Multistable perception

Multi -stable perception, shape change, or change in perception characterizes a rare phenomenon in everyday life spontaneously changing interpretations of a percept. Systematically produced, shape change -inducing stimuli are called optical illusions.

Definition

Unpredictable and willfully unavoidable " change" the perception occur mainly when viewing visual illusions on which more than one type of stimulus interpretation permit (so-called optical illusions, English technical term. Ambiguous patterns ). Well-known examples include, without limitation the Necker cube and some pictures by MC Escher and Salvador Dalí. Either change when you consider changing the meaning of an image ( by approximately alternately a face or just a pile of rocks in front of him looks ) or the impression of depth ( as in the case of the Necker cube ) or other aspects such as the direction of movement of some dynamic stimulus pattern, the figure background ratio of a two-dimensional mapping or consistency of a visual object and inverted perception and non-perception of the stimulus itself Interestingly, these effects occur also in very simple patterns. A simple cross with equal length straight bars that are perpendicular to each other may cause you. Sometimes the horizontal bar in front of the vertical and times these perceives before the horizontal

The fascinating thing about multistable perceptions is their absolute endogenous character as well as the dissociation of the perception of the actual stimulation. For the occurrence of perceptual changes it requires neither modifications of the stimuli themselves more actively changes on the part of the observer, such as eye movements or voluntary allocation of attention to the stimulus pattern.

Kippfiguren are related to visual puzzles, in which the task is to find a specific object in an image.

Influence on art and culture

Ambiguous figures that are perceived multi- stable, can already be found in mosaics of antiquity. In the imaging art mainly MC Escher and Salvador Dalí ( and, more rarely, also Paul Klee ) deals with multi- stable perception. Some works of Op Art trigger similar spontaneous reorganization of perception.

Within the philosophy especially Ludwig Wittgenstein's meditations on a multistable stimulus are ( William James' line drawing of a hare, which can also be interpreted as a ducks head), as well as the metaphorical use by Thomas S. Kuhn in the context of his theory to name the paradigm shift. Inspired by the neurophysiological findings in recent years have the interest of the philosophy of mind aroused again multistable perception phenomena.

Scientific background

The former psychophysics was not initially interested in the variety of perceptual phenomena. With the advent of the (especially Berlin ) Gestalt psychology in the early 20th century, this changed dramatically, but multistable perception phenomena have been a popular research object. With the demise of this school, interest in multistable phenomena subsided again. Since the 1980s, however multistable phenomena are back in the central interest of the psychology of perception. The key assumption is that seeing is an active sense of operation during which the brain tries to interpret the activation of the receptors sense. The active processes of this " perceptual organization " (see also: Gestalt laws ) seem when set against each other in conflict to prevent a unique solution. The visual system seems forced in this situation to " reorganize ", ie a probable interpretation of possibility to one or more other, go back and forth about the same probable solutions.

A certain degree of control over the process of change in perception can be learned. Some eye movements ( such as blinking and saccades ) to summon to a certain degree, such exchange. Also leave some stimulus manipulations to the external control of the changing states of awareness. All these influences have but as for preventing or generating the different modes of apprehension proved to be insufficient and only seem modulatory effect on the processes actually controlled to have.

The rate ( speed) of the change in perception varies greatly from person to person and between the different views. Multiple correlations with the intelligence quotient, with personality variables, the consumption of stimulants or certain brain injuries have been reported. However, subsequent studies failed to confirm some of these results. Consistent but a drop in the exchange rate with age appears to be.

The role of visual attention as the cause of spontaneous change in perception is controversial. Despite mutual influences, however, a clear dissociation between processes seems multistable perception and attention effects to exist - thus it is related, but independent mechanisms.

Neurobiological explanations

Most theories to multistable perception phenomena based on reciprocal relations between the alternative forms of perception ( percepts ), or the underlying ( neural ) mechanisms. All of these "classical" models assume that the " dominance " of a perceptual state, the " inhibition " ( inhibition) of each alternative forms of intuition due. The dominance of one percept is ended, that a " saturation " or " fatigue " leads to a flattening of the inhibition of the rival state. This thus gaining increasing upper hand until he ( " above threshold " ) is strong enough now to inhibit the formerly dominant state. After a certain time and this new state will be fatigued, and it is again taken to the first operating state. This process can be repeated ad infinitum. In electrical circuits can be such easy as " flip- flop " - implement multivibrators. In a more biologically oriented modification of this principle, the mutual inhibition between two neurons (or a group of nerve cells) lead to a similar behavior.

However, several arguments against the adoption of such a simple mechanism. In particular, the stochastic nature of the change process is a major challenge for all "classical" models of reciprocal interactions of rival percepts is: The perception does not oscillate (like a back and forth rocking system expected), but jumps in unpredictable intervals from one state to the next. Next, it seems difficult to explain the large interindividual differences in the exchange rate with this model. Functional magnetic resonance imaging (fMRI ) during spontaneous perception jumps investigation also showed that in this way, especially "higher" brain areas are activated (ie in the parietal and frontal lobes ), the function of which are usually associated with action planning and other cognitive phenomena.