A complete visual revision journey through the mind’s spotlight, perceptual construction, changing behaviour, memory architecture and the science of forgetting.
Mind camera की तरह सब record नहीं करता—वह चुनता है, organize करता है, सीखता है, meaning बनाता है और कई बार भूलकर भी बेहतर काम करता है।
Try “attention”, “illusion”, “reinforcement” or “forgetting”.
Forms, limits and classic phenomena
Attention is the selective allocation of limited processing resources to some information, goals or actions while other information receives less processing.
Attention केवल “देखना” नहीं; relevant information को priority देना और बाकी को suppress/ignore करना है।
Choose one stream/target and resist distractors.
Maintain readiness over time; vigilance tasks.
Coordinate two tasks; works best when demands/modalities differ or one task is automated.
Shift focus back and forth between tasks or rules.
| Traditional form | Meaning | Example |
|---|---|---|
| Involuntary attention | Captured by sudden/intense/novel stimulus | A loud crash pulls attention |
| Voluntary attention | Goal-directed effort | Reading despite noise |
| Habitual/non-voluntary | Interest or practice draws attention with little effort | A chess expert notices a meaningful pattern |
| External vs internal | Directed to environment vs thoughts/body states | Traffic signal vs mental calculation |
Failure to notice a visible unexpected object when attention is engaged elsewhere.
Failure to detect substantial environmental change, especially across interruption.
A unique basic feature (colour/orientation) can attract attention rapidly and in parallel.
| Attention task | What the participant does | What it measures |
|---|---|---|
| Dichotic listening / shadowing | Different messages to two ears; repeat one stream | Selection and unattended-message processing |
| Stroop task | Name ink colour while ignoring colour word | Selective attention, automaticity and inhibition |
| Visual search | Find target among distractors | Feature pop-out vs conjunction search |
| Continuous performance task | Monitor long stream for rare target | Sustained attention/vigilance |
Early filter, attenuation, late selection and capacity
Both ears / many stimuli
Before meaning
Selected message
An early all-or-none filter selects input by physical features before semantic analysis. Based on dichotic-listening findings.
| Model | Stage/mechanism | What it explains |
|---|---|---|
| Broadbent (1958) | Early filter based on physical features | Limited channel; unattended meaning should be largely lost |
| Treisman (1964) | Early attenuation, not total blocking | Own name/cocktail-party breakthrough due to low threshold |
| Deutsch & Deutsch (1963) | Late selection after semantic analysis | All inputs analysed for meaning; response selection is limited |
| Norman | Late selection plus pertinence | Current goals/expectancies raise activation of relevant inputs |
| Johnston & Heinz | Multimode selection | Selection can occur at different stages; later selection costs more capacity |
| Kahneman (1973) | Flexible limited-capacity resource | Arousal, task demands, policy and enduring intentions allocate effort |
Psychophysics, bottom-up/top-down processing and major approaches
Energy in environment
Receptor converts energy
Pathways process features
Figure, groups, objects
Context, memory, action
Detection and encoding of physical energy by sensory receptors and early pathways.
Organization and interpretation of sensory information into meaningful objects/events.
The whole has emergent organization not reducible to isolated sensations. Brain tends toward lawful, simple, stable forms (Prägnanz).
Explains perception through receptor tuning, feature detectors, pathways, cortical maps and distributed neural activity.
Input is transformed through stages: feature analysis, organization, recognition, decision and response, influenced by top-down knowledge.
| Psychophysical concept | Meaning/formula | Exam clue |
|---|---|---|
| Absolute threshold | Intensity detected 50% of trials | Not an unchanging fixed boundary |
| Difference threshold / JND | Smallest detectable difference, usually 50% criterion | Weber: ΔI / I = k |
| Fechner’s law | S = k log I | Sensation grows logarithmically with intensity |
| Stevens’ power law | S = kIⁿ | Exponent differs across modalities |
Ascending/descending series until judgment changes; vulnerable to anticipation/habituation.
Preselected intensities in random order; accurate but time-consuming.
Observer directly changes stimulus to threshold/match; quick but less controlled.
Figure–ground and laws of grouping
Near items group together.
Similar items form groups.
Missing parts are perceptually completed.
Elements follow smooth paths.
Figure appears shaped/near; ground continues behind.
Items moving together are grouped.
Perception tends toward the simplest, most stable and “good” organization permitted by the stimulus.
