Certain psychological attributes have been shown to be
more relevant for long term decision making.
 

Psychological Attributes vary on a fluid - stable continuum

Fluid attributes such as mood can change on an hour to hour basis. This instability indicates that moods are not great predictors of future behavior within a particular situation.

Attitudes and Opinions are also relatively fluid from 18 to 25.

Personal Values can also change over time.

The fluidity of the above attributes makes them less than optimal predictors of important behaviors
 
 

Stable Psychological Attributes
 
 

Stable attributes are essential in making long term predictions.

Some researchers, for example, believe that an individual�s personality is basically set by age 5.

Intelligence, although relatively fluid at an early age, is relatively
stable across the majority of adult years.

The validity of the SAT test, for example, is dependent on the stability of intelligence.

Broad classes of Interest are also relatively stable.
 
 

Due to the relative stability of measures of ability, interest, and personality, these three areas are the primary focus of people using psychological tests to predict future behavior.
 
 
 

One important assumption that is made when measuring these attributes is that :
 

All psychological attributes of interest are assumed to be normally distributed.
 

Therefore, all psychological attributes should reveal individual differences.
 

This assumption of normal distribution is necessary in order to analyze data with parametric statistics.
 
 
 

When using psychological attributes in making predictions, it is absolutely vital to match the appropriate attribute with the predicted behavior.

For example, measures of general intelligence wouldn�t be of much use in determining an appropriate psychological treatment.
 
 

Intelligence -- General Mental Ability
 
 

What is Intelligence ?

Intelligence is a construct, not a concrete object.

Researchers disagree on what the definition of intelligence should be.

Although we may not be able to definitively answer what intelligence is, we can list behaviors which we feel represent some level of intelligence:
 

Crossing a busy street without looking both ways.
 

Being able to solve a Rubiks cube without physically taking it apart and reassembling it.
 

Being able to get a super low airfare on priceline.com
 
 

These behaviors indicate various types and levels of intelligence.

Additionally, none of these behaviors alone can be said to represent the entire range of intelligent behavior.
 
 

Scientists believe that intelligence is a valid and useful construct for two reasons :
 

First, a wide variety of mental processing tasks show systematic individual variation. An individual who performs well on one measure of cognitive ability, will likely perform well on other measures of mental processing.

Second, this construct is related to success in a wide variety of life tasks : school performance, training programs, and work behaviors.

So, since intelligence does exhibit consistent individual differences and can be used to predict performance in a number of important areas, Psychologists study general mental ability extensively.
 
 

General Mental Ability (intelligence) : The performance of tasks involving the manipulation, retrieval, evaluation , and/or processing of information which shows individual differences.
 

Different theories of Intelligence

Spearman�s two-factor theory of intelligence (1904)

Spearman observed that an individual�s scores on any two cognitively demanding tasks were positively correlated. This led him to believe that a general intellectual factor (g), was responsible for this correlation.

Since the correlation isn�t perfect (r = 1), he stated that each test measures some portion of g.

Test Score = g +S + e;

Where S is the specific factor which is independent of g and e represents measurement error.

Three implications of Spearman�s work:

1. Since S is a test specific attribute, differences across tests are due to differences in g.

2. A good intelligence should be highly g loaded.

I.E. g should be measured disproportionately to S & e

3. An accurate measure of g should reliably predict performance on a wide range of mental tasks.
 
 
 

L. L. Thurstone and grouping factors.

Thurstone didn�t believe that the g factor could explain all variation across cognitive tests.

Thurstone theorized that there were common group factors present in different classes of tests.

For example, a reading comprehension test and a vocabulary test show greater correlation than do a reading comprehension test and a measure of numerical ability.

These group factors are independent of one another, but still related to g.

Thurstone (1938) hypothesized seven primary mental abilities, which together combined to create g:
 

Verbal Comprehension - vocabulary, reading, verbal analogies

Word Fluency --- anagrams, rhyming tests

Number -- mathematical operations

Space - spatial visualizations and mental transformation.

