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

A third approach to validating a model involves the use of error evidence. This
approach assumes that errors are artifacts, in the sense that they are a natural consequence
of an agent’s information processing, and that they are not a deliberate or
intended product of this processing.
One source of artifactual errors is the way information processing can be
constrained by limits on internal resources (memory or attention) or by external
demands (the need for real time responses). These restrictions on processing produce
bounded rationality (Simon, 1982). Another reason for artifactual errors lies
in the restrictions imposed by the particular structure-process pairing employed
by an information processor. “A tool too gains its power from the fact that it permits
certain actions and not others. For example, a hammer has to be rigid. It can
therefore not be used as a rope” (Weizenbaum, 1976, p. 37). Like a tool, a particular
structure-process pairing may not be suited for some tasks and therefore produces
errors when faced with them.
One example of the importance of error evidence is found in the large literature
on human, animal, and robot navigation (Cheng, 2005; Cheng & Newcombe, 2005;
Healy, 1998; Jonsson, 2002; Milford, 2008). How do organisms find their place in
the world? One approach to answering this question is to set up small, manageable
indoor environments. These “arenas” can provide a variety of cues to animals that
learn to navigate within them. If an agent is reinforced for visiting a particular location,
what cues does it use to return to this place?
One paradigm for addressing this question is the reorientation task invented
by Ken Cheng (1986). In the reorientation task, an agent is typically placed within
a rectangular arena. Reinforcement is typically provided at one of the corner locations
in the arena. That is, the agent is free to explore the arena, and eventually finds
a reward at a location of interest—it learns that this is the “goal location.” The agent
is then removed from the arena, disoriented, and returned to an (often different)
arena, with the task of using the available cues to relocate the goal. Of particular
interest are experimental conditions in which the arena has been altered from the
one in which the agent was originally trained.
An arena that is used in the reorientation task can provide two different
kinds of navigational information: geometric cues and feature cues (Cheng &
Newcombe, 2005). Geometric cues are relational, while feature cues are not.
A geometric property of a surface, line, or point is a property it possesses by virtue
of its position relative to other surfaces, lines, and points within the same space. A
non-geometric property is any property that cannot be described by relative position
alone. (Gallistel, 1990, p. 212)
In a rectangular arena, metric properties (e.g., wall lengths, angles between walls)
combined with an agent’s distinction between left and right (e.g., the long wall is
to the left of the short wall) provide geometric cues. Non-geometric cues or feature
104 Chapter 3