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Giulia Parovel, Alan Costall
The leaning tower illusion is a perceptual illusion in which two identical images of a tower photographed from below appear to diverge when juxtaposed. We manipulated the perceived obliqueness of the (upright) St Mark bell tower in Venice by modifying two parameters both related to the position of the camera with respect to the tower: (a) increasing the peripherality of the tower and (b) reducing the distance between the camera and the tower. The resulting images clearly show that the illusory leaning effect increases as a function of the obliqueness...
January 2018: I-Perception
(no author information available yet)
[This corrects the article DOI: 10.1177/2041669517726797.].
January 2018: I-Perception
Marco Barilari, Adélaïde de Heering, Virginie Crollen, Olivier Collignon, Roberto Bottini
Across cultures and languages, people find similarities between the products of different senses in mysterious ways. By studying what is called cross-modal correspondences, cognitive psychologists discovered that lemons are fast rather than slow, boulders are sour, and red is heavier than yellow. Are these cross-modal correspondences established via sensory perception or can they be learned merely through language? We contribute to this debate by demonstrating that early blind people who lack the perceptual experience of color also think that red is heavier than yellow but to a lesser extent than sighted do...
January 2018: I-Perception
Yi Yang, Midori Tokita, Akira Ishiguchi
A number of studies revealed that our visual system can extract different types of summary statistics, such as the mean and variance, from sets of items. Although the extraction of such summary statistics has been studied well in isolation, the relationship between these statistics remains unclear. In this study, we explored this issue using an individual differences approach. Observers viewed illustrations of strawberries and lollypops varying in size or orientation and performed four tasks in a within-subject design, namely mean and variance discrimination tasks with size and orientation domains...
January 2018: I-Perception
Allan C Dobbins, Jon K Grossmann
Objects rotating in depth with an ambiguous rotation direction frequently appear to rotate together. Corotation is especially strong when the objects are interpretable as having a shared axis. We manipulated the initial conditions of the experiment by having pairs of objects initially appear to be unambiguous, and then make either a sudden or gradual transition to ambiguous spin. We find that in neither case do coaxial counter-rotating objects persist in being perceived as counter-rotating. This implies that the perceptual constraint that favors coaxial corotation overrides the initial perceptual state of the objects...
January 2018: I-Perception
Dakota B Palmer, Yusuke Yamani, Taylor L Bobrow, Nicole D Karpinsky, Dean J Krusienski
Inattentional blindness is a failure to notice an unexpected event when attention is directed elsewhere. The current study examined participants' awareness of an unexpected object that maintained luminance contrast, switched the luminance once, or repetitively flashed. One hundred twenty participants performed a dynamic tracking task on a computer monitor for which they were instructed to count the number of movement deflections of an attended set of objects while ignoring other objects. On the critical trial, an unexpected cross that did not change its luminance (control condition), switched its luminance once (switch condition), or repetitively flashed (flash condition) traveled across the stimulus display...
January 2018: I-Perception
Vilayanur S Ramachandran, Chaipat Chunharas, Rachel Croft, Nader Batal
We report some new observations on what could be regarded as the world's simplest visual illusion-the autokinetic effect. When a single dim spot of light is viewed in a completely dark room, it moves vividly in random directions. During steady fixation, perhaps subtle eye movements cause the image to move and a failure to correct for this using eye movement command signals leads to motion perception. This is especially true because eye muscle fatigue can lead to miscalibration. However, if two dots are shown, they often move independently in different directions, which negate the eye movement theory...
January 2018: I-Perception
Valerie Nunez, Robert M Shapley, James Gordon
In the early visual cortex V1, there are currently only two known neural substrates for color perception: single-opponent and double-opponent cells. Our aim was to explore the relative contributions of these neurons to color perception. We measured the perceptual scaling of color saturation for equiluminant color checkerboard patterns (designed to stimulate double-opponent neurons preferentially) and uniformly colored squares (designed to stimulate only single-opponent neurons) at several cone contrasts. The spatially integrative responses of single-opponent neurons would produce the same response magnitude for checkerboards as for uniform squares of the same space-averaged cone contrast...
January 2018: I-Perception
Nicholas E Scott-Samuel, Hiroshi Ashida, P George Lovell, Tim S Meese, D Samuel Schwarzkopf
We report a confusing stimulus which demonstrates the power of local interpretation of three-dimensional structure to disrupt a coherent global perception.
January 2018: I-Perception
Takahiro Kawabe, Shin'ya Nishida
When two sequential video frames extracted from a single video clip are followed by the negative of the two frames, a viewer often experiences a visual illusion whereby a scene in the frames continuously moves in a single direction (four-stroke apparent motion). To create a four-stroke apparent motion display, the image intensities of the whole of the second pair of images are reversed. However, this intensity reversal creates a strong impression of flicker that can be undesirable for comfortable viewing. This study reports that four-stroke apparent motion can be induced by only reversing the luminance intensities in those spatial areas which contain motion signals in high-pass filtered images...
