679 resultados para Psychological ownership
Resumo:
Abstract
Resumo:
In the rubber hand illusion tactile stimulation seen on a rubber hand, that is synchronous with tactile stimulation felt on the hidden real hand, can lead to an illusion of ownership over the rubber hand. This illusion has been shown to produce a temperature decrease in the hidden hand, suggesting that such illusory ownership produces disownership of the real hand. Here we apply immersive virtual reality (VR) to experimentally investigate this with respect to sensitivity to temperature change. Forty participants experienced immersion in a VR with a virtual body (VB) seen from a first person perspective. For half the participants the VB was consistent in posture and movement with their own body, and in the other half there was inconsistency. Temperature sensitivity on the palm of the hand was measured before and during the virtual experience. The results show that temperature sensitivity decreased in the consistent compared to the inconsistent condition. Moreover, the change in sensitivity was significantly correlated with the subjective illusion of virtual arm ownership but modulated by the illusion of ownership over the full virtual body. This suggests that a full body ownership illusion results in a unification of the virtual and real bodies into one overall entity - with proprioception and tactile sensations on the real body integrated with the visual presence of the virtual body. The results are interpreted in the framework of a"body matrix" recently introduced into the literature.
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In body ownership illusions participants feel that a mannequin or virtual body (VB) is their own. Earlier results suggest that body ownership over a body seen from behind in extra personal space is possible when the surrogate body is visually stroked and tapped on its back, while spatially and temporal synchronous tactile stimulation is applied to the participant's back. This result has been disputed with the claim that the results can be explained by self-recognition rather than somatic body ownership. We carried out an experiment with 30 participants in a between-groups design. They all saw the back of a VB 1.2 m in front, that moved in real-time determined by upper body motion capture. All felt tactile stimulation on their back, and for 15 of them this was spatially and temporally synchronous with stimulation that they saw on the back of the VB, but asynchronous for the other 15. After 3 min a revolving fan above the VB descended and stopped at the position of the VB neck. A questionnaire assessed referral of touch to the VB, body ownership, the illusion of drifting forwards toward the VB, and the VB drifting backwards. Heart rate deceleration (HRD) and the amount of head movement during the threat period were used to assess the response to the threat from the fan. Results showed that although referral of touch was significantly greater in the synchronous condition than the asynchronous, there were no other differences between the conditions. However, a further multivariate analysis revealed that in the visuotactile synchronous condition HRD and head movement increased with the illusion of forward drift and decreased with backwards drift. Body ownership contributed positively to these drift sensations. Our conclusion is that the setup results in a contradiction-somatic feelings associated with a distant body-that the brain attempts to resolve by generating drift illusions that would make the two bodies coincide.
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The potential consequences of early and late puberty on the psychological and behavioural development of the adolescent are not well known. This paper presents focused analyses from the Swiss SMASH study, a self-administered questionnaire survey conducted among a representative sample of 7488 adolescents from 16 to 20 years old. Data from participants reporting early or late timing of puberty were compared with those reporting average timing of maturation. Early maturing girls reported a higher rate of dissatisfaction with body image (OR=1.32) and functional symptoms (OR=1.52) and reported engaging in sexual activity more often (OR=1.93). Early maturing boys reported engaging in exploratory behaviours (sexual intercourse, legal and illegal substance use) at a significantly higher rate (OR varying between 1.4 and 1.99). Both early and late maturing boys reported higher rates of dysfunctional eating patterns (OR=1.59 and 1.38, respectively), victimisation (OR=1.61 and 1.37, respectively) and depressive symptoms (OR=2.11 and 1.53, respectively). Clinicians should take into account the pubertal stage of their patients and provide them, as well as their parents, with appropriate counselling in the field of mental health and health behaviour.
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Psychological factors, such as depression or depressive symptoms and fear of falling are linked to falls among the aged. According to previous studies, they may increase the risk of falls and injurious falls. In addition, depression or a high amount of depressive symptoms and fear of falling may hinder participation in preventive activities. Despite the severe consequences of both conditions and their high prevalence among the aged, they have rarely been studied in the context of fall prevention. The study aimed to assess the effects of multifactorial fall prevention on the psychological risk factors of falling (depressive symptoms and fear of falling) among the community-dwelling aged at increased risk of falling. In addition, it aimed to determine factors predicting high adherence to preventive activities. Volunteers aged 65 or over, who had fallen during the year previous to randomisation were recruited. Participants (n=591) were randomised into an intervention or a control group. The intervention group received a multifactorial fall prevention programme including geriatric assessment, individual guidance on fall and fracture prevention, group- and home-based physical exercise, psychosocial group activities, lectures and home hazards assessment. The control group had a one-time counselling on fall and fracture prevention. The data on psychological risk factors of falling were collected by self-rated questionnaires. Multifactorial fall prevention was not effective in reducing depressive symptoms or fear of falling compared to one-time counselling in the total sample. However, in subgroup analyses, depressive symptoms reduced statistically significantly more among the men and older participants of the intervention group compared to the control group. Female gender, high physical and cognitive abilities and low self-perceived probability of falling were independent predictors of higher adherence in organised activities. In conclusion, few psychological benefits were gained during this multifactorial fall prevention trial. More attention should be focused on adherence, especially among the aged with functional disabilities.
