Phi-features and the Modular Architecture of - UMR 7023 - CNRS

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ceived. A rather odd real object can be constructed that presents the 2D projection
of the Penrose triangle when viewed from a certain angle, by dint of partial occlusions.
Yet acquaintance with it does not affect the perception of the impossible triangle.
It is mandatory. It is not particularly fast, and similar images (Escher drawings)
are perceived far more slowly, giving cognition time to eliminate the illusion
as impossible – yet it does not. The perceptual mechanisms underlying the illusions
are limited to the information in the image (domain-specific) and impenetrable
to other mental systems like knowledge of geometry (encapsulation). In Pylyshyn's
(1999) review of other evidence, low-level vision is generally encapsulated
from external cognitive systems, although there exist narrow channels of control
through attention modulation.
Low-level vision is a good example of a highly distinctive and autonomous
computational component with narrowly defined input and output pathways, fitting
Fodor's (1983) model of modularity. Other proposals have explored weaker
models for other cognitive domains (see the citations below (5)), among them the
language faculty. A good illustration comes from the relationship between syntax
and morphology, which will be further studied in chapter 2.
The Fodorian modules are containers whose envelope has narrow input and
output channels, but otherwise encapsulates its interior from external operations
and information. The classical Y/T-model in (6) conceptualizes the modularity of
syntax in this manner. Syntax has its own mechanisms or principles (Move, ccommand,
…) and information (theta-roles, Case, …). Its sole input is the lexicon,
or the morphology module in lexicalist approaches. It outputs to the external systems
of realization, PF, and interpretation, LF, but does not see within them, and
they do not affect it. These systems are modules, highly unique and autonomous
even for those that are most similar. Syntax and lexicalist morphology might both
be generative, recursive, pieces-based assembly systems, but they differ in the information
they see such as class features or phonology, in mechanisms such as
movement, and in their interaction that might be restricted to morphology providing
the atoms of syntax (cf. Di Sciullio and Williams 1986). Outside the systems
in (6) are others that use their output, with perhaps quite different properties. 2
(6) Y/T-model
Realization Interpretation
PF ← (Realizational Morphology) ← Syntax → LF
↑
(Lexicalist morphology)
↑
2 I speak of PF and LF as two modules. Each may involve discrete modules, for instance realizational
morphophology and phonology at PF, thematic and quantificational components at LF.
Similar left open is their generative or interpretive character. Chapter 2.1 returns to these issues
at PF; see further Chomsky (1995: 4.1, 2000a: 3.1), Jackendoff (2002).