Search results for "Visual Perception"

Psilocybin as an Inducer of Ego Death and Similar Experiences of Religious Provenance

2016

Abstract The purpose of this chapter is to provide an overview of the impact of hallucinogenic psilocybin on religious-type emotionality related to ego disintegration. Psilocybin as a typical hallucinogen evokes alternations of visual perception (enhances a development of pseudo-hallucinations, phantom visual perception, or hypnagogic experiences). These visual phenomena may be inspiring and are claimed to enhance aesthetic appreciation. Additionally the hallucinogen induces transient impairment of cognitive functions and psychological regression comparable to the signs of ego blurring and dissociative phenomena. The psilocybin effects, initially euphoric, may become emotionally perceived a…

Assessment of spatial perception for a multi-layer volumetric display: the effect of exocentric and egocentric distance on relative depth judgements

2020

Three-dimensional images on multiple depth layers of the volumetric display provide the physiological depth cues which ensure the high precision of depth judgements at close viewing distances and enhance the user experience. However, the contribution of physiological cues declines with an increase of viewing distance (egocentric distance), and the human spatial perception varies depending on the inter-stimuli distance (exocentric distance). We conducted a psychophysical experiment to test the perception of three-dimensional images rendered on the volumetric display depending on exocentric and egocentric stimuli distance. The constant angular size visual stimuli were displayed on different d…

Modulation of cortical motor outputs by the symbolic meaning of visual stimuli

2010

The observation of an action modulates motor cortical outputs in specific ways, in part through mediation of the mirror neuron system. Sometimes we infer a meaning to an observed action based on integration of the actual percept with memories. Here, we conducted a series of experiments in healthy adults to investigate whether such inferred meanings can also modulate motor cortical outputs in specific ways. We show that brief observation of a neutral stimulus mimicking a hand does not significantly modulate motor cortical excitability (Study 1) although, after prolonged exposure, it can lead to a relatively nonspecific modulation (Study 2). However, when such a neutral stimulus is preceded b…

A Posture Sequence Learning System for an Anthropomorphic Robotic Hand

2003

The paper presents a cognitive architecture for posture learning of an anthropomorphic robotic hand. Our approach is aimed to allow the robotic system to perform complex perceptual operations, to interact with an human user and to integrate the perceptions by a cognitive representation of the scene and the observed actions. The anthropomorphic robotic hand imitates the gestures acquired by the vision system in order to learn meaningful movements, to build its knowledge by different conceptual spaces and to perform complex interaction with the human operator.

2021

In the early 19th century, William H. Wollaston impressed the Royal Society of London with engravings of portraits. He manipulated facial features, such as the nose, and thereby dramatically changed the perceived gaze direction, although the eye region with iris and eye socket had remained unaltered. This Wollaston illusion can be thought of as head orientation attracting perceived gaze direction when the eye region is unchanged. In naturalistic viewing, the eye region changes with head orientation and typically produces a repulsion effect. Here we explore if there is a flip side to the illusion. Does the gaze direction also alter the perceived direction of the head? We used copies of the …

Insect brains use image interpolation mechanisms to recognise rotated objects.

2008

Recognising complex three-dimensional objects presents significant challenges to visual systems when these objects are rotated in depth. The image processing requirements for reliable individual recognition under these circumstances are computationally intensive since local features and their spatial relationships may significantly change as an object is rotated in the horizontal plane. Visual experience is known to be important in primate brains learning to recognise rotated objects, but currently it is unknown how animals with comparatively simple brains deal with the problem of reliably recognising objects when seen from different viewpoints. We show that the miniature brain of honeybees…

Knowledge and Beliefs About Developmental Dyslexia: A Comparison Between Pre-Service and In-Service Peruvian Teachers

2017

The purpose of this study was to investigate the knowledge, misconceptions, and knowledge gaps of Peruvian pre-service teachers (PSTs) and in-service teachers (ISTs). To do so, 112 PSTs and 113 ISTs completed the Knowledge and Beliefs About Developmental Dyslexia Scale (KBDDS). Results show that ISTs scored significantly higher than PSTs. Moreover, misconceptions and lack of information were higher in PSTs. The most noteworthy misconceptions were that dyslexia is due to poor visual perception and that letter or word reversals are the most important criterion in the identification of dyslexia. Age, years of teaching experience, prior exposure to a child with dyslexia, and self-efficacy were …

''Forward to the past''

2012

Carlini, Alessandro | Actis-Grosso, Rossana | Stucchi, Natale | Pozzo, Thierry; International audience; ''Our daily experience shows that the CNS is a highly efficient machine to predict the effect of actions into the future; are we so efficient also in reconstructing the past of an action? Previous studies demonstrated we are more effective in extrapolating the final position of a stimulus moving according to biological kinematic laws. Here we address the complementary question: are we more effective in extrapolating the starting position (SP) of a motion following a biological velocity profile? We presented a dot moving upward and corresponding to vertical arm movements that were masked i…

The Structure of Self-Consciousness: A Fourteenth-Century Debate

2007

Human Reaction Times: Linking Individual and Collective Behaviour Through Physics Modeling

2021

An individual’s reaction time data to visual stimuli have usually been represented in Experimental Psychology by means of an ex-Gaussian function. In most previous works, researchers have mainly aimed at finding a meaning for the parameters of the ex-Gaussian function which are known to correlate with cognitive disorders. Based on the recent evidence of correlations between the reaction time series to visual stimuli produced by different individuals within a group, we go beyond and propose a Physics-inspired model to represent the reaction time data of a coetaneous group of individuals. In doing so, a Maxwell–Boltzmann-like distribution appeared, the same distribution as for the velocities …