Sensation and Perception Flashcards
Sensation, Perception and Cognition
Sensation: registering stimulation of the senses Perception: processing and interpreting sensory information Cognition: using perceived information to learn, classify, comprehend
Bottom-up processing
Perception starts with physical characteristics of stimulus and basic sensory processes (e.g., feature detectors).
Gibson’s Theory of Direct Perception
Information in sensory receptors and sensory context enough for perception
Cues in environment aid perception
Directly perceive environment, do not need complex thought
e.g., texture detail = close
Top-down processing
Constructivism:
perceiver constructs perception of a stimulus using
cognition, knowledge and learning
Single cell recording
Action potentials of neurons recorded with microelectrode
inserted close to cell
Cortical recording requires section of skull to be removed
Only on humans if medical operation
(e.g., for epilepsy)
Identified selective cells (e.g., for certain orientations, direction of motion, faces)
Single cell recording continued
Single neurons can encode multimodal representations
of people!
Epilepsy patients implanted with depth electrodes, recording from single cells
Presented with photos, text name and spoken name of multiple people
Selective neurons in medial temporal lobe represent individuals in multiple sensory modalities
Lesioning
Transcranial Magnetic Stimulation (TMS) over posterior
superior temporal sulcus (STS) disrupts biological motion
Psychophysics
Quantifies relationship between physical stimuli and
sensation and perception
Threshold: change from one perceptual experience to another, e.g., now you see it, now you don’t!
Absolute threshold: smallest stimulus intensity needed for detection
Differential threshold: smallest difference between two stimuli that can be detected, ‘Just-noticeable difference’ (JND)
