Vision Science

Karanka, J., & Luque, D. (2004). Predicting collision: a connectionist model. In H. Bowman & C. Labiousse (Eds.), Connectionist Models of Cognition and Perception II (pp. 39 -48). London: World Scientific.

by David Luque Ruiz

Kinds of access: Different methods for report reveal different kinds of metacognitive access

by Kristian Sandberg

Co-authored with Morten Overgaard

The power of shadows: shadow stereopsis

by Anthony Medina

The influence of retinal eccentricity, stimulus size, and discriminability on hemispheric differences.

by Guy Tiberghien

Coherent neural representation of hand speed in humans revealed by MEG imaging

by Sylvain Baillet

Mary Jane, don’t deflate your Perception! Burge’s Perceptual Representationalism and Vision Science.

by Carlos M. Muñoz-Suárez

I argue that the version of Perceptual Representationalism extensively endorsed by Tyler Burge in his Origins of... more I argue that the version of Perceptual Representationalism extensively endorsed by Tyler Burge in his Origins of Objectivity (2010) captures an incomplete theory of perception. Although Burge offers compelling solutions to some core problems shaping perceptual psychology (i.e. the underdetermination problems), it neglects a third problem which has been of capital relevance in perceptual psychology and vision science: the problem of explaining the neurobiological correlates of the outcomes of perceptual systems. This indifference seems to elicit what I will call the explanatory ascent shaping Burge’s theory.

Crowding follows the binding of relative position and orientation

by John Greenwood

Greenwood, J.A., Bex, P.J., & Dakin, S.C. (2012). Crowding follows the binding of relative position and orientation. Journal of Vision, 12(3):18, 1-20.

Crowding - the deleterious influence of clutter on object recognition - disrupts the identification of visual features... more Crowding - the deleterious influence of clutter on object recognition - disrupts the identification of visual features as diverse as orientation, motion, and color. It is unclear whether this occurs via independent feature-specific crowding processes (preceding the feature binding process) or via a singular (late) mechanism tuned for combined features. To examine the relationship between feature binding and crowding, we measured interactions between the crowding of relative position and orientation. Stimuli were a target cross and two flanker crosses (each composed of two near-orthogonal lines), 15 degrees in the periphery. Observers judged either the orientation (clockwise/counterclockwise) of the near-horizontal target line, its position (up/down relative to the stimulus center), or both. For single-feature judgments, crowding affected position and orientation similarly: thresholds were elevated and responses biased in a manner suggesting that the target appeared more like the flankers. These effects were tuned for orientation, with near-orthogonal elements producing little crowding. This tuning allowed us to separate the predictions of independent (feature specific) and combined (singular) models: for an independent model, reduced crowding for one feature has no effect on crowding for other features, whereas a combined process affects either all features or none. When observers made conjoint judgments, a reduction of orientation crowding (by increasing target-flanker orientation differences) increased the rate of correct responses for both position and orientation, as predicted by our combined model. In contrast, our independent model incorrectly predicted a high rate of position errors, since the probability of positional crowding would be unaffected by changes in orientation. Thus, at least for these features, crowding is a singular process that affects bound position and orientation values in an all-or-none fashion.

Haigh on Purves: Brains: How they seem to work.

by Sarah M Haigh

Haigh, S. M. (2011).  Haigh on Purves: Brains: How they seem to work.  Perception, 40 (4), 507-508.

Matlab & Psychtoolbox Intro (German)

by Jochen Laubrock

Use link below ("View on bit.ly") for latest version

Matlab and Psychophysics Toolbox Introduction (in German), extended version (2009, past version was 2007)
aimed... more Matlab and Psychophysics Toolbox Introduction (in German), extended version (2009, past version was 2007)
aimed at students, not experts

Not a paper but class material; put in this section because academia.edu provides nicer stats for papers than for teaching material.

Einführung in Matlab und die Psychophysics Toolbox.

Matlab & Psychtoolbox Intro (German)

by Jochen Laubrock

Use link below ("View on bit.ly") for latest version

Matlab and Psychophysics Toolbox Introduction (in German), extended version (2009, past version was 2007)
aimed... more Matlab and Psychophysics Toolbox Introduction (in German), extended version (2009, past version was 2007)
aimed at students, not experts

Not a paper but class material; put in this section because academia.edu provides nicer stats for papers than for teaching material.

Einführung in Matlab und die Psychophysics Toolbox.

POSTER at ECVP 2011: Accommodation to chromatic gratings.

by Sarah M Haigh

Haigh, S. M., Allen, P. M., & Wilkins, A. J. (2011). Accommodation to chromatic gratings. Perception, 40 (ECVP Abstract Supplement), 80.

