Psychology
Chapter 10
Reasoning and intelligence

Reasoning: The process by which we use our memories in adaptive ways
Intelligence: our general capacity to reason

How people reason I: fast and slow thinking, analogies and induction

We reason by using our memories of previous experiences to make sense of present experiences or to plan the future.
To do so, we must perceive the similarities among various events we have experienced.

Fast and slow thinking

Cognitive processes could be placed on a continuum from automatic to effortful.

• At one extreme, automatic processes require none of the system’s limited resources, occur without intention or conscious awareness and do not interfere with the execution of other processes (or improve with practice, or vary with individual differences).
• At the other extreme effortful processes are everything that automatic processes are not.

It is useful to think of any cognitive process as falling somewhere along this continuum.

When solving problems, people have two general ways of processing. (Dual-processing theories).

• The automatic end of the information-processing continuum. Processing is fast, automatic and unconscious.
• Effortful side of the continuum. Processing is slow, effortful and conscious.

In many cases, when presented with a problem, you cannot shut of the ‘fast’ system, even if it may interfere with your arriving at the correct solution to a problem via the ‘slow’ system. (Like the stroop interference effect).

The ‘fast’ implicit system effortlessly produces impressions, feelings and intuitions that the ‘slow’ explicit system considers.
The effortful ‘slow’ system has potential control over the ‘fast’ system. (But when making routine decisions, the ‘fast’ system is in control. Like reading and making sense of language). The fast system even makes simple decisions, some of which are in contradiction to the correct solution that can only be derived by using the slow system.

Fast processing is not unique to humans. But no other species comes close to the effortful, explicit cognition displayed in Homo sapiens.

Analogies as foundation for reasoning

Two kinds of reasoning that depend quite explicitly on identifying similarities are:

• Analogical reasoning
  Analogy: a similarity in behavior, function or relationship between entities or situations that are in other respects quite different from each other.
• Inductive reasoning
  The attempt to infer some new principle or proposition form observations or facts that serve as clues.
  Intuition is based, unconsciously or consciously, on your deep knowledge of the concepts referred to in the problem and your understanding of the relationships between those concepts.

Success on analogical reasoning problems in highly dependent on the similarity between objects.

Use of analogies in scientific reasoning

Scientist often attempt to understand and explain natural phenomena by thinking of analogies to other phenomena that are better understood.

Uses of analogies in judicial an political reasoning and persuasion

Analogies are a fundamental component of human thought and persuasion.
Such reasoning is useful to the degree that the structural relationships in the analogy hold true.

Analogical reasoning: Fast or Slow?

It depends.
When the similarity relations are very familiar, processing is fast and almost automatic.
When the analogies are not so simple, slow, effortful processing is needed to solve the problems.

Successful performance on challenging analogical reasoning problems is related to components of executive functions in both adults and children.
Some researches claim that a rudimentary form of analogical reasoning is available to infants. 

Inductive reasoning and some biases in it

Inductive reasoning (or induction) is also called hypothesis construction.
(Because) the inferred proposition is at best and educated guess, not a logical necessity.
Your past observations of relationships have led you to induce a general rule.

Reasoning by use of analogies are examples of inductive reasoning.
Inductive reasoning is reasoning that is founded on perceived analogies or other similarities. The evidence from with one induces a conclusion is, ultimately, a set of past experiences that are in some way similar to one another or to the experience one is trying to explain or predict.

Thinking like a scientist

Scientific reasoning: generating hypotheses about how something in the world works, and hen systematically testing those hypotheses.

Scientific reasoning can improve with practice.
Scientific reasoning involves a high level of metacognition (the ability to think or to reflect upon what you know). It is a form of effortful thinking and develops over childhood and differs in individuals.

The availability bias

When we reason, we tend to rely too strongly on information that is readily available to us and ignore information that is less available.

The confirmation bias

People’s natural tendency is to try to confirm rather than disconfirm their current hypotheses. This is the confirmation bias.

The predictable-world bias

We are so strongly predisposed to find order in our world that we are inclined to ‘see’ or anticipate order even where it doesn’t exist.
The predictable word bias is a tendency to engage in inductive reasoning even in situations where such reasoning is pointless because the relationship in question is random.

