Psych 100 Exam Prep

Week 8 The Visual World

Accommodation

Helps determine depth.

Beta effect

The perception of motion that occurs when different images are presented next to each other in succession

Binocular depth cues

Depth cues that are created by retinal image disparity — that is, the space between our eyes — and which thus require the coordination of both eyes

Blind spot

A hole in our vision because there are no photoreceptor cells at the place where the optic nerve leaves the retina

Colour blindness

The inability to detect green and/or red colours

Cones

Visual neurons that are specialized in detecting fine detail and colours

Convergence

The inward turning of our eyes that is required to focus on objects that are less than about 50 feet away from us

Cornea

A clear covering that protects the eye and begins to focus the incoming light

Depth cues

Messages from our bodies and the external environment that supply us with information about space and distance.

Electromagnetic energy

Pulses of energy waves that can carry information from place to place

Farsighted

When the focus is behind the retina

Feature detector neurons

Specialized neurons, located in the visual cortex, that respond to the strength, angles, shapes, edges, and movements of a visual stimulus

Fovea

The central point of the retina

Gestalt

A meaningfully organized whole

Hue

The shade of a colour

Iris

The coloured part of the eye that controls the size of the pupil by constricting or dilating in response to light intensity

Lens

A structure that focuses the incoming light on the retina

Monocular depth cues

Depth cues that help us perceive depth using only one eye

Nearsighted

When the focus is in front of the retina

Opponent-process colour theory

Proposes that we analyze sensory information not in terms of three colours but rather in three sets of “opponent colours”: red-green, yellow-blue, and white-black

Optic nerve

A collection of millions of ganglion neurons that sends vast amounts of visual information, via the thalamus, to the brain

Phi phenomenon

We perceive a sensation of motion caused by the appearance and disappearance of objects that are near each other

Pupil

A small opening in the centre of the eye

Retina

The layer of tissue at the back of the eye that contains photoreceptor cells

Rods

Visual neurons that specialize in detecting black, white, and gray colours

Trichromatic colour theory

The colour we see depends on the mix of the signals from the three types of cones

Visible spectrum

The part of the electromagnetic spectrum that our eyes detect (only the range from about 400 to 700 billionths of a meter)

Visual accommodation

The process of changing the curvature of the lens to keep the light entering the eye focused on the retina

Visual cliff

A mechanism that gives the perception of a dangerous drop-off, in which infants can be safely tested for their perception of depth

Wavelength

The distance between one wave peak and the next wave peak

Bouncing balls illusion

The tendency to perceive two circles as bouncing off each other if the moment of their contact is accompanied by an auditory stimulus.

Crossmodal phenomena

Effects that concern the influence of the perception of one sensory modality on the perception of another.

Crossmodal receptive field

A receptive field that can be stimulated by a stimulus from more than one sensory modality.

Crossmodal stimulus

A stimulus with components in multiple sensory modalties that interact with each other.

Double flash illusion

The false perception of two visual flashes when a single flash is accompanied by two auditory beeps.

Integrated

The process by which the perceptual system combines information arising from more than one modality.

McGurk effect

An effect in which conflicting visual and auditory components of a speech stimulus result in an illusory percept.

Multimodal

Of or pertaining to multiple sensory modalities.

Multimodal perception

The effects that concurrent stimulation in more than one sensory modality has on the perception of events and objects in the world.

Multimodal phenomena

Effects that concern the binding of inputs from multiple sensory modalities.

Multisensory convergence zones

Regions in the brain that receive input from multiple unimodal areas processing different sensory modalities.

Multisensory enhancement

Multisensory enhancement is observed when the sources of stimulation are spatially related to one another.

Primary auditory cortex

A region of the cortex devoted to the processing of simple auditory information.

Primary visual cortex

A region of the cortex devoted to the processing of simple visual information.

Principle of Inverse Effectiveness

The finding that, in general, for a multimodal stimulus, if the response to each unimodal component (on its own) is weak, then the opportunity for multisensory enhancement is very large. However, if one component—by itself—is sufficient to evoke a strong response, then the effect on the response gained by simultaneously processing the other components of the stimulus will be relatively small.

Receptive field

The portion of the world to which a neuron will respond if an appropriate stimulus is present there.

Rubber hand illusion

The false perception of a fake hand as belonging to a perceiver, due to multimodal sensory information.

Sensory modalities

A type of sense; for example, vision or audition.

Spatial principle of multisensory integration

The finding that the superadditive effects of multisensory integration are observed when the sources of stimulation are spatially related to one another.

Superadditive effect of multisensory integration

The finding that responses to multimodal stimuli are typically greater than the sum of the independent responses to each unimodal component if it were presented on its own.

Unimodal

Of or pertaining to a single sensory modality.

Unimodal components

The parts of a stimulus relevant to one sensory modality at a time.

Unimodal cortex

A region of the brain devoted to the processing of information from a single sensory modality.