Chapter 4 - Sensation and Perception

Psychology 6th Edition - Schacter, Gilbert, Nock

sensation

simple stimulation of a sense organ

transduction

when sense receptors convert physical signals from the environment into neural signals that are sent to the central nervous system

perception

organization, identification, and interpretation of a sensation in order to form a mental representation.

Vibrations from a guitar string cause change in the air pressure that arrive in a person’s ear; this describes the ________.

sensation of the guitar

The smell of something burning reminds you that you forgot to set the timer on the stove; this describes the________.  

perception of a burning smell

Sugar activates TAS1R2 receptors on your tongue, triggering action potentials, and sending nerve impulses to the brainstem; this describes the________.

transduction of the taste of sugar

sensory adaptation

sensitivity to prolonged stimulation tends to decline over time as an organism adapts to current (unchanging) conditions.

When you first dive into a cold swimming pool, the temperature is shocking. But thanks to sensory adaptation ________.

your sensitivity to the cold will decline

Our sensory systems respond more strongly to ___________ than to constant stimulation.

changes in stimulation

psychophysics

methods that systematically relate the physical characteristics of a stimulus to an observer’s perception.

absolute threshold

the minimal intensity needed to just barely detect a stimulus in 50% of the trials. A threshold

sensitivity

how responsive we are to faint stimuli

acuity

how well we can distinguish two very similar stimuli

just noticeable difference (JND)

the minimal change in a stimulus (e.g., its loudness or brightness) that can just barely be detected.

weber’s law

for every sense domain, the change in a stimulus that is just noticeable is a constant proportion despite variation in intensities.

During a hearing test, many sounds were presented at such a low level of intensity that Absher could hardly even detect them. These sounds were below Absher's _____ threshold.

absolute

Methods that systematically relate the physical characteristics of a stimulus to an observer's perception are:

psychophysics.

As the volume of a sound increases, for example, the value of the Weber fraction ______; and the size of the just-noticeable difference in decibels _______.

remains the same; increases

Candice can tune her guitar more effectively than Dahlia because she is better at detecting whether specific strings are playing too sharp or too flat. Candice apparently perceives a ______ than Dahlia.

smaller just-noticeable difference

signal detection theory

the response to a stimulus depends both on a person’s sensitivity to the stimulus in the presence of noise and on a person’s decision criterion.

The Metro city police department consulted a psychic detective for 100 missing person cases. Of these cases, 50 bodies were ultimately recovered. The psychic claimed that 31 of these 50 individuals would be found close to water. Only 17 bodies predicted to be close to the water were within 500 meters of a body of water. The psychic had ________.

14 false alarms

A local sheriff is running for mayor. He claims that he's apprehended the perpetrator for every crime since he became sheriff. His opponent argues that the sheriff arrested someone who met the suspect's description for each offense, but many were later cleared. In other words, the opponent agrees that the sheriff has a high number of ______, but also has a high number of ______.

hits; false alarms

hit

signal present, observer identifies it

miss

signal present, observer does not identify it

false alarm

signal absent, observer identifies it

correct rejection

signal absent, observer does not identify it

According to signal detection theory, the criterion for parents listening for their newborn baby's cry is likely to be _____, while the criterion for a teen immersed in gaming to recognize the sound of their parent's voice calling them is expected to be ________. 

lax, strict

Spot the dog takes his job of protecting his owners' home very seriously. He sits at the window all day and barks whenever he perceives a threat. However, he often barks at innocuous things like squirrels running up a tree or a car door shutting across the street. In detecting threats, Spot makes many _____ due to a _____ decision criterion.

false alarms; lax

lax criterion

to think that anything like the signal must be the signal.

strict criterion

be less aware of possible signals

length

Hue or what we perceive as color

amplitude

brightness

purity

Saturation or richness of color

One of the world’s brightest flashlights is “The Torch” – in fact, the light energy it produces is so powerful that it can fry an egg, or start a fire, in just a few seconds. Which of the following aspects of The Torch’s light is so powerful? 

amplitude

cornea

a thick protective layer covering the outside of your eye.

pupil

hole in the iris

iris

a circular muscle, and when it contracts, it constricts the pupil

accommodation

the process whereby the eye maintains a clear image on the retina.

retina

a layer of light-sensitive tissue lining the back of the eyeball

cones

detect color, operate under normal daylight conditions, and allow us to focus on fine detail

rods

become active only under low-light conditions, for night vision

fovea

an area of the retina where vision is clearest and there are no rods at all.

bipolar cells

collect electrical signals from the rods and cones and transmit them to the outermost layer of the retina

retinal ganglion cells (RGCs)

organize the signals and send them to the brain.

blind spot

a location in the visual field that produces no sensation on the retina.

area v1

the part of the occipital lobe that contains the primary visual cortex.