How people reason II: Deduction and insight

Deductive reasoning: (or deduction) is the attempt to derive logically the consequences that must be true if certain premises are accepted as true.

Inductive reasoning is reasoned guesswork
Deductive reasoning is logical proof, assuming that the premises are true.

The concrete nature of deductive reasoning

Deductive problems: logic or content?

If people used formal logic to solve syllogisms, then it should not matter whether the statements in the problem are consistent with everyday experience, violate everyday experience or are nonsensical. All that should matter is the formal structure of the problem.
But! The content does matter!

The bias to use knowledge rather than formal logic in answering deductive reasoning questions can be construed as a bias to think inductively rather than deductively.
Our natural tendency is to reason by comparing the current information with our previous experience.

Part of the skill in solving problems that contradict our knowledge gained from past experiences lies in our ability or willingness to suppress that knowledge.

Humans evolved to be sensitive to being cheated when dealing with others and developed ‘cheater detectors’ that are limited to social contracts.

Deontic reasoning: reasoning about what one may, should or ought to do.

Elements of insight

Insight problems: problems that are specially designed to be unsolvable until one looks at them in a way that is different from the usual way.

Two examples of insight problems

The mutilated checkerboard problem.
The candle problem

Breaking out of a mental set: broadening perception and thought

Insight problems tend to be difficult because their solution depends on abandoning a well-established habit of perception or thought, referred to as a mental set, and then viewing the problem in a different way.

Functional fixedness: the failure to see an object as having a function other than its usual one.

Discovering a solution

Deliberate attention to aspects of the problem and materials that were not noticed before can lead to the sudden perception of a solution.

Functional fixedness and tools: a special case?

Functional fixedness is a common phenomenon.
It seems to be particularly prevalent when tools are used to solve problems.

From early age, people readily assume that tools are designed for an intended function → design stance

Given the central role of tools in human life and throughout human evolution, functional fixedness with respect to tools may be an adaptation.
Knowing what a tool is ‘for’ and using it exclusively for that purpose thus provides the user efficiency, although at the cost of some flexibility.

• Even 1 year olds have developed a ‘spoon’ (for example) category and how a spoon should be used.
• When children are shown a function of a tool, they are later less apt to use it for a different task, even though it would be well suited for it.
• The design stage with respect to tools is not found in other tool-using species.

Unconscious mental processes may lead to insight

Research suggest that the mental capacities required for solving insight problems are different from those required for deductive reasoning.

People’s ability to solve insight problems (and not syllogisms) correlates positively with their creativity.
Working-memory capacity (with correlates positively with deductive reasoning) does not correlate with the ability to achieve insight in insight problems.

People solve insight problems the best if they take an incubation period (some time off from the problem, do something else and then return to the problem)
During incubation period the person is unconsciously reorganizing the material related to the problem while consciously doing and thinking about other things.
Incubation appears to facilitate insight, not deduction.
Deduction requires conscious attention. It is a form of effortful slow thinking.

Unconscious fast mental processes (which do not involve working memory) are more important for solving insight problems than for solving deductive reasoning problems.
For example, reaching insight by priming.

The value of a happy, playful frame of mind

People are better at solving insight problems if they are made to feel happy than if they are in a serious or somber mood.
A happy mood improves people’s performance on various test of creativity and on the ability to see whole patterns, rather than just parts, in test of visual perception.

Broaden-and-build theory of positive emotions.
Negative emotions tend to narrow one’s focus of perception and thought. Those emotions lead people to focus only on the specific emotion-evoking objects and to think only routine, well-learned ways of responding.
Positive emotions (like playfulness) broaden one’s scope of perception and thought and increase creativity. They are felt when there is no imminent danger and one’s immediate biological needs are relatively well satisfied. That is the time to think creatively and to come up with new ideas and ways of dealing with the world.

Play is a time when people regularly view objects and information in new ways.

Cross-cultural differences in perception and reasoning

Responses of unschooled non-westerners to western-style logic questions

The way people approach test, their understanding of what is expected of them, is culturally dependent.

