Intelligence: the main themes
Discussions of intelligence can be counted on to offend one group, race, species or another! As Stephen Gould suggested in his Mismeasure of Man, -- a critique of nineteenth century efforts to relate brain size to intelligence -- the topic tends to bring out the prejudices of those working on the problem.
was a very original thinker, with many ideas on evolution is sometimes credited
with founding sociology.
...well developed nervous systems will display a relatively marked premeditation--an habitual representation of more various possibilities of cause, and conduct, and consequence--a greater tendency to suspend judgments and an easier modifiction of judgments that have been formed. Those having nervous systems less developed, and with fewer and simpler sets of connexions among their plexuses, will show less of hesitation--will be prone to premature conclusions difficult to change. Unlikenesses of this kind appear when we contrast the larger brained races with the smaller brained races--when from the comparatively judicical intellect of the civilized man, we pass to the intellect of the uncivilized man, sudden inferences , incapable of balancing evidence, and adhering obstinately to first impressions. And we may observe a difference similar in kind but smaller in degree between the modes of thought of men and women; for the women are the more quick to draw conclusions, and retain more pertinaciously the beliefs once formed......
<a href="http://www.cimm.jcu.edu.au/hist/stats/galton/">(1822-1911)</a> was Darwin's cousin and a prominent scientist, who among other accomplishments invented the concept of linear regression in his effort to understand the heredity of traits as well as actually try to quantify intelligence. He was also a founder of the widespread eugenics movement to improve the human race. By 1931, thirty states in the US had passed sterilization laws.
"I propose to show in this book that a man's natural abilities are derived by inheritance, under exactly the same limitations as are the form and physical features of the whole organic world. Consequently, as it is easy, notwithstanding those limitations, to obtain by careful selection a permanent breed of dogs or horses gifted with peculiar powers of running, or doing anything else, so it would be quite practicable to produce a highly gifted race of men by judicious marriages during several consecutive marriages."
Galton, F. (1869). Hereditary genius, an inquiry into its laws and consequences .
Darwin, Piaget .... almost everyone supposes intellect or reason helps the organism adapt! But Descartes earlier made an often neglected point -- if an accomplishment is too easy maybe its NOT done by intelligence ("reason") at all -- but instead it's just an instinct. The adaptation has already been accomplished in evolution and the individual just does it! This issue has resurfaced, for example, in criticism of Piaget and other theorists who presume abilities are constructed or learned without innate domain specific "assistance."
(1596-1650) responding to Montaigne's "Essays" on abilities of animals, argues
that automatic ability in animals does not show reason; instead it shows
"nature makes them behave as they do according to the disposition of their organs; just as a clock, composed only of wheels and weights and springs can count the hours and measure the time more accurately than we can with all our intelligence. Descartes, R. (1641) Discourse on Methods, Fifth Part.
This of course is consistent with the extreme neotenous condition of humans. Recall our discussion of the ontogeny of primate forelimbs-- also very unspecialized compared to other mammals.
While Descartes' argument comes out of a cultural, scientific, linguistic,
and religious environment quite remote from our own, it provides a high
contrast background against which to evaluate human and animal abilities. Just
because, for example, human children acquire language much more rapidly than
home-raised apes, are the humans more intelligent? Not if -- as Descartes put
it "nature makes them (children) behave as they do according to the
disposition of their organs.." The same is true regarding bipedalism.
We cannot assess the "intelligence" of an organism by observing it in its natural environment for which we suppose it is already well-adapted. The question is whether or how much of this adaptation is due to the "intelligence" of the individual rather than inheritance from its ancestors (ontogeny vs phylogeny, nurture vs nature). Thus it's conceivable that a well-adapted organism, highly specialized for its niche, is quite stupid!
The bottom line here is that comparisons among species on behavior that is "natural" to one of them makes conclusions about their respective "intelligence" very doubtful. If adaptive intelligence has any useful meaning, it must be applied assessed in situations where generalization or transfer to new settings is involved and innate factors do not weigh heavily on performance.
Apparently some behaviorist psychologists thought so in that they believed the general principles of behavior could be discovered using almost any species and that the only differences were in sensory-motor processes and perhaps size of memory. Although much of what they had to say about behavior in general seems now misguided, we might consider that the idea of "intelligence" is an intuitive concept better understood in terms of differential component processes including sensori-motor and memory processes, processing rates, motivation, domain-specific abilities, and the self-organizing characteristics of the brain as it develops in particular environments.
Psychologists' efforts to measure intelligence, general to compare within species: Galton, Binet, Terman, Yerkes... Lots of problems, some success.
The serious problems come on establishing validity; Binet and others focussed on schooling potential --with specific types of schools in mind!
