Kappa effect
Encyclopedia
Introduction
The Kappa Effect is a psychological phenomenon related to the perception of distance, time and speed. It is a temporal illusionTime perception
Time perception is a field of study within psychology and neuroscience. It refers to the sense of time, which differs from other senses since time cannot be directly perceived but must be reconstructed by the brain. Humans can perceive relatively short periods of time, in the order of milliseconds,...
that, in some cases, can alter one’s judgement of time. The Kappa effect arises when observers judge the amount of elapsed time between two stimuli
Stimulus (psychology)
In psychology, stimuli are energy patterns which are registered by the senses. In behaviorism and related stimulus–response theories, stimuli constitute the basis for behavior, whereas in perceptual psychology they constitute the basis for perception.In the second half of the 19th century, the...
in a sequence of consecutive stimuli. Stimuli can be visual, like flashes of light; auditory, like auditory tones; or tactile, like stimulation of the skin. When a subject is required to make judgments about ambiguous temporal intervals
Proper time
In relativity, proper time is the elapsed time between two events as measured by a clock that passes through both events. The proper time depends not only on the events but also on the motion of the clock between the events. An accelerated clock will measure a smaller elapsed time between two...
(the length of elapsed time) between each of these stimuli, they often base their decision on the familiar functional relations between spatial separation, time, and average velocity. These estimations of the length of time between stimuli can be influenced by the spatial separation, or the distance, between each of the stimuli. The elapsed time between two stimuli can be made to appear shorter (or longer) by decreasing (or increasing) the distance between the two stimuli Therefore, even when the the length of elapsed time between stimuli in a sequence is kept the same throughout the sequence, we tend to over-estimate the amount of time between each stimuli when the distance between them is longer. Equally, we tend to under-estimate the amount of elapsed time between each stimuli in a sequence when the distance between them is shorter.
Temporal Judgments and the Spatial Context
An individual tends to experience the Kappa effect when observing a sequence of stimuli in which the temporal separationSpacetime
In physics, spacetime is any mathematical model that combines space and time into a single continuum. Spacetime is usually interpreted with space as being three-dimensional and time playing the role of a fourth dimension that is of a different sort from the spatial dimensions...
(duration
Time
Time is a part of the measuring system used to sequence events, to compare the durations of events and the intervals between them, and to quantify rates of change such as the motions of objects....
) between each stimuli is constant, but the spatial separation
Spacetime
In physics, spacetime is any mathematical model that combines space and time into a single continuum. Spacetime is usually interpreted with space as being three-dimensional and time playing the role of a fourth dimension that is of a different sort from the spatial dimensions...
(distance
Proper length
In relativistic physics, proper length is an invariant measure of the distance between two spacelike-separated events, or of the length of a spacelike path within a spacetime....
) between each of the stimuli varies. As a result, the observer tends to base their judgments of the temporal separation between each stimuli on the spatial separation between each of these stimuli. Correspondingly, the Kappa effect is a temporal illusion that causes the observer to increase/decrease their judgments of temporal separation between stimuli as the spatial separation between these stimuli increases/decreases, even though the temporal separation between the stimuli stays constant . Studies often observe the kappa effect by using visual modality. For example, let's say three light sources, X, Y, and Z, are flashed successively in the dark with equal time intervals between each of the flashes. If the light sources are placed at different positions, with X and Y closer together than Y and Z, the kappa effect is created. This is because the time interval between the X and Y lights is perceived to be shorter than that between the Y and Z since the distance between X and Y is shorter
In contrast, the tau effect occurs when the spatial separation between stimuli is constant and the temporal separation is varied, resulting in the observer increasing/decreasing their judgment of spatial separation as temporal separation increases/decreases. For example, when the same light sources X, Y, and Z are flashed successively in the dark with a shorter time interval between X and Y than between Y and Z, the tau effect is created that X and Y are closer together in space than is Y and Z. .
Constant Velocity
The constant velocity hypothesis, a theory proposed by Jones and Huang (1982), attempts to account for this temporal illusion.When stimuli are displayed successively, our brain incorporates a prior expectation of speed when judging spatiotemporal intervals. This assumption of velocity can influence our perception of the distance between stimuli. For the judgment of spatial intervals, the visual system and our brain work together to incorporate knowledge of the average duration of the temporal intervals between stimuli and apply it to expected temporal intervals that would be required to traverse the given distance between two stimuli at constant velocity . The constant velocity hypothesis suggests that when individuals observe successive stimuli, they expect the temporal separation between each stimuli to reflect uniform motion Consequently, the observer assumes that a given distance in spatial separation between stimuli requires a certain amount of temporal separation that is based on uniform motionKinematics
Kinematics is the branch of classical mechanics that describes the motion of bodies and systems without consideration of the forces that cause the motion....
. Therefore, this assumption of motion
Motion (physics)
In physics, motion is a change in position of an object with respect to time. Change in action is the result of an unbalanced force. Motion is typically described in terms of velocity, acceleration, displacement and time . An object's velocity cannot change unless it is acted upon by a force, as...
is applied to sequences of things as they unfold. As a result, the kappa effect occurs when all of our knowledge about motion gets applied to these sequences, which sometimes causes us to make mistakes