The part of the retina that has the highest visual acuity is the ________.

fovea

When you walk from sunlight into a dark room, the ________ will become enlarged.

pupil

To see nearby objects, the ________ needs to become thickened.

lens

The location where light is transduced into neural signals when the light level is low is the ________.

retina

People have a blind spot where the ________ connects to the retina.

optic nerve

Accommodation occurs in the ________.

lens

The protective covering of the eye is the ________. 

cornea

The location that has a large concentration of cones is the ________. 

fovea

When someone has cataracts, the _________ will become clouded.

lens

When the iris enlarges, the ________ will become smaller.

pupil

Rods are __________

unable to detect differences in wavelength

The fovea of the eye ________.

is the central part of the retina where the cones are concentrated

The blind spot is ________.

the location where the optic nerve leaves the eyeball

color-opponent system

in which pairs of cone types (channels) work in opposition

Deuteranopia

a type of red-green colorblindness in which green cones (medium wavelengths) malfunction.

Protanopia

a type of red-green colorblindness in which red cones (long wavelengths) malfunction.

Tritanopia

blue-yellow colorblindness due to malfunctioning blue cones

Monochromacy

inability to see color because there are no cones or only one type of cone exists.

Due to the color-opponent system, if you viewed a red patch for a long time - causing the red cones to become adapted - what would happen if you then looked at a blank surface?

You’d see a green afterimage.

ventral stream

processes object and person details in a visual scene, the “what” pathway

Dorsal stream

processes info about how and where you see things, the “how” or “where” pathway

visual receptive field

the region of the visual field to which each neuron responds

visual form agnosia

the inability to recognize objects by sight

binding problem

how the brain links features together so that we see unified objects in our visual world rather than free-floating or miscombined features

After leaving the eye, visual information travels first to the ________, on to the ________, and finally to ________.

optic chiasm; lateral geniculate nucleus; occipital lobes

Hanna has had a stroke and can no longer see from her right eye, even though her eyeball and retina are fine. The damage in her visual system has occurred in the ________.

optic nerve of the right eye

Astigmatism is an optical defect when the eyeball cannot focus light as a sharp image on the retina correctly. People with astigmatism have blurry vision and usually need glasses. Which of the following best describes the cause of astigmatism?

The lens is not accommodating appropriately.

Hyperopia is when the ________.

eyeball is too short

Compared with cones, rods ___________.

are more sensitive to light

perpetual contsancy

even as aspects of sensory signals change, perception remains constant.

conceptual knowledge

the rich store of facts and other meaningful knowledge we have about a familiar object

perceptual organization

process of grouping and segregating features to create whole objects organized in meaningful ways

simplictiy

the visual system tends to select the simplest or most likely interpretation

closure

tend to fill in missing elements of a visual scene, allowing us to perceive edges that are separated by an interruption as belonging to complete objects.

continuity

Edges or contours that have the same orientation have what the Gestalt psychologists called good continuation, and we tend to group them together perceptually

similarity

Regions that are similar in color, lightness, shape, or texture are perceived as belonging to the same object.

proximity

Objects that are close together tend to be grouped together.

common fate

Elements of a visual image that move together are perceived as parts of a single moving object.

Edge assignment is important for the _________. 

perception of separation of figure from ground

monocular depth cues

aspects of a scene that yield information about depth when viewed with only one eye

Linear perspective

describes the phenomenon that parallel lines seem to converge as they recede into the distance

texture gradient

describes how textures such as parched ground look more detailed close up but more uniform and smooth when farther away

interposition

occurs when one object partly blocks another

relative height in the image

Objects that are closer to you tend to be lower in a visual scene, whereas faraway objects are higher up in your field of view.

binocular disparity

the difference in the retinal images of the two eyes that provides information about depth

Looking into an Ames room, the person on your left appears small, and the person on your right appears large. The fact that the floor slopes upward from the left to the right side of the room prevents you from using which monocular depth cue?

relative height in the image

Looking into an Ames room, the person on your left appears small, and the person on your right appears large. The tiles on the floor have been painted to appear the same shape and size throughout the room from your vantage point. Which monocular depth cue does this prevent you from using?

texture gradient

the phi phenomenon

We perceive motion when stimuli in close proximity appear and disappear each in the same location, in a specific sequence. 

apparent motion

perception of movement as a result of alternating signals appearing in rapid succession in different locations

biological motion perception

our ability to perceive biological motion critical for identifying individuals and various socially relevant features, such as their emotional state, personality characteristics, whether they are vulnerable to attack, or are engaging in deceptive actions

Most movies are filmed at 24 frames per second, meaning 24 still photos appear one after another each second. We perceive the 24 still images as a moving image because of…

apparent motion.

When an object moves across a complex background, it appears to move _______ than when it moves across a simple background.

faster

An example of the illusion of motion is…

when you are stopped at a traffic light, if the car next to you edges forward your brain interprets this as you moving backwards

The Waterfall illusion demonstrates:

motion aftereffects