Perception

Tourist perception of recreational environment and management in a marine protected area

by Giovanni Zurlini

A perceptual study of ethnicity and geographical location in London and Birmingham

by Eivind Torgersen

(forthcoming, 2012) In P. Stoeckle, S. Hansen, T. Streck and C. Schwartz (eds.) Dialectological and folk dialectological concepts of space [FRIAS Linguae & Litterae series]. Berlin: Mouton de Gruyter.

Allongements vocaliques en français de Belgique : approche expérimentale et perceptive

by Alice Bardiaux

co-authored with Philippe Boula de Mareüil
JEP, Grenoble, 4-8 juin 2012

Le présent article étudie l’allongement de certaines voyelles en français de Belgique ainsi que son influence sur la... more Le présent article étudie l’allongement de certaines voyelles en français de Belgique ainsi que son influence sur la perception de l’accent belge. À partir d’enregistrements effectués en Belgique, deux expériences perceptives ont été menées, auprès d’auditeurs belges et français : l’une a permis d’identifier de façon robuste des voyelles allongées perçues comme régionalement marquées par des experts ; l’autre, utilisant la modification/resynthèse de prosodie, a permis de tester l’impact de l’allongement vocalique dans la perception de l’accent belge chez des auditeurs naïfs. La première expérience a montré que la grande majorité des voyelles perçues comme allongées est en syllabe pénultième de mot ou appartient à des monosyllabes et que ces voyelles sont généralement nasales ou semi-fermées. La deuxième expérience suggère que, toutes choses égales par ailleurs, les échantillons de parole présentant des allongements vocaliques sont évalués avec un degré d’accent plus élevé que leurs contreparties sans allongement.

Allongements vocaliques en français de Belgique : une approche perceptive

by Alice Bardiaux

co-authored with Philippe Boula de Mareüil
published in proceedings of "La perception des accents du français hors de France. Avignon - 17-18 nov. 2011"

PERCEPTION AND ACTION: THE TASTE TEST: Perception and Action: the Taste Test

by Alessandra Tanesini

The Public Perception of Power Blackouts

by Helen Brayley

Co-authored with Miles Redfern and Z. Bo

Organismo e determinazione: il corpo nella dottrina della scienza di Fichte

by Giovanni Cogliandro

published in Etica & Politica / Ethics & Politics, XIII, 2011, 2, pp. 80-110

The essay is focused on J.G. Fichte‟s wide elaboration on the concept of body, mainly in the years from 1796 to 1799.... more The essay is focused on J.G. Fichte‟s wide elaboration on the concept of body, mainly in the years from 1796 to 1799. The point of view of transcendental philosophy is analyzed as a possible alternative both to the reductive empiricism and to the different forms of ideal-ism, by means of the concept of articulated and organized body. Further, I propose these concepts as useful tools for the analysis of some contemporary theories of perception (e.g., McDowell‟s and Brandom‟s).

Japanese Interest in “Hotaru” (Fireflies) and “Kabuto-Mushi” (Japanese Rhinoceros Beetles) Corresponds with Seasonality in Visible Abundance

by Kenta TAKADA

Takada, K. (2012) Japanese Interest in “Hotaru” (Fireflies) and “Kabuto-Mushi” (Japanese Rhinoceros Beetles) Corresponds with Seasonality in Visible Abundance. - Insects 2: 424-431 (in special issue: Feature Paper 2012)

Popularity of Different Lampyrid Species in Japanese Culture as Measured by Google Search Volume

by Kenta TAKADA

Takada, K. (2011) Popularity of different lampyrid species in Japanese culture as measured bu Google search volume. - Insects 2: 336-342 (in special issue: Insects in Pop Culture, Art, and Music)

Popularity of different coleopteran groups assessed by Google search volume in Japanese culture - Extraordinary attention of the Japanese to "Hotaru" (lampyrids) and "Kabuto-mushi" (dinastines) (Cultural entomology)

by Kenta TAKADA

Takada, K. (2010) Popularity of different coleopteran groups assessed by Google search volume in Japanese culture - Extraordinary attention of the Japanese to "Hotaru" (lampyrids) and "Kabuto-mushi" (dinastines) (Cultural entomology). - Elytra 38: 299-306

Between Russian Assertiveness and Insecurity: Georgia’s Political Challenges and Prospect After the Conflict

by Uluslararası İlişkiler

Kornely K. Kakachia, "Between Russian Assertiveness and Insecurity: Georgia’s Political Challenges and Prospect After the Conflict", Uluslararası İlişkiler, Cilt 7, Sayı 26 (Yaz), 2010

