Learning to perceive in the sensor motor approach: Piaget's theory of equilibration interpreted dynamically

Learning to perceive is faced with a classical paradox: if understanding is required for perception, how can we learn to perceive something new, something we do not yet understand? According to the sensorimotor approach, perception involves mastery of regular sensorimotor co-variations that depend on the agent and the environment, also known as the "laws" of sensorimotor contingencies (SMCs). In this sense, perception involves enacting relevant sensorimotor skills in each situation. It is important for this proposal that such skills can be learned and refined with experience and yet up to this date, the sensorimotor approach has had no explicit theory of perceptual learning. The situation is made more complex if we acknowledge the open-ended nature of human learning. In this paper we propose Piaget's theory of equilibration as a potential candidate to fulfill this role. This theory highlights the importance of intrinsic sensorimotor norms, in terms of the closure of sensorimotor schemes. It also explains how the equilibration of a sensorimotor organization faced with novelty or breakdowns proceeds by re-shaping pre-existing structures in coupling with dynamical regularities of the world. This way learning to perceive is guided by the equilibration of emerging forms of skillful coping with the world. We demonstrate the compatibility between Piaget's theory and the sensorimotor approach by providing a dynamical formalization of equilibration to give an explicit micro-genetic account of sensorimotor learning and, by extension, of how we learn to perceive. This allows us to draw important lessons in the form of general principles for open-ended sensorimotor learning, including the need for an intrinsic normative evaluation by the agent itself. We also explore implications of our micro-genetic account at the personal level.

Migración: Choque y adaptación sociocultural

390 p.

Spectroscopic properties and Judd-Ofelt theory analysis of Dy3+ doped oxyfluoride silicate glass

Dy3+ doped oxyfluoride silicate glass was prepared and its optical absorption, 1.3 mu m emission, and upconversion luminescence properties were studied. Furthermore, the Judd-Ofelt [Phys. Rev. 127, 750 (1962); J. Chem. Phys. 37, 511 (1962)] intensity parameters, oscillator strengths, spontaneous transition probability, fluorescence branching ratio and radiative lifetime were calculated by Judd-Ofelt theory, while stimulated emission cross section of H-6(9/2)+F-6(11/2)-> H-6(15/2) transition was calculated by McCumber theory [Phys. Rev. A. 134, 299 (1964)]. According to the obtained Judd-Ofelt intensity parameters Omega(2)=2.69x10(-20) cm(2), Omega(4)=1.64x10(-20) cm(2), and Omega(6)=1.64x10(-20) cm(2), the radiative lifetime was calculated to be 810 mu s for 1.3 mu m emission, whose full width at half maximum and sigma(e) were 115 nm and 2.21x10(-20)cm(2), respectively. In addition, near infrared to visible upconversion luminescence was observed and evaluated. The results suggest that Dy3+ doped oxyfluoride silicate glass can be used as potential host material for developing broadband optical amplifiers and laser applications.