Chapter 2. Prehension

330 CONSTRAINTS AND PHASES
9.1 The Black Box Revisited
In Chapter 1, the concept of a black box was introduced as a way
to study a complex behavior (see Figure 9.1). Using the working
definition of prehension, that is, the application of functionally
effective forces by the hand to an object for a task, given numerous
constraints, inputs to the black box were identified as the object and
task, while the output was prehensile behavior. Data from various
scientific disciplines and simulations from the engineering sciences
have been presented in order to shed light on the processing within
that black box.
Object Task
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Prehensile behavior
Figure 9.1 The black box revisited. Many levels of analysis are
involved in understanding the complex intereactions between
objects, tasks, and prehensile behavior.
9.1.1 Objects
In terms of the object, much evidence exists for what object
properties are available to the perceptual system. These data have
emerged from experiments in haptic exploration, visual
discrimination, wielding and jiggling, intrinsic and extrinsic property
perturbations. Two types of object properties have been studied:
extrinsic and intrinsic object properties. Extrinsic object properties are