Five and six-year-old children do not integrate visual-haptic information optimally
Single Paper Presentation

Monica Gori
IIT Italian Institute of Technology, DIST University of Genoa

Michela Del Viva
Department of psychology University of Florence, CNR Pisa Istituto di Neuroscienze

Giulio Sandini
IIT Italian Institute of Technology

David Burr
Department of psychology University of Florence, CNR Pisa Istituto di Neuroscienze

     Abstract ID Number: 95
     Full text: Not available
     Last modified: March 26, 2007
     Presentation date: 07/05/2007 2:00 PM in Quad General Lecture Theatre
     (View Schedule)

Abstract
Several recent studies suggest that information from our senses is integrated in a statistically optimal (Bayesian) fashion. Here we investigate whether young (5-8 year-old) children also integrate visual and haptic information optimally. Subjects of various ages judged the width of real plastic blocks using vision, touch or both. Visual judgments were degraded by blurring the image with a sheet of translucent perspex positioned at a variable distance from the blocks. For the bimodal judgments a conflict was introduced between the visual and haptic modalities. For all conditions, bias-free psychometric curves were calculated, yielding separated estimates of the perceived width (PSE) of the block and precision threshold. Adults combined visual and haptic information optimally, following the Bayesian prediction previously demonstrated with virtual reality methods (Ernst and Banks, Nature 2002). Young (5-yo) children were twice as bad as adults in both unimodal judgments, suggesting that these perceptual capacities do not reach maturation until about 8 years. But even more strikingly, there was little evidence of sensory integration in young children: for five and six-year-olds, bimodal thresholds were given by the haptic thresholds, with no two-cue improvement: and when in conflict, PSEs followed the haptic rather than the visual cues, far more than predicted by the Bayesian model. By eight years of age, threshold improvement and PSE were similar, but not identical to adults. These results suggest that integration of information across senses develops late in humans, at about 8 years of age, after the individual senses have matured; younger children trust touch more than sight.