1,721,019 research outputs found
Object grouping contingent upon background
No full textThis study analyzes grouping between singletons (line elements popping out by orientation gradient) when they segregate from textures of uniformly oriented line elements. In the first experiment three adjacent singletons formed a texture bar; in the second experiment the distance between two singletons to be grouped was manipulated. The observer's task was to discriminate the orientation of the global pattern made by the singletons. The results and the explanations suggested are that: (i) an inner gradient within the texture bar (when the singletons are reciprocally orthogonal) operates only at short distances and enhances discrimination, indicating an initial stage of texture segregation based on local processing. (ii) Spatial interactions between parallel singletons are present at short distances and reduce discrimination. (iii) An interruption of background how (directed along the orientation of background line elements) produced by the grouped pattern when orthogonal to it, enhances discrimination; this effect is present at both short and large distances between singletons, indicating a global process. (iv) Spatial interactions are present between parallel singletons even at large distances and independently of background orientation, suggesting that grouping generates a figural context within which features to be bound together interact. Moreover, flow interruption and figural context were absent in a detection task, thereby suggesting their specific involvement in grouping and figure binding. Overall, the results may indicate that grouping operates on already segmented line elements, across different orientations and over both short and long distances in between
Texture brightness filling-in
No full textThe masking procedure by Paradise and Nakayama was used to investigate brightness filling-in within textures made of line elements: a texture stimulus was masked by a second stimulus containing a square contour. When a uniform texture was presented, the texture region inside the masking square appeared darkened and a small number of texture elements were perceived with a degenerated shape, appearing as dim dots or shorter line elements; it is as if the line element expanded from a bright point to fill the entire region defined by its contour. If the texture stimulus was a texture patch segregating from the surrounding texture by an orientation gradient and this patch was inside the square mask, darkening was not as strong as in the previous condition, and masked line elements preserved their elongated shape. Brightness spreading was measured in two experiments using dichoptic presentations. Experiment 1 used an adjustment task and showed that the brightness of texture line elements spread from equiluminant borders between segregating textures. Experiment 2 used a matching task and demonstrated that spreading was blocked by segregation borders dependent on the orientation gradient between texture line elements. The selectivity for line orientation began 40-80 msec after texture onset and maximal spreading occurred at ~ 120 msec. These findings may indicate that two processes subserve filling-in within textures: the first spreads isotropically the mean stimulus luminance at an initial processing stage of image analysis; at a later stage, the second spreads a texture flow (both brightness and shape of line elements) directed along the orientation of texture line elements. The texture flow mechanism fills in with a texture surface the region bounded by segregation contours
Strange-face-in-the-mirror illusion.
Get PDFThis article reports a new visual illusion that has never described before. In normal observers gazing at one’s own face in the mirror for few minutes, at a low illumination level, produces the perception of strange faces. Observers see distortions of their own faces, but often all see skulls, archetypical faces, faces of relatives and deceased, and animals. In a laboratory set-up under controlled laboratory conditions in 50 healthy young volunteers (mean age 23 years) after about one minute all observers began to perceive apparitions. When a 10 minute session of mirror gazing ended participants reported experiencing striking effects including huge deformations of one’s own face (reported by 66% of individuals); a relative’s face with the features changed (18%), of whom 8% were still alive and 10% were deceased; an unknown person (28%); an archetypal face, such as that of an old woman, a child, or an image of an ancestor (28%); an animal face such as that of a cat or a pig (18%); and monstrous beings (48%). The illusion is relevant in the fields of face-perception, self-consciousness, embodied-cognition, mirror subject-other intersubjectivity
Dissociation and hallucinations in dyads engaged through interpersonal gazing
No full textInterpersonal gazing in dyads, when the two individuals in the dyad stare at each other in the eyes, is investigated in 20 healthy young individuals at low illumination for 10-min. Results indicate dissociative symptoms, dysmorphic face perceptions, and hallucination-like strange-face apparitions. Dissociative symptoms and face dysmorphia were correlated. Strange-face apparitions were non-correlated with dissociation and dysmorphia. These results indicate that dissociative symptoms and hallucinatory phenomena during interpersonal-gazing under low illumination can involve different processes. Strange-face apparitions may characterize the rebound to "reality" (perceptual reality caused by external stimulus and hallucinatory reality caused by internal input) from a dissociative state induced by sensory deprivation. These phenomena may explain psychodynamic projections of the subject's unconscious meanings into the other's face. The results indicate that interpersonal gazing in dyads can be an effective tool for studying experimentally-induced dissociative symptoms and hallucinatory-like apparitions
