Unit 3 AP Psych

Sensation and Perception

Sensation

Sensation

Sensation refers to the process by which our sensory receptors and nervous system detect and respond to stimuli from the environment. It involves the initial detection of sensory information, such as seeing, hearing, tasting, smelling, and touching. Sensation is the first step in the process of perception, where the brain interprets and gives meaning to the sensory information received.

Perception

ability to see, hear, or become aware of something through the senses.

Transduction

when you take an outside stimulus and it activates the sensory neurons (sensory receptors) and is transduced or transposes itself into an experience

Psychophysics

branch of psychology

deals with the relationships between physical stimuli and mental phenomena.

Subliminal

Hidden visual or auditory message that the conscious mind does not percieve

Weber’s Law

Physical proportion of change necessary before we “sense” the change.

The ratio of actual change in the stimulus compared to the perceived change.

Gestalt

• Origin of cognitive psychology. Ways that we put together information into patterns. All principles based on how we simplify the world

Figure Ground

• Organization of the visual field onto objects (figure) that stand out from the surrounding (grounds).  

Pragnanz

• meaning good figure. Law of good figure or simplicity. Holds objects in the environment are seen inna way that makes them appear very simple.  

Gestalt Grouping principles

• Proximity

• Similarity

• Continuity

• Conectedness

• Closure

Proximity

how we organize and group things based on how close they are from oneanother.

Similarity

objects that appear alike are grouped together.

Continuity

mind naturally follows a pattern that contains a continuous group.

Connectedness

objects that move in the same direction tend to be seen as one object or grouped together.

Closure

• basis to fill in gaps in the mind. Sees pieces of images and mind fills it in. 

Depth Perception

• The ability to perceive distance of objects in one’s visual field

• Perceive in Length, Width, and Depth

• two different types

  • Binocular Cues

  • Monocular Cues

Binocular Cues

• Require two eyes

• convergence

• retinal disparity

Monocular Cues

• Relative size:

• Interposition

• light and shadow

• Relative height

• Texture gradient

• Linear perspective

Wavelength

Distance between waves

Strobostopic Effect

objects appear to move at a slower speed than reality. This occurs when an object in motion is illuminated periodically with bursts of light.

Hue

Color

Convergence

Binocular Cue

• Neuromuscular Cue

• Two eyes move inward from near objects

• Two eyes straighten for further objects

Retinal disparity

Binocular Cue

• Images for eye differ

• closer the object the larger the difference

• further the object smaller the difference

Sensory Transduction

taking something physical and turning it sensory

Absolute Threshold

• the stimulant has to reach this in order to produce snesory.

• smallest amount of sensation you need to actually feel something

• usually very low

• chuldren’s are lower

Sensory Adaptation

Diminishes sensory awareness due to constant stimulation above the threshold

Difference Threshold

• Smallest amount of change in a stimulus

• Just- noticable differne

• Weber’s Law: The ratio to actual change in the stimulus compared to the perceived change

Signal Detection theory

How much stimulation is necessary to meet out absolute threshold

Helps us understand when we notice or not notice things

Bottom-Up Processing

1. First sense the stimulus

2. Then perceive and process the experience

Top-down Processing

1. First perceive and process experience

   • expectations

   • experiences

   • motivation

   • culture

   • emotion

2. Then sense the experience

Perceptual Set

Tendency to perceive some parts of sensory data and ignore others

Infuences are the same that on Top-down Processing

Schemas

They are mental frameworks for organizing and understanding the world around us.

Ex. what a true friend, what food we like or not

Functional Fixedness

cognitive bias that limits a person to use an object only in the way it is traditionally used

Context Effect

describes the influence of environmental factors on one's perception of a stimulus. The impact of context effects is considered to be part of top-down

The Vision Process

Light Waves enter the eye through Cornea, then it hits the Pupil, then goes through the lens and that sends it back to the retina which has the fovea for color and focus. Once the retina is stimulated neurons fire and form the optic nerves which which take the signal to the visual cortex.

Cornea

Thin outer covering of the eye

Iris

What allows light to come in by expanding and contracting the pupil

Pupil

The dark part of the eye where light actually comes in

Retina

• what contains the receptors for vision

• contains fovea (fovea=focus)

Optic nerve

When retina is stimulated neurons start to fire and form the optic nerve

Ganglions cells

For the optic nerve

Rodes and Cones

Rodes: receptors in the eye that detect movement

Cones: types of photoreceptors that work best in bright light conditions. Cones are very sensitive to acute detail and provide tremendous spatial resolution. They also are directly involved in our ability to perceive color.

Primary Visual Cortex

Occipital lobe. Vision is processed here

Feature detectors

• light

• line

• shape

• angle

• motion

Feature detectors

respond to lines and spheres and angles

Parallel Processing:

refers to our ability to deal with multiple stimuli simultaneously.

Hubel and diesel

Discovered that vision was processed in the Occipital lobe by doing experiments of cats. it was accidental.

