“Plateaus of learning are a characteristic feature of the learning process…

In the psychology of learning, a plateau refers to a stage in the learning curve where, despite continued practice, a learner's performance shows no visible improvement for a period before it rises again. This flat stretch does not mean learning has stopped — it usually reflects consolidation of sub-skills, temporary fatigue, or a shift in strategy — and different theorists are credited in standard pedagogy reference material with specific descriptions of this phenomenon.

The exact description given in the question — that plateaus indicate a period during the learning process where no improvement in performance is made — is the definition attributed to Ross in the standard reference material used for teacher-eligibility exams, and it matches the official UPTET 2019 Paper 1 answer key for this item.

• Skinner is associated with operant conditioning and the shaping of behaviour through reinforcement schedules, not with describing the no-improvement stretch of the learning curve.

• Hollingworth's work centres on the psychology of adolescence and gifted or exceptional children, unrelated to this specific description of learning plateaus.

• Gates and others are credited with a related but differently framed idea about learning curves approaching an apparent ceiling of further gains; the exact wording quoted in the question is not the phrasing attributed to them in the standard reference material for this exam.

Hence, the description quoted in the question is the one attributed to Ross.