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1.
Sci Rep ; 14(1): 10040, 2024 05 02.
Article in English | MEDLINE | ID: mdl-38693189

ABSTRACT

Investigation of visual illusions helps us understand how we process visual information. For example, face pareidolia, the misperception of illusory faces in objects, could be used to understand how we process real faces. However, it remains unclear whether this illusion emerges from errors in face detection or from slower, cognitive processes. Here, our logic is straightforward; if examples of face pareidolia activate the mechanisms that rapidly detect faces in visual environments, then participants will look at objects more quickly when the objects also contain illusory faces. To test this hypothesis, we sampled continuous eye movements during a fast saccadic choice task-participants were required to select either faces or food items. During this task, pairs of stimuli were positioned close to the initial fixation point or further away, in the periphery. As expected, the participants were faster to look at face targets than food targets. Importantly, we also discovered an advantage for food items with illusory faces but, this advantage was limited to the peripheral condition. These findings are among the first to demonstrate that the face pareidolia illusion persists in the periphery and, thus, it is likely to be a consequence of erroneous face detection.


Subject(s)
Illusions , Humans , Female , Male , Adult , Illusions/physiology , Young Adult , Visual Perception/physiology , Photic Stimulation , Face/physiology , Facial Recognition/physiology , Eye Movements/physiology , Pattern Recognition, Visual/physiology
2.
Elife ; 132024 May 29.
Article in English | MEDLINE | ID: mdl-38809774

ABSTRACT

In the 'double-drift' illusion, local motion within a window moving in the periphery of the visual field alters the window's perceived path. The illusion is strong even when the eyes track a target whose motion matches the window so that the stimulus remains stable on the retina. This implies that the illusion involves the integration of retinal signals with non-retinal eye-movement signals. To identify where in the brain this integration occurs, we measured BOLD fMRI responses in visual cortex while subjects experienced the double-drift illusion. We then used a combination of univariate and multivariate decoding analyses to identify (1) which brain areas were sensitive to the illusion and (2) whether these brain areas contained information about the illusory stimulus trajectory. We identified a number of cortical areas that responded more strongly during the illusion than a control condition that was matched for low-level stimulus properties. Only in area hMT+ was it possible to decode the illusory trajectory. We additionally performed a number of important controls that rule out possible low-level confounds. Concurrent eye tracking confirmed that subjects accurately tracked the moving target; we were unable to decode the illusion trajectory using eye position measurements recorded during fMRI scanning, ruling out explanations based on differences in oculomotor behavior. Our results provide evidence for a perceptual representation in human visual cortex that incorporates extraretinal information.


Subject(s)
Illusions , Magnetic Resonance Imaging , Motion Perception , Visual Cortex , Humans , Motion Perception/physiology , Female , Male , Visual Cortex/physiology , Visual Cortex/diagnostic imaging , Adult , Illusions/physiology , Eye Movements/physiology , Young Adult , Photic Stimulation , Brain Mapping , Brain/physiology , Brain/diagnostic imaging
3.
Sci Rep ; 14(1): 12414, 2024 05 30.
Article in English | MEDLINE | ID: mdl-38816488

ABSTRACT

Numerous efforts have been made to test the OPTIMAL theory of motor learning in healthy children and adult populations. However, only a small number of studies have tested this theory in children with cognitive-motor disorders, such as developmental coordination disorder (DCD). The present study aims to examine the individual and additive effects of a visual illusion and self-controlled practice on a golf putting task in children at risk for DCD based on the OPTIMAL theory. Forty children at risk for DCD (mean age = 8.57 ± 1.05 years) were randomly assigned to four experimental groups (1-small visual illusion + self-controlled practice; 2-big visual illusion + self-controlled practice; 3-small visual illusion + yoked; 4-big visual illusion + yoked). Following 12 pretest trials of a golf putting task, the participants completed 5 blocks of 12 trials of practice on the first day. A retention test (12 trials) and a transfer dual-task test (12 trials) were conducted on the second day. The results indicated that in retention test the big visual illusion + self-controlled practice group was significantly better than the small visual illusion + yoked group (p = 0.01), while there was not any other significant difference between groups at retention test as well as between all groups at practice phase and transfer test (p > 0.05 for all comparisons). In other words, an additive effect has been observed just in the retention test but not the practice phase as well as transfer test. In general, the results of this study support the OPTIMAL theory of motor learning in children at risk for DCD and suggests to all educators who work with these children to use the combination of the visual illusion with self-controlled practice to improve the motor learning of children at risk for DCD.


