Unit 2 Psychology

Sensation

detecting physical energy with our sense organs (eyes, ears, nose, tongue, skin)

Perception

the brain’s interpretation of the raw sensory information 

Illusion

 the way we perceive a stimulus doesn’t match its physical reality

Transduction

conversion of an external stimulus into a neural signal

Sensory receptors

specialized cells designed to convert a certain kind of external information into a neural signal

Sensory adaptation

Sensory neurons adjust their sensitivity based on recent stimulus history

Aftereffects

opposing sensory or perceptual distortions that occur after adaptation

wavelength in sound is what

pitch

wavelength in light is what

color

Psychophysics

study of how our sensations (psychological events) correspond to physical events in the world

Absolute threshold

the lowest level of a stimulus needed for the nervous system to detect a change 50% of the time 

Just Noticeable Differences (JND)

the smallest change in the intensity of a stimulus we can detect

Weber’s Law

the stronger the stimulus, the bigger the change needed to detect it; the amount of stimulus energy required to produce a JND is a constant fraction of stimulus intensity

signal

what you are trying to detect

noise

similar stimulu that might compete with the signal and interfere with your ability to detect the signal

Signal-to-noise ratio

The difficulty of detecting the signal depends on the strength of the signal in relation to the strength of the noise

What will happen if you adjust your response criterion so that you never have any misses?

A. It will increase false alarms (the more yes’s, the more false alarms) 

B. It will decrease false alarms

What will happen if you increase your rate of correct rejections?

A. Your rate of misses will increase

B. Your rate of misses will decrease

Dichotic listening

play different information through each ear of headphones. Information reported only from the attended ear 

Inattentional blindness

occurs when unattended stimuli are ignored as if they weren’t there

Change blindness

is a version of this that occurs when you fail to detect

obvious changes in your environment

Bottom-up processing

Bottom-up processing

Type of bottom-up processing

sensation & perception

Top- Down processing

processing influenced by previous learning and knowledge 

Type of top-down processing

perception

Sclera

white part

Pupil

circular hole where light enters

Iris

colored portion of the eye that controls pupil size - lets in more or less light

Cornea

a curved, transparent layer covering the iris and pupil that helps focus light (take out contacts to avoid irritation of the cornea)

Lens

oval-shaped disc that bends light

Accommodation

changing the lens’ shape to focus on near/far objects

Myopia (nearsightedness):

the eye is too long

Hyperopia (farsightedness)

the eye is too short

Retina

membrane at the back of the eye responsible for converting light into a neural signal

Fovea

central portion of the retina, responsible for visual acuity (very small - takes up 1% of retinal size)

Acuity

sharpness of vision

Saccades

small jerky movements of the eye, allowing for rapid changes of focus 

Rods

Respond under low levels of light

◦ Not color sensitive

◦ More common outside of the fovea

Cones

◦ Sensitive to fine detail

◦ Primarily located in the fovea

◦ Color Sensitive

◦ Less plentiful than rods

Optic nerve

•  bundle of axons that travels from the retina to the

• brain

Blind Spot

• area of the retina where the optic nerve exits the eye

The highest density of cones in the retina is found

A. At the periphery

B. At the optic nerve

C. In the fovea

D. In the sclera

What part of your visual system helps you to see things in low levels of light?

A. Your fovea

B. Rods

C. Cones

D. Your lens

Your right visual field is represented in the left hemisphere of your brain.

A. True

B. False

Hue

color of light

Trichromatic Theory

color vision is based on three primary colors:

blue, green, and red

Opponent Process Theory

We perceive colors in terms of three pairs

of opponent colors:-

• Red-green

• Blue-yellow

• Black-white

Color blindness

inability to see some or all colors

Depth perception

ability to judge distance and spatial relations

Binocular disparity

• each eye sees slightly different images; brains can judge depth

Convergence

 eyes rotate inward to see near objects

Relative size

• distant objects look smaller than closer objects

Texture gradient

the texture is bigger the closer you are

Interposition

•  Closer objects appear in front of distant

• objects

Linear Perspective

• Parallel lines converge with distance

Height in Plane

• Distant objects appear higher than closer objects

Light and Shadow

 shadows can tell us about form

 Motion parallax

• Closer objects pass more quickly than distant objects

Perceptual Constancy

We perceive objects as constant despite the change in sensations that arise from those objects.

