Sensation, Attention and Perception
👁️ 2.4 Sensation, Attention and Perception (संवेदना, ध्यान और बोध)
Paper 1 – Foundations of Psychology
🧠 Overview
This topic explores how we detect, focus on, and interpret sensory information from the environment. These processes form the foundation of all higher-level cognition like thinking, decision-making, and emotional response.
🔍 I. Sensation (संवेदना)
Sensation is the initial process of detecting physical energy (stimuli) such as light, sound, or touch through our sensory organs, which then send signals to the brain.
🧪 Key Concepts:
1. Thresholds
- Absolute Threshold: Minimum stimulus needed to detect a sensation 50% of the time.
👉 Example: In a dark room, the faintest sound you can hear is your absolute threshold for hearing. - Difference Threshold (Just Noticeable Difference – JND): Smallest detectable difference between two stimuli.
👉 Example: Noticing the difference between two volumes of sound in a phone call.
2. Signal Detection Theory
- Explains how detection is influenced by:
- Stimulus strength
- Background noise
- Individual expectations or biases
👉 Example: A soldier on night duty is more likely to detect faint sounds due to alertness and training, even if the sound is weak.
3. Vigilance and Sustained Attention
- The ability to maintain alertness over long periods for rare or infrequent signals.
👉 Example: Air traffic controllers must stay alert for small radar changes that signal emergencies.
🎯 II. Attention (ध्यान)
Attention is the process of selectively focusing on specific stimuli while ignoring others.
🔍 Factors Influencing Attention
1. Internal (Subjective) Factors:
- Motivation
- Interest
- Fatigue
- Past experiences
👉 Example: A mother easily wakes up to her baby’s cry, even in deep sleep, due to emotional significance.
2. External (Objective) Factors:
- Intensity and Size: Loud sounds or bright lights grab more attention
- Contrast: Something different from the background stands out
- Movement: Moving objects attract more attention
- Novelty: New or unfamiliar stimuli hold attention longer
👉 Example: Flashy mobile ads with animation are designed to grab attention via contrast and movement.
👁️ III. Perception (बोध)
Perception is the process of interpreting sensory information so that it becomes meaningful. It is not passive but active and shaped by experience, memory, and expectation.
🧱 Key Concepts:
1. Perceptual Organisation (Gestalt Principles)
- The brain organizes stimuli into coherent patterns:
- Figure-ground (what stands out vs. background)
- Proximity (nearby elements grouped together)
- Similarity, Continuity, Closure
👉 Example: Seeing a triangle even when part of its lines are missing (closure principle).
2. Influence of Past Experience
- Our past shapes what we expect to see.
👉 Example: A person familiar with Hindi script can easily recognize “नमस्ते” even if some letters are blurred.
3. Perceptual Defence
- We may block or distort uncomfortable stimuli unconsciously.
👉 Example: A student avoiding looking at a low grade on their test paper.
4. Space, Depth and Size Perception
- We perceive 3D depth and relative sizes using:
- Binocular cues (like retinal disparity)
- Monocular cues (like linear perspective, texture gradient)
👉 Example: Railway tracks appearing to converge at a distance.
5. Perceptual Readiness
- When we are “set” to perceive something, we are more likely to do so.
👉 Example: After watching a horror movie, you may interpret random noises as ghosts.
6. Plasticity of Perception
- Perception can change with experience or training.
👉 Example: Radiologists can detect subtle shadows in X-rays that laypersons can’t — due to training.
7. Subliminal Perception
- Perception of stimuli below the threshold of awareness, which may still influence behaviour.
👉 Example: Subliminal messaging in ads (e.g., flashing the word “BUY” below conscious awareness) — controversial and not fully supported by evidence.
8. Extrasensory Perception (ESP)
- Refers to perception without using known senses, such as telepathy, clairvoyance.
👉 Example: Widely studied but lacks scientific reliability; still popular in Indian cultural narratives.
9. Culture and Perception
- Cultural background affects how we interpret stimuli.
👉 Example: Western children, used to geometric environments, perform better on certain 2D-3D illusion tasks than tribal children in India who grow up in organic, non-linear surroundings.
🧘♀️ Real-life Applications in India
| Field | Application |
|---|---|
| Military Psychology | Signal detection and vigilance training for radar operators |
| Aviation and Railways | Attention and perceptual training for pilots, loco pilots |
| Digital Education | Graphic design of e-learning apps uses attention-grabbing tools |
| Traffic Signage | Red colour for stop signs due to its high attention-capturing capacity |
| Public Health | Anti-smoking ads use perceptual defence theory — grotesque images force re-evaluation of risk |
| Forensic Psychology | Witness perception varies based on stress and cultural bias |
🧠 Conclusion
Sensation, attention, and perception work together to help us make sense of the world.
- Sensation is what we receive,
- Attention is what we focus on,
- Perception is how we interpret it.
Their functioning affects everything from learning and communication to driving and decision-making. Psychologists use this understanding in therapy, education, marketing, military training, and even AI design.
