Illusory conjunctions

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Illusory conjunctions are psychological effects in which participants combine features of two objects into one object. There are visual illusory conjunctions, auditory illusory conjunctions, and illusory conjunctions produced by combinations of visual and tactile stimuli. Visual illusory conjunctions are thought to occur due to a lack of visual spatial attention, which depends on fixation and (amongst other things) the amount of time allotted to focus on an object. With a short span of time to interpret an object, blending of different aspects within a region of the visual field – like shapes and colors – can occasionally be skewed, which results in visual illusory conjunctions. For example, in a study designed by Anne Treisman and Schmidt, participants were required to view a visual presentation of numbers and shapes in different colors. Some shapes were larger than others but all shapes and numbers were evenly spaced and shown for just 200 ms (followed by a mask). When the participants were asked to recall the shapes they reported answers such as a small green triangle instead of a small green circle. If the space between the objects is smaller, illusory conjunctions occur more often.

Contents

Example of an Illusory Conjunction between two different shapes of different colors forming an entirely new object Illusory conjunction to.jpg
Example of an Illusory Conjunction between two different shapes of different colors forming an entirely new object

Visual

Along with feature integration, the location of the perceived illusory object in vision is a combined result of the constituent objects' locations, but the similarity of the features is what increases the likelihood of an illusory conjunction. [1] In order for an illusory conjunction to occur, the two objects that are not the focus of attention need to be within the visual field. The closer two objects are, the more likely the illusory conjunction is to occur. [2] The increased likelihood of an illusory conjunction to occur when the objects are closer together may be due to a difference in processing compared with when the objects are more distant from each other. One theory supports that the decrease in illusory conjunctions with increased distance between objects is due to the use of bi-hemispheric input processing, making closer objects more likely to be conjoined because only one of the cerebral hemispheres sees and processes both objects that are involved in an illusory conjunction. [3] Although proximity increases the likelihood of an illusory conjunction, illusory conjunctions formed between objects can occur even when the objects are distant, though still within the attentional field. When objects are outside of attention in order for an illusory conjunction to occur they must be adjacent to each other to combine features. [4] Objects become more susceptible to illusory conjunction not only due to relation to each other, but also in relation to the density of objects in the attentional location. As the density of objects increases, there is more division of attention, which increases the possibility of forming of an illusory conjunction. [5]

Alternative theories

It has been suggested that research in support of illusory conjunctions is not adequate in terms of the methods used to analyze the data and that illusory conjunctions are actually confusions between target and nontarget objects. [6] It has also been found in a few studies on visual illusory conjunctions that two objects that are not the focus of attention are also more likely to be combined when they are adjacent to each other. Although it would seem more common for objects to combine when they are not the focus of attention it is more likely for an illusory conjunction to occur when objects are the focus of attention. [2] Visual illusory conjunctions can occur in long and brief exposure times along with the different levels of attention paid to the objects involved. [7]

Memory

Illusory conjunctions can also occur in memory. In vision, images can be combined through a lapse in memory of an image that is filled by physical stimuli. [8] Illusory conjunctions often occur through memory errors because the situations in which illusory conjunctions happen involve multiple tasks or tasks that commonly divide a person's attention. [9] While memory errors can aid in the formation of illusory conjunctions their formation is not dependent on memory errors. [10] These memory errors can be caused by a multitude of objects in a space increases the amount of things to be processed and stored to memory increases. This increase in objects creates a prime situation for memory to lapse and form an illusory conjunction. [5] Illusory conjunctions in short term auditory memory occur also. When a set of tones is played in a sequence, illusory conjunctions of 'what' and 'when' can occur. For example, if a sequence of tones begins with the note C, and later includes the note C#, and the note C# is repeated at the end of the sequence, there is a tendency for listeners to assume erroneously that this last note had also been the first note in the sequence. [11] Illusory conjunctions of pitch and duration in tone sequences also occur. [12]

