Soft constraints in interactive behavior: the case of ignoring perfect knowledge in-the-world for imperfect knowledge in-the-head

Constraints and dependencies among the elements of embodied cognition form patterns or microstrategies of interactive behavior. Hard constraints determine which microstrategies are possible. Soft constraints determine which of the possible microstrategies are most likely to be selected. When selection is non-deliberate or automatic the least effort microstrategy is chosen. In calculating the effort required to execute a microstrategy each of the three types of operations, memory retrieval, perception, and action, are given equal weight; that is, perceptual-motor activity does not have a privileged status with respect to memory. Soft constraints can work contrary to the designer’s intentions by making the access of perfect knowledge in-the-world more effortful than the access of imperfect knowledge in-the-head. These implications of soft constraints are tested in two experiments. In experiment 1 we varied the perceptual-motor effort of accessing knowledge in-the-world as well as the effort of retrieving items from memory. In experiment 2 we replicated one of the experiment 1 conditions to collect eye movement data. The results suggest that milliseconds matter. Soft constraints lead to a reliance on knowledge in-the-head even when the absolute difference in perceptual-motor versus memory retrieval effort is small, and even when relying on memory leads to a higher error rate and lower performance. We discuss the implications of Supplementary data associated with this article can be found, in the online version, at doi:10.1016/ j.cogsci.2003.12.001 An earlier, much simpler version of this report was presented as an eight-page conference paper at CHI2001. That paper is archived as Gray and Fu (2001). ∗ Corresponding author. E-mail address: [email protected] (W.D. Gray). 0364-0213/$ – see front matter © 2004 Cognitive Science Society, Inc. All rights reserved. doi:10.1016/j.cogsci.2003.12.001 2 W.D. Gray, W.-T. Fu / Cognitive Science xxx (2004) xxx–xxx soft constraints for routine interactive behavior, accounts of embodied cognition, and tool and interface design. © 2004 Cognitive Science Society, Inc. All rights reserved.