Perceived depth reversals of images on a concave screen.

Reverspectives and hollow masks cause a reversal of perceived depth when observed from a position beyond certain critical distances, even if viewed binocularly. Their 3D structures or images invariably contain a linear perspective, shading, or familiarity cue to depth. Using a concave screen, we demonstrate a novel type of perceived depth reversal in binocular viewing with a variety of depth cues.

State anxiety influences P300 and P600 event-related potentials over parietal regions in the hollow-mask illusion experiment.

The hollow-mask illusion is an optical illusion where a concave face is perceived as convex. It has been demonstrated that individuals with schizophrenia and anxiety are less susceptible to the illusion than controls. Previous research has shown that the P300 and P600 event-related potentials (ERPs) are affected in individuals with schizophrenia. Here, we examined whether individual differences in neuroticism and anxiety scores, traits that have been suggested to be risk factors for schizophrenia and anxiety disorders, affect ERPs of healthy participants while they view concave faces. Our results confirm that the participants were susceptible to the illusion, misperceiving concave faces as convex. We additionally demonstrate significant interactions of the concave condition with state anxiety in central and parietal electrodes for P300 and parietal areas for P600, but not with neuroticism and trait anxiety. The state anxiety interactions were driven by low-state anxiety participants showing lower amplitudes for concave faces compared to convex. The P300 and P600 amplitudes were smaller when a concave face activated a convex face memory representation, since the stimulus did not match the active representation. The opposite pattern was evident in high-state anxiety participants in regard to state anxiety interaction and the hollow-mask illusion, demonstrating larger P300 and P600 amplitudes to concave faces suggesting impaired late information processing in this group. This could be explained by impaired allocation of attentional resources in high-state anxiety leading to hyperarousal to concave faces that are unexpected mismatches to standard memory representations, as opposed to expected convex faces.

A inversão visual da profundidade na esquizofrenia / The visual inversion of depth perception in the schizophrenia

RESUMO Objetivo Revisar a literatura científica sobre a inversão visual da profundidade na esquizofrenia. Métodos Foi realizada uma busca nos principais indexadores com os descritores relacionados a esquizofrenia, percepção visual de profundidade e ilusão da máscara côncava. Resultado Foram encontrados 12 estudos envolvendo indivíduos com esquizofrenia e a inversão visual da profundidade. Conclusão Há necessidade de mais investigações que coletem mais informações no sentido de delimitar em que condições a inversão visual da profundidade ocorre ou não em indivíduos com esquizofrenia.

ABSTRACT Objective To review the scientific literature on the visual inversion of depth in schizophrenia. Methods A search was made on the main indexers with the descriptors related to schizophrenia, visual perception of depth and illusion of the concave mask. Result Twelve studies involving individuals with schizophrenia and visual depth inversion were found. Conclusion There is a need for more research that collects more information in order to delimit under what conditions the visual inversion of depth occurs or not in individuals with schizophrenia.

Hollow mask illusion - is it really a test for schizophrenia? / Czy iluzja wkleslej maski rzeczywiscie jest testem na schizofrenie?

OBJECTIVES: The aim of the study was an assessment of the phenomenon of depth perception in schizophrenic patients compared to healthy subjects. METHODS: We conducted a comparison erroneous assessment of the concave side of the mask as convex, using the popular website presenting rotating Charlie Chaplin's mask. The study was performed in patients hospitalized at the Stanislaw Kryzan Psychiatric Hospital in Starogard Gdanski diagnosed with paranoid and undifferentiated schizophrenia based on ICD-10 criteria and control group matched for age and education; each group included 58 subjects. RESULTS: The correct perception of depth in the hollow mask illusion regards approx. 30% of patients with paranoid and undifferentiated schizophrenia during exacerbation and it is three times higher in this group than in the general population. Except the number of relapses and hospitalization in anamnesis, it shows no correlation with another clinical and demographic data such as: the age of onset, the duration of illness, and results on Positive and Negative Syndrome Scale (PANSS). CONCLUSIONS: The correct perception of the hollow mask may be potentially one of the subsequent premises for the diagnosis of schizophrenia in doubtful cases. The simplicity and general availability is also an argument for conducting the test.

Disruptions in neural connectivity associated with reduced susceptibility to a depth inversion illusion in youth at ultra high risk for psychosis.

