What is perception?
- The process in which our minds construct the reality we experience through sensory information
Key Terms
| Perception | The process by which the brain interprets sensory information to create our experience of reality. |
| Reality | The world as we experience it, constructed by the brain’s interpretation of sensory signals. |
| Transduction | The conversion of physical stimuli (like light or sound) into neural signals by sensory organs. |
| Psychophysics | The scientific study of the relationship between physical stimuli and the sensations and perceptions they produce. |
The Steps of Perception
- Physical Stimulus
- Transduction by Sense Organs
- Neural encoding & Transmission
- Psychological Interpretation
What is reality?
- Complex mix of stimuli + expectations + prior knowledge
Human Senses
The 5 Senses
- Vision (Sight)
- Hearing (Audition)
- Smell (Olfaction)
- Taste (Gustation)
- Touch (Tactile)
More complex senses:
- Balance (Equilibrioception)
- Body Awareness (Proprioception)
- Temperature (Thermoception)
Perception Across Psychological Spectrum
Neuropsychological Disorders
Apperceptive Agnosia
Definition: A disorder where individuals cannot form a coherent percept of objects, even though their basic vision is intact.
Symptoms: Difficulty copying shapes or recognizing objects, often producing drawings that are unrecognizable.
Case Example: A patient asked to copy an anchor draws a jumble of lines, unable to capture its overall form.
Significance: Indicates a breakdown early in the visual processing pathway, helping clinicians localize brain damage.
Associative Agnosia
Definition: A disorder where individuals can accurately copy objects but cannot identify or assign meaning to them.
Symptoms: Perfectly reproducing a drawing of an object, yet unable to say what it is.
Case Example: A patient copies an anchor flawlessly but cannot recognize it as an anchor (see the image below).
Significance: Suggests intact perception but impaired connection to stored knowledge, pointing to higher-level processing deficits.
Prosopagnosia (Face Blindness)
Definition: A specific inability to recognize faces, despite normal vision and intelligence.
Symptoms: Difficulty identifying familiar people, often relying on voice or other cues.
Case Example: A person cannot recognize close friends or family members by face alone, even though they can describe facial features.
Significance: Highlights the specialized nature of face perception and its neural underpinnings, often linked to damage in the fusiform gyrus.
Perception in Clinical Psychology
- Body image distortion
- Perceptual Biases in Anxiety
- Impaired Emotion Recognition
Perception in Forensic Psychology
Weapon Focus Effect
- Witnesses focus on weapon, ignoring other detail
- Less accurate recall
Line up identification errors
- simultaneous presentation
- Poor filler selection
- Witnesses just choose someone who looks similar, even if they aren’t sure
Other-race effect
- people are better at recognising faces of their own race
Perception in Organisational Psychology
Jump Jet Illusion
- Pilots misread visual cues –> bad landings
- Pilots trained to trust flight instruments >> visual perception cues
Sensory overload & alarm designs
- Specialised alarm sounds to break through very busy environments
Perceptual Illusions
Spatial Vision Illusions
- Cafe Wall Illusion
- Fraser Spiral
Colour Vision Illusions
- Viral Illusion Dress
Motion Illusions
- Rotating Snakes
- Motion Aftereffect
Depth Illusion
- Ames Room
- 3D pavement art
Perceptual Organisation Illusions
- Ambiguous figures
- Gestalt Grouping Principles
Perception organisation = brain’s ability to group & interpret complex visual scenes
