44 Amodal Perception Anamorphosis partly inspired by the “transactional approach” of philosopher John Dewey (who first saw the demon- The Ames demonstrations were not unprecedented, strations in 1946, and then corresponded with in the sense that they have much in common with Ames until 1951). Ames believed, as Dewey did, an historic artistic distortion technique called that we are not passive recipients of a given reality, anamorphosis, and to other perspective illusions but instead are active participants in a give-and-take employed in the design of theatrical sets. exchange (a “transaction”) in which split-second In anamorphic constructions, the image looks assumptions are made about the nature of reality. distorted when viewed frontally (as is customary) The demonstrations have also had lasting effects but correctly proportioned when seen from the on other aspects of culture. Even today, one or side (often indicated by a peephole). For example, more of the demonstrations are invariably men- Ames was well acquainted with the work of scien- tioned in textbooks on perception, and it is not tist and philosopher Hermann von Helmholtz, uncommon for one or more to appear in television who more than 50 years before had noted that an documentaries, video clips, cinematic special infinite variety of distorted rooms could be devised effects, or advertising commercials. that, from a monocular peephole, would nonethe- less seem to be normal. Roy R. Behrens Far in advance of Helmholtz, this same kind of visual distortion was used as early as 1485 by See also Magic and Perception; Object Perception; Leonardo da Vinci (and probably even earlier by Pictorial Depiction and Perception Chinese artists) as an offshoot of perspective. As early as the 16th century, a group of Dutch artists Further Readings made anamorphic “peepshows” called perspectyf- kas or perspective cabinets, a few of which still Behrens, R. R. (1994). Adelbert Ames and the cockeyed exist and are now on display in museums. These room. Print, 48, 92–97. artistic constructions have much in common with Behrens, R. R. (1998). The artistic and scientific the Ames distorted room, the chair demonstration, collaboration of Blanche Ames Ames and Adelbert and the rotating trapezoid window. In fact, many Ames II. Leonardo, 31, 47–54. of the Ames demonstrations make use of trapezoids Behrens, R. R. (1999). Adelbert Ames, Fritz Heider, and that appear rectangular, tilted surfaces that appear the chair demonstration. Gestalt Theory, 21, 184–190. to be flat, or flat surfaces that appear tilted. Cantril, H. (Ed.). (1960). The morning notes of Adelbert Most of the Ames demonstrations require (or at Ames, Jr. New Brunswick, NJ: Rutgers University Press. least work optimally with) a monocular peephole. Ittelson, W. H. (1968). The Ames demonstrations in perception. New York: Hafner. This is because they rely on the fact that any num- Kilpatrick, F. P. (Ed.). (1961). Explorations in ber of external constructions could produce the transactional psychology. New York: New York same retinal image. Ames explicitly stated that (as University Press. Helmholtz had noted) he could have constructed an infinite number of distorted rooms, no two of which would have the same physical shape, yet each would appear to be normal. In the end, he AMOD A L PERCE P TION only constructed a few. Amodal (meaning “without” modality) perception is Implications perception of information that is common or redun- The Ames demonstrations might never have become dant across multiple senses (e.g., auditory, visual, well known had they not been embraced and pro- tactile). Amodal information includes changes along moted by other people who saw them as palpable three basic parameters of stimulation—time, space, evidence of their own convictions. They were of and intensity. Properties of objects and events such as particular value to proponents of transactional psy- temporal synchrony, rhythm, tempo, duration, inten- chology (not to be confused with transactional sity, and co-location are common across auditory, analysis), a 1950s spin-off of pragmatism that was visual, and proprioceptive stimulation. Properties Amodal Perception 45 such as shape, substance, and texture are common and events even though our senses provide specific across visual and tactile stimulation. For example, information through separate sensory channels. the same rhythm and tempo can be detected by see- How are these different sources of stimulation ing or hearing the pianist strike the notes of the key- bound together? Further, why do our senses pro- board, and the same size, shape, and texture can be vide overlapping and redundant information for detected by seeing or feeling an apple. many qualities of objects? The concept of amodal Virtually all events occur across time, are distrib- perception addresses these important questions uted across space, and have a characteristic inten- and dates back more than 2,000 years to the time sity pattern, so virtually all events provide amodal of Aristotle. Aristotle proposed a sensus communis information. For example, speech comprises (an amodal or common sense) that detected quali- changes in audiovisual synchrony, tempo, rhythm, ties that were common to several senses. These and intonation (intensity changes) that are com- common sensibles included number, form, rest, mon to the movements of the face and the sounds movement, magnitude, and unity—information of the voice. Self-motion produces proprioceptive that today is considered amodal. feedback (information from the muscles, joints, and Centuries later, philosophers such as John vestibular system) that is synchronized and shares Locke and George Berkeley took a different temporal and intensity changes with the sight of approach to the question of perceiving object and self-motion (e.g., seeing and feeling one’s hand event unity. They proposed that sensations had to move). Perceiving amodal information is critically be interpreted and integrated across the senses important for organizing early perceptual and cog- before a person could perceive meaningful objects nitive development and for accurate perception of and events. Until recently, developmental psychol- everyday events in children and adults alike. ogists, including Jean Piaget, thought this process The term amodal has also been used in a differ- of integration developed gradually through experi- ent sense—to refer to perception in the absence of ence with objects. By coordinating and associating direct information from a specific sense modality. what one sees with what one feels and hears, one For example, in visual perception, amodal comple- could construct a coherent, three-dimensional tion describes how we perceive a unitary shape world of objects and events. (e.g., a ball), even when part of the object or shape This constructivist view was not seriously ques- is occluded (hidden) behind another object (e.g., a tioned until James J. Gibson’s ecological view of block). Even infants can accurately perceive a par- perception emerged in the 1960s, and a view more tially hidden shape if the occluder is moved back consistent with that of Aristotle’s reemerged. Gibson and forth, progressively revealing and then hiding proposed that the different forms of stimulation the object’s contours. Scientists propose that we from the senses were not a problem for perception, perceive unitary shape by detecting visual invari- but rather provided an important basis for perceiv- ants (patterns that remain constant across change) ing unitary objects and events. Our senses, he pro- through object motion, whereas others maintain posed, work together as a unified perceptual system that we must fill in the missing information by to pick up information that is invariant or common inference or cognitive processes. Whatever the pro- across the senses—that is, amodal information. If cess, the term amodal referring to incomplete we attend to amodal information, then there is no information is not consistent with the previous need to learn to integrate stimulation across the definition (which refers to information that is fully senses to perceive unified objects. Temporal syn- available and can be directly perceived through chrony (the most basic form of amodal information) more than one sense) and, thus, will not be dis- has been described as the glue that binds stimulation cussed further. This entry describes the history, across the senses. For example, by attending to syn- theory, and development of amodal perception. chrony, the sounds and sights of a single person speaking would be perceived as united. Sights and sounds that are perfectly synchronized belong History and Theory together and constitute unitary events. Detecting For centuries, philosophers and scientists have this information prevents the accidental association been intrigued by how we perceive unified objects of unrelated but concurrent sensory stimulation. 46 Animal Chemical Sensitivity Development them to visually select an object they have previ- ously explored only tactually. Amodal information Researchers now know that even very young can also be used to create the illusion of unity as in infants are skilled at detecting amodal informa- the ventriloquism effect. The ventriloquist creates tion, including temporal synchrony, tempo, rhythm, amodal information by moving the puppet’s mouth intensity changes, shape, texture, substance, and in time with his own speech sounds and can there- prosody in speech. Amodal information is highly fore fool the audience