Associative Memory -- rote memory

Perceptual Speed -- quickness in noticing similarities and differences

Reasoning - skill in inductive, deductive, and math problems

Thurstone thought it more important to measure these separately than to simply assess g.
 
 
 

Cattell (1963) theorized two types of general intelligence:
 
 

Fluid Intelligence : the ability to see relationships, i.e. analogies and number and digit series completion.

For example : 2 4 8 16 ___ ___ ___
 
 

Crystallized Intelligence: an individuals acquired set of knowledge and skills.

In cognitive psychology, crystallized intelligence is further divided into:
 

Declarative Knowledge: Fact based information

Procedural Knowledge: How to do things.
 

Fluid and Crystallized intelligence measures are highly correlated.

However, they show different developmental patterns, so they may be conceptually distinct.
 
 
 
 
 
 

Hierarchical Models of Intelligence

Vernon (1960) borrowed from both Spearman and Thurstone in his conception of intelligence.

General intelligence, g can be broken down into two major group factors --- Verbal-Educational, and Spatial - Motor.

In turn, these major group factors can be broken down into minor group factors, and these minor factors account for patterns of association seen in cognitive ability tests.
 

Carrol�s (1993) three levels of cognitive ability model follows the same principle. However, Carrol�s model was developed with the aid of factor-analysis, a statistical technique which clusters responses on a particular dimension.

Carrol�s general factor g is broken up into 7 classes of broad abilities:

Fluid Intelligence

Crystallized Intelligence

General Memory

Visual Perception

Auditory Perception

Retrieval Ability

Cognitive Speediness

These broad abilities can be broken up into specific abilities

Hierarchical Models suggest that both broad and general abilities can be measured.

The key is to determine what you are trying to predict, and to match the type of intelligence which is most relevant to making your predictions.

If you wanted a general classification of children, for example, than a standard measure of g would be highly appropriate.

If you wanted to be able to distinguish among different levels of mechanical abilities, then a narrowly focused ability test would be more appropriate.
 
 
 

Guilford�s Structure of Intellect Model
 

Rejecting the idea of g, Guilford has theorized that intelligence is best seen as a function of Content, Operations, and Products in a three dimensional model.

Guilford identified 6 types of specific operations,

5 types of specific content, and 6 types of products produced by thought. All together this represents 180 different types of specific intelligence.
 
 
 

Cognitive Processes and Intelligence

Robert Sternberg focuses on what produces intelligent thought, rather than how to measure it.

Sternberg�s conceptualization of intelligence deals with how intelligent behavior is generated, what behaviors are intelligent in specific environments, and when a specific behavior is intelligent.

Sternberg is more interested in how intelligence is created and how the mind works than in strictly deciding how to measure intelligence.
 

Cognitive theories like Sternberg's will have profound impact on the next generation of intelligence tests.
 
 
 
 

Modern statistical calculation of intelligence

IQ -- Intelligence quotient

The Stanford-Binet test of 1916 calculated I.Q. as follows:

IQ = (MA/CA) x 100

MA = mental age CA = chronological (actual) age

Because Mental Age doesn�t typically grow after 25, this method underestimates most adult IQS.

On modern tests, a deviation IQ is obtained.

By comparing your actual score on an intelligence test to the average score on that test, we determine whether you are above average, below average , or average in intelligence.

We take the raw data from the test (your score, the average, and the standard deviation) and we statistically transform the score into a distribution where the mean is 100 and the standard deviation is 15.

Because this is a normal (bell curve) distribution, we can

state with certainty where you fall within the population.
 

Characteristics of a good test of General Mental Ability
 
 

1. Broad sampling of tasks : If you believe that there are 7 (or 180) Broad classes of mental ability, then you should have problems which address each type of mental category.

2. Sufficient sample of items within task type. 30 or more would be statistically ideal, less than 10 would be statistically shaky.

3. General Intelligence tests should not test specific content. Achievement type items, which show mastery of specific subject area, should be kept to an absolute minimum. Remember, we want to tap into the process of intelligent action, not retrieval of specific facts.

4. Indifference of the indicator: underlining the point made in three, the specific content of a test item is not nearly as important as the content of the underlying process which produces a specific answer.