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1.
Sci Rep ; 9(1): 14440, 2019 10 08.
Artigo em Inglês | MEDLINE | ID: mdl-31595003

RESUMO

Changes in the retinal size of stationary objects provide a cue to the observer's motion in the environment: Increases indicate the observer's forward motion, and decreases backward motion. In this study, a series of images each comprising a pair of pine-tree figures were translated into auditory modality using sensory substitution software. Resulting auditory stimuli were presented in an ascending sequence (i.e. increasing in intensity and bandwidth compatible with forward motion), descending sequence (i.e. decreasing in intensity and bandwidth compatible with backward motion), or in a scrambled order. During the presentation of stimuli, blindfolded participants estimated the lengths of wooden sticks by haptics. Results showed that those exposed to the stimuli compatible with forward motion underestimated the lengths of the sticks. This consistent underestimation may share some aspects with visual size-contrast effects such as the Ebbinghaus illusion. In contrast, participants in the other two conditions did not show such magnitude of error in size estimation; which is consistent with the "adaptive perceptual bias" towards acoustic increases in intensity and bandwidth. In sum, we report a novel cross-modal size-contrast illusion, which reveals that auditory motion cues compatible with listeners' forward motion modulate haptic representations of object size.

2.
Iperception ; 10(4): 2041669519856906, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31384414

RESUMO

Reversed apparent motion (or reversed phi) can be seen during a continuous dissolve between a positive and a spatially shifted negative version of the same image. Similar reversed effects can be seen in stereo when positive and spatially shifted negative images are presented separately to the two eyes or in a Vernier alignment task when the two images are juxtaposed one above the other. Gregory and Heard reported similar effects that they called "phenomenal phenomena." Here, we investigate the similarities between these different effects and put forward a simple, spatial-smoothing explanation that can account for both the direction and magnitude of the reversed effects in the motion, stereo and Vernier domains. In addition, we consider whether the striking motion effects seen when viewing Kitaoka's colour-dependent Fraser-Wilcox figures are related to the reversed phi illusion, given the similarity of the luminance profiles.

3.
Iperception ; 9(3): 2041669518776986, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29854378

RESUMO

We compare two versions of two known phenomena, the Curvature blindness and the Kite mesh illusions, to highlight how similar manipulations lead to blindness to curvature and blindness to illusory curvature, respectively. The critical factor is a change in luminance polarity; this factor interferes with the computation of curvature along the contour, for both real and illusory curvature.

4.
Front Psychol ; 9: 345, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29599739

RESUMO

The cerebral cortex predicts visual motion to adapt human behavior to surrounding objects moving in real time. Although the underlying mechanisms are still unknown, predictive coding is one of the leading theories. Predictive coding assumes that the brain's internal models (which are acquired through learning) predict the visual world at all times and that errors between the prediction and the actual sensory input further refine the internal models. In the past year, deep neural networks based on predictive coding were reported for a video prediction machine called PredNet. If the theory substantially reproduces the visual information processing of the cerebral cortex, then PredNet can be expected to represent the human visual perception of motion. In this study, PredNet was trained with natural scene videos of the self-motion of the viewer, and the motion prediction ability of the obtained computer model was verified using unlearned videos. We found that the computer model accurately predicted the magnitude and direction of motion of a rotating propeller in unlearned videos. Surprisingly, it also represented the rotational motion for illusion images that were not moving physically, much like human visual perception. While the trained network accurately reproduced the direction of illusory rotation, it did not detect motion components in negative control pictures wherein people do not perceive illusory motion. This research supports the exciting idea that the mechanism assumed by the predictive coding theory is one of basis of motion illusion generation. Using sensory illusions as indicators of human perception, deep neural networks are expected to contribute significantly to the development of brain research.

5.
Iperception ; 9(1): 2041669517749601, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29344332

RESUMO

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.

6.
Iperception ; 8(3): 2041669517707972, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28560014

RESUMO

The perceived speed of a ring of equally spaced dots moving around a circular path appears faster as the number of dots increases (Ho & Anstis, 2013, Best Illusion of the Year contest). We measured this "spinner" effect with radial sinusoidal gratings, using a 2AFC procedure where participants selected the faster one between two briefly presented gratings of different spatial frequencies (SFs) rotating at various angular speeds. Compared with the reference stimulus with 4 c/rev (0.64 c/rad), participants consistently overestimated the angular speed for test stimuli of higher radial SFs but underestimated that for a test stimulus of lower radial SFs. The spinner effect increased in magnitude but saturated rapidly as the test radial SF increased. Similar effects were observed with translating linear sinusoidal gratings of different SFs. Our results support the idea that human speed perception is biased by temporal frequency, which physically goes up as SF increases when the speed is held constant. Hence, the more dots or lines, the greater the perceived speed when they are moving coherently in a defined area.