Common region, connectedness, symmetry and parallelism can organize elements, often strongly and rapidly.
Size, shape and colour constancy with classic demonstrations
Perceived size remains relatively stable despite retinal image shrinking with distance. Size–distance scaling combines image size and perceived distance.
Object shape appears stable despite changing retinal projection with viewing angle.
Surface colour/lightness remains relatively stable despite illumination changes; context and relative reflectance matter.
Contextual orientation and learned depth/shape assumptions bias perceived length. Cultural exposure to “carpentered” environments can change illusion strength.
Which line looks longer?
| Illusion | What appears distorted | Key explanation |
|---|---|---|
| Ponzo | Equal lines look unequal | Converging perspective implies different depth |
| Moon illusion | Horizon moon appears larger | Apparent distance/context; size–distance scaling |
| Ebbinghaus | Equal circles look different | Surrounding-size contrast |
| Ames room | People look dramatically different in size | Distorted room is perceived as rectangular, corrupting distance estimate |
Pattern, distance and motion cues
Feature detection, contour integration, Gestalt grouping and object recognition combine local parts into stable forms. Figure–ground precedes many object judgments.
Monocular/pictorial: usable with one eye. Oculomotor: convergence/accommodation. Binocular: disparity and stereopsis.
| Movement perception | Meaning | Example |
|---|---|---|
| Real movement | Physical displacement over time | Moving car |
| Apparent / phi movement | Successive stationary lights appear to move | Cinema, signs |
| Induced movement | Movement of frame makes stationary target seem to move | Clouds make moon appear moving |
| Autokinetic effect | Stationary light in darkness appears to drift | Used by Sherif to study norm formation |
Perceptual set, styles, subliminal findings and ecological perspective
Needs, threat and value bias attention and interpretation. Hungry people notice food cues faster; anxiety raises threat vigilance.
Past experience, priming, expectation and schemas make some interpretations more accessible.
Built environments, language, social practices and attentional habits influence susceptibility to illusions and context/object emphasis.
Field-dependent: perception strongly influenced by surrounding field; social/context orientation often stronger. Field-independent: better separation of item from context; measured by Embedded Figures Test.
Perception is direct pickup of information available in the environment, especially invariants in the optic array. Affordances are action possibilities relative to an organism.
Chair “sitting afford” करती है—meaning केवल head के अंदर नहीं, organism–environment relation में है।
Stimuli presented below reported awareness can sometimes produce small, short-lived priming effects under controlled conditions. Evidence does not support powerful hidden messages controlling complex behaviour. Effects depend on threshold definition, attention, stimulus relevance, masking, motivation and response measure.
d′, criterion, four outcomes and how objects are recognized
Balanced trade-off between misses and false alarms.
Separation of signal+noise and noise distributions. Higher d′ means better discrimination and is ideally independent of response bias.
Decision threshold shaped by payoffs, prior probability, cost of errors, motivation and expectation. Liberal criterion raises hits and false alarms.
| Pattern-recognition account | Core idea | Strength/limit |
|---|---|---|
| Template matching | Input compared with stored exact template | Simple; struggles with size/rotation/variation |
| Feature analysis | Recognize distinctive components/features | Explains letter detectors; needs feature combination |
| Prototype | Compare input with ideal/average category representation | Handles variation; boundaries may be fuzzy |
| Recognition-by-components | Biederman: objects built from geons and relations | Viewpoint-tolerant structural description |
| Top-down interactive | Context and knowledge feed back to feature processing | Explains word-superiority/context effects |
Thorndike, Guthrie and Hull compared
Trial-and-error learning forms stimulus–response bonds.
A movement becomes associated with the stimulus pattern present when it occurs.
Formal hypothetico-deductive theory: drive × habit contributes to performance.
| Theorist | Learning mechanism | Role of reinforcement | Signature phrase |
|---|---|---|---|
| Thorndike | S–R connection selected by consequences | Strengthens/weakens bonds | Law of Effect |
| Guthrie | Stimulus–movement contiguity | Not essential for forming association | One-trial / recency |
| Hull | Habit × drive; drive reduction | Essential through drive reduction | Systematic mathematical theory |
Procedure, phenomena, timing and theoretical issues
Bell (NS) → no specific salivation
Repeated predictive pairing
Learned response to predictor
| Phenomenon | Meaning | Exam clue |
|---|---|---|
| Acquisition | CS–US relation is learned; CR grows | Contingency/predictiveness matters, not mere pairing count |
| Extinction | Repeated CS without US reduces CR | New inhibitory learning, not simple erasure |
| Spontaneous recovery | CR returns after rest following extinction | Shows original learning persists |
| Generalization | Similar stimuli elicit CR | Gradient around CS |
| Discrimination | Respond to CS+ but not CS− | Differential reinforcement |
| Higher-order conditioning | Established CS conditions another stimulus | No direct US pairing for new CS |
Delayed forward usually strongest: CS begins before and overlaps US. Trace: gap between CS offset and US. Simultaneous is weaker; backward often inhibitory/poor.
