, 2019).

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Intellectual disability and IQ tests: A study on the cognitive decline among children suffering from medulloblastoma, a nervous system tumour, was done. The disease is known to cause decline in information processing speed and visual motor tasks. Many patients were logical right in the tests but because they were slow in processing information, their IQ score on the wechsler scale was low which takes into account such factors for generating IQ score. Hence it is important that a proper neuropsychological assessment is done rather than just relying on a single score through IQ score (Wegenschimmel, 2017).

Colmar et al., (2006) have found that there are psychometric issues in IQ tests and that IQ tests have limitations in diagnosing intellectual disability. Most IQ tests are designed for normal people and tasks in these tests may not be age appropriate for intellectually disabeled.

IQ tests and School performance: IQ tests are used in schools for intellectual assessment of students. However, IQ scores do not explain the reason behind a student lagging in a specific academic task. For that, specific cognitive abilities need to be judged along with IQ scores to come to a right conclusion.(Ortiz & Lella, 2010).

IQ tests and Job performance: The use of IQ tests in predicting job performance is often cited as the usefulness of IQ tests. However, the problem with IQ tests predicting job performance is that appraisals in jobs are often subjected to bias like halo bias and may not correlate with IQ score. (Richardson, 2015).

IQ tests and Genetics: Studies on twins have found that IQ is heritable and that genes influence intelligence. Like all other traits intelligence is also inherited, however it is never 100%. To what extent intelligence gets inherited depends on the type of environment given. Unfavourable environment will never let genes fully express the qualities related to intelligence. Various cross-sectional and longitudinal studies have shown that the influence of genes on intelligence increases gradually from infancy to adulthood. (Plomin, 2015) .

CONCLUSION

As the world is becoming more knowledge oriented and skill driven, the role of intelligence and its measurement is becoming an important field of study. IQ tests are the most common method of intellectual assessment for all ages. For diagnosing any intellectual disability, they are the most objective tool available.Today, intelligence tests play a vital role in determining the future of an individual. Their role in diagnosing intellectual disability is also important for taking the right therapeutic approaches. Since its first use, IQ tests have through many modifications, updations and adaptations. In future also many new things will be added in IQ tests as the knowledge of intelligence

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and intellectual disability increases. The papers reviewed by us have shown that intelligence can be measured for all ages, from childhood to elderly. Intelligence tests like APGAR can measure intelligence of a newborn and also predict the future course of intellectual development in later life. Measuring intelligence and intellectual disability is a complicated task and although the IQ tests are comprehensive, cannot throw light on every aspect of one’s intelligence. The role of genetics, environment, culture and emotions on intelligence may not get reflected on IQ tests. It is important that the validity of IQ tests be improved so that interpretation and prediction of performance can be made more accurate. More knowledge we have about IQ tests and its limitations, the more they can be made better.

Implications

On the basis of our study we find that focus should be more on filling the gaps in the interpretation of IQ scores in such a way that more realistic predictions of future performance can be done. These gaps in interpretation of IQ score can result in error in judgement. For example a high score in IQ tests may not necessarily translate into good performance in the areas of life which demands high emotional regulation for achieving desirable results. Since IQ scores depend on many factors that can affect the cognition during the test like motivation, emotional state and many environmental factors like family stress, it is important that these factors should be incorporated while interpreting the performance on IQ tests. Our study has also found that for diagnosing intellectual disability, it is important to focus on adaptability skills rather than just IQ scores.

Contribution to the Existing Literature

Our review article comprehensively covers important intelligence tests for all age groups, which we did not find in any other paper. Our paper will be a ready reference for counsellors, teachers and professionals who want to have a comprehensive on intelligence tests for different age groups starting from the birth of a child.

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ABOUT THE AUTHORS

Subodh Kumar, Research Scholar – Department of Psychology, Banaras Hindu University, Varanasi, U.P., India.

Divye Kartikey, Student – Discipline of Psychology, IGNOU, New Delhi, India.

Tara Singh, Professor – Department of Psychology, Banaras Hindu University, Varanasi, U.P., India.

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