January 2018: I-Perception
Séamas Weech, Nikolaus F Troje
Depth-ambiguous point-light walkers are most frequently seen as facing-the-viewer (FTV). It has been argued that the FTV bias depends on recognising the stimulus as a person. Accordingly, reducing the social relevance of biological motion by presenting stimuli upside down has been shown to reduce FTV bias. Here, we replicated the experiment that reported this finding and added stick figure walkers to the task in order to assess the effect of explicit shape information on facing bias for inverted figures. We measured the FTV bias for upright and inverted stick figure walkers and point-light walkers presented in different azimuth orientations...
January 2018: I-Perception
Arthur Shapiro, Laysa Hedjar, Erica Dixon, Akiyoshi Kitaoka
Kitaoka's Tomato is a color illusion in which a semitransparent blue-green field is placed on top of a red object (a tomato). The tomato appears red even though the pixels would appear green if viewed in isolation. We show that this phenomenon can be explained by a high-pass filter and by histogram equalization. The results suggest that this illusion does not require complex inferences about color constancy; rather, the tomato's red is available in the physical stimulus at the appropriate spatial scale and dynamic range...
January 2018: I-Perception
David Weiss, Christoph Witzel, Karl Gegenfurtner
We investigated several sensory and cognitive determinants of colour constancy across 40 illumination hues. In the first experiment, we measured colour naming for the illumination and for the colour induced by the illumination on the colorimetric grey. Results confirmed that the induced colours are approximately complementary to the colour of the illumination. In the second experiment, we measured colour constancy using achromatic adjustments. Average colour constancy was perfect under the blue daylight illumination and decreased in colour directions away from the blue daylight illumination due to undershooting and a strong blue bias...
November 2017: I-Perception
Hiroyuki Ito, Tomomi Koizumi
A new illusion is reported. A visual object suddenly appearing on a red background sometimes causes an impression of flicker or double flash. In Experiment 1, a red, green, or blue object was presented on a red, green, blue, or gray background. Participants evaluated the illusion strength in reference to the physical flicker of a gray object presented in central vision. The results show that the green or blue object presented on the red background caused the illusion. In Experiment 2, the effect of retinal eccentricity on the illusion was tested...
November 2017: I-Perception
Peter Ulric Tse
Building on the modal and amodal completion work of Kanizsa, Carman and Welch showed that binocular stereo viewing of two disparate images can give rise to a percept of 3D curved, nonclosed illusory contours and surfaces. Here, it is shown that binocular presentation can also give rise to the percept of closed curved surfaces or volumes that appear to vary smoothly across discrete depths in binocularly fused images, although in fact only two binocular disparities are discretely defined between corresponding contour elements of the inducing elements...
November 2017: I-Perception
(no author information available yet)
[This corrects the article DOI: 10.1177/2041669517743523.].
November 2017: I-Perception
Kimele Persaud, Pernille Hemmer, Celeste Kidd, Steven Piantadosi
Expectations learned from our perceptual experiences, culture, and language can shape how we perceive, interact with, and remember features of the past. Here, we questioned whether environment also plays a role. We tested recognition memory for color in Bolivia's indigenous Tsimanè people, who experience a different color environment than standard U.S. POPULATIONS: We found that memory regressed differently between the groups, lending credence to the idea that environmental variations engender differences in expectations, and in turn perceptual memory for color...
November 2017: I-Perception
Klaudia Pochopien, Manfred Fahle
Prisms shifting the visual input sideways produce a mismatch between the visual versus felt position of one's hand. Prism adaptation eliminates this mismatch, realigning hand proprioception with visual input. Whether this realignment concerns exclusively the visuo-(hand)motor system or it generalizes to acoustic inputs is controversial. We here show that there is indeed a slight influence of visual adaptation on the perceived direction of acoustic sources. However, this shift in perceived auditory direction can be fully explained by a subconscious head rotation during prism exposure and by changes in arm proprioception...
November 2017: I-Perception
Laura Fademrecht, Judith Nieuwenhuis, Isabelle Bülthoff, Nick Barraclough, Stephan de la Rosa
So far, action recognition has been mainly examined with small point-light human stimuli presented alone within a narrow central area of the observer's visual field. Yet, we need to recognize the actions of life-size humans viewed alone or surrounded by bystanders, whether they are seen in central or peripheral vision. Here, we examined the mechanisms in central vision and far periphery (40° eccentricity) involved in the recognition of the actions of a life-size actor (target) and their sensitivity to the presence of a crowd surrounding the target...
November 2017: I-Perception
Masahide Yuasa
Many previous studies on inference of social behaviors using geometric shapes have explored causality, animacy, intention, and desire inferred from the movements of such shapes; however, inference of communicative atmosphere in terms of friendliness/antagonism using geometric shapes has not yet been studied well. This study investigated how a friendly/antagonistic communicative atmosphere was inferred from the movement of two egg shapes. We developed animations for these shapes involving forward/backward/parallel tilts with coincidence/incoincidence of synchronous movement...
November 2017: I-Perception
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