Article about "Rules of Language"

[cbmvax!uunet!math.ucla.edu!jimc]

A review of:  Pinker, Steven, "Rules of Language", Science v253 p530 
	(2 Aug 1991).  Info in [[ double brackets ]] is my commentary;
	the rest is freely paraphrased.  

The associationist theory of language is [[ simplified ]] that you learn
language by experiencing the conjunction of words and referent events,
and the brain's main job is to store and retrieve such associations.  
The rule theory alleges that the brain is programmed to do grammatical
transformations on language input thereby to deliver useful meaning;
in some versions the transformations are wholly learned while others
suspect a genetic or hardwired component.  

Research shows that all three are true simultaneously.  English past
tense inflection has a specially simple form and has proven useful to
probe the issue.  A number of studies are reviewed in this article. 
The hypothesis is that regular pasts (like walk-walked) will be
processed algorithmically while irregulars (like sing-sang) are
associational.  Therefore the two word classes should be affected
differently in several classes of experiments -- and they are.

Frequency affects association but not algorithms.  Take an irregular
verb common in the present but not the past (e.g. "Excuse me if I
*forgo* the pleasure..." compared to "I *forwent* the pleasure..."); 
the past form sounds weird.  Whereas a similar cliche with a regular
verb doesn't sound weird in the past (e.g. "suffer fools gladly" vs.
"suffered fools gladly").  When a person is shown a present form and
is required to say the past tense as fast as possible, common irregular
past forms come out faster than rare pasts (the present frequency being
equal -- 16 to 29 msec difference) whereas when the verbs are regular
the difference is less than 2 msec.  

Irregular verbs fall into similarity classes, e.g. {sing-sang,
ring-rang, spring-sprang}.  Imaginary words like spling which are
similar to a big class are more often inflected with the class than
words in a small class, suggesting that association is at work. 
Whereas, when a foreign word which fails to fit English verb stem
morphology is inflected, the regular algorithm applies with no problem,
as in "rhumba'ed".

If rules and associations are handled by different brain areas, inflected
words which are transformed a second time should react differently
depending on whether they are regular or irregular.  For example, verbs
derived from nouns are always inflected regularly even if the root is
irregular: "high-sticked" not "high-stuck" because the hockey stick (noun)
is raised.  When the verb-oid "line-drive" is presented as noun-based
(hit a line drive) it is inflected regularly while if verb-based (drive
a car along a line) it is irregular (line-drived vs. line-drove).  

A similar example [[ transitive diklujvo! ]] occurs with transitive
compounds when the noun is plural; irregular plurals are accepted while
regular ones are not.  "Mice-infested" and "teethmarks" are OK while
"rats-infested" and "clawsmarks" are not, because the irregulars are
processed by association in a step upstream of compounding whereas
regular plurals are processed in some downstream step and hence are not
available when needed for the compound.  Children show similar effects
before they could possibly have learned such a pattern from listening
to adults.  

If regular and irregular forms are handled by different brain areas,
children should learn them at different times, and brain damage should
affect them unequally.  Children learn irregular pasts, then regular
pasts afterward, and when they do they over-regularize (e.g.
come-comed) when they fail to associate, a mistake they did not make
earlier.

Several syndromes of brain damage lead to high error rates in (among
other things) regular past tenses, but irregular past tenses are
affected much less, suggesting that algorithmic grammar is impaired but
association is not.  One such syndrome has a substantial inherited
component.  Another syndrome is associated with injury to Broca's area.

"Focusing on a single rule of grammar, we find evidence for a system
that is modular, independent of real-world meaning, non-associative
(unaffected by frequency and similarity), sensitive to abstract formal
distinctions (for example, root vs. derived, noun vs. verb), more
sophisticated than the kinds of "rules" that are explicitly taught,
developing on a schedule not timed by environmental input, organized by
principles that could not have been learned, possibly with a distinct
neural and genetic substrate."

[[ ... coexisting with an associative word processor. ]]

[[ Some of the examples given in the article suggest that there is
hardware support for compound words, and at least some of their
processing occurs before (or coincident with?) the algorithmic
transformation of regular plurals and past tenses. 

A tempting conclusion (for me) is that large classes of compound words
are processed algorithmically by hardware pre-provided for them. 
Possibly this question is decidable, but the data in the article don't
give an answer to it.  In any case, compound words are clearly closely
related to algorithms supported by hardware.  

It must be understood that the hardware is capable of supporting a
broad range of grammatical algorithms, but the human learns specific
ones (within hardware capacity) from his environment.  The visual
cortex is another example in which hardware is present but has to learn
from the experience of sight.

Dubious is the relation of the hardware grammatical transformations to
grammar rules inferred by the analytical mind.  The distinction between
compounds of regular vs. irregular plurals is an example of a rule which
is important to the hardware but of negative interest to today's style of
grammarian -- "Not irregular crap again?!"  I am particularly struck that
morphology, grammar and semantics are hopelessly commingled, whereas a
foundation design goal of -gua!spi was to segregate them to the maximum
possible degree.  A second striking lesson is that both theories coexist;
it is not true that there is one right answer.  

The brain is capable of supporting a jungle jumble grammar which drives
an analyst up the wall.  But that doesn't mean the Lojban (and -gua!spi)
people ought to push the brain to its limit in that particular direction.
Our quest for simplicity and regularity brings us other benefits that
were not relevant to our randomly evolved ancestors.  ]]

		-- jimc