Bağımsızlığından bugüne Gürcistan Sovyet sonrası ülkeler arasında en bağımsızlık düşünceli ülkelerden biridir.... more Bağımsızlığından bugüne Gürcistan Sovyet sonrası ülkeler arasında en bağımsızlık düşünceli ülkelerden biridir. Gürcistan’ın Avrupa ve transatlantik topluma yakın olma isteği arttıkça Rusya ile ilişkileri kötüleşmiştir. Rus saldırısı sonrasından ve global ekonomik kriz döneminde, Gürcistan Avro-Atlantik bölgesi ile entegrasyonunu belirsiz geleceğini şiddetlendiren güvenlik ikilemi ile karşı karşıya kalmaktadır. Bu makale Gürcistan’daki siyasal tehditleri ve Gürcistan’da ideolojik mücadeleyi kazanmayı amaçlayan Rusya diplomasisinin “yeni tonunu” incelemektedir. Aynı zamanda Gürcü-Rus savaşından sonra Gürcistan ulusal strateji meseleleri ve Gürcü-Rus ilişkilerinin geleceğini tartışmaktadır.

The hierarchical order of processes underlying the direction illusion and the direction aftereffect

by Kevin Brooks

Farrell-Whelan, M., Wenderoth, P. & Brooks, K. R. (in press). The hierarchical order of processes underlying the direction illusion and the direction aftereffect. Perception, accepted 19 Mar 2012.

Motion perception involves the processing of velocity signals through several hierarchical stages of the visual... more Motion perception involves the processing of velocity signals through several hierarchical stages of the visual cortex. To better understand this process, a number of studies have sought to localize the neural substrates of two misperceptions of motion direction, the direction illusion (DI) and the direction aftereffect (DAE). These studies have produced contradictory evidence as to the hierarchical order of the processing stages from which the respective phenomena arise. We have used a simple stimulus configuration to further investigate the sequential order of processes giving rise to the DI and DAE. To this end, we measured the two phenomena invoked in combination, and also manually parsed this combined effect into its two constituents by measuring the two phenomena individually in both possible sequential orders. Comparing the outcomes from each order to the outcome from the combined effect allowed us to test the tenability of two models: the DAE-first model and the DI-first model. Our results indicate that DAE-invoking activity does not occur earlier in the motion processing hierarchy than DI-invoking activity. Although the DI-first model is not inconsistent with our data, the possible involvement of non-sequential processing may be better able to reconcile these results with those of previous studies.

Sensitivity to feature displacement in familiar and unfamiliar faces: Beyond the internal/external feature distinction

by Kevin Brooks

Brooks, K. R. & Kemp, R. I. (2007). Sensitivity to feature displacement in familiar and unfamiliar faces: Beyond the internal/external feature distinction. Perception, 36, 1646-1659, http://www.perceptionweb.com/abstract.cgi?id=p5675, doi:10.1068/p5675

Previous studies of face recognition and of face matching have shown a general improvement for the processing of... more Previous studies of face recognition and of face matching have shown a general improvement for the processing of internal features as a face becomes more familiar to the participant. In this study, we used a psychophysical two-alternative forced choice paradigm to investigate thresholds for the detection of a displacement of the eyes, nose, mouth, or ears for familiar and unfamiliar faces. No clear division between internal and external features was observed. Rather, for familiar (compared to unfamiliar) faces participants were more sensitive to displacements of internal features such as the eyes or the nose; yet, for our third internal feature--the mouth--no such difference was observed. Despite large displacements, many subjects were unable to perform above chance when stimuli involved shifts in the position of the ears. These results are consistent with the proposal that familiarity effects may be mediated by the construction of a robust representation of a face, although the involvement of attention in the encoding of face stimuli cannot be ruled out. Furthermore, these effects are mediated by information from a spatial configuration of features, rather than by purely feature-based information.

Spatial scale of stereomotion speed processing

by Kevin Brooks

Brooks, K. R. & Stone L. S. (2006). Spatial scale of stereomotion speed processing. Journal of Vision, 6, 1257-1266, http://journalofvision.org/6/11/9, doi:10.1167/6.11.9