• Non-westerners, who haven’t attended western-style schools, often find it absurd or presumptuous to respond to questions outside their realm of experiences.
• Non-westerners are more likely than westerners to answer logic questions in practical, functional terms rather than in terms of abstract properties.

The difference in reasoning may be one of preference more than of ability.

An east-west difference: focus on wholes versus parts

East Asians perceive and reason more holistically and less analytically than do westerners.
In perceptual test, East Asians tend to focus on and remember the whole scene and the interrelationship among objects, whereas westerners then to focus on and remember the more prominent individual objects of the scene as separate entities, abstracted from their background. 

East Asians’ attention to background context, and interrelationships apparently helps them to reason differently in some ways from the way westerners do.

The practice and theory of intelligence testing

Intelligence: the variable capacity that underlies individual differences in reasoning, solving problems, and acquiring new knowledge.

A brief history of intelligence testing

The subjects are grouped into four categories.

• The verbal comprehension
  Provides an index of verbal abilities
  Vocabulary, similarities and information
• Perceptual reasoning
  Spatial and quantitative reasoning
  Block design, matrix reasoning, and visual puzzles
• Working memory
  Digit span and Arithmetic
• Processing speed
  Symbol search and coding

The scoring system for every modern intelligence test uses results obtained from large samples of individuals who have already taken the test.
These results are uses as normative data to translate each individual’s raw score on an intelligence test into an IQ score.
The mean is 100.

The validity of intelligence tests as predictors of achievement

IQ scores do correlate moderately well with grades in school. The correlation coefficients in various studies range from 0.3 to 0.7

The relation between IQ and employment could be secondary to the fact that people with high IQ s perform better in school.
The strength of the correlation between IQ and Job performance depends on the type of job.
IQ scores also predict health and longevity.

The concept of general intelligence and attempts to explain it

General intelligence (g)

The positive manifold: people who scored high on any one test also, on average, tended to score high on all other tests.
Thus some common factor is measured by every mental test. This is g, general intelligence
General intelligence is the underlying ability that contributes to a person’s performance on all mental tests.
In their view, every mental test is partly a measure of g and partly a measure of some more specific ability that is unique to that test. The best measures of g are derived from averaging the scores on many diverse mental tests.

Fluid intelligence and crystallized intelligence

General intelligence is not one factor but two.

• Fluid intelligence
  The ability to perceive relationships among stimuli independently of previous specific practice or instruction concerning those relationships.
  It is best measured by test in which people identify similarities or lawful differences between stimulus items that they have never previously experienced. Or between two items so common that everyone in the tested population have experienced them.
  Biologically determined and reflect by test of memory span, speed of processing and spatial thinking.
• Crystallized intelligence
  Mental ability derived directly from previous experience.
  Best assessed in test of knowledge.

Cattell based this theory largely on the factor analysis of scores on many different mental tests.
Measures of fluid and crystallized intelligence change differently with age.

Crystallized and fluid intelligence scores correlate positively.

Mental speed as a possible basis for g

Might some basic cognitive abilities underlie general intelligence?

Inspection time; the minimal time that subjects need to look at or listen to a pair of stimuli to detect the difference between them.
There is a correlation.

Executive functions as a possible basis for g

Executive functions (working memory, switching and inhibition) are, either together or separately, hypothesized to underlie g.

People with different levels of intellectual attainment differ in executive functions.

People who perform well on intelligence test are those who can control their mental resources in a way that allows for efficiency in problem solving.

Some psychologist consider fluid and executive functions to be essentially the same concept.

General intelligence as an evolutionary adaption for novelty

From an evolutionary perspective, it is reasonable to assume that general intelligence evolved in humans as a means of solving problems that are evolutionarily novel.

Genetic and environmental contributions to intelligence

The answer to the nature-nurture question concerning IQ is it depends. It depends on just whose IQ you are comparing.

Nature, nurture and IQ differences

The environment and genes are both essential for any trait to develop.

How do nature and nurture interact to produce a particular pattern of development or of intelligence?

The concept of heritability

Heritability: the degree to which variation in a particular trait, within a particular population of individuals, stems from genetic differences as opposed to environmental differences.
It is quantified by a statistic called the heritability coefficient, which ranges from 0 (none of the differences in a trait are attributed to inheritance) to 1 (100 percent of the differences in a trait are attributed to inheritance).

