intelligence-98 perspectives
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.
Spencer
<a
href="http://socserv2.socsci.mcmaster.ca/~econ/ugcm/3ll3/spencer/">(1820-1903)</a>
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......
Francis
Galton,
<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."
Descartes
(1596-1650) responding to Montaigne's "Essays" on abilities of animals, argues
that automatic ability in animals does not show reason; instead it shows
none!
"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)
Learning
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.
(HP)
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.........
assessment of human intelligence
Many
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.
The
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.
See
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.
TGE
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
"intelligence."
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
Thorndike,
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.
Argued
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.
Harry
Harlow pioneered methods of evaluating "learning set" ability -- the ability to
form and use a rule -- across species using his Wisconsin General Testing
Apparatus (WGTA).
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.
Relative
brain size has been shown to predict rule -learning (above) and even "curiosity
(below)."
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
Obtaining
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.
The
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.
