Vocabulary Terms for Chapter 8

Our attention is automatically drawn to salient objects.

A condition in which damage to an area of the cortex involved in motion perception causes blindness to motion.

An object is physically moving across our field of view.

Perception of motion when there is actually none.

An illusion of movement that occurs when two objects separated in space are presented rapidly, one after another, separated by a brief time interval.

The illusory movement of one object (usually smaller) that is caused by the movement of another object (usually a large one) that is near by.

An illusion that occurs after a person views a moving stimulus & then sees movement in the opposite direction when viewing a stationary stimulus immediately afterward.

Aftereffect of movement that occurs after viewing a stimulus moving in one direction, such as a waterfall; viewing the waterfall makes other objects appear to move in the opposite direction.

The structured pattern of light created by the presence of objects, surfaces, & textures in the environment.

Occurs when one object moves relative to the environment, so that the stationary background is covered & uncovered by the moving object. This local disturbance indicates that the object is moving relative to the environment.

Information for movement that occurs when all elements in a scene move.

Signals caused by movement of a stimulus across the receptors are processed by a delay unit and an output unit so that signals are generated by movement in one direction but not in the opposite direction.

The theory that explains motion perception as being determined both by movement of the image on the retina & by signals that indicate movement of the eyes.

The signal that occurs when an image moves across the visual receptors.

The signal that is sent to the eye muscles when the observer moves the eyes.

A copy of the motor signal that is sent to the eye muscles to cause movement of the eye.

A structure hypothesized by the corollary discharge theory of movement perception.

Perception begins here. It is the region of the occipital lobe where information from the retinas first reaches the cortex. Neurons on this cortex respond to movement of the ends of objects.

Contains many directionally sensitive cells in this area. Evidence comes from experiments that have used moving dot displays in which the direction of motion of individual dots can be varied.

Perception in which arrays of moving dots are used as stimuli.

Presenting a strong magnetic field to the head that temporarily disrupts the functioning of a specific area of the brain.

• a small electrode is inserted into the cortex, &

• an electrical current passed through the electrode activating specific groups of neurons affects perception

Observation of a small portion of a larger stimulus leads to misleading information about direction of movement. This can result

In the perception of apparent motion, the principle that apparent movement tends to occur along the shortest path between 2 stimuli.

A biological motion stimulus created by placing small lights on people’s joints & then filming the patterns created by these lights when people walk & carry out other actions in the dark.

Striate Cortex (V1): Direction of motion across small receptive fields.

Middle Temporal Area (MT): Direction & speed of object motion.

Medial Superior Temporal Area (MST): Processing optic flow, locating moving objects, & reaching for moving objects.

Superior Temporal Sulcus (STS): Perception of motion related to animals & people (biological motion).