psych 10 sensation and perception

What is sensation?

The physical process of detecting environmental stimuli through sense organs (eyes, ears, nose, skin, tongue).

What is perception?

 The psychological process of interpreting sensory information.

 Difference between sensation and perception?

 Sensation = detecting; Perception = interpreting.

What is psychophysics?

Study of how physical stimuli relate to our psychological experience of them.

What is an absolute threshold?

The minimum stimulus intensity detectable 50% of the time.

What is the difference threshold (JND)?

The smallest detectable difference between two stimuli 50% of the time.

 What does Weber’s Law state?

JND is a constant proportion of the original stimulus. The bigger the original stimulus, the bigger the change needed to notice it.

What is top-down processing?

Perception influenced by expectations or prior knowledge.

What is bottom-up processing?

Perception built from individual sensory inputs without prior knowledge.

What is signal detection theory?

Detection depends on sensitivity + decision criteria; influenced by experience, expectation, motivation, fatigue.

What is sensory adaptation?

Decreased sensitivity to a constant or repeated stimulus.

What is selective attention?

Focusing on one stimulus while ignoring others.

 What is inattentional blindness?

Failure to notice objects outside the focus of attention.

What is change blindness?

Failure to notice visual changes in a scene

What is the retina?

Light-sensitive layer at the back of the eye containing photoreceptors (rods & cones) that transduce light into neural signals.

What are rods?

Photoreceptors for low-light and black/white vision.

What are cones?

Photoreceptors for color and detail, function best in bright light.

Trichromatic theory of color vision?

 3 types of cones sensitive to short (blue), medium (green), long (red) wavelengths.

Opponent process theory?

: Colors perceived in opposing pairs: red/green, blue/yellow, white/black; explains afterimages.

Signal travels from eye to brain how?

Retina → Optic nerve → Thalamus → Primary visual cortex (V1)

What are feature detectors?

Neurons in V1 that respond selectively to specific features like edges, lines, or angles.

What are the visual processing streams?

• Dorsal (“Where”) → spatial location, motion (occipital → parietal).
  
  

Ventral (“What”) → object/face recognition (occipital → temporal).

Visual agnosia?

Cannot recognize objects despite normal vision.

 Prosopagnosia?

 Cannot recognize faces; can see features but not identity.

Depth perception cues?

• Monocular: relative size, height, linear perspective, light/shadow, interposition
  
  

• Binocular: retinal disparity, convergence
  
  

How does sound travel in the ear?

Pinna → Ear canal → Eardrum → Ossicles → Cochlea (hair cells) → Auditory nerve → Brain

 Types of hearing loss?

• Conductive: Middle ear problem; sound not amplified
  
  

Sensorineural: Damage to cochlea or auditory nerve

What is sound localization?

Determining direction of sound using timing and intensity differences between ears.

What is multimodal perception?

Integration of multiple senses to interpret events

 McGurk Effect?

Visual input can change what we hear.

Synesthesia?

Stimulation of one sense triggers experiences in another (e.g., seeing colors when hearing music).