Patients with psychosis exhibit a reduced susceptibility to depth inversion illusions (DII) in which a physically concave surface is perceived as convex (e.g., the hollow mask illusion). Here, we examined the extent to which lessened susceptibility to DII characterized youth at ultra high risk (UHR) for psychosis. In this study, 44 UHR participants and 29 healthy controls judged the apparent convexity of face-like human masks, two of which were concave and the other convex. One of the concave masks was painted with realistic texture to enhance the illusion; the other was shown without such texture. Networks involved with top-down and bottom-up processing were evaluated with resting state functional connectivity magnetic resonance imaging (fcMRI). We examined regions associated with the fronto-parietal network and the visual system and their relations with susceptibility to DII. Consistent with prior studies, the UHR group was less susceptible to DII (i.e., they were characterized by more veridical perception of the stimuli) than the healthy control group. Veridical responses were related to weaker connectivity within the fronto-parietal network, and this relationship was stronger in the UHR group, suggesting possible abnormalities of top-down modulation of sensory signals. This could serve as a vulnerability marker and a further clue to the pathogenesis of psychosis.

Seeing more clearly through psychosis: Depth inversion illusions are normal in bipolar disorder but reduced in schizophrenia.

Schizophrenia patients with more positive symptoms are less susceptible to depth inversion illusions (DIIs) in which concave objects appear as convex. It remains unclear, however, the extent to which this perceptual advantage uniquely characterizes the schizophrenia phenotype. To address the foregoing, we compared 30 bipolar disorder patients to a previously published sample of healthy controls (N=25) and schizophrenia patients (N=30). The task in all cases was to judge the apparent convexity of physically concave faces and scenes. Half of the concave objects were painted with realistic texture to enhance the convexity illusion and the remaining objects were untextured to reduce the illusion. Subjects viewed objects stereoscopically or via monocular motion parallax depth cues. For each group, DIIs were stronger with texture than without, and weaker with stereoscopic information than without, indicating a uniformly normal response to stimulus alterations across groups. Bipolar patients experienced DIIs more frequently than schizophrenia patients but as commonly as controls, irrespective of the face/scene category, texture, or viewing condition (motion/stereo). More severe positive and disorganized symptoms predicted reduced DIIs for schizophrenia patients and across all patients. These results suggest that people with schizophrenia, but not bipolar disorder, more accurately perceive object depth structure. Psychotic symptoms-or their accompanying neural dysfunction-may primarily drive the effect presumably through eroding the visual system's generalized tendency to construe unusual or ambiguous surfaces as convex. Because such symptoms are by definition more common in schizophrenia, DIIs are at once state-sensitive and diagnostically specific, offering a potential biomarker for the presence of acute psychosis.

Percepção monocular da profundidade ou relevo na ilusão da máscara côncava na esquizofrenia / Monocular depth perception or relief in the hollow-face illusion in the schizophrenia / Percepción monocular de la profundidad o relieve en la ilusión de la mascara hueca en la esquizofrenia

Este trabalho foi desenvolvido com o propósito de investigar a percepção monocular da profundidade ou relevo da máscara côncava por 29 indivíduos saudáveis, sete indivíduos com esquizofrenia sob uso de antipsicótico por um período inferior ou igual a quatro semanas e 29 sob uso de antipsicótico por um período superior a quatro semanas. Os três grupos classificaram o reverso de uma máscara policromada em duas situações de iluminação, por cima e por baixo. Os resultados indicaram que a maioria dos indivíduos com esquizofrenia inverteu a profundidade da máscara côncava na condição de observação monocular e perceberam-na como convexa, sendo, portanto, suscetíveis à ilusão da máscara côncava. Os indivíduos com esquizofrenia sob uso de medicação antipsicótica pelo período superior a quatro semanas estimaram a convexidade da máscara côncava iluminada por cima em menor comprimento comparados aos indivíduos saudáveis...

The goal of the present study was to investigate the monocular perception of the depth or relief of the concave mask by 29 healthy subjects: seven individuals with schizophrenia under use of antipsychotic for a period less than or equal to four week and 29 under use of antipsychotic for a period bigger than four week. The three groups classified the reverse of a mask in two situations polychromatic illumination from above and below. The results showed most of the subjects with schizophrenia made the monocular depth inversion of a concave mask and perceived it as convex. The individuals with schizophrenia on antipsychotic medication for longer than four weeks period estimated the convexity of illuminated concave mask over into shorter length compared to healthy individuals and therefore susceptible to the illusion of concave mask...

