Psych Exam 2 - CH 6 (sensation and perception)

Sensation

our sensory receptors and nervous system detect stimuli from the environment.

Perception

when the brain organizes and interprets those sensory inputs into meaningful experiences

What is bottom-up processing?

Analysis that begins with the sensory receptors and works up to the brain’s integration of sensory information (data-driven).

What is top-down processing?

Information processing guided by higher-level mental processes—drawing on experiences, expectations, and knowledge (concept-driven)

What three steps are basic to all our sensory systems?

• Reception – Receiving sensory stimulation.

• Transduction – Transforming that energy into neural impulses.

• Transmission – Delivering the information to the brain.

absolute threshold

The minimum stimulation needed to detect a particular stimulus 50% of the time.

Q: What is a difference threshold (just noticeable difference)?

The minimum difference between two stimuli required to detect a difference 50% of the time.

Q: How are we affected by subliminal stimulation?,

We can process stimuli below our absolute threshold for conscious awareness, but it usually has only a subtle, fleeting effect on behavior or thinking.

Q: What is the function of sensory adaptation?

It allows us to focus on changes in our environment by reducing sensitivity to constant, unchanging stimuli.

Q: How do expectations context motivation and emotions influence perception? 

Expectations: Shape what we notice or interpret. Context: Can alter perception (e.g., “eel on the wagon” → “wheel”). Motivation: Energizes perception toward desired goals. Emotions: Influence how we interpret ambiguous stimuli.

Cornea

Bends light to help focus it.

pupil

Pupil allows light in

Iris

adjusts its size to control how much light enters.

Lens

Changes shape to focus light on the retina

Retina

Light-sensitive inner surface that contains rods and cones, the receptors that begin processing visual information.

Rods

• Respond in dim light.

• Detect black, white, and gray.

• Located in peripheral retina.

Cones 

• Work in bright light.

• Detect color and fine detail.

• Concentrated in the fovea.

Young-Helmholtz Trichromatic Theory:

• Three color theory

• The retina has three types of color receptors (red, green, blue).

• When stimulated in combination, they produce all colors.

parralle processing 

the brains ability to process many aspects of a visual scene - color motion form and depth - at the same time

The characteristic of light that determines the color we experience, such as blue or green, is its _____.

wavelength - determines hue 

opponent process theory

cells process pairs (red/green , blue/yellow, black,white)

feature detectors 

found in visual cortex ( occipitol lobe) - Specialized neurons respond to specific features — edges, lines, angles, movement (Hubel & Wiesel’s discovery).

The amplitude of a light wave determines our perception of

amplitude - determines intensity and brightness

Depth Perception:

ability to judge distance in 3d

binocular cues 

use both eyes 

retinal disparity

difference between the two eyes images gives depth

monocular

one eye

motion perception 

Brain interprets shrinking objects as moving away, enlarging ones as approaching. - interpostion, linerai PERSPECTIVE, relative size

interposition

one object overlaps another, the blocked object is perceived as being farther away.

linear perspective

parallel lines appear to converge with distance; the more they converge, the greater the perceived distance.

relative size

if two objects are similar in size, the one that appears smaller is perceived as being farther away

Gestalt psychology

“The whole is greater than the sum of its parts.” - emphasized our tendency to integrate pieces of information into meaningful wholes.

Figure-Ground

The organization of the visual field into objects (figures) that stand out from their surroundings (ground)

Grouping

perceptual tendency to organize stimuli into coherent groups (proximity, continuity, closure, or similarity).

Phi Phenomenon

An illusion of movement created when two or more adjacent lights blink on and off in quick succession (like a marquee sign).

Perceptual Constancies

We perceive objects as unchanging (color, shape, size) even as lighting or viewing angles change.

The visual cliff experiments suggest that

crawling human infants and very young animals perceive depth

In experiments, people have worn glasses that turned their visual fields upside down. After a period of adjustment, they learned to function quite well. This ability is called _____.

Perceptual adaptation

Frequency

Number of complete wavelengths per second; determines pitch (high or low tone).

Amplitude: Hearing

Height of the wave; determines loudness (volume).

How does the ear transform sound energy into neural messages?

Sound waves enter the outer ear

travel through the auditory canal

to the eardrum, causing it to vibrate

Vibrations move through the ossicles

The stirrup transmits vibrations to the cochlea in the inner ear

The cochlear fluid moves, bending hair cells on the basilar membrane, triggering neural impulses.

These impulses travel via the auditory nerve to the auditory cortex in the temporal lobe.

Loudness:

Determined by the number of activated hair cells

Sound location:

The brain uses differences in timing and intensity between ears to locate a sound source.

Pitch - Place theory:

Different sound frequencies stimulate different areas of the cochlea’s basilar membrane (high pitches).

Frequency theory

The rate of neural impulses matches the sound frequency (low pitches).

What are the four basic touch sensations

pressure, warmth, cold, and pain.

and how do we sense touch?

Touch is sensed through specialized receptor cells in the skin, which send information through the spinal cord to the somatosensory cortex in the brain.

taste and smell similarity and difference

Both are chemical senses; molecules must bind to receptors.

Taste = direct contact

smell- odor binds to receptors in olfactory bulb - bypass thalamus

Kinesthesia

Sensing body part position and movement through receptors in muscles, tendons, and joints

Vestibular sense:

Sensing balance and head movement via the semicircular canals and vestibular sacs in the inner ear.

Embodied cognition:

he idea that body sensations, gestures, and states influence our cognitive preferences and judgments (e.g., holding a warm drink may make us feel socially warmer).

Sensory interaction

One sense may influence another (e.g., smell affects taste; visual cues influence what we hear — the McGurk effect).

The snail-shaped tube in the inner ear, where sound waves are converted into neural activity, is called the _____.

Cochlea

The sensory receptors found mostly in the skin that detect painful temperatures, pressure, or chemicals are called _____.

Nociceptors

The gate-control theory of pain proposes that

small spinal cord nerve fibers = most pain signals,

large-fiber activity = close access to those pain signals.

We have specialized nerve receptors for detecting which five tastes? How did this ability aid our ancestors?

• Five tastes: Sweet, sour, salty, bitter, umami (savory).

• Evolutionary purpose: Helped ancestors identify nutrients and avoid toxins (e.g., sweet = energy, bitter = poison warning).

_____ is your sense of body position and movement. Your _____ specifically monitors your head’s movement, with sensors in the inner ear.

Kinesthesia, vestibular sense

Why do you feel a little dizzy immediately after a roller-coaster ride?

The fluid in your semicircular canals continues to move after you stop, sending mixed signals to your brain, creating a temporary feeling of dizziness.

A food’s aroma can greatly enhance its taste. This is an example of

sensory interaction

ESP (Extrasensory Perception)

controversial claim that perception can occur without sensory input — meaning a person could supposedly know, feel, or see things beyond the five senses (sight, hearing, touch, taste, smell).

What are the main ESP phenomena, and what does research say about them?

telepathy, clairvoyance, precognition, psychokinesis are esp claims but research find no consistent replicable evidence