Chapter 5: Sensation and Perception - PSYC 100

What is the physical stimuli of olfactory (smell)?

Odourants (airbone chemicals)

What is the physical stimuli of somatosensory (touch, heat, pain)?

Pressure or damage to the skin

What is the physical stimuli of gustatory (taste)?

Chemicals (typically in food)

What is the physical stimuli of auditory (hearing)?

Sound waves

What is the physical stimuli of visual (sight)?

Light (photons)

What are the two critical processes for interpreting our environment?

Sensation and perception

What is sensory transduction?

The process of converting environmental stimuli into neural impulses.

What type of sensory receptors are involved in smell?

Olfactory receptor neurons that detect odourants.

What is the absolute threshold for smell?

A drop of perfume diffused throughout a six-room apartment.

What is the difference threshold (just noticeable difference)?

The minimal difference needed to notice a difference between two stimuli.

What is sensory adaptation?

The reduced response of sensory cells due to repeated stimulation.

What is bottom-up processing?

Perception that starts with environmental stimuli and progresses to complex brain processing.

What is top-down processing?

Perception influenced by cognitive processes like memory or expectations.

What are the five commonly understood senses?

Smell, taste, touch, sound, and sight.

What are the two additional senses beyond the commonly understood five?

Kinesthetic (body movement and posture) and vestibular (head position and movement).

What are papillae?

Bumps on the tongue that contain clusters of taste buds.

What are the five taste receptors on the tongue?

Sweet, sour, bitter, salt, and umami.

How do olfactory receptor neurons function?

They convert chemical signals from odourants into neural impulses that travel to the brain.

What is the role of the amygdala and hippocampus in smell?

They receive neural impulses from olfactory receptors, linking smell to memory and emotion.

What sensory information contributes to the overall sensation of eating?

Inputs from touch receptors located on the tongue and the texture of food.

What preference do newborns show regarding smell?

A preference for the odour of their mother's milk.

What taste preference do infants exhibit at birth?

A preference for sweet tastes and an aversion to bitter tastes.

What is a perceptual set?

The readiness to interpret a certain stimulus in a specific way.

What is the significance of sensory sensitivity?

It depends on experience, expectations, and consequences for failure.

What is the role of the gustatory nerve?

It transmits neural impulses from taste buds to the brain.

What is the purpose of individual differences in taste and smell?

They likely serve as a survival adaptation to prevent ingesting toxic objects.

How do females generally compare to males in terms of olfactory sensitivity?

Females are generally more sensitive to odours than males.

What is a 'super-taster'?

A person who has a high sense of taste and is more sensitive to certain flavors.

What is ageusia?

The inability to taste, which is a rare disorder.

Define anosmia.

The inability to detect odours.

What does hyposmia refer to?

A reduced ability to smell.

What is reflex epilepsy in relation to smell?

A seizure that occurs only after exposure to a specific odour.

How can specific odours affect migraine headaches?

Certain odours can trigger migraines.

What is the tactile or somatosensory system composed of?

It includes pressure, touch, temperature, vibration, and pain.

What are free nerve endings responsible for?

They detect touch, pressure, pain, and temperature.

Where are Meissner's corpuscles located and what do they detect?

Located in hairless skin areas like fingertips and palms, they detect sensitive touch.

What is the function of Merkel's discs?

They transduce information about light to moderate pressure against the skin.

What do Ruffini's end-organs register?

They register heavy pressure and joint movement.

What do Pacinian corpuscles respond to?

They respond to vibrations and heavy pressure.

What are the two pathways of pain?

The fast pathway (sharp, localized pain) and the slow pathway (burning pain).

How does the fast pathway of pain function?

It travels along myelinated neurons to the brain quickly.

What is the role of endorphins and enkephalins?

They are naturally occurring chemicals that have pain-relieving properties.

What is chronic pain?

The most common abnormality associated with the somatosensory system.

What is the cocktail party effect?

The brain's ability to pick up relevant sounds in a noisy environment.

What is the frequency of sound measured in?

Hertz (Hz), representing cycles per second.

What determines the pitch of sound?

The frequency of sound waves.

What are the ossicles in the middle ear?

The three smallest bones: malleus (hammer), incus (anvil), and stapes (stirrup).

What is the tonotopic map?

A representation in the auditory cortex where specific frequencies are received by specific areas.

What is perfect pitch?

The ability to recognize or produce any note on a musical scale.

What is tinnitus?

A ringing in the ear caused by abnormalities in the ear.

What is the role of cochlear implants?

They are medical devices implanted in the ear to help treat hearing loss.

How does sound localization work?

Using cues like general loudness, loudness in each ear, and timing to determine sound direction.

What is the function of the iris in the eye?

Muscles in the iris adjust pupil size to control the amount of light entering the eye.

What is the function of the lens in the eye?