Strange-face illusions during inter-subjective gazing
Get PDFIn normal observers, gazing at one’s own face in the mirror for a few minutes, at a low
illumination level, triggers the perception of strange faces, a new visual illusion that has
been named ‘strange-face in the mirror’. Individuals see huge distortions of their own faces,
but they often see monstrous beings, archetypal faces, faces of relatives and deceased, and
animals. In the experiment described here, strange-face illusions were perceived when two
individuals, in a dimly lit room, gazed at each other in the face. Inter-subjective gazing
compared to mirror-gazing produced a higher number of different strange-faces. Inter-subjective
strange-face illusions were always dissociative of the subject’s self and supported
moderate feeling of their reality, indicating a temporary lost of self-agency. Unconscious
synchronization of event-related responses to illusions was found between members in
some pairs. Synchrony of illusions may indicate that unconscious response–coordination
is caused by the illusion–conjunction of crossed dissociative strange-faces, which are perceived
as projections into each other’s visual face of reciprocal embodied representations
within the pair. Inter-subjective strange-face illusions may be explained by the subject’s
embodied representations (somaesthetic, kinaesthetic and motor facial pattern) and the
other’s visual face binding. Unconscious facial mimicry may promote inter-subjective
illusion–conjunction, then unconscious joint-action and response–coordination
The role of the background: texture segregation and figure-ground segmentation
No full textThe effects of a texture surround composed of line elements on a stimulus within which a target line element segregates, were studied. Detection and discrimination of the target when it had the same orientation as the surround were impaired at short presentation time; on the other hand, no effect was present when they were reciprocally orthogonal. These results are interpreted as background completion in texture segregation; a texture made up of similar elements is represented as a continuous surface with contour and contrast of an embedded element inhibited. This interpretation is further confirmed with a simple line protruding from an annulus. Generally, the results are taken as evidence that local features are prevented from segmenting when they are parts of a global entity
Anima, Mente e Cervello in Psicologia
Get PDFLa possibilità di introdurre il concetto di Anima all’interno della psicologia cognitivista – che ammette soltanto i due livelli epistemologici della Mente, a livello psicologico, e del Cervello, a livello neurofisiologico – è discussa prendendo in considerazione quattro aspetti a sostegno del concetto di Anima: (a) per diverse filosofie e religioni antiche, l’Anima è il dèmone personale e, per la psicologia analitica di Jung, l’Anima è un archetipo del Sé; (b) l’Anima è in relazione con l’armonia e i fenomeni a-causali dell’accadere psichico, in particolare le sincronicità tra psiche, intesa come microcosmo, e macrocosmo; (c) l’Anima è in relazione con l’esperienza di infinitezza e di istantaneità dell’attimo, a-temporale e a-causale, come è per esempio descritta nell’enigma dello Zarathustra di Nietzsche; (d) l’Anima è in relazione con il «non-senso» che caratterizza ogni formulazione metafisica delle esperienze di spiritualità e di infinitezza, secondo Wittgenstein. Alcuni risultati sperimentali in psicologia (Caputo, Strange-face-in-the-mirror illusion) e diversi aspetti fenomenologici dei suoni e della musica suggeriscono una spiegazione in base al concetto di Anima
Split-mirror gazing increases dissociative states and illusions of self-identity
No full textPrevious studies found that mirror-gazing at the subject's reflected own face, under a low illumination level, produces acute dissociation. In the present study, a split-mirror was used, which divides the subject's reflected face vertically into two half-faces, and dissociative states were compared to single-mirror gazing. Twelve healthy naïve individuals, who were sampled from students of an Art Academy, volunteered in a within-subject experiment. Dissociative states were measured through a 9-item self-report questionnaire on three scales: illusions of face deformation (derealization); illusions of body detachment (depersonalization); illusions of different self-identity (dissociated identity). Results showed that split-mirror gazing increased dissociation with respect to single-mirror gazing. Illusions of different self-identity, such as double-identity (i.e., left-identity versus right-identity) or double-personality, increased during split-mirror gazing with respect to single-mirror gazing, whereas illusions of face deformation and body detachment were unchanged. Findings support the distinction between detachment and compartmentalization, and may provide a tool for experimental investigation of dissociative identity disorder (DID). Finally, the students' portraits illustrated illusions of self-identity in split-mirror gazing: left-identity (portrayed in the right side of drawings) displayed illusions of more negative personalities and/or emotions, while right-identity (portrayed in the left side) showed more positive features
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