INTELLIGENCE: Its Meaning and Measurement

I. Definition

Intelligence comes from the Latin word “intellectus” which means perception or comprehension. It is interchangeably called “mental ability”. It is the global capacity to act purposely, to think rationally, and to deal effectively with the environment. Meanwhile, Bustos defined intelligence as a composite of general and specific abilities characterizing an individuals level of neurological functioning in the context of his effectively applied experience and manifested in his dynamic coping with the challenges for adjustment which makes day – to – day living while Ceci defined it as the ability for complex thinking and reasoning.

II. Origin and Nature of Intelligence

• Hereditary Influence 

          Sir Francis Galton, an early investigator of individual differences, observed that there were family differences in ability and concluded mental ability was hereditary.  Heritability is defined as the extent to which genetic individual differences contribute to individual differences in observed behavior

• Environmental Influence

1. Changing environmental conditions
 People are being exposed via televisions and other media resulting in an increasing amount of information.
2. Environmental Deprivation
Intelligence can be reduced by the absence of certain forms of environmental stimulation early in life.
3. Environmental Enrichment
removing children from unproductive, restricted environments and placing them in more favorable settings seems to enhance their intellectual growth.
4.School Environment
Students who attend school regularly score higher on intelligence tests than students who attend irregularly.

5.Biological Factors Influencing Environment 

Many biological factors that children encounter while growing up can affect their intelligence. These are: (1) prolonged malnutrtion and; (2) alcohol and drugs

III. Intelligence Tests

• Characteristics of intelligence tests

1. Validity

It is the extent to which a test measure what it purpose to measure. For intelligence test, these four types of validity are to be considered with guided question: (1) Face Validity; (2) Content Validity; (3) Concurrent Validity and; (4) Predictive Validity

2. Reliability
It refers to the accuracy, precision or consistency of a score obtained through the test.
3. Practicability\utility
It refers to the ease and feasibility of administering the test.  Practicability would include “efficiency.”

• Salient Intelligence tests

   A. Wechsler Scales - are a series of standardized tests used to evaluate cognitive abilities and intellectual abilities in children and adults.

   Characteristics of Wechsler Subtests:

A. Verbal Scale 

 Information - general information and in part assess learning and memory

 Comprehension- tap social comprehension, the ability to organize and apply knowledge.

 Similarities- determine the ability to analyze relationships. 

 Arithmetic- provides measure of an ability to work with arithmetic problems.

 Vocabulary- measures one’s ability to learn words and express their feelings

 Digit Span\sentences- asks the examinee to repeat the series of numbers in the sequence

 Letter-number Sequencing- taps marking memory

B. Performance Scale

 Picture Arrangement- measures the ability to perceive and visually organize a sketch

 Block Design- tap the ability to comprehend or size up  a whole situation, attention , concentration and able to see cause and effect.

 Object Assembly- pattern recognition & psychomotor speed.

 Coding \Animal Pegs- taps learning ability, rote recall ability, psychomotor speed, concentration and attention.

 Mazes- measures perceptual motor skills, psychomotor speed.

 Geometric Design- provides index of child’s perceptual motor skills.

 Symbol Search- taps cognitive processing speed.

 Matrix Reasoning- a nonverbal analogy task designed to tap perceptual organizing abilities and reasoning

B. Stanford-Binet Test - an individually administered measured of an individuals intellectual status. It became the standard by which other tests were judged, due to the care with which it had been developed, its validity, and its use of the “IQ” concept.  

Subtests of the Stanford Binet test
1. Verbal reasoning
2. Abstract/visual Reasoning
3. Short term memory

IV. Intelligence Quotient
An index of measured intelligence expressed as the ratio of tested mental age to chronological age, multiplied by 100.
IQ (intelligence quotient) = MA (mental age)
        CA (chronological age) x 100
V. Levels of Intelligence

• Mental Retardation or feeblemindness

Mental retardation is a general term used to refer to hundreds of conditions that share common symptoms of subnormal intellectual functioning and impaired adaptive behavior that seem to originate during the developmental period of the individual. 

