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During autoscopic phenomena, people perceive a double of themselves in extrapersonal space. Such clinical allocentric self-experiences sometimes co-occur with auditory hallucinations, yet experimental setups to induce similar illusions in healthy participants have generally neglected acoustic cues. We investigated whether feeling the presence of an auditory double could be provoked experimentally by recording healthy participants’ own versus another person’s voice and movements using binaural headphones from an egocentric (the participants' own) and an allocentric (a dummy head located elsewhere) perspective. When hearing themselves allocentrically, participants reported feeling a self-identified presence extracorporeally, an arguably distinct quality of autoscopy. Our results suggest that participants without hallucinatory experiences localized their own voice closer to themselves compared to that of another person. Explorative findings suggest that distinct patterns for hallucinators should be further investigated. This study suggests a successful induction of the feeling of an acoustic doppelganger, bridging clinical phenomena and experimental work.

The phenomenon of sensory attenuation, that is, the perceptual reduction of intensity for self-generated stimuli, is considered a neurocognitive basis for self-other distinction. Corroboratory, such perceptual attenuation has been shown to be dependent on the sense of embodiment, that is, the perceptual incorporation of an object or body part into one’s body representation. In the present study, we tested whether this relationship is transferrable to unilateral upper limb amputees using a prosthesis. Thirteen participants were asked to touch their foot sole with a) their intact hand (self-touch), b) their prosthesis (prosthesis-touch), or c) let it be touched by another person (other-touch). Intensity of touch was assessed with a questionnaire. In addition, prosthesis embodiment was assessed by the recently introduced Prosthesis Embodiment Scale in nine participants. We found that both self-touch as well as prosthesis-touch was characterized by significant perceptual attenuation compared to other-touch, while self- and prosthesis-touch did not differ. By calculating an index reflecting how similar prosthesis-touch was to self- or other touch and correlating this index with perceived prosthesis embodiment, we found that the more embodied the prosthesis was, the more similar was its elicited touch perception to actual self-touch. This association was specific for prosthesis embodiment, since neither prosthesis satisfaction nor prosthesis adjustment showed a similar relationship. These findings are further evidence that perceptually embodied prostheses can be represented as an actual limb by the users’ sensorimotor system, which might have important implications for future prosthetic rehabilitation.

Three studies examined the self-enhancement function of autobiographical memory (measured with subjective temporal distance of memories). Participants recalled a memory of an attained and a failed goal and rated the subjective distance between each memory and the present. Study 1 showed that young adults with higher self-esteem felt closer to memories of attained goals and farther from failure memories than those with lower self-esteem. In Study 2, young, middle-aged and older adults with higher self-esteem felt closer to success memories, whereas self-esteem was unrelated to the temporal distance of failure memories. In both studies, feeling closer to success memories (and far from failure) led to enhanced mood. In Study 3, state self-esteem was experimentally manipulated. The manipulation had no effect on young and older adults, but middle-aged adults whose self-esteem was decreased, felt closer to success memories than failure memories. Results are discussed in relation to the temporal self-appraisal theory.

In two studies, we examined the emotional valence of memories used for mood-enhancement in relation to memories serving self, social and directive functions. Our sample included a total of 263 participants aged between 45 and 82 years. In Study 1, participants recalled memories in response to 51 cue words. In Study 2, participants recalled 32 memories that served the four functions (eight memories per function). We used multilevel modeling to take into consideration the hierarchical nature of our datasets (memories nested within individuals). Study 1 showed that emotional valence was positively associated with mood-enhancement and social functions, whereas negatively related to self and directive functions. This relation was strongest for the mood-enhancement function. In Study 2, mood-enhancing memories were rated as more positive than self, social and directive memories. We discussed results in terms of the tripartite model of memory functions and proposed that mood-enhancement should represent a distinct function.

Responding to bivalent stimuli (i.e., stimuli with features relevant for different tasks) slows subsequent performance. In prospective memory research, prospective memory targets can be considered as bivalent stimuli because they typically involve features relevant for both the prospective memory task and the ongoing task. The purpose of this study was to investigate how responding to a prospective memory target slows subsequent performance. In two experiments, we embedded the prospective memory task in a task-switching paradigm and we manipulated the degree of task-set overlap between the prospective memory task and the ongoing task. The results showed consistent after-effects of responding to prospective memory targets. The specific trajectory of the slowing depended on the amount of task-set overlap. These results demonstrate that responding to prospective memory targets results in after-effects, a so far neglected cost on ongoing task performance.

Visual, somatosensory, and perspectival cues normally provide congruent information about where the self is experienced. Separating those cues by virtual reality techniques, recent studies found that self-location was systematically biased to where a visual-tactile event was seen. Here we developed a novel, repeatable and implicit measure of self-location to compare and extend previous protocols. We investigated illusory self-location and associated phenomenological aspects in a lying body position that facilitates clinically observed abnormal self-location (as on out-of-body experiences). The results confirm that the self is located to where touch is seen. This leads to either predictable lowering or elevation of self-localization, and the latter was accompanied by sensations of floating, as during out-of-body experiences. Using a novel measurement we show that the unitary and localized character of the self can be experimentally separated from both the origin of the visual perspective and the location of the seen body, which is compatible with clinical data.

Mulder and colleagues [Mulder, T., Hochstenbach, J., Dijkstra, P. U., Geertzen, J. H. B. (2008). Born to adapt, but not in your dreams. Consciousness and Cognition, 17, 1266-1271.] report that a majority of amputees continue to experience a normally-limbed body during their night dreams. They interprete this observation as a failure of the body schema to adapt to the new body shape. The present note does not question this interpretation, but points to the already existing literature on the phenomenology of the phantom limb in dreams. A summary of published investigations is complemented by a note on phantom phenomena in the dreams of paraplegic patients and persons born without a limb. Integration of the available data allows the recommendation for prospective studies to consider dream content in more detail. For instance, "adaptation" to the loss of a limb can also manifest itself by seeing oneself surrounded by amputees. Such projective types of anosognosia ("transitivism") in nocturnal dreams should also be experimentally induced in normally-limbed individuals, and some relevant techniques are mentioned.