2.4 Assesment of intelligence

2.4 Assesment of intelligence

A good intelligence test includes

• Standardization of administration

• Variety of task

• Norm referencing

What are intelligence tests used for?

• Selection

• Diagnosis

• Evaluation

Remember is the test?

• reliable

• validated

• useful

Reliability

• Internal: Items that measure the same construct

• Measures the consistency of test results

• Test-retest → Similar IQ scores in different times

- IQ scores can fluctuate (± 15)

- Is it accurate to assign a single IQ score based on one test administration? NO

The test provides consistent results over time and across different settings.

Test-retest:

Similar IQ scores in different times

(Consistency of a test over time.)

Validity

• intelligence tests may not measure all aspects of intelligence (multiple intelligences theories vs singular intelligence)

• intelligence is influenced by cultural and contextual factors

• refers to how well a test measures what it is supposed to measure

Usefulness

• Intelligence tests predict academic/ job performance but their predictive power diminishes over time and is affected by situational factors

• Present limitations guiding educational interventions

• refers to how well a test serves its intended purpose in real-life settings — whether in education, clinical practice, job placement, or research.

Instruments for measuring intelligence

Wechsler Adult Intelligence Scale (WAIS

Wechsler Adult Intelligence Scale (WAIS

• four different versions

•  scales have been revised to incorporate improvements and adapt scales to the current population

1st version Wechsler

• He designed and standardized among a sample of 1,500 adults

• known as Wechsler Intelligence Scale 

In 1955 Wechsler introduced two tests

1. Wechsler Adult Intelligence Scale (WAIS)

2. Wechsler Scale for Children (WISC) 

Wechsler Adult Intelligence Scale (WAIS

• adults aged between 16 and 75

 Wechsler Scale for Children (WISC) 

•  children aged between 5 and 16 years.

 importance of including verbal & nonverbal tests

✓ Verbal scale

✓ Manipulative scale

✓ Total IQ

Wechsler's original test

assess intellectual ability

such as:

• Verbal comprehension

• Abstract reasoning

• Perceptual organization

• Quantitative reasoning

1st version WAIS (Wechsler)

• WAIS (Wechsler Adult Intelligence Scale, 1955).

• Evaluates: total IQ, verbal IQ, manipulative IQ

Includes 11 tests:

Information, Comprehension, Arithmetic, Similarities, Digits, Vocabulary, Number Key, Incomplete Figures, Cubes, Comic Books and Puzzles.

The 1st version includes, how many tests?

Includes 11 tests:

Information, Comprehension, Arithmetic, Similarities, Digits, Vocabulary, Number Key, Incomplete Figures, Cubes, Comic Books and Puzzles.

2nd version WAIS (Wechsler):

- WAIS - R 

3rd version WAIS (Wechsler)

WAIS - III 

4th version WAIS (Wechsler)

• the version of test which we use today

• Includes 1 general scale (total IQ) and 4 subscales:

  Verbal Comprehension Scale

  Perceptual Reasoning Scale

  Working Memory Scale

  Processing speed scale

Materials

• Technical and interpretation manual.

• Application and correction manual.

• Stimulus booklets

• Response booklet

• Bicolor cubes

• Correction templates

Qualification level in the test? Must be introduced by who?

• a person with from an advanced degree in Psychology

Questionnaire description (purpose, application, age, duration)

• to assess the intellectual aptitude of adults

• individual

• 16 -89 years old

• 60 minutes for 10 main tests

• 90 minutes for complete application

Cognitive areas evaluated in the test (the scales)

• Verbal comprehension

• Perceptual reasoning

• Working memory

• Processing speed

General intellectual aptitude (total IQ)

Verbal comprehension scales main tests:

• Similarities

• Vocabulary

• Information

Verbal comprehension scales optional test

• Comprehension

Similarities

• verbal comprehension scale

• 18 items

• Composed of words of common objects or concepts

• AIM: evaluate verbal reasoning and concept formation

Example of similarities:

How are they similar?

orange - pear;

dog - lion;

table - chair

Vocabulary

• verbal comprehension scale

• Task 1: name object presented on the picture.

• Task 2: define words that the examiner names.

• Aim: to evaluate the subject's lexicon and formation of

  verbal concepts.

• the range of words gets harder to define

Example of Vocabulary

What does the word rivalry mean.

• what does an apple mean?