Wilkins, Tang, Irabor and Coutts (2008) measured discomfort from isoluminant square-wave gratings and showed that the... more Wilkins, Tang, Irabor and Coutts (2008) measured discomfort from isoluminant square-wave gratings and showed that the discomfort increased with the separation within the CIE UCS diagram of the chromaticities of the component bars, regardless of the hue. The gratings with larger separation elicited a cortical haemodynamic response of greater magnitude. The discomfort and larger haemodynamic response may arise because accommodative mechanisms relax when the chromaticity difference is large – Allen at al. (2010) found a greater lag of accommodation to achromatic gratings for those who found them uncomfortable. We therefore used an open field autorefractor to measure the accommodative response to the gratings. No correlation was found between the separation of chromaticities and the accommodative response, suggesting that the discomfort is not due to a failure to accommodate to the stimuli. However, participants who experienced pattern-related visual stress, showed a greater accommodative lag to the gratings overall than those who were symptom-free. This suggests that although accommodative mechanisms are unlikely to cause the discomfort, those who find gratings uncomfortable generally relax their accommodation when looking at an uncomfortable target.

References
Allen, P., Hussain, A., Usherwood, C., Wilkins, A. (2010). Pattern-related visual stress, chromaticity and accommodation. Investigative Ophthalmology and Visual Science, 2010(51), 6843-6849.
Wilkins, A. J., Tang, P., Irabor, J., Baningham, L., Coutts, L. . (2008). Cortical haemodynamic response to coloured gratings. Perception, 37(ECVP Abstract Supplement), 144.

Aversion to patterns and cortical hyperexcitability in migraine.

by Sarah M Haigh

Haigh, S. M., Karanovic, O., Wilkinson, F., and Wilkins, A. J. (2011). Aversion to patterns and cortical hyperexcitability in migraine. Cephalalgia, 32, 236-240.

Background: Patients with migraine are averse to certain visual stimuli, such as flicker and striped patterns that... more Background: Patients with migraine are averse to certain visual stimuli, such as flicker and striped patterns that evoke paroxysmal EEG activity in patients with photosensitive epilepsy. Migraineurs demonstrate a hyper-responsiveness to such stimuli, and there is debate as to whether the aversion and hyper-responsiveness are due to a hyperexcitability of the cortex similar to that in patients with photosensitive epilepsy. In these patients grating patterns with certain spatial characteristics can be epileptogenic, depending critically on their movement. If the contours of the grating drift continually, the grating is not epileptogenic, but if the contours are static or if their direction is repeatedly and rapidly reversed so as to vibrate, the grating then becomes highly epileptogenic.
Methods: We compared aversion to vibrating, drifting and static gratings in migraineurs and controls. The contrast of each grating was gradually increased, but only until the participant felt discomfort, so as to obtain a contrast threshold for aversion with minimal exposure.
Results: Migraineurs had lower thresholds than the Control Group, indicating greater aversion. For both groups the threshold was higher (aversion was lower) for static than for both types of moving gratings. The drifting gratings were more aversive than the vibrating gratings when both groups were combined.
Conclusion: The findings suggest that the aversion shown by migraineurs is not attributable to a cortical hyperexcitability similar to that in photosensitive epilepsy.

POSTER at AVA 2011: Colour separation and aversion

by Sarah M Haigh

Haigh S M, Tang P, Barningham L, Coutts L, Allen P M, Wilkins A J, 2012, "Colour separation and aversion" i-Perception 3(4) 232

Aversion to achromatic patterns is well documented but relatively little is known about discomfort from chromatic... more Aversion to achromatic patterns is well documented but relatively little is known about discomfort from chromatic patterns. Large colour differences are uncommon in the natural environment and deviation from natural statistics makes images uncomfortable (Fernandez & Wilkins, 2008, Perception, 37(7), 1098-113; Juricevic, Land, Wilkins & Webster, 2010, Perception, 39(7), 884-899). We report twelve studies documenting a linear increase in aversion to chromatic square-wave gratings as a function of the separation in UCS chromaticity between the component bars, independent of their luminance contrast. Two possible explanations for the aversion were investigated: (1) accommodative response, or (2) cortical metabolic demand. We found no correlation between chromaticity separation and accommodative lag or variance in lag, measured using an open-field autorefractor. However, near infrared spectroscopy of the occipital cortex revealed a larger oxyhaemoglobin response to patterns with large chromaticity separation. The aversion may be cortical in origin and does not appear to be due to accommodation.

Evolution of eye size and shape in primates

by Callum Ross

Ross, C.F. and Kirk, E.C. (2007) Evolution of eye size and shape in primates. Journal of Human Evolution 52:294-313.