Este estudio fue desarrollado con el objetivo de investigar la percepción monocular de la profundidad o relieve de una máscara hueca por 29 sujetos saludables, 7 con esquizofrenia bajo uso de medicación antipsicótica durante un período igual o inferior a 4 semanas y 29 bajo uso de medicación antipsicótica por un período mayor de 4 semanas. Los 3 grupos clasificaron el reverso de una máscara hueca policromada en dos situaciones de iluminación, por encima y por debajo de la cabeza. Los resultados mostraron que la mayoría de los sujetos con esquizofrenia han invertido el fondo cóncavo de la máscara hueca en la condición de observación monocular y percibieron-no como convexo. Ellos fueron susceptibles a la ilusión de la máscara hueca. Además, los sujetos con esquizofrenia en uso de medicación antipsicótica durante un periodo mayor de 4 semanas juzgaron la convexidad de la máscara hueca iluminada por encima en menor dimensión, en comparación a los saludables...

Percepção monocular da profundidade ou relevo na ilusão da máscara côncava na esquizofrenia / Monocular depth perception or relief in the hollow-face illusion in the schizophrenia / Percepción monocular de la profundidad o relieve en la ilusión de la mascara hueca en la esquizofrenia

Este trabalho foi desenvolvido com o propósito de investigar a percepção monocular da profundidade ou relevo da máscara côncava por 29 indivíduos saudáveis, sete indivíduos com esquizofrenia sob uso de antipsicótico por um período inferior ou igual a quatro semanas e 29 sob uso de antipsicótico por um período superior a quatro semanas. Os três grupos classificaram o reverso de uma máscara policromada em duas situações de iluminação, por cima e por baixo. Os resultados indicaram que a maioria dos indivíduos com esquizofrenia inverteu a profundidade da máscara côncava na condição de observação monocular e perceberam-na como convexa, sendo, portanto, suscetíveis à ilusão da máscara côncava. Os indivíduos com esquizofrenia sob uso de medicação antipsicótica pelo período superior a quatro semanas estimaram a convexidade da máscara côncava iluminada por cima em menor comprimento comparados aos indivíduos saudáveis.(AU)

The goal of the present study was to investigate the monocular perception of the depth or relief of the concave mask by 29 healthy subjects: seven individuals with schizophrenia under use of antipsychotic for a period less than or equal to four week and 29 under use of antipsychotic for a period bigger than four week. The three groups classified the reverse of a mask in two situations polychromatic illumination from above and below. The results showed most of the subjects with schizophrenia made the monocular depth inversion of a concave mask and perceived it as convex. The individuals with schizophrenia on antipsychotic medication for longer than four weeks period estimated the convexity of illuminated concave mask over into shorter length compared to healthy individuals and therefore susceptible to the illusion of concave mask.(AU)

Este estudio fue desarrollado con el objetivo de investigar la percepción monocular de la profundidad o relieve de una máscara hueca por 29 sujetos saludables, 7 con esquizofrenia bajo uso de medicación antipsicótica durante un período igual o inferior a 4 semanas y 29 bajo uso de medicación antipsicótica por un período mayor de 4 semanas. Los 3 grupos clasificaron el reverso de una máscara hueca policromada en dos situaciones de iluminación, por encima y por debajo de la cabeza. Los resultados mostraron que la mayoría de los sujetos con esquizofrenia han invertido el fondo cóncavo de la máscara hueca en la condición de observación monocular y percibieron-no como convexo. Ellos fueron susceptibles a la ilusión de la máscara hueca. Además, los sujetos con esquizofrenia en uso de medicación antipsicótica durante un periodo mayor de 4 semanas juzgaron la convexidad de la máscara hueca iluminada por encima en menor dimensión, en comparación a los saludables.(AU)

"Exorcist illusion": Twisting necks in the hollow-face and hollow-torso illusions.

We combine a convex facial mask with a concave torso-or vice versa-thus creating a single rigid object with a transition area at the neck, where convexity changes to concavity. This combination creates stunning illusions when the rigid object is set to motion. The two simplest effects are (1) when the object is rotated about its axis, the head appears to twist with respect to the torso, as in "The Exorcist" film; (2) when it is rotated around an axis parallel to the shoulders, the head appears to hinge around the torso. More complex illusory effects result from more complex motions. The involvement of higher-level perceptual processes may account for the illusory effects.