Psychological Review, Vol 133(1), Jan 2026, 41-65; doi:10.1037/rev0000544
Memory is formed through repeated action and perception. The primitive manifestation of this type of memory in infants has been observed through a procedure called mobile paradigm. Three-month-old infants can retain behavioral changes during interaction with a mobile for a week without reminders, and this retention can be prolonged for 2–4 weeks with reminders. However, precisely what infants can remember and how memory retention and reactivation work at this young age remains unclear. In this article, we introduce dynamical systems models that replicate this form of memory by incorporating two dynamic properties. The first dynamic process is responsible for creating and retaining a memory of the experience of controlling movement generation to interact with the environment. While this memory can be used in retention tests of learned behaviors, it undergoes a gradual decay. The second property involves asymmetric bifurcation, through which a memory of the circular causality between self-movement and environmental events is formed. This memory, related to agency, persists and enables reactivation of the decayed memory of learned behaviors. Our simulation suggests that memory emerges as an embodiment of internal dynamics through the repetition of action and perception. The form of retained memory in the mobile paradigm is comparable to that in the A-not-B error and habituation–dishabituation tasks. The theory of dynamical systems unifies experimental results regarding memory in early life as an embodied process, with the maturation of the memory system originating from the embodied process between the brain, body, and environment. (PsycInfo Database Record (c) 2026 APA, all rights reserved)