Auditory

Auditory illusory conjunctions occur either when two sounds are presented in different positions in space, but a single sound is heard, or when two different sounds are presented in different positions in space, but some of them are heard in the wrong spatial location. In the octave illusion, the listener is presented via earphones with a 20-second sequence consisting of two alternating tones that are an octave apart, and are repeatedly presented in alternation. The tones are 250 ms in duration. The same sequence is presented to the two ears, but when the right ear receives the high tone the left ear receives the low tone, and vice versa. Most listeners hear this sequence as a single tone that repeatedly changes both in pitch and in location. [13] It has been suggested that time limitations contribute to this auditory illusory conjunction [12] but see other explanations in terms of separate 'what' and 'where' pathways. [14] [15] [16] In the scale illusion, the listener is presented via headphones with a scale with alternating tones switching from ear to ear. The scale is presented in both ascending and descending form, such that when a tone from the ascending scale is in the right ear, a tone from the descending scale is in the left ear. [17] This gives rise to illusory conjunctions of pitch and location, such that all the higher tones are heard in one ear and all the lower tones in the other ear. Similar illusory conjunctions give rise to the chromatic illusion, the glissando illusion, and the cambiata illusion. [18]

Vision and touch

Illusory conjunctions can also occur between vision and touch. This happens when a seen object is attributed to textures that someone is feeling. This phenomenon is also more common when only one of the cerebral hemispheres is perceiving and processing the visual and tactile stimuli. [19]

See also

Related Research Articles

Auditory illusions are illusions of real sound or outside stimulus. These false perceptions are the equivalent of an optical illusion: the listener hears either sounds which are not present in the stimulus, or sounds that should not be possible given the circumstance on how they were created.

The octave illusion is an auditory illusion discovered by Diana Deutsch in 1973. It is produced when two tones that are an octave apart are repeatedly played in alternation ("high-low-high-low") through stereo headphones. The same sequence is played to both ears simultaneously; however when the right ear receives the high tone, the left ear receives the low tone, and conversely. Instead of hearing two alternating pitches, most subjects instead hear a single tone that alternates between ears while at the same time its pitch alternates between high and low.

<span class="mw-page-title-main">Subitizing</span> Assessing the quantity of objects in a visual scene without individually counting each item

Subitizing is the rapid, accurate, and confident judgments of numbers performed for small numbers of items. The term was coined in 1949 by E. L. Kaufman et al., and is derived from the Latin adjective subitus and captures a feeling of immediately knowing how many items lie within the visual scene, when the number of items present falls within the subitizing range. Sets larger than about four to five items cannot be subitized unless the items appear in a pattern with which the person is familiar. Large, familiar sets might be counted one-by-one. A person could also estimate the number of a large set—a skill similar to, but different from, subitizing.

<span class="mw-page-title-main">Anne Treisman</span> English cognitive psychologist (1935–2018)

Anne Marie Treisman was an English psychologist who specialised in cognitive psychology.

Diana Deutsch is a British-American psychologist from London, England. She is a professor of psychology at the University of California, San Diego, and is a prominent researcher on the psychology of music. Deutsch is primarily known for her discoveries in music and speech illusions. She also studies the cognitive foundation of musical grammars, which consists of the way people hold musical pitches in memory, and how people relate the sounds of music and speech to each other. In addition, she is known for her work on absolute pitch, which she has shown is far more prevalent among speakers of tonal languages. Deutsch is the author of Musical Illusions and Phantom Words: How Music and Speech Unlock Mysteries of the Brain (2019), the editor for Psychology of Music, and also the compact discs Musical Illusions and Paradoxes (1995) and Phantom Words and Other Curiosities (2003).

Feature integration theory is a theory of attention developed in 1980 by Anne Treisman and Garry Gelade that suggests that when perceiving a stimulus, features are "registered early, automatically, and in parallel, while objects are identified separately" and at a later stage in processing. The theory has been one of the most influential psychological models of human visual attention.