7.
Iperception ; 6(6): 2041669515622085, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27551366

RESUMO

In the "footsteps illusion", light and dark squares travel at constant speed across black and white stripes. The squares appear to move faster and slower as their contrast against the stripes varies. We now demonstrate some second-order footsteps illusions, in which all edges are defined by colors or textures-even though luminance-based neural motion detectors are blind to such edges.

8.
Perception ; 43(9): 914-25, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25420331

RESUMO

The color-dependent motion illusion in stationary images--a special type of the Fraser-Wilcox illusion--is introduced and discussed. The direction of illusory motion changes depending on whether the image is of high or low luminance and whether the room is bright or dark. This dimorphism of illusion was confirmed by surveys. It is suggested that two different spatial arrangements of color can produce the motion illusion. One is a spatial arrangement where long- and short-wavelength color regions sandwich a darker strip; the other is where the same color regions sandwich a brighter strip.


Assuntos
Percepção de Cores/fisiologia , Percepção de Movimento/fisiologia , Ilusões Ópticas/fisiologia , Adulto , Humanos
9.
Perception ; 42(8): 828-34, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24303747

RESUMO

We investigated illusory motion perception in 6-to-8-month-old infants using a static figure which produces strong illusory motion. In experiment 1 we prepared a control figure, which was physically similar to the illusory motion figure but which did not produce illusory motion. We presented the illusory figure and the control figure side-by-side, and measured infants' looking time at the target illusory figure. Results showed that the infants' looking time at the illusory figure was significantly longer than that for the control. In experiment 2 we made another set of stimuli consisting of the same local pattern used in experiment 1, but which did not produce illusory motion. The results showed that no preferences were observed in experiment 2. These results suggest that 6-to-8-month-old infants perceive illusory motion in static figures.


Assuntos
Percepção de Movimento/fisiologia , Ilusões Ópticas/fisiologia , Humanos , Lactente , Testes Neuropsicológicos
10.
Perception ; 42(9): 1001-5, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24386721

RESUMO

Ilusory self-motion (vection) can be induced by large areas of visual motion stimulation. Here we demonstrate for the first time that illusory expansion can induce vection in the absence of any physical display motion.


Assuntos
Percepção de Movimento/fisiologia , Ilusões Ópticas/fisiologia , Estimulação Luminosa/métodos , Análise de Variância , Humanos , Movimento (Física) , Campos Visuais/fisiologia
11.
Front Psychol ; 3: 528, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23226138

RESUMO

This study investigated the relationship between the magnitude of illusory motion in the variants of the "Rotating Snakes" pattern and the visual preference among such patterns. In Experiment 1 we manipulated the outer contour and the internal geometrical structure of the figure to test for corresponding modulations in the perceived illusion magnitude. The strength of illusory motion was estimated by the method of adjustment where the speed of a standard moving figure was matched to the speed of the perceived illusory motion in test figures. We observed modulation of the perceived strength of illusory motion congruent with our geometrical manipulations. In Experiment 2, we directly compared the magnitude of the perceived illusory motion and the preference for these patterns by a method of paired comparison. Images differing in illusion magnitude showed corresponding differences in the reported preference for these patterns. In addition, further analysis revealed that the geometry and lower level image characteristics also substantially contributed to the observed preference ratings. Together these results support the idea that presence of illusory effect and geometrical characteristics determine affective preference for images, as they may be regarded as more interesting, surprising, or fascinating.

12.
Perception ; 41(7): 840-53, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23155735

RESUMO

We quantitatively examined the difference in perceived size between upright and inverted faces using the method of constant stimuli. The stimuli included eight face images modified from two cartoon faces produced by Kitaoka (2007, http://www.psy.ritsumei.ac.jp/-akitaoka/kao-e.html and 2008, Cognitive Psychology 5 177-185) and six photographic faces, including a photographic face used by Thompson (2010, http://illusionncontest.neuralcorrelate.com/2010/the-fat-face-thin-fft-ilusion/). Experiment 1 showed that an upright face and outline were perceived to be significantly smaller than an inverted face and outline, respectively. Moreover, the amount of the size underestimation in the face stimulus condition was significantly larger than that in the outline stimulus condition. Experiment 2 showed that an upright face was perceived to be significantly smaller than 90 degrees and 270 degrees rotated faces, whereas an inverted face was not perceived to be significantly larger than a 90 degrees or 270 degrees rotated face. Experiment 3 showed that upright faces were perceived to be significantly smaller than upright and inverted outlines, whereas inverted faces were not perceived to be significantly larger than upright or inverted outlines. Experiments 4 and 5 showed that upright photographic faces were also perceived to be significantly smaller than inverted photographic faces. These results provide quantitative evidence for a size underestimation of upright faces.