To examine the spatial scale of the mechanisms supporting the perception of motion in depth defined by binocular cues,... more To examine the spatial scale of the mechanisms supporting the perception of motion in depth defined by binocular cues, we measured stereomotion speed discrimination thresholds as a function of stimulus size using a two-interval speed comparison task. Stimuli were either random dot stereogram (RDS) bars featuring both the changing disparity (CD) and the interocular velocity difference (IOVD) cues to motion in depth or dynamic random dot stereogram (DRDS) bars featuring the CD cue alone. Monocular speed discrimination performance was also assessed, using half-images of the RDS stimulus. In addition, subjects’ stereoacuity for stationary versions of the binocular stimuli was measured. Stimuli ranged in vertical extent from 1.25 to 40 min. Sensitivity to speed differences was strongly related to stimulus height for DRDS stimuli. Performance decreased rapidly as stimulus size was reduced, becoming nearly random for heights below 5 min. However, for RDS stimuli, speed discrimination performance declined with reductions in stimulus size at a far slower rate, providing superior performance at every stimulus size used. Monocular performance was superior still for the majority of subjects, yet showed a similar rate of decline to binocular RDS stimuli. We conclude that the spatial resolution of the CD mechanism and its static disparity inputs is, on average, nearly nine times more coarse than the IOVD system and its monocular motion inputs. Static stereoacuity controls show that this finding cannot be explained by differences in the disparity signals available in our RDS and DRDS stimuli.

Stereomotion suppression and the perception of speed: accuracy and precision as a function of 3D trajectory

by Kevin Brooks

Brooks, K. R. & Stone L. S. (2006). Stereomotion suppression and the perception of speed: accuracy and precision as a function of 3D trajectory. Journal of Vision, 6, 1214-1223, http://journalofvision.org/6/11/6, doi:10.1167/6.11.6

The precision and accuracy of speed discrimination performance for stereomotion stimuli were assessed for several... more The precision and accuracy of speed discrimination performance for stereomotion stimuli were assessed for several receding 3D trajectories confined to the horizontal meridian. It has previously been demonstrated in a variety of tasks that detection thresholds are substantially higher when subjects observe a stereomotion stimulus than when simply viewing one of its component monocular half-imagesVa phenomenon known as stereomotion suppression (C. W. Tyler, 1971). Using monocularly visible motion in depth targets, we found mean speed discrimination thresholds to be higher for stereomotion,
compared with monocular lateral speed discrimination thresholds for equivalent stimuli, demonstrating a disadvantage for binocular viewing in the case of speed discrimination as well. Furthermore, speed discrimination thresholds for motion in depth were not systematically affected by trajectory angle; hence, the disadvantage of binocular viewing persists even when there are concurrent changes in binocular visual direction. Lastly, there was a tendency for oblique trajectories of stereomotion to be perceived as faster than equally rapid motion receding directly away from the subject along the midline. Our data, in addition to earlier stereomotion suppression observations, are consistent with a stereomotion system that takes a noisy, weighted difference of the stimulus velocities in the two eyes to compute motion in depth.

The swinging doors of perception: Stereomotion without binocular matching

by Kevin Brooks

Brooks, K. R. & Gillam, B. J. (2006). The swinging doors of perception: stereomotion without binocular matching. Journal of Vision, 6, 685-695, http://journalofvision.org/6/7/2, doi:10.1167/6.7.2

Until recently, it was considered necessary for features in the two eyes to be matched before the evaluation of... more Until recently, it was considered necessary for features in the two eyes to be matched before the evaluation of differences in their locations (binocular disparities) could reveal depth information. Motion in depth can also be perceived binocularly from related changes in the locations of matched binocular features. However, unmatched features can arise when a binocular object occludes more distant features in one eye but not the other. The presence and extent of such features can provide quantitative depth information, although perceived depth relative to geometrical predictions may vary from one such arrangement to another. The ability of humans to perceive motion in depth from unmatched stimuli has not previously been explored. Here, we use B. Gillam, S. Blackburn, and K. Nakayama’s (1999) ‘‘monocular gap’’ stimuli to investigate perception of motion in depth simulated by a change in the extent of a monocularly occluded feature in a binocular display. Settings of a motion in depth probe revealed that the magnitude of perceived motion in depth is generally as large as that for a stimulus containing matchable binocular features. We show that our stimuli provide disambiguating information not present in similar static stimuli. We conclude that in the computation of motion in depth, a binocular match is not required. A new cue--dynamic half-occlusion--can be used to reach an accurate percept.

Quantitative perceived depth from sequential monocular decamouflage

by Kevin Brooks

Brooks, K. R. & Gillam, B. J. (2006). Quantitative perceived depth from sequential monocular decamouflage. Vision Research, 46, 605-613. doi:10.1016/j.visres.2005.06.015

We present a novel binocular stimulus without conventional disparity cues whose presence and depth are revealed by... more We present a novel binocular stimulus without conventional disparity cues whose presence and depth are revealed by sequential monocular stimulation (delay P 80 ms). Vertical white lines were occluded as they passed behind an otherwise camouflaged black rectangular target. The location (and instant) of the occlusion event, decamouflaging the target
s edges, differed in the two eyes. Probe settings to match the depth of the black rectangular target showed a monotonic increase with simulated depth. Control tests discounted the possibility of subjects integrating retinal disparities over an extended temporal window or using temporal disparity. Sequential monocular decamouflage was found to be as precise and accurate as conventional simultaneous stereopsis with equivalent depths and exposure durations.