Light Waves

the Stimuli

• Wavelength: distance between each wave. Determines hue. Short =cool (Purple= 400nm). Long =warm (red=650nm)

• Amplitude; height of the wave . intensity of the color.

Trichromatic Theory

First stage of color processing.

Ypung and Helmohits (1802)

• Photoreceptors ( cones) work in teams of three

  1. red

  2. green

  3. blue

• Combinations of cones firing make up all the colors in the visual spectrum

• The strength of the signal determines how the brain interprets color

• as light hits the retina cones are stimulated and create sensation of color.

Opponent.process theory

Second stage of color

As visual information is transferred from the photoreceptor cells (cones) to the ganglion cells, some neurons are excited (turned on), while others are inhibited (turned off).

• They work through opponent process

• neurons turn on and off during this process

• explains phenomenon of afterimages

Color blindness

Result of lack of functioning color receptors for color. Inability to distinguish excitatory form inhibitory signals or may have unresponsive cones.

Monochromat

Most rare. Can only see black white or gray

Dichromat

Common. have trouble distinguishing Red and green or Yellow and blue.

Trichromat

No limitations of color

Physical illusion

A type of illusion

• distortions of scale

• based on manipulation of monocular cues for depth perception

Physiological Illusion

A type of illusion

• visual system gets overstimulated

• excitement or fatigue of photoreceptors

• fatigue of stimulation of feature detectors in visual cortex.

Cognitive Illusion

A type of Illusion

• mismatch between what you perceive and what you sense

• top-down processing

• perceptual set

• context cues

• manipulation of Gestalt principle

Audition

Ability to process sound and interpret sensations.

Frequency

Number of waves that occur at a certain time

Pitch

Quality of a sound governed by the rate of vibrations producing it; the degree of highness or lowness of a tone.

Outer ear

Pinna, auditory canal, and tympatic membrane

Middle ear

Three solid tiny bones

• the hammer, or malleus;

• the anvil, or incus;

• the stirrup, or stapes.

Inner Ear

Cochlea: Hearing

Semicircular Canals: Balance

Cochela

fluid-filled, spiral-shaped cavity found in the inner ear that plays role in hearing and participates in the process of auditory transduction.

Sensorineural Hearing Loss

affects loudness, clarity, and range of sounds.

Solution: hearing aids and/or cochlear implants

Conduction Hearing Loss

Sound waves don’t process normally through outer and middle ear

Solution: medicine or surgery,

Place Theory

proposes an explanation of how human beings perceive pitch. According to place theory, the hair cells and nerve fibers of the cochlea are divided into different regions that detect specific sound frequencies.

Pinna

external flop of skin and cartilage that regulates vibrations and protects the ear

Auditory canal

part of the outer ear that leads to tympanic membrane

Tympanic Membrane

the eardrum. separates outer from middle ear and vibrates with sound

Hammer, Anvil, and Stirrup

bones inside of the ossicles that transmit sound to the oval window

Hair cells

Trigger neural impulses to the brain via auditory nerve

Organ of Corti

produces nerve impulses to respond to sound vibrations (inside cochlea)

Basilar Membrane

pressure changes in cochlear fluids

Oval WIndow

Get sound vibrations to the cochlea

Place theory

an explanation of how human beings perceive pitch. According to place theory, the hair cells and nerve fibers of the cochlea are divided into different regions that detect specific sound frequencies.

Touch

ability to perceive an object or other stimulus that comes into contact with the surface of the skin

Gate Control Theory

mechanism in the spinal cord, in which pain signals can be sent up to the brain to be processed to accentuate the possible perceived pain, or attenuate it at the spinal cord itself.

Kinesthesis:

provides information through receptors in the muscles, tendons, and joints, enabling humans and other animals to control and coordinate their movements, including walking, talking, facial expressions, gestures, and posture.

Vestibular sense

carries impulses involved in maintaining equilibrium. It arises in the primary vestibular bipolar neurons whose cell bodies make up the Scarpa ganglion in the internal auditory canal.

Gustation

Taste

Chemical sense

Olfaction

Smell

Chemical Sense

Synesthesia

Synesthesia is when your brain routes sensory information through multiple unrelated senses, causing you to experience more than one sense simultaneously.

Extrasensory Perception

perception that occurs independently of the known sensory processes.

Gustav Fechner

founded the field of psychophysics and is considered to be the founder of modern experimental psychology as a field. He discovered the Fechner Color Effect which is the observation of different colors when black and white patterns are moving at a high speed.

David Hubel:

Demonstrated that neurons in the occipital lobe's visual cortex receive information from individual ganglion cells in the retina (feature detector cells). Also proved that the brain divides a visual scene into several subdimensions(color, movement, etc.) and processes each separately.

Ernst Weber

Weber's law is the principle that states that the just-noticeable difference between two stimuli is a function of the magnitude of the original stimulus.

Torsten Wiesel

discovery of the critical period in visual system development as well as research on visual information processing by the visual cortex of the brain.