Introduction (1)
Fodor’s modularity thesis popularized faculty approaches to cognitive psychology.
This theory bears a striking resemblance to the phenomenological theory that Merleau-Ponty
proposed two decades earlier. Both theories employ a trichotomous functional architecture
to explain cognition and view perception as a mid-level processing of information that
lies between the world and consciousness. The key feature that differentiates the views is
whether that middle level of processing is completely impenetrable by consciousness. If
Fodor was to relax his strong position of the impenetrability of information in modules,
modules could both be somewhat encapsulated and maintain a general independence from
consciousness. Then only the degree of perception’s independance from consciousness
would distinguish his theory from Merleau-Ponty’s. Currently, both theories can
account for the substantive, outward, behavior of humans. Only the procedural behavior,
the internal process, differentiates the theories. The conundrum of deciding between the
theories is resolvable by an empirical critical experiment. While this will require more
knowledge of cognitive psychology, current evidence suggests that Merleau-Ponty was
correct and the mind is less encapsulated than Fodor's original claim.
The Two Theories and Their Resemblance
Merleau-Ponty distinguishes three aspects of the psychological process; basic
sensations, perception, and the associations of memory (Merleau-Ponty, 1994). Basic
sensations receive raw information from the world and transduce them for our perceptual
processes. Perception unifies the infinite amount of information about our environment,
from our environment, into a meaningful structure. Perception is interpretive, but its
presentation of the world is as distal and objective. There are three central features of
perception for Merleau-Ponty. First, perception is synthesized independently by the body
and not by the mind (consciousness). He states,
"It is not the epistemological subject who brings out synthesis, but the
body, when it escapes from dispersion, pulls itself together and tends by all means in its
power toward one single goal (Merleau-Ponty, 1994, p. 232),"
and secondly,
"primary perception is a non-thetic, pre-objective, and pre-conscious
experience (p. 242)."
Perception acquaints the viewer with a directed object, not by creating objects in
consciousness — qualia, but by being a conduit to the observed object. The final
feature of perception is its informational opaqueness. Our bodies supply us with
representations of the world and our consciousness is not aware of the qualities within
our prestructured perceptual devices. Therefore we cannot make judgments about the
fundamental assumptions of the mapping systems implicit within perception. The third
aspect of the psychological processes, association of memories, is the thetic aspect of
our phenomenological experience. It is responsible for conscious thought, which includes
the fixation of beliefs.
Like Merleau-Ponty, Fodor divides psychological processing into a three-part functional
taxonomy. These parts are: transducers, modules (input systems) and a central system
(Fodor, 1983; 1985). Transducers, like Merleau-Ponty’s sensations, take external
stimuli and transform it for the input systems to use. Modules are rigidly specialized,
domain specific, innately specified, autonomous, unassembled input systems that are
encapsulated. Encapsulation entails that the inference producing mechanisms have general
features of their architecture that constrain both their access to background information
and the information that they output. Thus modules are structures so that: i)
minimally some information that is accessible to the cognitive process is unavailable to
the module and ii) the operation the module performs has access to only the
information in the database of that module and the retransmitted stimulus. Finally,
central systems globally and isotropically access information. This is typical
unencapsulated behavior — it is holistic and Quinian (Fodor, 1983, p. 117). Central
systems are responsible for the cognitively penetrable psychological behavior,
consciousness, and fixes beliefs from representations supplied to it by modules.
There are obvious similarities between Fodor’s modularity thesis and
Merleau-Ponty's theory of psychological processing. First, both transducers and sensations
receive information from stimuli and retransmit it to a middle level system to process.
Merleau-Ponty refers to this level as perception and Fodor calls the level a function of
modules. In each case this level, perception, is prior to the fixation of belief and
belief fixation occurs in consciousness (a central system). Second, both theories have
perceptual processes create representations of the objective world, instead of proximal
reflections of the stimuli. For example, Merleau-Ponty writes, "we make perception
out of things perceived (1994, p. 5)." Third, perceptual systems are prestructured
and this structure determines how information is presented. Again Merleau-Ponty states,
"that within the organism the structure depends on variables such as the biological
meaning of the situation (p. 11)." Fodor argues that,
"Perception is built to detect what is right here, right now—what is
available, for example, for eating and being eaten... So the function of perception, from
this vantage point, is to propose to thought a representation of the world from which such
variability [information unimportant for survival] has been effectively filtered (Fodor,
1985, p. 4)."
