What is the main cause of a plateau in the learning process?

→ What is the main psychological cause of a 'learning plateau' in the learning process? → What is meant by 'Transfer of Learning' in teaching? → What is the main cause of a 'plateau' in learning? → In the deep analysis of the dynamics of learning curves, specifically the 'convex curve' (decreasing returns curve) and 'concave curve' (increasing returns curve), when a learner begins acquiring a complex skill where learning progress is very rapid in the initial stage, but gradually with practice the rate of learning continuously declines and ultimately approaches a plateau, which of the following statements is the most authentic and scientifically accurate regarding this type of learning curve and its psychological causes? → What is the primary cause of a 'Plateau of Learning' in the learning process? → Which primary psychological or physiological factor is considered most responsible for the formation of a learning plateau, and what condition does a 'convex curve' represent in the context of learning curves?