Resumo:
In body ownership illusions participants feel that a mannequin or virtual body (VB) is their own. Earlier results suggest that body ownership over a body seen from behind in extra personal space is possible when the surrogate body is visually stroked and tapped on its back, while spatially and temporal synchronous tactile stimulation is applied to the participant's back. This result has been disputed with the claim that the results can be explained by self-recognition rather than somatic body ownership. We carried out an experiment with 30 participants in a between-groups design. They all saw the back of a VB 1.2 m in front, that moved in real-time determined by upper body motion capture. All felt tactile stimulation on their back, and for 15 of them this was spatially and temporally synchronous with stimulation that they saw on the back of the VB, but asynchronous for the other 15. After 3 min a revolving fan above the VB descended and stopped at the position of the VB neck. A questionnaire assessed referral of touch to the VB, body ownership, the illusion of drifting forwards toward the VB, and the VB drifting backwards. Heart rate deceleration (HRD) and the amount of head movement during the threat period were used to assess the response to the threat from the fan. Results showed that although referral of touch was significantly greater in the synchronous condition than the asynchronous, there were no other differences between the conditions. However, a further multivariate analysis revealed that in the visuotactile synchronous condition HRD and head movement increased with the illusion of forward drift and decreased with backwards drift. Body ownership contributed positively to these drift sensations. Our conclusion is that the setup results in a contradiction-somatic feelings associated with a distant body-that the brain attempts to resolve by generating drift illusions that would make the two bodies coincide.
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Previous work has reported that it is not difficult to give people the illusion of ownership over an artificial body, providing a powerful tool for the investigation of the neural and cognitive mechanisms underlying body perception and self consciousness. We present an experimental study that uses immersive virtual reality (IVR) focused on identifying the perceptual building blocks of this illusion. We systematically manipulated visuotactile and visual sensorimotor contingencies, visual perspective, and the appearance of the virtual body in order to assess their relative role and mutual interaction. Consistent results from subjective reports and physiological measures showed that a first person perspective over a fake humanoid body is essential for eliciting a body ownership illusion. We found that the illusion of ownership can be generated when the virtual body has a realistic skin tone and spatially substitutes the real body seen from a first person perspective. In this case there is no need for an additional contribution of congruent visuotactile or sensorimotor cues. Additionally, we found that the processing of incongruent perceptual cues can be modulated by the level of the illusion: when the illusion is strong, incongruent cues are not experienced as incorrect. Participants exposed to asynchronous visuotactile stimulation can experience the ownership illusion and perceive touch as originating from an object seen to contact the virtual body. Analogously, when the level of realism of the virtual body is not high enough and/or when there is no spatial overlap between the two bodies, then the contribution of congruent multisensory and/or sensorimotor cues is required for evoking the illusion. On the basis of these results and inspired by findings from neurophysiological recordings in the monkey, we propose a model that accounts for many of the results reported in the literature.
Resumo:
Previous studies have examined the experience of owning a virtual surrogate body or body part through specific combinations of cross-modal multisensory stimulation. Both visuomotor (VM) and visuotactile (VT) synchronous stimulation have been shown to be important for inducing a body ownership illusion, each tested separately or both in combination. In this study we compared the relative importance of these two cross-modal correlations, when both are provided in the same immersive virtual reality setup and the same experiment. We systematically manipulated VT and VM contingencies in order to assess their relative role and mutual interaction. Moreover, we present a new method for measuring the induced body ownership illusion through time, by recording reports of breaks in the illusion of ownership ("breaks") throughout the experimental phase. The balance of the evidence, from both questionnaires and analysis of the breaks, suggests that while VM synchronous stimulation contributes the greatest to the attainment of the illusion, a disruption of either (through asynchronous stimulation) contributes equally to the probability of a break in the illusion.
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Physical and psychological stress cause different patterns of changes in the fluorescence intensity of nigral and tuberoinfundibular DA neurons which point to changes in neuronal activity. In order to investigate possible interactions between alpha-MSH (alpha-melanotropin) and DA systems in stress, systemic and intraventricular injections of antiserum against alpha-MSH were made. The functional state of DA neurons was assessed by histochemical microfluorimetry and hormone levels were measured by radioimmunossay. Antiserum against alpha-MSH was found to affect the functional state of DA neurons, but only thorugh the intravenous route. Under physical stress i.v. injection of antiserum against alpha-MSH was accompanied by elevated levels of activity of the DA neurons of the substantia nigra. An intraventricular injection of the same antiserum was ineffective. In psychological stress, an effect was again seen only after intravenous injection of antiserum against alpha-MSH. In this situation, the activity in DA cell groups of the substantia nigra, ventral tegmental area and tubero-infundibular system was increased after antiserum injection. Possible influences from manipulations were checked; certain effects which depended upon experimental situation were noted. Our data suggest a modulatory influence of circulating alpha-MSH on the functional state of central DA systems.