Fourth, the perceptual processes’ architectural procedures are informationally
opaque, i.e., the fundamental assumptions implicit within the perceptual processes
are not observable or accessible by consciousness.
The Theoretical Variances and a Schema for Adjudication
The key difference between Fodor and Merleau-Ponty rests on Fodor’s strong claim
about encapsulated systems, i.e., they are informationally impenetrable. To Fodor,
modules only employ a preprogrammed theory of mapping distal causes to proximate effects
and nothing else. The flow of information in psychological processing is unidirectional, i.e.,
from transducers to modules to the central system. Consequently the central system cannot
influence, in any way, how humans perceive things.
To Merleau-Ponty, there are instances where the consciousness can
‘communicate’ with perception to effect how perception interprets information
from basic sensations. In the case of sexuality, Merleau-Ponty suggests that perception
cannot account for a complete sexual context, "perception has lost its erotic nature
(Merleau-Ponty, 1994, p. 159)." Instead, erotic perceptions and experiences are a
product of inter-communications with his trichotomous functional processes. He states
that,
"sexuality is not an autonomous cycle, it has internal links with the whole
active and cognitive being, these three sectors of behavior displaying a typical
structure, and standing in a relationship to each other of reciprocal expression (p.
157)."
Merleau-Ponty also suggests cross modal communication in aspects of tactile and visual
perception. Thus, to Merleau-Ponty perception is informationally penetrable.
To determine if perception is informationally impenetrable, we need to show that some
other system can affect a particular module’s output. McGurke and Mcdonald (1979)
document behavior that supports such as case. They revealed that visual stimuli directly
affect phonetic perception. Their research suggests the most plausible explanation of the
observed phenomena is the existence of inter-module communication. Presumably the visual
module sends information to the auditory module to determine the sound of particular
phonemes. While this phenomenon is not a top-down instance of consciousness influencing
perception, it does give evidence for cross modal, i.e., intermodular,
communication. This would disprove the strongest conception of the encapsulation of
modules, such as the version proposed for language research by Forster (1979).
A more interesting case of penetrable information flow is top-down aspects of
cognition, viz., consciousness affecting perception. This instance is most
noticeable when faced with noisy stimuli. The famous picture of a Dalmatian on a dappled
background illustrates how we can discern images from seemingly chaotic fields by
consciously restricting the domain that we search. If we do not see the image and are
informed of its presence, we look for and often discover the canine. Phonetic
identification probably best illustrates this type of phenomena. Often we may listen to a
song and perceive an incorrect lyric, such as, "let Milo open the door." Later
when you learn that the lyric is actually, "let my love open the door," you from
that moment on hear the lyric correctly. Samuel’s (1981) work on phonetic restoration
rigorously identifies how the context of a sound contributes to how we hear it. If we play
a pseudo-word and a blocking sound, e.g., ‘basi’ and a beep, the context
surrounding the noisy stimulus will determine what phoneme the subject hears. In the above
case, the context could determine if the subject hears ‘basis’ or
‘basic’.
It appears that in these instances consciousness is somehow priming perceptual devices,
modules. The prime instructs the module to restrict its processing to a particular context
or domain. It acts as a heuristic given to the module that allows the module to identify a
particular representation. Thus, this priming of a perceptual device, or module, greatly
prunes the inappropriate potential search options and makes the problem of identification
tractable. Coincidentally the perceiver can notice the pattern faster.
The above instances suggest evidence contrary to the claim that perceptual modules are
synchronically impenetrable to background cognitive knowledge. Fodor (1992) admits that
such a schema is implausible. Instead, he allows a lesser degree of informational
penetrability to modules, i.e., they are diachronically penetrable. In effect,
training and experience can affect the availability of certain contexts or background
theories to modules. Fodor states,
"Parsing may be modular, but children must learn something about
their language from the language they hear; why else would children living in China so
often grow up speaking Chinese? (1992, p. 248)"
Likewise, Fodor reluctantly accepts top-down instances of perception. He writes,
"perception is diachronically penetrable only within strictly — maybe
endogenously — defined limits (Fodor, 1992, p. 248)." Fodor’s theory then
allows for the central system to train modules along a rigidly defined range. This level
of cognitive influence can train a module much in the same way a training set for a
back-propagation connectionist machine molds the overall machine. Simply, the central
system can create a limited set of feedback that will develop the module’s
capability, but these instances are not common. This level of cognitive influence on
modules, however, is not as interactive as Merleau-Ponty’s theory and does not
conform with the aforementioned evidence for the cognitive priming of modules.
