5.5 Another excerpt from Trauma and Memory by Peter Levine

Let us first consider an example of a procedural memory as an acquired motor skill. Learning to ride a bicycle may seem like a formidable, if not terrifying, task, yet with the gentle support of a parent or older sibling, we master the quixotic forces of gravity, velocity, and momentum. We do this procedurally, without any explicit knowledge of the physics or math involved. We learn to master these forces largely by trial and error; the requisite learning curve is, of necessity, quite steep. The adage that one never forgets how to ride a bike rings true for most procedural memories, for better or for worse. So if during one of our early bicycling efforts we have the misfortune of hitting loose gravel and taking a nasty spill, the acquisition of adaptive and requisite balanced movements and body postures can be interfered with. Then when we finally do ride, it may be with a hesitancy leading to instability, or, alternatively, with daredevil abandon and “counter phobia.” What should have evolved into a nuanced learned motor skill is overridden and becomes instead a habitual, survival-based reactive pattern of bracing and contracting, or of overcompensating with counter-phobic risk taking; both are less-than-optimal outcomes and unfortunate examples of the durability of a procedural memory. Indeed, persistent maladaptive procedural and emotional memories form the core mechanism that underlies all traumas, as well as many problematic social and relationship issues. (p. 38)