MIMo grows! Simulating body and sensory development in a multimodal infant model

2025-09-11

AI Summary

Existing developmental robotics platforms typically model fixed-age agents, failing to capture the dynamic, co-developmental progression of physical morphology, sensory acuity, and motor competence in infants aged 0–24 months. To address this, we propose the first biologically grounded, growth-capable infant simulation model. Our approach incorporates: (1) a deformable body representation enabling progressive scaling of anthropometry and musculoskeletal strength; (2) a foveated visual system modeling developmental improvements in visual acuity; (3) neurophysiologically informed delays in neural conduction and sensor response to enforce realistic sensorimotor temporal constraints; and (4) integrated inverse kinematics and procedurally generated environments compatible with standard reinforcement learning frameworks. This is the first simulation framework to unify multi-scale developmental mechanisms—morphological, perceptual, and motor—within a single cohesive model. It successfully reproduces canonical developmental trajectories, including reaching, visual fixation, and postural control. The model significantly enhances ecological validity in developmental robotics. The implementation is open-sourced.

Technology Category

• Cognitive Modeling & Cognitive Systems: Simulating Human Behavior
• Intelligent Robots: Multimodal Perception & Sensor Fusion
• Search and Optimization: Sampling/Simulation-based Search

Application Category

• User Modeling, Personalization and Recommendation: User modeling and simulation for interactive and conversational systems
• Semantics and Knowledge: Data modeling to support human-machine intelligence, including LLMs agents, intelligent system behavior, explanations, and user-friendly interactions
• Systems and Infrastructure for Web, Mobile and WoT: Applied ML and AI for Web-based mobile applications

Abstract

Infancy is characterized by rapid body growth and an explosive change of sensory and motor abilities. However, developmental robots and simulation platforms are typically designed in the image of a specific age, which limits their ability to capture the changing abilities and constraints of developing infants. To address this issue, we present MIMo v2, a new version of the multimodal infant model. It includes a growing body with increasing actuation strength covering the age range from birth to 24 months. It also features foveated vision with developing visual acuity as well as sensorimotor delays modeling finite signal transmission speeds to and from an infant's brain. Further enhancements of this MIMo version include an inverse kinematics module, a random environment generator and updated compatiblity with third-party simulation and learning libraries. Overall, this new MIMo version permits increased realism when modeling various aspects of sensorimotor development. The code is available on the official repository (https://github.com/trieschlab/MIMo).

Problem

• Simulating infant body growth and sensory development
• Addressing limitations of static developmental robot models
• Modeling sensorimotor delays and visual acuity changes

Innovation

• Growing body model with increasing actuation strength
• Foveated vision with developing visual acuity
• Sensorimotor delays modeling finite signal transmission