Heritability does not say anything about how much of any trait is due to genetic factors, only what percentage of the difference in a trait within a specific population can be attributed to inheritance, on average.

The more variable environments are between people in a population, the lower heritability will be.
So it is relative.

Family studies of the heritability of intelligence

Comparing groups of people who differ in their degree of genetic relationship to see how much they differ in the trait in question.

Tightly controlled studies of adoptees and twins.

A common way to estimate the heritability of IQ is to compare the correlation in IQ scores of identical twins with that of fraternal twins.

Heritability = (r identical twins – r nonidentical twins) X 2
The heritability of intelligence is 0.52 so 52 percent of the difference in intelligence between people is attributed to genetics.

Another way to assess heritability if IQ is to study the IQ correlation of pairs of identical twins who were adopted at an early age into separate homes.
By using this method, the estimated heritability for IQ is 0,73

The studies suggest that genetic differences account for roughly 30 to 50 percent of the IQ variance among children and for considerably more than 50 percent of the IQ variance among adults in the population that were studied.

Heritability estimates of IQ vary with environmental factors for people in the same population.
Heritability increases with improved environmental conditions. Harmful environments have an especially strong impact on the development of certain traits, whereas average or above-average environments will have little influence beyond that contributed genetics.

Fluid ad crystallized intelligence separately indicate that the two are about equally heritable.

The short-lived influence of family environment

As long as unrelated siblings (raised together) are still children, their IQ does correlate positively with each other, but the correlation is lost completely by the time they reach adulthood.

Taking all the studies together, the average IQ correlation for genetically unrelated children living in the same family is 0.25 and the average for genetically unrelated adults who had been raised in the same family is -0.01 or essentially 0.
Other categories of children raised in the same family also decline as the children enter adulthood, but the greater the degree of genetic relationship, the smaller the decline.
Families have a moderately strong early influence on children’s IQ but the effect fades as the children become adults.
The advantage or disadvantage of being raised in a particular home disappears by early adulthood. Children who grow into adulthood increasingly choose their own environments and their genetic differences influence the kinds of environments they choose.

Effects of personality and live experiences on intelligence

Intelligence is maintained and strengthened through active, intellectual engagement with the world.

Openness to experience includes the characteristics of curiosity, independence of mind and broad interest. Openness appears to correlate at least as strongly with measures of fluid intelligence as with measures of crystallized intelligence.
Intellectual engagement does not just increase one’s store of knowledge, but also one’s capacity for mental gymnastics.

Engagement in intellectually challenging leisure-time activities can increase intellectual flexibility.
These effects are greater for older adults than for younger adults.

Origins of IQ differences between cultural groups

Comparison of racial or cultural groups routinely reveal average differences in IQ.

Why within-group heritability coefficients can’t be applied to between-group differences

The heritability of a trait within a group tells us nothing about differences between groups.

Evidence that black-white IQ differences are cultural in origin

In many countries, blacks and whites are not truly distinct races in a biological sense but, rather, in are different cultural groups.
The amount of genetic variation within each group is far greater than the average difference between them.
The social designation of black or white is most likely the critical variable in determining the black-white IQ difference.

• IQ test are biased, based on skills and knowledge deemed important by the majority culture, but perhaps not the minority culture.
• Stereotype threat. When people are made aware of negative stereotypes for their particular social group, they tend to confirm them.

Different types of minority status can have different effects on IQ

• Voluntary minorities
  Groups who emigrated in hopes of bettering themselves, who typically see themselves as well off compared with those left behind, and those who see themselves as on their way up, regardless of who the dominant majority may see them.
• Involuntary (or caste like) minorities
  Became minorities through being conquered, colonized or enslaved. They were or are treated as if they are a separate, inferior class.
  Perform more poorly

It is the sense that one is an outcast, and that standard routes to achievement are cut off, that oppresses caste like minorities and depresses their scholastic achievements and IQ s.

The historical increase in IQ

The average IQ score keeps rising.
This is called the Flynn effect.

The greatest increases are in the tests geared toward fluid intelligence.

The increase can be due mainly the changes in modern life.