Subject(s)
Illusions , Learning , Motor Skills Disorders , Humans , Child , Male , Female , Illusions/physiology , Motor Skills/physiology , Psychomotor Performance/physiology
4.
Nat Commun ; 15(1): 3141, 2024 Apr 23.
Article in English | MEDLINE | ID: mdl-38653975

ABSTRACT

Brightness illusions are a powerful tool in studying vision, yet their neural correlates are poorly understood. Based on a human paradigm, we presented illusory drifting gratings to mice. Primary visual cortex (V1) neurons responded to illusory gratings, matching their direction selectivity for real gratings, and they tracked the spatial phase offset between illusory and real gratings. Illusion responses were delayed compared to real gratings, in line with the theory that processing illusions requires feedback from higher visual areas (HVAs). We provide support for this theory by showing a reduced V1 response to illusions, but not real gratings, following HVAs optogenetic inhibition. Finally, we used the pupil response (PR) as an indirect perceptual report and showed that the mouse PR matches the human PR to perceived luminance changes. Our findings resolve debates over whether V1 neurons are involved in processing illusions and highlight the involvement of feedback from HVAs.


Subject(s)
Neurons , Optogenetics , Photic Stimulation , Primary Visual Cortex , Animals , Neurons/physiology , Primary Visual Cortex/physiology , Mice , Male , Humans , Female , Visual Perception/physiology , Illusions/physiology , Optical Illusions/physiology , Mice, Inbred C57BL , Pupil/physiology , Visual Cortex/physiology , Visual Cortex/cytology
5.
Sci Rep ; 14(1): 9302, 2024 04 23.
Article in English | MEDLINE | ID: mdl-38654060

ABSTRACT

We capitalized on the respiratory bodily illusion that we discovered in a previous study and called 'Embreathment' where we showed that breathing modulates corporeal awareness in men. Despite the relevance of the issue, no such studies are available in women. To bridge this gap, we tested whether the synchronization of avatar-participant respiration patterns influenced females' bodily awareness. We collected cardiac and respiratory interoceptive measures, administered body (dis)satisfaction questionnaires, and tracked participants' menstrual cycles via a mobile app. Our approach allowed us to characterize the 'Embreathment' illusion in women, and explore the relationships between menstrual cycle, interoception and body image. We found that breathing was as crucial as visual appearance in eliciting feelings of ownership and held greater significance than any other cue with respect to body agency in both women and men. Moreover, a positive correlation between menstrual cycle days and body image concerns, and a negative correlation between interoceptive sensibility and body dissatisfaction were found, confirming that women's body dissatisfaction arises during the last days of menstrual cycle and is associated with interoception. These findings have potential implications for corporeal awareness alterations in clinical conditions like eating disorders and schizophrenia.


Subject(s)
Awareness , Body Image , Illusions , Interoception , Virtual Reality , Humans , Female , Body Image/psychology , Adult , Illusions/physiology , Young Adult , Interoception/physiology , Male , Menstrual Cycle/physiology , Menstrual Cycle/psychology , Surveys and Questionnaires , Respiration , Body Dissatisfaction/psychology
6.
Sci Rep ; 14(1): 8690, 2024 04 15.
Article in English | MEDLINE | ID: mdl-38622216