Monocular Transparency and unpaired stereopsis

by Kevin Brooks

Grove, P. M., Brooks, K. R., Anderson, B. L. & Gillam, B. J. (2006). Monocular transparency and unpaired stereopsis. Vision Research, 46, 3041-3053. doi:10.1016/j.visres.2006.05.003

Howard and Duke [Howard, I.P., & Duke, P.A. (2003). Monocular transparency generates quantitative depth. Vision... more Howard and Duke [Howard, I.P., & Duke, P.A. (2003). Monocular transparency generates quantitative depth. Vision Research, 43, 2615–2621] recently proposed a new source of binocular information they claim is used to recover depth in stereoscopic displays. They argued that these displays lack conventional disparity and that the metrical depth experienced results from transparency rather than occlusion relations. Using a variety of modified versions of their stimuli, we show here that the conditions for transparency are not required to elicit the depth experienced in their stereograms. We demonstrated that quantitative and precise depth depended not on the presence of transparency but on the presence of horizontal contours of the same contrast polarity. Depth was attenuated, particularly at larger target offsets, when horizontal contours had opposite contrast polarity for at least a portion of their length. We also show that a demonstration Howard and Duke used to control for the role of horizontal contours can be understood as an example of Gillam et al.’s Gillam, B.J., Blackburn, S., & Nakayama, K. (1999). Stereopsis based on monocular gaps: metrical coding of depth and slant without matching contours. Vision Research, 39, 493–502 monocular gap stereopsis; a form of binocular occlusion. In summary the findings reported by Howard and Duke can be understood by known processes for the computation of binocular disparity and binocular occlusion.

Human discrimination of visual direction of motion with and without smooth pursuit eye movements

by Kevin Brooks

Krukowski, A. E., Pirog, K. A., Beutter, B. R., Brooks, K. R. & Stone, L. S. (2003). Human discrimination of visual direction of motion with and without smooth pursuit eye movements. Journal of Vision, 3, 831-840, http://journalofvision.org/3/11/16/, doi:10.1167/3.11.16.

It has long been known that ocular pursuit of a moving target has a major influence on its perceived speed (Aubert,... more It has long been known that ocular pursuit of a moving target has a major influence on its perceived speed (Aubert, 1886; Fleischl, 1882). However, little is known about the effect of smooth pursuit on the perception of target direction. Here we compare the precision of human visual-direction judgments under two oculomotor conditions (pursuit vs. fixation). We also examine the impact of stimulus duration (200 ms vs. ~800 ms) and absolute direction (cardinal vs. oblique). Our main finding is that direction discrimination thresholds in the fixation and pursuit conditions are indistinguishable. Furthermore, the two oculomotor conditions showed oblique effects of similar magnitudes. These data suggest that the neural direction signals supporting perception are the same with or without pursuit, despite remarkably different retinal stimulation. During fixation, the stimulus information is restricted to large, purely peripheral retinal motion, while during steady-state pursuit, the stimulus information consists of small, unreliable foveal retinal motion and a large efference-copy signal. A parsimonious explanation of our findings is that the signal limiting the precision of direction judgments is a neural estimate of target motion in head-centered (or world-centered) coordinates (i.e., a combined retinal and eye motion signal) as found in the medial superior temporal area (MST), and not simply an estimate of retinal motion as found in the middle temporal area (MT).

Perceived speed of motion in depth is reduced in the periphery

by Kevin Brooks

Brooks, K. & Mather, G., (2000). Perceived speed of motion in depth is reduced in the periphery. Vision Research, 40, 3507-3516.

The perceived speed of motion in depth (MID) for a monocularly visible target was measured in central and peripheral... more The perceived speed of motion in depth (MID) for a monocularly visible target was measured in central and peripheral vision using a 2AFC speed discrimination task. Only binocular cues to MID were available: changing disparity and interocular velocity difference (IOVD). Perceived speed for monocular lateral motion and perceived depth for static disparity were also assessed, again in both central and peripheral vision. The purpose of the experiment was to assess the relative contributions of changing disparity and IOVD cues to the perceived speed of stereomotion. Although peripheral stimuli appeared to lie at approximately the same depth as their central counterparts, their apparent speed was reduced. Monocular/lateral and binocular/MID speeds were reduced to a similar extent. It seems that reduced apparent monocular speed leads to reduced perceived MID speed, despite the fact that the disparity system appears to be unaffected. These results suggest that the IOVD cue makes a significant contribution to MID speed perception.