Shape constancy

perceived shape is constant, even though the shape of the image (on retina) varies

Color constancy

perceive stimuli as consistent color across varied conditions

When you see a friend from far away, they are very small in your field of view. What keeps you from thinking “Oh my gosh, my friend shrank!”?

A. Perceptual constancy

B. Photoreceptors

C. Optic Chiasm

D. Primary Visual Cortex

Gestalt Psychology

the brain creates a perception that is more than simply a sum of available sensory inputs, and it does so in predictable ways

Figure-ground relationship

figures are integrated units of perception (figure=object/person; ground=background). 

Proximity

things that are close to one another tend to be grouped together

Similarity

things that are alike tend to be grouped together

Law of continuity (good continuation

 we are more likely to perceive continuous, smooth-flowing lines rather than jagged, broken lines

Principle of closure

we organize our perceptions into complete objects rather than a series of parts

Pattern perception

our ability to discriminate among different figures and shapes 

Perceptual hypotheses

an educated guess that we make while interpreting sensory information 

Common fate

objects moving at the same direction and at the same

speed are perceived as a group.

Synchrony

 stimuli that are perceived to occur at the same time are

perceived as part of the same event

Learning

change in an organism’s behavior or thoughts as a result of

Experience.

Non-Associative Learning

• A form of learning that involves responding to a single stimulus.

Habituation

• process of responding less strongly over time to repeated stimuli; getting used to a stimulus; usually a neutral Stimulus

Sensitization

•  process of responding more strongly over time to repeated stimuli; usually a dangerous or irritating stimulus

Associative Learning

Occurs when an organism makes connections between 2 or more stimuli/events that occur together in the environment

Classical Conditioning

•  A form of learning in which two stimuli are repeatedly paired

Unconditioned stimulus (US)

• Produces a reflexive/automatic response

Unconditioned response (UR)

• That automatic response (already there, not learned)

Conditioned stimulus (CS)

•  Initially neutral, becomes associated with UCS

Conditioned response (CR)

• Automatic response now triggered by CS

Acquisition

• Learning phase; when UCS is paired with CS

Extinction

• CS appears alone and the CR weakens, CR is eventually eliminated (CR becomes extinct)

Spontaneous recovery

• Extinct CR suddenly emerges again

• after a delay

Renewal Effect

Sometimes a response is extinguished

Generalization

respond to stimuli that are similar to the conditioned stimulus 

Discrimination

Respond to a particular stimulus but not similar stimuli

Blocking

A prior association with a conditioned stimulus prevents learning

of an association with another stimulus.

Preparedness

Biological predisposition to learn some associations more quickly than other associations.

Taste Aversion Conditioning

• Associating nausea with food

Fear Conditioning

Negative associations can be so powerful that

they are learned extremely rapidly.

Chronic Drug Use

When a drug is used, it is associated with the cues present at the same time.

Little Albert was conditioned to fear a rat, but he also showed fearful

responses to a rabbit, dog, fur coat. This demonstrates:

B. Stimulus Generalization

Advertisements often portray young, attractive people having fun in order

to induce positive emotions in prospective consumers, which will then

lead them to purchase the product. When evoked by the product alone,

those positive emotions serve as the

B. conditioned response.

When Ana was recovering from food poisoning as a child, she could only

eat soft foods such as mashed bananas. Now, as an adult, she can’t stand

the taste of bananas, even though they weren’t what made her sick.

A. conditioned taste aversion

Operant Conditioning

• Change in voluntary behaviors as a result of the consequences.

Thorndike’s Law of Effect

• behavior is a function of its consequences

Basic assumption

• Learning is controlled by the consequences of the organism’s behavior

Discriminative stimulus

• any stimulus that signals the presence of reinforcement.