ABSTRACT

In the era of artificial intelligence, privacy empowerment illusion has become a crucial means for digital enterprises and platforms to "manipulate" users and create an illusion of control. This topic has also become an urgent and pressing concern for current research. However, the existing studies are limited in terms of their perspectives and methodologies, making it challenging to fully explain why users express concerns about privacy empowerment illusion but repeatedly disclose their personal information. This study combines the associative-propositional evaluation model (APE) and cognitive load theory, using event-related potential (ERP) technology to investigate the underlying mechanisms of how the comprehensibility and interpretability of privacy empowerment illusion cues affect users' immediate attitudes and privacy disclosure behaviours; these mechanisms are mediated by psychological processing and cognitive load differences. Behavioural research results indicate that in the context of privacy empowerment illusion cues with low comprehensibility, users are more inclined to disclose their private information when faced with high interpretability than they are when faced with low interpretability. EEG results show that in the context of privacy empowerment illusion cues with low comprehensibility, high interpretability induces greater P2 amplitudes than does low interpretability; low interpretability induces greater N2 amplitudes than does high interpretability. This study extends the scopes of the APE model and cognitive load theory in the field of privacy research, providing new insights into privacy attitudes. Doing so offers a valuable framework through which digital enterprises can gain a deeper understanding of users' genuine privacy attitudes and immediate reactions under privacy empowerment illusion situations. This understanding can help increase user privacy protection and improve their overall online experience, making it highly relevant and beneficial.


Subject(s)
Hominidae , Illusions , Humans , Animals , Privacy/psychology , Disclosure , Cues , Artificial Intelligence , Cognition
7.
PLoS One ; 19(4): e0297850, 2024.
Article in English | MEDLINE | ID: mdl-38625848

ABSTRACT

Power can increase overconfidence and illusory thinking. We investigated whether power is also related to the illusion of explanatory depth (IOED), people's tendency to think they understand the world in more detail, coherence, and depth than they actually do. Abstract thinking was reported as a reason for the IOED, and according to the social distance theory of power, power increases abstract thinking. We linked these literatures and tested construal style as a mediator. Further, predispositions can moderate effects of power and we considered narcissism as a candidate because narcissism leads to overconfidence and may thus increase the IOED especially in combination with high power. In three preregistered studies (total N = 607), we manipulated power or measured feelings of power. We found evidence for the IOED (regarding explanatory knowledge about devices). Power led to general overconfidence but had only a small impact on the IOED. Power and narcissism had a small interactive effect on the IOED. Meta-analytical techniques suggest that previous findings on the construal-style-IOED link show only weak evidential value. Implications refer to research on management, power, and overconfidence.


Subject(s)
Illusions , Humans , Cognition , Thinking , Emotions , Surveys and Questionnaires
8.
PLoS One ; 19(4): e0295342, 2024.
Article in English | MEDLINE | ID: mdl-38568979

ABSTRACT

It has been shown that observing a face being touched or moving in synchrony with our own face increases self-identification with the former which might alter both cognitive and affective processes. The induction of this phenomenon, termed enfacement illusion, has often relied on laboratory tools that are unavailable to a large audience. However, digital face filters applications are nowadays regularly used and might provide an interesting tool to study similar mechanisms in a wider population. Digital filters are able to render our faces in real time while changing important facial features, for example, rendering them more masculine or feminine according to normative standards. Recent literature using full-body illusions has shown that participants' own gender identity shifts when embodying a different gendered avatar. Here we studied whether participants' filtered faces, observed while moving in synchrony with their own face, may induce an enfacement illusion and if so, modulate their gender identity. We collected data from 35 female and 33 male participants who observed a stereotypically gender mismatched version of themselves either moving synchronously or asynchronously with their own face on a screen. Our findings showed a successful induction of the enfacement illusion in the synchronous condition according to a questionnaire addressing the feelings of ownership, agency and perceived similarity. However, we found no evidence of gender identity being modulated, neither in explicit nor in implicit measures of gender identification. We discuss the distinction between full-body and facial processing and the relevance of studying widely accessible devices that may impact the sense of a bodily self and our cognition, emotion and behaviour.


Subject(s)
Illusions , Touch Perception , Humans , Male , Female , Gender Identity , Self Concept , Touch
9.
Medicina (Kaunas) ; 60(4)2024 Apr 06.
Article in English | MEDLINE | ID: mdl-38674252

