Donald H. Mershon, Ph.D.
Professor of Psychology
Formerly: Associate Department Head & Director of Graduate Programs
For Graduate-Program Forms, Documents and FAQ on-line, go to: The DGP's PageIncludes brochures on current programs and many forms used in administeringthese programs, as well as a section of frequently asked questions (and their answers).
Department of Psychology (Box 7650)
NC State University, Raleigh, NC 27695
Phone: (919) 515-1724 (office)FAX: (919) 515-1716
(The best chance of reaching me at the office is MWF afternoons.)
email: don_mershon@ncsu.edu
Graduate Program in Human Factors and Ergonomics
PSY 400 Perception
SYLLABUS (Fall 2011) (pdf)PSY 500 Visual Perception
SYLLABUS (Spring 2011) (pdf)Reading List (Spring 2011)PSY 700 Audition and Other Non-Visual Senses
SYLLABUS (Spring 1999) (pdf)PSY 825 Advanced Problems in Perception (variable content)
SPRING 2000: Perceptual Organization: Old and New
SYLLABUS (Spring 2000) (pdf)To access pdf files, download Adobe Acrobat Reader for free.
On Auditory Localization.......
Philbeck, J. W., & Mershon, D. H. (2002). Knowledge about typical source output influences perceived auditory distance. Journal of the Acoustical Society of America, 111,1980-1983.
Vocal effort (a stimulus dimension related to vocal output power) is known to influence the judged distance of speech sounds. The present research examined the extent to which this influence is based on changes in vocal effort across individual stimuli versus knowledge accumulated through long-term experience. Speech recordings were presented to 192 blindfolded listeners at three levels of vocal effort. Even upon the first presentation, shouting voices were reported as appearing farthest, whispered voices closest. This suggests that auditory distance perception can be affected by past experience in a way that does not require explicit comparisons between individual stimuli.
Min, Y-K., & Mershon, D. H. (2005). An adjacency effect in auditory distance perception. Acta Acustica united with Acustica, 91, 480-489.
Previously demonstrated as a factor in perceiving visual space, the Adjacency Principle (which asserts that the effectiveness of cues between perceptual "objects" is a direct function of their spatial adjacency) also applies to perceiving auditory space. Apparent locations of two (reference) sounds were manipulated using visual capture. A physically Near source at 2 m, 10 deg left of midline, and a physically Far source at 5 m, 10 deg right of midline, were reversed in perceived relative distance (i.e., the physically nearer source appeared farther than the physically farther one). Listeners judged the distances of the referents, as well as the distances of three Test sounds. Test sounds all originated from 3 m, but one was directionally closer to the Near referent, one directionally closer to the Far referent and one mid-way between the referents. Control conditions demonstrated that auditory information was sufficient for perceiving Test sounds as equidistant. When the Near referent was incorrectly experienced as being farther, however, the reported distances of the Test sounds were significantly altered. Test sounds were heard in relation to the spatially most-adjacent referent, indicating that the Adjacency Principle serves as a general organizational factor in spatial perception, across at least two modalities.
On Perceiving Visual Distance.......
Young, K. R., Mershon, D. H., & Hicks, L. J. (2002). The Far-Anchor Effect: Errors in the perception of motion and implications for aviation safety. Human Factors, 44, 133-143.
The Far-Anchor Effect is responsible for a motion-in-depth illusion which has only recently been recognized. When viewing conditions are limited, motions in depth of a farther target in a two-object display may readily be perceived as opposite motions in depth of the nearer target. The present studies determined whether this error could be avoided through controlled fixation, or training with feedback. Under conditions of reduced visibility, participants (college students) viewed sixty-four two-target presentations, varying in the position of the moving target and its direction of motion. Neither fixation instructions nor informational feedback about motion errors affected the occurrence of the basic illusion. Nor did a vertical separation of the targets eliminate the main effect, indicating the robustness of the motion illusion under some relatively realistic variations. Such errors in judging motion in depth have significance, for both mid-air collisions between aircraft and ground-incursion accidents under conditions of reduced visibility. Potential applications include the elaboration of examples used in pilot training programs or in training programs for ground personnel.
The WEB sites on this page represent only a small sample of the total information available on sensory systems and perception. The mass of frequently-changing data, however, makes full monitoring of every site a clear impossibility. While I think you'll discover many interesting things among the listed sites, I can not vouch for the exact accuracy of each and every piece of information you may find. Please use your own background and a healthy sense of skepticism in evaluating what you read. URLs last verified on 8-19-10.
Fun Things (large collection of perceptual illusions and demonstrations)
http://www.yorku.ca/eye/funthing.htmJoy of Visual Perception (an enormous collection of perceptual stuff, including the illustration of specific facts and many links to additional information and research)
http://www.yorku.ca/eye/toc-sub.htmIllusionworks (another extensive site; both introductory and advanced explanations are provided)
http://psylux.psych.tu-dresden.de/i1/kaw/diverses%20Material/www.illusionworks.com/Another very cool, extensive WEB site (Pennsylvania State University)
http://psych.la.psu.edu/clip/Perception.htmThe Grand Illusion
http://www.grand-illusions.com/The Ultimate Guide to Optical Illusions
http://www.gopromos.com/Article/The+Ultimate+Guide+to+Optical+Illusions/7349/Default.aspx
Microscopy primer (introduction to the physics of light)
http://micro.magnet.fsu.edu/primer/lightandcolor/java.htmlHyperphysics (a very broadly-ranging site, including many pages on both light and sound)
http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html
University of Sussex site on visual physiology
http://www.lifesci.sussex.ac.uk/home/George_Mather/Linked%20Pages/Physiol/Basic and Applied Anatomy (the eye and visual system, including descriptions of several diseases)
http://library.thinkquest.org/J002330/St. Luke's Cararact & Laser Institute (a link to multiple links related to eye diseases and disorders)
http://www.stlukeseye.com/Conditions/
Haskins Laboratories (research and demonstrations on speech and speech synthesis)
http://www.haskins.yale.edu/understandingspeech.html
UC - Santa Cruz Perceptual Science Laboratory -- includes some interesting links to research on face perception and lip-reading research.
http://mambo.ucsc.edu/Self-tests on Your Knowledge of Vision and Visual Perception
http://sun.science.wayne.edu/~wpoff/cor/sen/vision.htmlPerceptual Processes in Action (University of Queensland) -- may be temporarily down
http://www.hms.uq.edu.au/percept/events.htmLightness and Color Demonstrations by Dr. Dale Purves (Duke University: Duke-NUS Graduate Medical School in Singapore)
http://www.purveslab.net/The Magic Eye (2-D and 3-D illusions, plus other information on stereoscopic phenomena and assorted visual pathologies, such as amblyopia and dyslexia)
http://www.vision3d.com/San Franscisco Exploratorium (great science museum; visit if you're ever in San Francisco)
http://www.exploratorium.edu/exhibits/f_exhibits.html
And, finally, a site which serves a different purpose:
ENGLISH USAGE SITE (helps clarify a huge host of common errors: lie-lay, effect-affect, etc.)
http://www.wsu.edu/~brians/errors/
A special group of faculty at various institutions in North and South Carolina.