Mind, Body, World- Foundations of Cognitive Science, 2013a

usiness of carrying out reverse engineering (Dennett, 1998). They start with a complete,
pre-existing cognitive agent. They then observe its behaviour, not to mention
how the behaviour is affected by various experimental manipulations. The results
of these observations are frequently used to create theories in the form of computer
simulations (Newell & Simon, 1961). For instance, Newell and Simon (1972) collected
data in the form of verbal protocols, and then used these protocols to derive
working production systems. In other words, when analytic methodologies are
used, the collection of data precedes the creation of a model.
The analytic nature of most cognitive science is reflected in its primary
methodology, functional analysis, a prototypical example of reverse engineering
(Cummins, 1975, 1983). Functional analysis dictates a top-down decomposition
from the broad and abstract (i.e., computational specification of functions) to the
narrower and more concrete (i.e., architecture and implementation).
Even the natural computation approach in vision endorsed a top-down analytic
approach, moving from computational to implementational analyses instead of in
the opposite direction. This was because higher-level analyses were used to guide
interpretations of the lower levels.
In order to understand why the receptive fields are as they are—why they are circularly
symmetrical and why their excitatory and inhibitory regions have characteristic
shapes and distributions—we have to know a little of the theory of differential
operators, band-pass channels, and the mathematics of the uncertainty principle.
(Marr, 1982, p. 28)
An alternative approach is synthetic, not analytic; it is bottom-up instead of topdown;
and it applies forward engineering instead of reverse engineering. This
approach has been called synthetic psychology (Braitenberg, 1984). In synthetic psychology,
one takes a set of primitive building blocks of interest and creates a working
system from them. The behaviour of this system is observed in order to determine
what surprising phenomena might emerge from simple components, particularly
when they are embedded in an interesting or complex environment. As a result, in
synthetic psychology, models precede data, because they are the source of data.
The forward engineering that characterizes synthetic psychology proceeds as
a bottom-up construction (and later exploration) of a cognitive model. Braitenberg
(1984) argued that this approach would produce simpler theories than those produced
by analytic methodologies, because analytic models fail to recognize the
influence of the environment, falling prey to what is known as the frame of reference
problem (Pfeifer & Scheier, 1999). Also, analytic techniques have only indirect
access to internal components, in contrast to the complete knowledge of such structures
that is possessed by a synthetic designer.
420 Chapter 9