Modelling the initial phase of the human rod photoreceptor response to the onset of steady illumination

by Vin Shen Ban

Selective internal operations in the recognition of locally and globally point-inverted patterns

by David Foster

Performance in discriminating rotated 'same' patterns from 'different' patterns may decrease with rotation angle up to... more Performance in discriminating rotated 'same' patterns from 'different' patterns may decrease with rotation angle up to about 90° and then increase with angle up to 180°. This anomalously improved performance under 180° pattern rotation or point-inversion can be explained by assuming that patterns are internally represented in terms of local features and their spatial-order relations ('left of', 'above', etc.), and that, in pattern comparison, an efficient internal sense-reversal operation occurs (transforming 'left of' to 'right of', etc.). Previous experiments suggested that local features and spatial relations could not be efficiently separated in some pattern-comparison tasks. This hypothesis was tested by measuring 'same-different' discrimination performance under four transformations: point-inversion i 1 of the whole pattern, point-inversion lF of local features alone, point-inversion lp of local-feature positions alone, and identity transformation Id. The results suggested that internal sense-reversal operations could be applied selectively and efficiently, provided that local features were well separated. Under this condition performances for lF and l were about the same whereas performance for lp was significantly worse, the latter performance resulting possibly from an attempt to apply internal global and local sense-reversal operations serially.

The Ghosts in the Computer: The role of agency and animacy attributions in "ghost controls"

by Francys Subiaul

Paterson JR, Garcia-Bellido DC, Lee MSY, Brock GA, Jago JB, Edgecombe GD. 2011. Acute vision in the giant Cambrian predator Anomalocaris and the origin of compound eyes. Nature 480: 237-240 [Cover Story]

by Michael S. Y. Lee

For a video summary see here...
http://www.youtube.com/watch?v=a1fNidLedEA

For coverage by the New York Times, National Geographic etc see here...
http://www.nytimes.com/2011/12/13/science/anomalocaris-fossil-reveals-eyes-with-16000-lenses.html
http://news.nationalgeographic.com/news/2011/11/111212-shrimp-vision-eyes-predator-ancient-animals-science-oceans/
http://news.sciencemag.org/sciencenow/2011/12/scienceshot-hide-and-seek-in-the.html
http://www.nature.com/news/an-eye-opening-fossil-1.9586
http://www.guardian.co.uk/science/2011/dec/07/predator-compound-eyes-stalks-cambrian?newsfeed=true
http://www.newscientist.com/article/dn21251-first-top-predator-was-giant-shrimp-with-amazing-eyes.html
http://www.cosmosmagazine.com/news/5067/ancient-killer-had-excellent-vision
http://www.abc.net.au/science/articles/2011/12/08/3385661.htm
http://blogs.discovermagazine.com/notrocketscience/2011/12/07/anomalocaris-sharp-eyes-predator/
http://www.adelaidenow.com.au/news/south-australia/ancient-fossilised-eyes-found-on-kangaroo-island/story-e6frea83-1226216822949
http://www.google.com/hostednews/ukpress/article/ALeqM5iL6eLQuVAMLpnIT1-WUJuV7NPouw?docId=N0312111323262686001A
http://www.examiner.com/paelenotology-science-news-in-national/my-what-big-eyes-you-have-the-better-to-eat-you-with-my-dear
http://www.msnbc.msn.com/id/45587188/ns/technology_and_science-science/#.TuL9HUqrYrU
http://www.csmonitor.com/Science/2011/1208/Ancient-predator-had-eyes-with-16-000-lenses
http://news.discovery.com/animals/superpredator-eyes-111207.html
http://www.canberratimes.com.au/news/lifestyle/technology/science/the-eyes-have-it-worlds-oldest-predator-found/2385621.aspx
http://theconversation.edu.au/ancient-super-predator-had-excellent-vision-4650
http://www.metro.co.uk/news/world/884230-eyes-of-earths-first-super-predator-found-in-australia
http://www.sciencecodex.com/read/worlds_first_super_predator_had_remarkable_vision-82733

Allen, E.C., Beilock, S.L., & Shevell, S.K. (2012). Individual differences in simultaneous color constancy are related to working memory. Journal of the Optical Society of America A, 29, A52-A59.

by Elizabeth Allen

Few studies have investigated the possible role of higher-level cognitive mechanisms in color constancy. Follow- ing... more Few studies have investigated the possible role of higher-level cognitive mechanisms in color constancy. Follow- ing up on previous work with successive color constancy [J. Exper. Psychol. Learn. Mem. Cogn. 37, 1014 (2011)], the current study examined the relation between simultaneous color constancy and working memory—the ability to maintain a desired representation while suppressing irrelevant information. Higher working memory was associated with poorer simultaneous color constancy of a chromatically complex stimulus. Ways in which the executive attention mechanism of working memory may account for this are discussed. This finding supports a role for higher-level cognitive mechanisms in color constancy and is the first to demonstrate a relation between simultaneous color constancy and a complex cognitive ability.

The Network Behind Dynamic Spatio-temporal Patterns: Building Low-complexity Retinal Models in CNN Based on Morphology, Pharmacology and Physiology

by Erik Nemeth