Assuntos
Face , Reconhecimento Visual de Modelos/fisiologia , Percepção de Tamanho/fisiologia , Adulto , Feminino , Humanos , Masculino , Testes Neuropsicológicos , Adulto Jovem
13.
Iperception ; 3(2): 112-40, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23145272

RESUMO

Visual illusions constitute an interesting perceptual phenomenon, but they also have an aesthetic and affective dimension. We hypothesized that the illusive nature itself causes the increased aesthetic and affective valence of illusions compared with their non-illusory counterparts. We created pairs of stimuli. One qualified as a standard visual illusion whereas the other one did not, although they were matched in as many perceptual dimensions as possible. The phenomenal quality of being an illusion had significant effects on "Aesthetic Experience" (fascinating, irresistible, exceptional, etc), "Evaluation" (pleasant, cheerful, clear, bright, etc), "Arousal" (interesting, imaginative, complex, diverse, etc), and "Regularity" (balanced, coherent, clear, realistic, etc). A subsequent multiple regression analysis suggested that Arousal was a better predictor of Aesthetic Experience than Evaluation. The findings of this study demonstrate that illusion is a phenomenal quality of the percept which has measurable aesthetic and affective valence.

14.
J Neurosci ; 32(41): 14344-54, 2012 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-23055505

RESUMO

A physically stationary stimulus surrounded by a moving stimulus appears to move in the opposite direction. There are similarities between the characteristics of this phenomenon of induced motion and surround suppression of directionally selective neurons in the brain. Here, functional magnetic resonance imaging was used to investigate the link between the subjective perception of induced motion and cortical activity. The visual stimuli consisted of a central drifting sinusoid surrounded by a moving random-dot pattern. The change in cortical activity in response to changes in speed and direction of the central stimulus was measured. The human cortical area hMT+ showed the greatest activation when the central stimulus moved at a fast speed in the direction opposite to that of the surround. More importantly, the activity in this area was the lowest when the central stimulus moved in the same direction as the surround and at a speed such that the central stimulus appeared to be stationary. The results indicate that the activity in hMT+ is related to perceived speed modulated by induced motion rather than to physical speed or a kinetic boundary. Early visual areas (V1, V2, V3, and V3A) showed a similar pattern; however, the relationship to perceived speed was not as clear as that in hMT+. These results suggest that hMT+ may be a neural correlate of induced motion perception and play an important role in contrasting motion signals in relation to their surrounding context and adaptively modulating our motion perception depending on the spatial context.


Assuntos
Encéfalo/fisiologia , Percepção de Movimento/fisiologia , Estimulação Luminosa/métodos , Desempenho Psicomotor/fisiologia , Vias Visuais/fisiologia , Adulto , Feminino , Humanos , Imagem por Ressonância Magnética/métodos , Masculino
15.
Brain Nerve ; 64(7): 779-91, 2012 Jul.
Artigo em Japonês | MEDLINE | ID: mdl-22764350

RESUMO

A variety of "face illusions," including the gaze illusion, face inversion effects, geometrical illusions, reversible figures, and other interesting phenomena related to face perception, are reviewed in the present report, with many sample images. The "gaze illusion" or the illusion of eye direction includes the Wollaston illusion, the luminance-induced gaze shift, the Bogart illusion, the eye-shadow-dependent gaze illusion, the Mona Lisa effect, etc. "Face inversion effects" refer to the Thatcher illusion, the fat face-thin illusion, underestimation of the upright face, the nose-shortening illusion of the inverted face, etc. "Geometrical illusions" include the Lee-Freire illusion, Yang's iris illusion, overestimation of the farther eye, the eye-shadow-dependent eye-size illusion, etc. "Reversible figures" contain the whole-part reversible figure, Rubin's vase-face illusion, or hybrid images. "Other interesting phenomena" include the flashed face distortion effect, the presidential illusion, predominance of the mouth or eyebrows over eye expression, the eye direction aftereffect, etc. It is suggested that some of these phenomena are highly specific to face perception.


Assuntos
Face , Ilusões , Reconhecimento Visual de Modelos , Percepção Visual/fisiologia , Cosméticos , Humanos , Estimulação Luminosa
16.
Neuroimage ; 61(4): 1143-52, 2012 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-22450297

RESUMO

The "Rotating Snakes" figure elicits a clear sense of anomalous motion in stationary repetitive patterns. We used an event-related fMRI adaptation paradigm to investigate cortical mechanisms underlying the illusory motion. Following an adapting stimulus (S1) and a blank period, a probe stimulus (S2) that elicited illusory motion either in the same or in the opposite direction was presented. Attention was controlled by a fixation task, and control experiments precluded explanations in terms of artefacts of local adaptation, afterimages, or involuntary eye movements. Recorded BOLD responses were smaller for S2 in the same direction than S2 in the opposite direction in V1-V4, V3A, and MT+, indicating direction-selective adaptation. Adaptation in MT+ was correlated with adaptation in V1 but not in V4. With possible downstream inheritance of adaptation, it is most likely that adaptation predominantly occurred in V1. The results extend our previous findings of activation in MT+ (I. Kuriki, H. Ashida, I. Murakami, and A. Kitaoka, 2008), revealing the activity of the cortical network for motion processing from V1 towards MT+. This provides evidence for the role of front-end motion detectors, which has been assumed in proposed models of the illusion.