A well-established predictor prevents learning about a new redundant cue—surprise/prediction error matters.
Biological relevance constrains associations, e.g., taste-aversion learning can occur after long delay and one trial.
Consequences, paradigms, schedules and theory
Add pleasant consequence → behaviour increases.
Remove/avoid aversive event → behaviour increases.
Add aversive consequence → behaviour decreases.
Remove valued event → behaviour decreases.
| Schedule | Rule | Response pattern | Example |
|---|---|---|---|
| FR | After fixed number of responses | High rate + post-reinforcement pause | Piece-rate pay |
| VR | After unpredictable response count | Very high steady rate; resistant to extinction | Gambling |
| FI | First response after fixed time | Scallop: pause then acceleration | Checking near scheduled deadline |
| VI | First response after varying time | Moderate steady rate | Checking unpredictable messages |
| Instrumental concept | Exam-ready meaning |
|---|---|
| Discrete-trial paradigm | Each trial has a clear start/end, often a maze choice; commonly associated with instrumental learning research. |
| Free-operant paradigm | Organism responds repeatedly at its own pace in a Skinner box; response rate is central. |
| Partial reinforcement extinction effect | Intermittently reinforced behaviour usually persists longer during extinction than continuously reinforced behaviour. |
| Crespi contrast effect | Performance shifts sharply after an unexpected increase or decrease in reward magnitude. |
| Reinforcement variables | Delay, amount/quality, deprivation, contingency, consistency and competing reinforcers influence learning/performance. |
Reinforce successive approximations toward target behaviour.
Link responses where each produces cue for next; forward or backward training.
Escape ends present aversive event; avoidance prevents expected aversive event.
Assessment, intervention and ethical application
Observable target behaviour
Frequency, duration, context
Antecedent–Behaviour–Consequence
Change cues/consequences/skills
Generalization and maintenance
| Technique | Learning basis | Application |
|---|---|---|
| Systematic desensitization | Counterconditioning + graded exposure + relaxation | Fear hierarchy/phobias |
| Token economy | Conditioned generalized reinforcers | Classroom, ward, rehabilitation settings |
| Contingency management | Explicit reward contingent on verified target | Substance use and health behaviour |
| Time-out | Temporary removal from reinforcement | Reduce problem behaviour when used carefully |
| Response cost | Remove earned reinforcer | Loss of points/tokens |
| Aversion procedures | Pair unwanted behaviour/cue with aversive outcome | Limited, ethically sensitive use |
A high-probability activity can reinforce a low-probability activity: “After study, play.”
Consent, least restrictive effective method, dignity, data-based review, reinforcement before punishment, cultural fit and maintenance planning.
Learning beyond simple S–R bonds
Rats can acquire cognitive maps without immediate reward; reinforcement affects performance/motivation more than acquisition itself. Purposive behaviour is goal-directed.
Learning by observing a model and consequences; direct reinforcement is not required for acquisition.
Attention → Retention → Reproduction → Motivation| Learning form | Typical task | Core variables/phenomena |
|---|---|---|
| Serial learning | Recall items in presented order | Position, chaining, serial anticipation |
| Paired-associate learning | Stimulus word → response word | Association strength, imagery, meaningfulness |
| Free recall | Recall items in any order | Clustering, organization, primacy/recency |
| Discrimination learning | Respond differently to similar stimuli | Positive/negative instances, errorless learning, transposition |
| Concept learning | Classify by rule/common attributes | Hypothesis testing, prototypes, exemplars |
Seeing a model rewarded increases imitation; seeing punishment may inhibit performance.
Generalization extends response across similar stimuli; discrimination narrows it to the relevant cue.
Synaptic plasticity, systems and consolidation
Rapid relational/episodic learning and consolidation of declarative memories; supports spatial maps.
