Unit 3: Sensations and Perception Modules

Sensation

The process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment

Perception

The process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events

Bottom-up Processing

Starts with sensory input, the brain attempts to understand. We process this way when we have no proper knowledge

Top-Down Processing

Selective Attention

Our tendency to focus on just a particular stimulus among the many that are being received. This is a conscious effort.

Cocktail Party Effect

Our ability to attend to one voice among many other voices. Once someone someone says your name, for instance, our mind instantly brings that previously unattended voice into consciousness.

Stroop Effect

Read colors in in black quicker and with fewer errors than if they are presented in incongruent colors

Selective Inattention

The screening out of unwanted stimuli because it causes anxiety or because it is thought to be of no importance

Inattentional Blindness

Change Blindness

Failure to notice changes in the visual environment

What three steps are basic to all our sensory systems?

1. Receive 2. Transform 3. Deliver

Transduction

Conversion of one form of energy, such as light waves, into another, like neural impulse, that our brain can deliver. Our sensory organs use transduction to convert external stimuli to brain language.

Psychophysics

The study of the relationship between the physical characteristics of stimuli, such as intensity, and our physical experience of them

Absolute Threshold

The lowest level of stimulation that a person can detect

Difference Threshold

the smallest change in stimulation that a person can detect

Weber‘s Law

To perceive a difference, two stimuli must differ by a constant percentage. Also studies the relationship between stimuli and sensation.

Signal Detection Theory

A theory predicting how and when we detect the presence of faint stimuli amid background stimulation

what are the two conditions of signal detection theory?

1. The strength of the signal 2. Our(the subjects) psychological state

Subliminal Perception

The perception of a stimulus below the threshold for conscious recognition

Sensory Adaptation

diminished sensitivity to stimuli as a consequence of constant stimulation

Perceptual Set

A mental predisposition to perceive one thing and not another

Parapsychology

The study of paranormal phenomena, including ESP and psychokinesis

Wavelength

distance from one peak to the next

Hue

the color we experience, comes in basic colors of red, green, and blue

Intensity

amount of its energy measured by amplitude or height

Cornea

the outer layer, transparent, convex and covers the front part of the eye, its shape bends light toward the center of the eyeball

Pupil

opening in the iris, black part at the center of the eye

Iris

colored part of the eye, a muscle that adjusts by opening and closing(dilating and constricting) in response to the brightness in the environment to let in more or less light

Lens

light passes through the lens, transparent structure behind the pupil, curved and flexible and changes its curvature to help focus images

Aqueous Humor

behind the pupil and iris, chamber filled with watery fluid

Vitreous Humor

light waves pass through this jelly-like fluid on the way to the retina

Retina

light-sensitive layer at the back of the eye, contains receptors called cones and rods

Accommodation

Before passing through the retina, the lens flips an image and focuses the inverted image

Rods

detect black/white/grey and can work in very dim light for night vision

Cones

function only in bright light and allow us to perceive color

fovea

cones are located in and around the fovea, central point of the retina

optic nerves

send signals to the brain, some fibers cross into the thalamus at the optic chias, signals travel to the occipital lobe

peripheral vision

the eye’s ability to see things on the side of our vision when looking straight ahead

tunnel vision

absence of peripheral vision

blind spot

where the optic nerve leaves the eye, a hole in the retina, there’s no photoreceptors, you cannot see

Trichromatic Theory

earliest theory as to why we only see color within the visible spectrum

Opponent-Process Theory

focuses on what happens in the brain rather than in the eye

Myopia

nearsightedness

Presbyopia

farsightedness

Afterimage

a phenomenon when a visual sensation remains after the stimulus is removed

Astigmatism

cornea is irregularly shaped

Glaucoma

damage to the optic nerve and destroyed vision

Feature Detectors

react to the strength of visual stimuli as thus responding to shapes, angles, edges, lines, and movement in our field of vision

Parallel Processing

feature detectors can react to visual stimuli simultaneously

Gestalt

The brain has a tendency to integrate pieces of information into a meaningful whole

Figure-ground

The figure is what is focused on and the ground is the blurry background- which is likely ignored

Proximity

the space between objects determines the way you perceive them

Similarity

we group items with similar looks(race, gender, ethnicity)

Continuity

Our eyes want to move through one object into another fluidly

Connectedness

we see items connected by a visual element as more related than items not connected

Closure

we fill in missing pieces of images to form a whole

Depth Perception

the ability to see the world in 3D and know how far away the objects are

Binocular Cues

Using both eyes in concert to judge depth

Retinal Display

by comparing retinal images from two eyes, the brain commutes distance- the greater the disparity, the closer the object

Convergence

based on how far inward the eye moves when focused on an object

Monocular Cues

cues that only require one eye

Linear Convergence

makes parallel lines appear to converge at a vanishing point on the horizon

Interposition

the partial blocking of one object by another object, laving the perspective that the blocking object is closer

Relative Size

causes us to perceive something as further away because it looks smaller than an object in a foreground that we assume is a smaller size

Relative Height

makes objects higher in your field of vision appear farther

Relative Clarity

makes clearer objects appear closer

Light and Shadow

nearby objects reflect more light to our eyes than distant ones

Motion Parallax

objects closer to us appear to move faster than those farther away

Phi Phenomenon

the movement of a series of pictures at a rate that suggests movement

Perceptual Constancy

a top-down process that recognizes objects without being perceived by changes in color, brightness, shape, or size