(a) Differentiate between classical and operant conditioning. Discuss their applications with suitable examples. (20 marks) (b)…

(a) Classical and operant conditioning

Classical conditioning, described by Pavlov, is learning by association between two stimuli: a neutral stimulus becomes a conditioned stimulus (CS) after pairing with an unconditioned stimulus (US), eliciting a conditioned response (CR). Its mechanism is S-S*, the response is involuntary, and it is elicited by a CS that has preceded the US. Pavlov’s dog salivating to a bell illustrates this. Operant conditioning, described by Skinner, is learning by consequences: a voluntary emitted response is strengthened or weakened by reinforcement or punishment. Its mechanism is R-S*, the response is voluntary, and it follows an antecedent stimulus and is followed by a consequence. Skinner’s box, where a rat presses a lever for food, illustrates this. Thus, classical conditioning changes stimulus-stimulus associations for elicited behaviour, while operant conditioning changes response-stimulus associations for emitted behaviour. Applications differ. Systematic desensitisation for anxiety disorders and aversion therapy for alcohol or substance dependence use classical principles by pairing feared or unwanted cues with relaxation or nausea. In India, systematic desensitisation has been used for classroom phobia and school avoidance, and NIMHANS, Bengaluru, provides behaviour therapy for anxiety and substance abuse in clinical settings. Operant principles are used in behaviour modification for autism, token economies in psychiatric rehabilitation, and biofeedback training, which uses contingent feedback to regulate physiological responses. Indian psychiatric rehabilitation programmes have used token economies to shape attendance, hygiene and social skills.

(b) Depth perception

Depth perception relies on monocular and binocular cues. Monocular cues work with one eye: linear perspective, where parallel lines appear to converge; texture gradient, where surface detail becomes finer with distance; relative size, where smaller retinal images are judged farther; interposition, where one object blocks another; aerial perspective, where distant objects appear hazier and bluer; and motion parallax, where nearer objects shift more across the retina during head or body movement. Binocular cues require both eyes: retinal disparity, the difference between the two retinal images, and convergence, the inward turning of the eyes for near objects. These cues support driving, sports, threading a needle, and artisanal craft such as pottery or woodwork, where accurate depth judgments are essential. Neurologically, retinal disparity is processed in visual cortical areas, and stereopsis matures during infancy and early childhood. Cross-cultural work, including Hudson's (1960) pictorial depth studies and Segall et al.’s carpentered-world hypothesis, suggests that exposure to rectilinear built environments may increase reliance on pictorial cues; Indian tribal and urban comparisons have examined variation in cue use, linked to environmental exposure rather than innate ability.

(c) Memory and forgetting

Memory is a constructive process involving encoding, storage and retrieval, while forgetting is the failure or degradation of one or more of these stages. Forgetting may arise from decay, interference, motivated forgetting, or retrieval failure due to poor cues or context. The multistore model of Atkinson and Shiffrin describes sensory memory, short-term memory and long-term memory, linked by control processes such as attention and rehearsal. It identifies duration and capacity limits, such as short-term memory holding about 7 ± 2 items, but it is limited because it treats stores as fixed boxes and underplays active construction, working memory and retrieval cues. Metamemory, studied by Flavell, is knowledge about one’s own memory: knowledge of person, strategies and phenomena, including feeling-of-knowing judgments. It helps learners plan, monitor and control study, and metamemory training can improve recall in students and older adults. Indian relevance includes NCERT’s educational psychology materials and classroom memory-training studies, the yoga-psychological concept of smriti as recollection, and contemporary research from NIMHANS on cognitive ageing.