Information

• Verbal comprehension scale

• Task: To answer orally questions about general

  knowledge.

  Aim: To assess the ability to acquire, store and retrieve

  knowledge.

example of information test

What is the capital of Spain?

The index of Verbal comprehension assesses

• the ability to understand, generate and transfer verbal information.

• (how well a person thinks and learns using language)

Perceptual reasoning scales main tests

• Cubes

• Matrices

• Visual puzzles

Perceptual reasoning scales optional tests

• Scales

• Incomplete figures

Cubes test

• Perceptual reasoning scales

• 14 items

• 30 seconds to complete

• Task: to reproduce with colored cubes the models represented in plates.

• Aim: to evaluate the ability to analyze and synthesize abstract visual stimuli.

Example of Cubes test

• the person observes the psychologist creating a image of the cubes, the task is to create as similar image of the cubes as the psychologist

Matrices

• Perceptual reasoning scales

• 26 items

• Task: to observe a matrix or an incomplete series and select the correct one among different options.

• Aim: to evaluate fluid intelligence, general visual intelligence, spatial aptitude and classification

Example of Matrices

• the person must complete the photo by selecting the correct item to the rest

Visual puzzles

• Perceptual reasoning scales

• 26 items

• Task: the examiner shows a puzzle that the subject must reproduce by selecting the 3 images that complete it.

• Objective: to evaluate non-verbal reasoning, ability to analyze & synthesize visual stimuli.

The index of Perceptual reasoning measures

• The ability to process visual and spatial information, as well as to reason and solve problems with that information

Working memory scales main test

• Digit span

• Arithmetic

Working memory scales optional tests

• Letters and numbers sequencing

Digits span

• Working memory scales

• 24 items

• Task 1: digits in direct order.

  Task 2: digits in reverse order.

  Task 3: digits in increasing order

• Aim: to evaluate learning, memory, attention,

  auditory processing of information

Example of digit span (photo)

Arithmetic

• Working memory scales

• 22 items

• Task: mentally solve a series of arithmetic problems and give an answer in the time limit.

• Aim: to evaluate mental representations, concentration, attention,

  short and long term memory.

Example of Arithmetic

• Arithmetic problems

• Paula is 23 years old and Mario is 15 years older. How old is Mario?

The index of Working memory assesses

• The ability to retain and manipulate information in short-term memory.

Processing speed scales main tests:

• Digital symbol-coding

• Symbol search

Processing speed scales optional tests

• Cancellation

Symbol search

• Processing speed scales

• 60 items

• Task: to observe two model symbols & determine whether or not they are among another group of symbols in a limited time.

• Aim: to evaluate visual short-term memory, visual-motor coordination, cognitive flexibility, visual discrimination

Example of symbol search test

• the time is limited

• identify if the items corresponds to the table

  

Digital symbol-coding

• Processing speed scales

• 135 items

• Task: copy symbols matched to numbers in a limited time.

• Aim: to assess processing speed, visual short-term memory, learning ability, and psychomotor speed.

Example of Digital symbol-coding

The index of Processing speed measures

• duration: 1 min 30 seconds

• the speed with which visual information can be processed efficiently.

Punctuation of EACH TEST

• The direct scores obtained in each of the tests are transformed into scalar scores:

  - Mean (M)= 10

  - Standard deviation (SD) = 3

Punctuation of the 4 general scales & IQ

• 4 general scales & IQ:

• M = 100 & SD = 15

Ecological validity

• General intelligence related to work performance, psychological well-being.

• Specific domains not clearly related to other aspects.

• how well the results of a test or study apply to real life or everyday situations.

Practical WAIS applications

• most universal test applied

• Great practical and clinical utility.

• Used for more than 70 years in different contexts:

  • Identification of intellectual disabilities

  • Learning disorders

  • Clinical intervention

  • Neuropsychological evaluation.

The results of intelligence assessment tests can help in

•  early detection of cognitive impairment:

✓ First signs impairment: 20-29 years.

✓ Significant impairment: > 55 years.

• we can therefore evaluate cognitive impairment in the patient

Areas of cognitive impairment

•  Processing speed.

• Executive functioning

• Sensory acuity

• Psychomotor aptitude.

• Working memory

• Attention

Scores obtained on the tests may be invalidated due to:

• Application errors

• Recent exposure to the items

• Physical and sensory limitations of the subject

• Erroneous response patterns (I don't know, always the same answers).