The lens changes shape to focus light on the retina.

Where are photoreceptors located in the eye?

Photoreceptors (rods and cones) are located in the retina.

What are the two classes of photoreceptors and what do they do?

Rods and cones; they transduce light waves into neural impulses.

What are the characteristics of rods?

Detect light, used for periphery and night vision, not as acute as cones, and there are over 100 million of them.

What are the characteristics of cones?

Used for central and color vision, very acute (clear vision), concentrated in the fovea, and there are 4.5 to 6 million of them.

What is the fovea?

The center of the retina that contains all cones, responsible for very acute vision.

Define hue in the context of color vision.

The experience of color based on the wavelength of light (e.g., green, blue, red).

What is saturation (purity) of color?

How bright or vivid a color appears.

What is brightness in the context of color vision?

How much light is reflected from an object.

Explain the Trichromatic Theory of color vision.

There are three different sensors for color, each responding to a different range of light wavelengths; the variety of colors arises from combining these three.

Explain the Opponent Process Theory of color vision.

Color pairs (red-green, yellow-blue, black-white) work to inhibit one another in color perception, supported by the inability to see mixes like 'reddish-green' or 'bluish-yellow'.

What is color blindness?

The inability to distinguish between certain colors (most commonly red and green), often due to a shortage of cones in specific color ranges.

What carries messages from each eye to the visual cortex?

The optic nerve carries messages from the visual field of each eye to the visual cortex (occipital lobe).

How does the visual pathway process information?

Axons of retinal ganglion cells exit the eye via the blind spot, form the optic nerve, project to the thalamus, and then neurons from the thalamus project to the visual cortex.

What is the 'What' Pathway responsible for?

Determining the identity of an object.

What is visual agnosia?

Damage to the 'what' pathway, resulting in the inability to visually recognize objects.

What is prosopagnosia?

A form of visual agnosia where people cannot recognize faces.

What is the 'Where' Pathway responsible for?

Locating objects in space.

What is hemi-neglect?

Damage to the 'where' pathway, causing individuals to ignore one side of their visual field (e.g., eating food on only one side of a plate).

Define Gestalt Law of Proximity.

Objects that are physically close together are grouped together.

Define Gestalt Law of Similarity.

Similar objects are grouped together.

Define Gestalt Law of Continuity.

Objects that continue a pattern are grouped together.

Define Gestalt Law of Closure.

We fill in small gaps in objects so that they are perceived as whole objects.

Define the Gestalt principle of Figure-Ground.

The tendency to perceive one aspect as the figure and the other as the background.

What are binocular cues for depth perception?

Cues from both eyes, including retinal disparity and convergence.

What is retinal disparity?

The different images of objects cast on the retinas of each eye, used as a binocular cue for depth.

What is convergence in depth perception?

The tendency of the eyes to move toward each other as we focus on objects up close, serving as a binocular cue.

What are monocular cues for depth perception?

Cues from one eye, such as relative height, texture gradient, relative size, and linear perspective.

How does relative height contribute to depth perception?

Objects higher in our visual plane are perceived as farther away than those that are lower.

How does texture gradient contribute to depth perception?

We see more details of textured surfaces that are closer to us.

How does relative size contribute to depth perception?

When two objects known to be similar in size are viewed, the smaller-appearing one is perceived as farther away.

How does linear perspective contribute to depth perception?

Parallel lines appear to converge in the distance.

What is the Müller-Lyer illusion?

An illusion where two lines of the same length appear different due to the direction of arrowheads at their ends.

What is the Ponzo illusion?

An illusion where converging lines make an upper bar seem larger than a physically identical lower bar.

What is perceptual constancy?

Our top-down tendency to view objects as unchanging, despite shifts in the environmental stimuli we receive.

What is size constancy?

We perceive objects as the same size, regardless of the distance from which they are viewed.

What is shape constancy?

We perceive an object as the same shape, no matter from what angle it is viewed.

What is the Ames room an example of?

A perceptual illusion where a distorted room creates the impression that individuals change in size as they move through it, demonstrating size constancy principles.

How does visual acuity develop in newborns?

Newborns can see, but their vision improves significantly by two months of age, reaching adult-like acuity by eight months.

What is strabismus?

A lack of coordinated movement of both eyes, affecting about 2\%-\%4 of the population.

What is amblyopia?

A loss of visual abilities in a weaker eye due to abnormal development of the brain's visual cortex from uncoordinated visual stimulation during childhood.

What is Braille?

A form of reading skill used by individuals with visual impairments.

What is the kinesthetic sense?

Receptor cells in our muscles tell the brain when we are moving and where our body parts are in space, relating to body movement and posture.

What is the vestibular sense?

Located in the semicircular canals of our inner ears, it detects head position and movement, informing us if we are standing up or swaying.