Page 51 - Deep Learning

34 Introduction

results from brain imaging studies show that every complex activity draws on
multiple areas of the cortex, and that many areas contribute to multiple types
of activities. 25, 26 Psychometric research attempted to analyze the mind into dis-
tinct abilities or factors, defined by the correlations among different kinds of
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psychological tests. Examples include numerical, verbal and visual abilities.
However, the concept of an ability has limited explanatory power, because the
definition of a psychometric ability does not describe how people go about
performing test items.
An approach that has enabled at least some progress is to begin with the
functions of our cognitive system and then hypothesize specific processes that
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carry out those functions. Common sense suggests that there are at least five
major cognitive functions: perceiving, remembering, thinking (including rea-
soning and decision making), acting and learning, each of which is imple-
mented by multiple cognitive mechanisms and processes. To turn this list into
a theory of cognition is to be more precise about the cognitive mechanisms
and processes that implement each function.
Perception creates representations of the immediate present – the
here-and-now – and requires processes that allocate attention, identify col-
ors, recognize objects, estimate relative distances and so on. Remembering
requires that representations are encoded into long-term memory and
maintained over time. For the information to be useful, there must also be
a process for retrieving a representation when needed. Thinking draws new
conclusions from existing information, and the relevant processes determine
which conclusions can be reached. Deductive reasoning requires processes
for selecting premises and applying inference rules, while analogical reason-
ing requires processes for selecting an analogue and for mapping that ana-
logue onto the case at hand, and so on. Decision making requires processes
for generating alternative options, for evaluating their likely utility and for
choosing among them. Action – planning and execution – requires processes
that expand goals into subgoals, call upon actions and apply them to the situ-
ation at hand. Learning, finally, is a meta-function; it produces changes in the
other cognitive functions.
A sequence of mental processes can generate three streams of events: a
succession of subjective experiences, a stream of actions and a sequence of
utterances; see Figure 2.1. Any one process might be expressed in one, any
two or all three streams. For example, my memory representation of the spa-
tial layout of the university campus where I work allows me to visualize a
bird’s-eye view of the campus (a subjective event), to find my way to a par-
ticular building across campus (action) or to give directions to someone else