Emotional salience and fear conditioning; modulates memory strength under arousal.
Habit, action selection and reinforcement learning; dopamine encodes reward prediction error.
Motor adaptation, timing and conditioned response learning such as eyeblink conditioning.
Long-term distributed knowledge representations; gradual integration with existing schemas.
Rules, working memory, strategy, goal maintenance and flexible control.
Coincident activity relieves NMDA Mg²⁺ block, Ca²⁺ enters, signalling increases AMPA function/number and can drive structural change.
Hebbian principle: correlated pre + post activity strengthens connectionLower/prolonged activity patterns can weaken synapses. LTD helps refinement, flexibility and preventing saturation.
Attention + feature binding
Minutes/hours; molecular stabilization
Hippocampal–cortical reorganization
Pattern completion/reactivation
Reactivated memory can update
Encoding, storage, retrieval and the multi-store architecture
Environmental information
Large, modality-specific, fleeting
Selects into STM/WM
Active maintenance/manipulation
Durable distributed representation
Transform information into usable representation. Elaboration, imagery, organization and self-reference deepen encoding.
Maintain information across time through synaptic and systems-level change.
Access stored information through recall, recognition, reconstruction and relearning.
| Store | Capacity | Duration | Key feature |
|---|---|---|---|
| Iconic memory | Very large visual snapshot | About a fraction of a second | Sperling partial-report advantage |
| Echoic memory | Large auditory trace | Several seconds | Supports temporal speech integration |
| STM | Traditionally 7±2; modern focus ~4 chunks | Roughly 15–30 seconds without active maintenance | Chunking expands effective capacity |
| LTM | Very large | Potentially lifelong | Meaning, organization and retrieval cues matter |
Craik & Lockhart: semantic, elaborative processing generally yields better retention than shallow visual/phonemic processing.
Retrieval improves when cues/context overlap those present at encoding. Transfer-appropriate processing emphasizes match between study and test operations.
Baddeley’s model and the taxonomy of LTM
Attentional control, switching, inhibition, updating and coordination; limited capacity.
Phonological store + articulatory rehearsal. Word-length and phonological-similarity effects.
Maintains/manipulates visual form, spatial location and movement.
Limited multimodal workspace binding loop, sketchpad and LTM into episodes.
Knowledge supplies meaning, schemas, vocabulary, strategies and familiar chunks.
Vivid confidence for surprising emotional events, but not immune to distortion or forgetting.
Personal semantic knowledge + episodic recollection, shaped by goals and self-schema.
Remembering to perform a future intention; event-based or time-based.
Theories, interference and final retrieval practice
Memory trace weakens with time/nonuse. Time alone is difficult to separate from interference; stronger account for brief sensory/STM traces.
Memory exists but appropriate cues are absent. Tip-of-the-tongue and context effects illustrate temporary inaccessibility.
Information was never adequately encoded due to weak attention or shallow processing.
Competing memories disrupt retrieval, especially when similar.
Intentional suppression or defensive processes reduce access; repression is theoretically important but hard to verify.
Injury, drugs, sleep loss or disruption can prevent stabilization; amnesia patterns may result.
Old → harms New. Old password intrudes when recalling new password.
PRO = past pushes forwardNew → harms Old. New phone number makes old number harder to recall.
RETRO = recent reaches backward| Memory phenomenon | Meaning |
|---|---|
| Serial-position effect | Primacy (early items, LTM/rehearsal) + recency (last items, current STM). |
| Tip-of-the-tongue | Partial activation: feeling of knowing plus fragments, but target currently inaccessible. |
| False memory | Confident recollection can be distorted by suggestion, schemas and source-monitoring errors. |
| Relearning/savings | Faster learning on second occasion shows retention even without recall. |
| Directed forgetting | Instruction to forget reduces later recall, especially through control/segregation strategies. |
Treisman’s attenuator weakens unattended messages rather than eliminating them.
Common fate groups items that move together.
A liberal criterion says “signal” more often, increasing both hits and false alarms.
Guthrie emphasized stimulus–movement contiguity and one-trial association.
Return of the CR supports extinction as new learning rather than erasure.
Fixed interval creates post-reinforcement pause followed by acceleration toward the expected time.
Tolman showed learning can occur before reinforcement is introduced.
Baddeley added the episodic buffer to bind multimodal information and LTM.
Retroactive interference travels backward: new interferes with old.
Procedural skills and habits are implicit/nondeclarative.
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