Title

Fractality of exploration in perceptual learning

Date of Completion

January 2010

Keywords

Psychology, Behavioral|Psychology, Experimental

Degree

Ph.D.

Abstract

This dissertation documents three experiments investigating the potential effect of fractal fluctuations in exploratory behaviors in the change of perceptual judgments. Specifically, Experiment 1 dealt strictly with haptic perception and tests participants' ability to judge geometrical properties of unseen wielded objects. It introduced a four-block structure in which the first and fourth blocks are a pretest and posttest, respectively, and the middle two blocks are used for training by visual feedback following each judgment. Results of Experiment 1 suggested that the fractality of fluctuations in manual wielding predicts accuracy in judging the object's geometric properties. With the same task and four-block structure, Experiment 2 sought to establish that the fractality of fluctuations in head sway predicts use of visual feedback to improve these judgments. Experiment 2 also investigated the relationship between fractality in head sway and fractality in manual wielding to determine how fluctuations at the head, incident to visual feedback, might influence fluctuations at the hand. Results suggested that fractal fluctuations in head sway predict the use of optical information and promote later fractal fluctuations at the hand during visual feedback. Departing from haptic perception, Experiment 3 tested visual judgments of the same objects as in Experiments 1 and 2, over four blocks but without any feedback. Experiment 3 sought to replicate effects for fractality of fluctuations in head sway and to determine whether or not the relationship between head and hand fractalities found in Experiment 2 was relevant to the coordination of the visual and the haptic perceptual subsystems. Results suggested that fractal fluctuations in head sway predicted the use of optical information during tasks without manual wielding but did not influence later fractal fluctuations at the hand. Taken together, the results of these experiments suggest that the fractality of exploratory behaviors optimizes use of available information for perception and provides a substrate for the multimodal coordination of perceptual subsystems during perceptual learning. ^