Is there just one factor in "intelligence" or is a concept with many diverse parts, more or less independent of each other? Or both?
Similar to the above distinction, this terminology arises in developmental studies concerned with the origins of "modular" abilities, i.e. the extent to which different skills or abilities are interrelated or correlated or exchange information. (e.g Tomasello & Call, 1997, sec, 12)
arbitrary rules, e.g. which container has the food. There's evidence that, if
properly controlled to eliminate sensory or motor advantages, relatively larger
brains learn arbitrary rules, generally to get food (adapt?) more quickly.
Harlow developed the concept of "learning set" to express this idea of "learning to learn" -- i.e. become increasingly effective in problem solving problems of a certain type with experience.
This proved a useful test of the role of environment; Kohts, Kelloggs', Hayes' and recent studies of human "enculturated" apes show some important similarities and limits of apes vs. children. (See "social/cultural" below.)
Studies of brain size, structure, processes, nutrition and various social deficits on intelligence.
The role of environment and social structure in modulating intelligent behavior is one focus of Bryne's book. Recently it has been observed that IQ scores on standardized tests have been rising across generations --the so-called "Flynn effect." Extrapolating across the 100 years of these tests, an individual scoring in the top 10% in 1900 would be in the bottom 10% today with the very same performance. This is quite a change that must be due to social/cultural factors -- schooling, parenting, health and nutrition factors.
In addition to sensory-motor abilities and memory, such factors as temprament, curiosity, attention, and motivation determine intelligent behavior. IS there any need for the concept of intelligence itself?
Anything leading to larger brains, e.g. social structure (Dunbar); foraging (Milton); neoteny and related factors (Gould), throwing (Calvin), tools, language.........
psychometric measures devised to measure differences in human intelligence over
the last 100 years.
Intelligence tests today tend to have a combination of general and specific factors, with debates on every dimension --theoretical and applied.
Intelligence is the general apparatus that governs one's adaption to one's environment by generating structures (schemes, concepts) in interaction with that environment. It is more or less constant across members of a species.
Intelligence aids the child in constructing the concepts fundamental to knowledge of the world out of basic sensorimotor reflexes and interactions with the world. Much of this is achieved in the first two years -- the "sensorimotor period."
This same intelligence is applied to the social world.
early Piaget studied these topics, then turned to the infant's sensorimotor
beginnings upon which in TGE, socialization depends.
Recent research based on new methods of working with infants has cast doubt some of Piaget's conclusions in that rudiments of knowledge in various specific domains like object permanence, language, and even number are present in the first year.
Chevalier-Skolnikoff, S. (1977). A Piagetian model for describing and comparing
socialization in monkey, ape, and human infants.
Tomasello and Call (1997) apply these concepts to foraging and social cognition.
itself is undergoing much criticism in regard to its claims on human
development, especially in regard to human language and its demand that all
abilities be derived from a small set of sensori-motor processes and general
Recent research on infants suggests they come equipped with much more specific structure than Piaget believed.
Piaget was also concerned with "consciousness" and how various abilities interact and are extended by human culture, e.g. science.
These are usually based on animal research
student of William James and teacher of Yerkes(?), was perhaps the first
psychologist to experimentally explore the nature of intelligence in animals.
He is known for his "law of effect."
In his research on cebus monkeys and other birds and mammals, Thorndike proposed there was only associative trial and error activity; success on a trial increased its probability of use. There is an important truth here; the problem lies in characterizing how "trials" come about are and are evaluated. In addition, successes and/or errors must be somehow taken account of. He suggested several behavioral differences corresponding to differences in intelligence -- the rapidity that error trials were inhibited and "imitation" that served to elevate one "trial" over another. Few animals other than humans showed evidence of imitation. This remains a controversial issue today.
Thorndike, E. L. (1901). The mental life of the monkeys. Psychological Monographs, 3, 1-57.
some apes used "insight" based on his observation of their manner of solutions.
He contrasted this with trial and error processes developed by Thorndike.
"the insight of the chimpanzee shows itself to be principally determined by his
optical comprehension of the situation..p. 277 in many cases in which the
chimpanzee stops acting with insight, it may have been simply that the lie of
the land was too much for his visual grasp (relative "weakness of shape
perception"). Thus "insight" seems to involve an ability to manipulate in
one's head the visual scene imagining a solution.
Kohler, W. (1925). The mentality of apes. New York: Harcourt, Brace and Co.
See PC, e.g. Tinklepaugh.