Nevertheless, Fodor does not have to accept that the above cases confirm top-down
processing. Variations or plasticity in output from noisy environments may not necessarily
be a feature of the informational penetrability of modules (Karmiloff-Smith, 1992). A
serial feedforward, i.e., unidirectional and encapsulated, modular architecture
could account for instances of processing information about ambiguous contexts (Borland
& Cutler, 1996). The modules could be producing two, or more, representations for the
central system to select. Alternatively, Jordan and Jacobs (1992) proposed that with
divergent computation multiple modules could be acting on a single input source to offer
variant outputs for evaluation. The priming feature actually acts as a contextual cue
within consciousness, i.e., the identification of the representation influenced by
the cue occurs in the central system and not in the modules (perception).
While this answer appears to ignore interesting perceptual identification tasks, the
claim simply states that the filtering process doesn’t occur within the modules.
Instead, discerning phenomena occurs in consciousness or in a preconscious state within
the central system. Therefore, the aforementioned noisy stimuli cases can be consistent
with Fodor’s modularity theory provided that the central system is sometimes
performing an unconscious selection or filtering process that chooses representations in
light of their appropriateness.
One should note that keeping modules informationally impenetrable reduces the role
modules play in perception. Now the central system is responsible for performing
particular acts of perception. Mainly, modules supply the central system with a set of
representations and the central system must in turn apply environmental cues to use as a
filter for selecting the ‘perceived’ representation. This modification or
filtering process directly affects the later process of the central system, i.e.,
the fixing of a belief to the representation. Thus this taxonomy blurs the clarity of
separating conscious behavior from subconscious manipulation of information that presents
the image to consciousness. Failing to crisply make this distinction between these
processes, ceteris paribus, makes maintaining informational impenetrability a less
desirable psychological taxonomy.
However, our bias to have a psychology that distinctly identifies our phenomenological
experiences is not a definitive tool for determining the degree of informational opacity
of modules. Essentially the claim about the informational impenetrability of modules is
empirical (McClamrock, 1989). Cognitive psychology needs to determine more about
information structure of the mind to determine the degree of top-down behavior that
influences perception. With more information about the procedural behavior of the
psychological process of cognition, we could create a critical test to verify the level in
which modules are informationally impenetrable.
Conclusion
I have shown that Merleau-Ponty and Fodor have a number of similarities between their
taxonomies of cognition. The key feature that differentiates the two lies in determining
the particular information flow into perception and consciousness. Merleau-Ponty argues
that cross modalities can affect various perceptual processes. On the other hand, Fodor
argues that the information flow is generally unidirectional and modules are
informationally impenetrable. With instances of noisy stimuli, people do appear to have
some ability to consciously effect their perception (Wolfe, 1990). Fodor can explain this
phenomenon by creating a taxonomy that can produce the same substantive behavior without
implementing bi-directional or recurrent modules. Thus, determining which theory is better
is a matter of gaining more information about cognitive behavior and setting up a critical
experiment. If modules could be slightly influenced by particular processes, either
through rigid inter-module connections or similar communicative links between
consciousness and modules, then the modules could be generally informationally
impenetrable (to a degree) and explain priming. Until Fodor allows for this, or drops the
requirement of informational impenetrability completely, his theory will differ from
Merleau-Ponty’s in a procedurally interesting way.
Currently, any reference to encapsulation within cognitive science is remarkably subtle
(Dell, 1996). While the underlying cortical structures of the brain display a certain
degree of independence (Shallice, 1988) support their possible modularity and
independence, there is compelling evidence that these structures have recurrent
connections (Sejnowski & Churchland, 1989). Further, evidence also suggests the
computation of vastly distributed representations within cognition (Georgopoulos, Taira,
& Lukashin, 1993). Consequently, the most fecund interpretation among today's research
in modularity rests on an interpretation that allows for partial or occasional
bi-directional processing of information (Spivey-Knowlton & Eberhard, 1996). This
interpretation runs contrary to Fodor's informational impenetrability requirement for
modules and is remarkably close to Merleau-Ponty's phenomenology.
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