PSY252 - Sensation/Perception Study Guide

Absorption of energy by sensory organs and the conversion of energy into an electrical signal used by the nervous system

Sensation

Translating sensory input into something meaningful

Perception

Hearing a loud crashing noise from the sky, interpreting that as thunder.

Example of sensation & perception

Receptors convert physical signals into neural responses (electrical signals)

Conversion transduction

Perception is a mirror that reflects the world perfectly

False (actually an interpretation of info in the world)

Wavelengths posses color themselves

False

Distance over which an electromagnetic wave repeats peaks

Wavelength

When we look at the world, we are demonstrating controlled hallucinating

True

Perceptions are heavily influenced by expectations from prior experiences and stored knowledge

True

A physicist who proposed the mind could be studied by examining the relationship between physical stimulation and a person’s experience.

Gustav Fechner

Study of quantitative relationship between physical stimuli and the sensations they produce

Psychophysics

Smallest intensity that can be detected

Absolute threshold

Why do identification tasks measure reaction time, instead of accuracy?

Accuracy has a ceiling effect (100% correct) so not effective

Cornea (rigid layer refracts light also filters against bacteria/injury)

Iris (regulates amount of light that enters by adjusting the pupil

Lens (adjusts focus by changing curvature)

Retina (in back of the eye, visualreceptors: cones for detail/color, rods for low light)

Close objects are seen clearly, further objects are seen blurry

Nearsightedness

Distant objects seen clearly, close objects seen blurry

Farsightedness

Cornea or lens has an uneven curvature and uneven light curvature

Astigmatism

Hole in retina where axons leave, blood vessels enter

Optic disc (blind spot)

Characteristics of rods

100 million

100x more sensitive

Improves sight in low lighting

Peripheral

Characteristics of cones

6 million

Color/ detail

Center of retina

Neurons that process visual information and transmit to the brain via optic nerve

Ganglion cells

Pattern of light that produces a neutral response in a cell

Receptive field

ganglion cells respond more when light falls in the center, and less in the surround

center surround arrangement

X-shaped structure where optic nerves cross for depth perception and peripherals

Optic chasm

Signals from right visual field go to the left hemisphere

Contralateral organization

Hubel and Wiesel (1962)

Discovered neurons in the PVC have specialized receptive fields and when stimulated, changes a neuron’s firing rate

Kanwisher (1997)

Used FMRI to examine brain activity in faces vs. objects (more activity for faces)

Also lines and edges at specific orientations

Suggests humans see 3D objects by breaking them down into basic shapes called “geons”

Recognition-by-components theory

mental predisposition to perceive stimuli in a certain way based on expectations, experiences, culture, etc.

Perceptual set (top-down processing)

Tendency to have the same perception even when features are changing

Perceptual constancy

Bottom-up processing

Slower analysis of details (more cognition)

6 gestalt principles

Proximity (objects close perceived as together)

Similarity

Closure (brain fills in missing info for incomplete objects)

Simplicity (prefer simplest form)

Good continuation (preference for flowing lines)

Common fate (synchronization)

Morton & Johnson (1991)

Discovered newborns preferred formed faces over disfigured ones or blank faces

Phenomenon where distinct stimuli is instantly detected among various subtle stimuli

Pop-out effect (for upright faces)

Tendency to perceive faces as wholes rather than separate parts

Holistic processing

Arrangement/distance of facial features

Configural information

Localized facial features appear normal when inverted, but appear off when face is turned upright

Thatcher effect

Individuals have difficulty recognizing faces of familiar people

Prosopagnosia