<span class="mw-page-title-main">Cocktail party effect</span> Ability of the brain to focus on a single auditory stimulus by filtering out background noise

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The cutaneous rabbit illusion is a tactile illusion evoked by tapping two or more separate regions of the skin in rapid succession. The illusion is most readily evoked on regions of the body surface that have relatively poor spatial acuity, such as the forearm. A rapid sequence of taps delivered first near the wrist and then near the elbow creates the sensation of sequential taps hopping up the arm from the wrist towards the elbow, although no physical stimulus was applied between the two actual stimulus locations. Similarly, stimuli delivered first near the elbow then near the wrist evoke the illusory perception of taps hopping from elbow towards wrist. The illusion was discovered by Frank Geldard and Carl Sherrick of Princeton University, in the early 1970s, and further characterized by Geldard (1982) and in many subsequent studies. Geldard and Sherrick likened the perception to that of a rabbit hopping along the skin, giving the phenomenon its name. While the rabbit illusion has been most extensively studied in the tactile domain, analogous sensory saltation illusions have been observed in audition and vision. The word "saltation" refers to the leaping or jumping nature of the percept.

<span class="mw-page-title-main">Albert Bregman</span> Canadian psychologist and academic (1936–2023)

Albert Stanley Bregman was a Canadian academic and researcher in experimental psychology, cognitive science, and Gestalt psychology, primarily in the perceptual organization of sound.

Representational momentum is a small, but reliable, error in our visual perception of moving objects. Representational moment was discovered and named by Jennifer Freyd and Ronald Finke. Instead of knowing the exact location of a moving object, viewers actually think it is a bit further along its trajectory as time goes forward. For example, people viewing an object moving from left to right that suddenly disappears will report they saw it a bit further to the right than where it actually vanished. While not a big error, it has been found in a variety of different events ranging from simple rotations to camera movement through a scene. The name "representational momentum" initially reflected the idea that the forward displacement was the result of the perceptual system having internalized, or evolved to include, basic principles of Newtonian physics, but it has come to mean forward displacements that continue a presented pattern along a variety of dimensions, not just position or orientation. As with many areas of cognitive psychology, theories can focus on bottom-up or top-down aspects of the task. Bottom-up theories of representational momentum highlight the role of eye movements and stimulus presentation, while top-down theories highlight the role of the observer's experience and expectations regarding the presented event.

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The speech-to-song illusion is an auditory illusion discovered by Diana Deutsch in 1995. A spoken phrase is repeated several times, without altering it in any way, and without providing any context. This repetition causes the phrase to transform perceptually from speech into song. Though mostly notable with languages that are non-tone, like English and German, it is possible to happen with tone languages, like Thai and Mandarin.

