Who is notable for being kept in a box during conditioning experiments?

The correct answer is notable because it refers to the famous psychological experiment involving Little Albert, conducted by John B. Watson and Rosalie Rayner in 1920. In this study, they aimed to demonstrate classical conditioning. Little Albert was a healthy, 9-month-old infant who was conditioned to fear a white rat by associating its presence with loud, frightening sounds. While the experiment is often remembered for its ethical implications and methodology, the use of an enclosed space (referred to as a "box") was part of the setup to ensure Little Albert's behavior could be observed without external distractions. This experiment illustrated the principles of associative learning and has been foundational in understanding emotional responses in both humans and animals.

The other options do not relate to any recognized psychological study involving conditioning and reinforcement, thus they lack the historical and academic significance associated with Little Albert's case.