Harlow pioneered methods of evaluating "learning set" ability -- the ability to
form and use a rule -- across species using his Wisconsin General Testing
Passingham (1982) summarizes much of the research in the figure below, showing performance of various species on a two-choice visual discrimination task in which the organism picks one of two objects with a hidden reward under it. Essentially the subject must learn a rule --that the food is under a certain type of object despite other changes in position or features of the objects--and follow that rule in choosing.
Sketched from Fig. 5.8 in Passingham (1980).
Passingham concludes from these data that when mammals are ranked in terms of their improvement over a series of these problems, their rank is predicted by Jerison's (1973) measure of surplus brain cells.
brain size has been shown to predict rule -learning (above) and even "curiosity
Passingham notes that relative brain size predicts well the responsiveness ("curiosity") of zoo animals to novel objects over time. Suppose animals just get bored after exhausting their repertoire of responses to the object. Perhaps brain size indirectly reflects the variety of responses available to various species. Primates have the obvious handling advantage over carnivores, for example. And humans have a linguistic repertoire far exceeding that of any other primate.
Responsive of zoo animals to novel objects
Sketched after Fig. 5.10, Passingham (1980)
Obviously if brain size evolved due to natural selection, there must be heritable component. Recent estimates in terms of correlation indicate an r about .5 or so.
Darwin, Harlow, Bowlby and attachment
a complex synergistic relationship (see figure below) between nutrition and intelligence
food plays a double role.
In phylogeny of a species, it drives evolution of the necessary mental capacities for obtaining food as well as in ontogeny of an individual, nutrition plays a complex role in maximizing the intelligence of the organism. (See diagram below adapted from Brown and Pollitt (1996) on the complex effects of malnutrition.)
Adequate nutrition is also fundamental to fertility thus linking foraging to the spread of "intelligence" in the population. Thus foraging involves a syergetic combination of factors relating to intelligence.
Humphries (1976) and others have suggested that social cognition is so important in primate society, that big brains are needed to deal with this social complexity, e.g. facial recognition, keeping tabs on dominance, communication, etc.
a variety of heterochronous factors might be involved. There are many ways to skin a cat!
Throwing and a variety of tool-using activities might have conspired to increase brain size.
It seems possible that human language requires a specialized and large brain to deal with the phonology, syntax, huge lexicon, and semantic structures involved.
Several factors, acting synergistically, may be involved.
Might this just be a correlated result of selection for some other factor like body size alone?
How "well" do organisms' represent and interact with conspecifics and other relevant species?
A human-based code (HBC) is a means of communication between humans and animals that is based on a human language though without its complexity in most cases. The signs, tokens, and sign-boards used in various research projects are HBCs.
A pair of individuals "essentially shape one another's behavior in repeated instances of a social interaction. PC 301" In this way a behavior that initially was not a signal becomes one as each of the pair can use the behavior by virtue of the expected response of the other. Think of humans interacting in familiar settings, e.g. ordering in a favorite restaurant or a potential sexual encounter with an intimate partner.
Lots of anecdotes, but hard to show reliably in non-humans as a result of representations of other minds.
While it is natural to think of apes "aping" one another, the actual state of affairs in most natural settings is not clear. There are several ways knowledge can be transmitted from verbal instruction, modelling and imitation, to various combinations of trial and error facilitated by a social presence. See Tomasello and Call (1997, p. 279) on chimp tool use, for example. Bryne (1996)
From Fig. 5.2 in Bryne, p.62. A classification of the various explanations of social influences on learning related to the idea of priming brain "records" by observing another organism.
Data from Gould (1977), Passingham (1980) and reflection suggest a complex of interrelated characteristics are observed in intelligent creatures. Many of these derive from the neotenous condition of primates but can be expected to reflect "intelligence" in other species who happen to have similar characteristics.
This probably is important in representing experience and "working memory."
The more experience to accumulate.
The better to shape the brain for new circumstances and to learn from experienced adults.
Manipulating a limb or vocal tract requires a brain capable of representing, planning, and transmitting information. These manipulations themselves may be useful or their brain space might be used for other intelligent activity.
puppetmeister metaphor is useful here; how may strings and how often must you
pull them gives a rough indication of the sophistication of the system.
Generally speaking, more degrees of freedom require greater information flow
per unit time.
The most complex example is probably speech, where Darley, F. L., Aronson, A. E., & Brown, J. R. (1975). Motor speech disorders . Philadelphia: Saunders estimate 14,000 muscles must be controlled and at a very rapid rate!
Both brain requirements and social functions are important.
Vision requires a sophisticated nervous system that can be used for "intelligent" actions--vision thus is perhaps a useful preadaption for intelligence. It may be particularly important enabling the use of visual imagery in problem solving. See Piaget's "figurative intelligence" and Kohler's "insight", etc.