According to IQ level, these individuals below 70 are potentially mentally retarded. Whether they require institutional or other specialized care depends in large part upon the general social situation in which they find themselves.

1. Severe Mentally Retarded (Custodial)
 IQ’s below 25 ;M.A. of less than 3 years
 the lowest  in intelligence
 incapable of learning to any noticeable degree
 require close supervision and care in such simple habits.

2. Moderate  Mentally Retarded (Trainable)
 IQ’s between 25 and 50; M.A. of 3 to 8 years
 higher in the scales of intelligence than the custodial.
 cannot learn to read, spell, or do arithmetic.
 seldom acquire much of a speaking vocabulary.
3. Mild Mentally Retarded (Educable)
 higher of the mentally retarded group.
 IQ of 50 to 70 and, as adults; M.A.of 8 to 11 years.

 can usually complete the first three or four grades of elementary school but fails frequently and is considered stupid by teachers and fellow students.  

• The Borderline Defective to Very Superior Intelligence Level.

1.  Borderline Defective
-IQ scores of 70 and 80
-Quite capable of following routine if sufficient patience is exerted to establish.
2. Low Average
-IQ scores between 80 and 90
-can learn all the basic skills-reading, writing, and motor activities but frequently with some difficulty.
3. Normal or Average
-IQ scores between 90 and 110.
-the vast bulk of the population, 50 per cent or more, falls into this category.
-Have the capacity for relatively easy accomplishments of skills demanded.
4. High average
The group with IQ’s of 110 to 120 is not nearly so well-defined as the counterpart on the opposite side of the average group.
5. Superior
The group with IQ’s 120 to 130 include the largest number of those with the capacity for reasonably easy accomplishment of the schooling necessary for professional scientific work.
6.Very Superior  
Those with IQ’s of 130 to 140 are classified as very superior.

A genius refers “to those who manifest very superior general intelligence” often defined as 140 or greater and who have demonstrated their superiority through an unusually high level of achievement in an intellectually demanding pursuit. Prodigy, on the other hand, is generally used to refer to individuals who have achieved special distinction in a specific enterprise, usually at an early age, but without the requirement of superior psychometric (test) intelligence.  

VI. Theories of Intelligence

• The Psychometric Approach of Charles Spearman presents the measurement (metric) of individual differences in behaviours and abilities. Spearman required that people need a certain “general” ability, which he called “g”. Additionally, he also suggested that each tasks or all tasks require the use of a “specific” ability, which he called “s”. Thus, intelligence consists of general ability plus an unknown number of specific abilities such as mechanical, musical, mathematical, logical, and spatial ability.
• Fluid and Crystallized Intelligence by Raymond B. Catell explained that fluid intelligence is the capacity to develop ability to learn new skills and it also consists of the power of reasoning and using information, the ability to perceive relationship, solve unfamiliar problems, and gain new types of knowledge, whereas, crystallized intelligence consists of acquired skills and knowledge and the application of that knowledge to the specific content of a person experience. It also includes the skills previously automatically learned and practiced by someone who has had the training and education for years.
• Multiple Intelligences by Howard Gardner claimed that people have numerous unrelated forms of intelligence. 

• Triarchic Theory of Intelligence of Robert Stenberg formulated the detailed processes of intelligence called “Triarchic theory” . This theory deals with the three aspects of intelligence as stated below:

1. The cognitive process that occur within the individual includes components such as learning the necessary information, planning an approach to a problem, and combining the knowledge with the plan to solve a problem.
2. The identification of situations that require intelligence i.e. to differentiate novel situations from repeated situations, they require different responses.
3. The relationship between intelligence and the external world wherein an intelligent person either adapts to the environment or tries to improve the environment, or if fails, escapes to better environment.