References

  1. ↑ Hazeltine, R. E., Prinzmetal, W., & Elliott, K. (1997). If it is absent, where is it? Locating illusory conjunctions. Journal of Experimental Psychology: Human Perception and Performance, 23(1), 263-263-277. doi : 10.1037/0096-1523.23.1.263
  2. 1 2 Cohen, A., & Ivry, R. (1989). Illusory conjunctions inside and outside the focus of attention. Journal of Experimental Psychology: Human Perception and Performance, 15(4), 650-650-663. doi : 10.1037/0096-1523.15.4.650
  3. ↑ Liederman, J. & Sohn, Y. (1999). Presentation of words to separate hemispheres prevents interword illusory conjunctions. International Journal of Neuroscience, Vol 97(1-2), 1999, 1-16. doi : 10.3109/00207459908994299
  4. ↑ Cohen, A., & Ivry, R. B. (1991). Density effects in conjunction search: Evidence for a coarse location mechanism of feature integration. Journal of Experimental Psychology: Human Perception and Performance, 17(4), 891-901. doi : 10.1037/0096-1523.17.4.891
  5. 1 2 Pelli, D. G., Cavanagh, P., Desimone, R., Tjan, B., & Treisman, A. (2007). Crowding: Including illusory conjunctions, surround suppression, and attention. Journal of Vision, Vol 7(2), 2007, 1.
  6. ↑ Donk, M. (2001). Illusory conjunctions die hard: A reply to Prinzmetal, Diedrichsen, and Irvy (2001). Journal of Experimental Psychology: Human Perception and Performance, 27(3), 542-542-546. doi : 10.1037/0096-1523.27.3.542
  7. ↑ Prinzmetal, W., Henderson, D., & Ivry, R. (1995). Loosening the constraints on illusory conjunctions: Assessing the roles of exposure duration and attention. Journal of Experimental Psychology: Human Perception and Performance, 21(6), 1362-1362-1375. doi : 10.1037/0096-1523.21.6.1362
  8. ↑ Craver-Lemley, C., Arterberry, M. E., & Reeves, A. (1999). "Illusory" illusory conjunctions: The conjoining of features of visual and imagined stimuli. Journal of Experimental Psychology: Human Perception and Performance, 25(4), 1036-1036-1049. doi : 10.1037/0096-1523.25.4.1036
  9. ↑ Navon, D. & Ehrlich, B. (1995). Illusory conjunctions: Does inattention really matter?" Cognitive Psychology, Vol 29(1), Aug 1995, 59-83. doi : 10.1006/cogp.1995.1012
  10. ↑ Treisman, A. & Schmidt, H. (1982). Illusory conjunctions in the perception of objects" Cognitive Psychology, Vol 14(1), Jan 1982, 107-141. doi : 10.1016/0010-0285(82)90006-8
  11. ↑ Deutsch, D. (1970). "Dislocation of Tones in a Musical Sequence: a Memory Illusion". Nature. 226 (5242): 286. Bibcode:1970Natur.226..286D. doi: 10.1038/226286a0 . PMID   5437526. S2CID   4259045. Weblink PDF Document
  12. 1 2 Thompson, W. F., Hall, M. D., & Pressing, J. (2001). Illusory conjunctions of pitch and duration in unfamiliar tone sequences. Journal of Experimental Psychology: Human Perception and Performance, 27(1), 128-128-140. doi : 10.1037/0096-1523.27.1.128
  13. ↑ Deutsch, D. (1974). "An auditory illusion". Nature. 251 (5473): 307–309. Bibcode:1974Natur.251..307D. doi:10.1038/251307a0. PMID   4427654. S2CID   4273134. Weblink PDF Document
  14. ↑ Deutsch, D. (1975). "Two-channel listening to musical scales". Journal of the Acoustical Society of America. 57 (5): 1156–1160. Bibcode:1975ASAJ...57.1156D. doi:10.1121/1.380573. PMID   1127169. PDF Document
  15. ↑ Deutsch, D. (1975). "Musical Illusions". Scientific American. 233 (4): 92–104. Bibcode:1975SciAm.233d..92D. doi:10.1038/scientificamerican1075-92. PMID   1162325. Weblink PDF Document
  16. ↑ Deutsch, D.; Roll, P. L. (1976). "Separate "what" and "where" decision mechanisms in processing a dichotic tonal sequence". Journal of Experimental Psychology: Human Perception and Performance. 2 (1): 23–29. doi:10.1037/0096-1523.2.1.23. PMID   1262796. Weblink PDF Document
  17. ↑ Deutsch, D. (1981). "The Octave Illusion and Auditory Perceptual Integration. In Tobias, J.V., and Schubert, E.D.". Hearing Research and Theory. 1: 99–142. PDF Document
  18. ↑ Deutsch, D. (2013). Grouping mechanisms in music. In D. Deutsch (Ed.). pp. 183–248. doi:10.1016/B978-0-12-381460-9.00006-7. ISBN   9780123814609.{{cite book}}: |journal= ignored (help) Weblink PDF Document
  19. ↑ Cinel, C., Humphreys, G. W., & Poli, R. (2002). Cross-modal illusory conjunctions between vision and touch. Journal of Experimental Psychology: Human Perception and Performance, Vol 28(5), Oct 2002, 1243-1266. doi : 10.1037/0096-1523.28.5.1243
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