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The aim of this doctoral thesis was to study personality characteristics of patients at an early stage of Alzheimer's disease (AD), and more specifically to describe personality and its changes over time, and to explore its possible links with psychological and symptoms (BPS) and cognitive level. The results were compared to those of a group of participants without cognitive disorder through three empirical studies. In the first study, the findings showed significant personality changes that follow a specific trend in the clinical group. The profil of personality changes showed an increase in Neuroticism and a decrease in Extraversion, Openess to experiences, and Conscientiousness over time. The second study highlighted that personality and BPS occur early in the cours of AD. Recognizing them as possible precoce signs of neurodegeneration may prove to be a key factor for early detection and intervention. In the third study, a significant association between personality changes and cognitive status was observed in the patients with incipient AD. Thus, changes in Neuroticism and Conscientiousness were linked with cognitive deterioration, whereas decreased Openness to experiences and Conscientiousness over time predicted loss of independence in daily functioning. Other well-known factors such as age, education level or civil status were taken into account to predict cognitive decline. The three studies suggested five important implications: (1) cost-effective screening should take into account premorbid and specific personality changes; (2) psycho-educative interventions should provide information on the possible personality changes and BPS that may occur at the beginning of the disease; (3) using personality traits alongside other variables in the future studies on prevention might help to better understand AD's etiology; (4) individual treatment plans (psychotherapeutic, social, and pharmacological) might be adapted to the specific changes in personality profiles; (5) more researches are needed to study the impact of social-cultural and lifestyle variables on the development of AD.
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Tämän tutkimuksen tarkoituksena on osallistua osuustoiminnallisesta omistajuudesta käytävään keskusteluun. Tutkimuksen tavoitteena on kuvailla miten omistajuus ja jäsenyys ovat olleet esillä OP- ryhmän henkilöstölehdissä, sekä ymmärtää mitä merkityksiä omistajuudelle ja jäsenyydelle on annettu eri vuosien aikana. Tutkimus on luonteeltaan kvalitatiivinen. Pyrin vastaamaan tutkimuskysymyksiin tekstiaineiston pohjalta. Käytän valmiita aineistoja, jotka käsittävät OP- ryhmän henkilöstölehdet vuosilta 1980- 2005. Tutkimuksessa analysoidaan ja tulkitaan omistajuutta ja jäsenyyttä omistajuuden psykologisen, sosiaalisen, ja institutionaalisen dimension kautta. Tutkimuksen kohdeorganisaation on OP- ryhmä. Tällä hetkellä OP- ryhmään kuuluu 238 itsenäisesti toimivaa osuuspankkia, Osuuspankkikeskus ja OKO, Osuuspankkien keskuspankki Oyj. Tutkimustulosten mukaan voidaan todeta, että OP- ryhmän omistajajäsenyys on rakentunut pitkälti institutionaalisen eli taloudellisen omistajuuden ympärille.
Resumo:
Tutkimuksen tavoitteena on selvittää, onko perheomistajuus, eli yksityisomistus, kannattavampi omistusmuoto kuin institutionaalinen omistajuus ja, onko yrityksen iällä ja koolla vaikutusta perheyritysten menestymiseen. Aikaisempaan tutkimustietoon tukeutuen, tutkimuksen aluksi käydään myös läpi perheomistajuuteen yleisesti liitettyjä ominaispiirteitä sekä perheyritysten menestymistä verrattuna ei-perheyrityksiin. Empiirinen analyysi perheomistajuuden vaikutuksista yrityksen kannattavuuteen sekä yrityksen iän ja koon vaikutuksista perheyritysten menestymiseen toteutetaan kahden otoksen avulla, jotka koostuvat listaamattomista norjalaisista pienistä ja keskisuurista yrityksistä (pk-yrityksistä). Näin ollen satunnaisotos ja päätoimialaotos, johon listaamattomat pk-yritykset on valittu satunnaisesti Norjan tärkeimmiltä toimialoilta, analysoidaan erikseen. Analyysi toteutetaan käyttäen lineaarista regressioanalyysia. Vaikka satunnaisotoksen perusteella perheyritykset eivät näytä olevan ei-perheyrityksiä kannattavampia, päätoimialaotos osoittaa, että listaamattomissa pk-yrityksissä perhe- eli yksityisomistajuus on merkittävästi institutionaalista omistajuutta kannattavampi omistusmuoto. Eritoten nuoret ja pienet yritykset vastaavat perheyritysten paremmasta kannattavuudesta.