Assuntos
Adaptação Fisiológica/fisiologia , Imagem por Ressonância Magnética , Percepção de Movimento/fisiologia , Ilusões Ópticas/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Córtex Visual/fisiologia , Adulto , Humanos , Interpretação de Imagem Assistida por Computador , Masculino , Estimulação Luminosa , Adulto Jovem
17.
Perception ; 40(6): 751-6, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21936304

RESUMO

An illusion produced by duplicating facial parts, which can cause an unstable feeling for many observers, was investigated. We examined factors that contribute to the unstable feeling. The results suggest that this illusion is specific to face perception, and the unstable feeling may be generated by difficulty in keeping attention directed to either of the duplicated facial parts.


Assuntos
Face , Percepção de Movimento , Ilusões Ópticas , Reconhecimento Visual de Modelos , Distorção da Percepção , Atenção , Humanos , Japão , Orientação
18.
Perception ; 40(5): 608-20, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21882723

RESUMO

We quantitatively examined the effect of stimulus duration on the extinction illusion. A white disc was presented or not presented at an intersection of a grey grid (intersection configuration) or on a homogeneous background (background configuration). The extinction illusion was quantified as the subtraction of no-disc responses in the background configuration (ie baseline) from no-disc responses in the intersection configuration, when the disc was presented. Experiment 1 showed a temporal effect: the extinction illusion increased as stimulus duration increased; this temporal effect was observed when the disc was presented at 9 deg from the fixation point and when the stimulus duration was 1000-6000 ms. Experiment 2 showed a visual field anisotropy: the extinction illusion occurred more frequently in the upper visual field than in the lower visual field, when the stimulus duration was 200 ms; the anisotropy was not observed when the stimulus duration was 6000 ms. Experiment 3 showed an alley-length effect: when the grid alley was long, the extinction illusion occurred more frequently in the 6000 ms condition than in the 200 ms condition; the temporal effect was not observed when the grid alley was short. These results suggest that the temporal effect of the extinction illusion might be due to perceptual filling-in of luminance information of the grid alley.


Assuntos
Atenção , Extinção Psicológica , Fixação Ocular , Ilusões Ópticas , Orientação , Reconhecimento Visual de Modelos , Sensibilidades de Contraste , Discriminação Psicológica , Humanos , Tempo de Reação , Percepção de Tamanho
19.
Vision Res ; 50(23): 2381-90, 2010 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-20875830

RESUMO

The perceived relative position of a moving object is frequently shifted as compared to the relative position of the object in the real world. The illusions have traditionally been explained by temporal models that influence the perceptual latency of visual objects. However, another compelling theory has recently been proposed on the basis of spatial models that directly influence the coded location of visual objects. In this study, spatial models were further supported by three different types of illusions composed of apparent motions, in which the perceived relative positions of stationary but apparently moving objects were shifted. One of three illusions was developed as a novel type of illusion in this paper (kebab illusion). The relative position shift of a stationary object suggested that spatial models play important roles on assignment of position of moving object as well as temporal models. A mechanism that integrated temporal and spatial models is also discussed.


Assuntos
Percepção de Movimento/fisiologia , Ilusões Ópticas , Adulto , Humanos , Pessoa de Meia-Idade , Modelos Teóricos , Adulto Jovem
20.
Vision Res ; 50(3): 315-29, 2010 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-19969011

RESUMO

A new class of patterns, composed of repeating patches of asymmetric intensity profile, elicit strong perception of illusory motion. We propose that the main cause of this illusion is erroneous estimation of image motion induced by fixational eye movements. Image motion is estimated with spatial and temporal energy filters, which are symmetric in space, but asymmetric (causal) in time. That is, only the past, but not the future, is used to estimate the temporal energy. It is shown that such filters mis-estimate the motion of locally asymmetric intensity signals at certain spatial frequencies. In an experiment the perception of the different illusory signals was quantitatively compared by nulling the illusory motion with opposing real motion, and was found to be predicted well by the model.


Assuntos
Fixação Ocular/fisiologia , Percepção de Movimento/fisiologia , Ilusões Ópticas , Algoritmos , Movimentos Oculares/fisiologia , Humanos , Modelos Teóricos , Ilusões Ópticas/fisiologia
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