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Updated: Jan 19, 2026
Measurement of the Hand Transmitted Vibration of the Human Hand Arm System During Operation of a Hand Tractor
Published on: June 16, 2021
Hand size underestimation grows during childhood
Lucilla Cardinali1, Andrea Serino2, Monica Gori3
1Fondazione Istituto Italiano di Tecnologia, Genova, Italy. lucilla.cardinali@iit.it.
Insights
Children aged 6-10 underestimate their hand size, a distortion that grows with age. This body representation bias, unlike object estimation, appears functional for interacting with the environment.
Area of Science:
- Developmental neuroscience
- Body representation
- Sensory perception
Background:
- Cortical body size representations are known to be distorted in adults.
- The developmental trajectory of these representations in children is largely unknown.
Purpose of the Study:
- To investigate how hand size is represented in typically developing children aged 6 to 10.
- To determine if body size underestimation is present and how it evolves during childhood.
Main Methods:
- Children aged 6-10 estimated their hand size using visual and haptic sensory modalities.
- Object size estimation was used as a control condition.
Main Results:
- A significant underestimation of hand size was observed in children as young as 6.
- This distortion increased with age and was independent of the sensory modality used.
- No such bias was found when estimating object sizes, indicating specificity to body representation.
Conclusions:
- The brain's representation of body size does not perfectly track natural growth during childhood.
- Despite the distortion, motor behavior and perception remain unimpaired, suggesting a functional or compensated mechanism for environmental interaction.
Abstract:
Cortical body size representations are distorted in the adult, from low-level motor and sensory maps to higher levels multisensory and cognitive representations. Little is known about how such representations are built and evolve during infancy and childhood. Here we investigated how hand size is represented in typically developing children aged 6 to 10. Participants were asked to estimate their hand size using two different sensory modalities (visual or haptic). We found a distortion (underestimation) already present in the youngest children. Crucially, such distortion increases with age and regardless of the sensory modality used to access the representation. Finally, underestimation is specific for the body as no bias was found for object estimation. This study suggests that the brain does not keep up with the natural body growth. However, since motor behavior nor perception were impaired, the distortion seems functional and/or compensated for, for proper interaction with the external environment.
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