Topic: Emergence of the Perceptual Magnet Effect by Plausible Neuronal Phenomena by Mr. Au Ching Pong
Posted - 10/03/2003 : 12:17:17
Au Ching Pong
Department of Chinese, Translation and Linguistics
Research Student Seminar
Mr. Au Ching Pong
City University of Hong Kong
Emergence of the Perceptual Magnet Effect by Plausible Neuronal Phenomena
Time: 4:30 - 6:00 pm
Date: 14th March 2003 (Friday)
Venue: P4909, City University of Hong Kong
The "perceptual magnet effect" refers to warping of the perceptual space near the prototypes of the phonemes (Kuhl, 1991). The formation of this effect is found in the perception of infants younger than one year old and the infants' categorizing abilities in their native language improve as they grow up throughout their first half-year (Kuhl et al, 1992). Since infants' access to the meaning of utterances is still very limited around one year old, the perceptual magnet effect is likely to be a self-organizing process.
Guenther and Gjaja (1996) suggested that the emergence of the perceptual magnet effect comes from the non-uniformity of the auditory map due to the language-specific auditory experience. They demonstrated this phenomenon by using self-organizing maps successfully. However, in their model, the use of single neurons to represent formant values of human speech is not likely to be realistic. In this presentation, I will introduce a cellular level dynamic model with a more realistic input representation to demonstrate the effect.
The algorithm in the present model is inspired by the biological findings that a large number of neurons die during early brain development and the hypothesis that survival of neurons is dependent on various factors such as stimulation from the environment (reviewed in Oppenheim, 1991, 1999). The neurons in the model do not die if the units are activated enough. Then the surviving units spread their dendritic connections when they are further stimulated. Based on this survive-and-spread algorithm, the perceptual magnet effect emerges depending on the linguistic experience of the system.
- Kuhl, P. K. (1991), Human adults and human infants show a "perceptual magnet effect" for the prototypes of speech categories, monkeys do not. Perception & Psychophysics, 50, 93-107.
- Kuhl, P. K., Williams, K. A., Lacerda, F., Stevens, K. N. & Lindblom, B. (1992). Linguistic experience alters phonetic perception in infants by 6 months of age. Science, 255, 606-608.
- Guenther F. H. and Gjaja M. N. (1996), The Perceptual Magnet Effect as an Emergent Property of Neural Map Formation. Journal of the Acoustical Society of America, 100, 1111-1121.
- Oppenheim, R. W. (1991) Cell Death During Development of the Nervous System, Annual Review of Neuroscience, 1991, 14:453-501.
- Oppenheim, R. W. (1999) Programmed Cell Death, Fundamental Neuroscience, pp611-635.
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