Sensory process perception Eesha Sharma MD Sense organs

Sensory process & perception Eesha Sharma, MD

Sense organs

Receptor potential Generator potential

Psychophysics • Gustav Theodor Fechner, 1860 • Quantitative relationship between physical stimuli and the sensations and perceptions they effect – Subject’s experience or behavior • Objectively measurable stimuli – Absolute thresholds – Discrimination thresholds – Scaling

Perception Sensation Apperception Experience

Perceptual processes • • Attention Form perception Visual depth perception Constancy Movement perception Plasticity Individual differences

Attention • The perceptual process that selects certain inputs for inclusion in our conscious experience, or awareness, at any given time

Filtering Serial processing Parallel processing Processing capacity

Form perception • Recognition of a figure on a ground

Contours

Organization • Gestalt: The whole is more than the sum of its parts • Laws of perceptual organization – Proximity – Similarity – Symmetry or good figure – Continuation – Closure

Visual depth perception • Monocular cues – Linear perspective – Clearness – Interposition – Shadows – Gradients of texture – Movement • Binocular cues – Retinal disparity

Constancy • Size constancy – Results when the object and its background change together in such a way that the relationship between them stays the same – Moon in the night sky • Brightness constancy – Result of unchanged brightness ratios

Movement perception • Real motion perception – Constancy: because of unchanged relationship between object and its background – The brain comparator • Apparent motion – Stroboscopic motion – Autokinetic effect – Induced movement

Plasticity • Visual deprivation – Sensitive period – Nature and nurture

Individual differences • Perceptual learning – An increase in the ability to extract information from the environment as a result of experience or practice with the stimulation coming from it – Ornithologists; Blind people • Set – Readiness or priming for certain kinds of sensory input • Motives and needs – Rorschach inkblots • Perceptual-cognitive style – Flexibility – Field dependence