ABSTRACT

Background and Objectives: Parkinson's disease (PD) is associated with various non-motor symptoms, including minor hallucinations, comprising visual illusions and presence and passage hallucinations. Despite their occurrence, even in newly diagnosed PD patients, data regarding the prevalence and characteristics of minor hallucinations, visual illusions in particular, remain limited. The aim of this study was to address this knowledge gap by assessing the prevalence of minor hallucinations in PD patients, with a focus on visual illusions. Materials and Methods: In this prospective pilot study, we enrolled 35 PD patients without dementia and 35 age- and gender-matched PD-unaffected individuals. Cognitive function was assessed using the Montreal Cognitive Assessment, clinical data were collected, and all subjects were assessed via questionnaires regarding 20 types of visual illusions and other minor hallucinations. Results: The prevalence of minor hallucinations was significantly higher among PD patients compared to controls (45.7% vs. 11.4%, p = 0.003). PD patients reported visual illusions and presence hallucinations more frequently than the controls (37.1% vs. 8.6% and 22.9% vs. 2.9%, p = 0.009 and p = 0.028, respectively), with no significant difference in passage hallucinations (20% vs. 8.6%, p = 0.306). In the PD group, the most frequently observed visual illusions were complex visual illusions, kinetopsia, and pelopsia; the latter was also the most common visual illusion in the control group. PD patients experiencing visual illusions were more likely to report presence hallucinations compared to patients without visual illusions (53.8% vs. 4.5%, p = 0.002); no significant differences in other clinical characteristics were found. Conclusions: Minor hallucinations are a common phenomenon among PD patients without dementia, with a higher prevalence than among healthy controls. Visual illusions are the most prevalent type of minor hallucinations, affecting more than a third of PD patients, with complex visual illusions, kinetopsia, and pelopsia being the most frequently reported types.


Subject(s)
Hallucinations , Illusions , Parkinson Disease , Humans , Parkinson Disease/complications , Parkinson Disease/physiopathology , Parkinson Disease/psychology , Parkinson Disease/epidemiology , Hallucinations/epidemiology , Hallucinations/etiology , Female , Male , Lithuania/epidemiology , Aged , Prospective Studies , Illusions/physiology , Illusions/psychology , Middle Aged , Pilot Projects , Prevalence , Surveys and Questionnaires
10.
Proc Natl Acad Sci U S A ; 121(17): e2400086121, 2024 Apr 23.
Article in English | MEDLINE | ID: mdl-38621132

ABSTRACT

Vision can provide useful cues about the geometric properties of an object, like its size, distance, pose, and shape. But how the brain merges these properties into a complete sensory representation of a three-dimensional object is poorly understood. To address this gap, we investigated a visual illusion in which humans misperceive the shape of an object due to a small change in one eye's retinal image. We first show that this illusion affects percepts of a highly familiar object under completely natural viewing conditions. Specifically, people perceived their own rectangular mobile phone to have a trapezoidal shape. We then investigate the perceptual underpinnings of this illusion by asking people to report both the perceived shape and pose of controlled stimuli. Our results suggest that the shape illusion results from distorted cues to object pose. In addition to yielding insights into object perception, this work informs our understanding of how the brain combines information from multiple visual cues in natural settings. The shape illusion can occur when people wear everyday prescription spectacles; thus, these findings also provide insight into the cue combination challenges that some spectacle wearers experience on a regular basis.


Subject(s)
Illusions , Humans , Brain , Cues
11.
Rev Clin Esp (Barc) ; 224(5): 334-335, 2024 May.
Article in English | MEDLINE | ID: mdl-38582349

Subject(s)
Illusions , Humans
12.
Article in English | MEDLINE | ID: mdl-38656862

ABSTRACT

Illusory directional sensations are generated through asymmetric vibrations applied to the fingertips and have been utilized to induce upper-limb motions in the rehabilitation and training of patients with visual impairment. However, its effects on motor control remain unclear. This study aimed to verify the effects of illusory directional sensations on wrist motion. We conducted objective and subjective evaluations of wrist motion during a motor task, while inducing an illusory directional sensation that was congruent or incongruent with wrist motion. We found that, when motion and illusory directional sensations were congruent, the sense of agency for motion decreased. This indicates an induction sensation of the hand being moved by the illusion. Interestingly, although no physical force was applied to the hand, the angular velocity of the wrist was higher in the congruent condition than that in the no-stimulation condition. The angular velocity of the wrist and electromyography signals of the agonist muscles were weakly positively correlated, suggesting that the participants may have increased their wrist velocity. In other words, the congruence between the direction of motion and illusory directional sensation induced the sensation of the hand being moved, even though the participants' wrist-motion velocity increased. This phenomenon can be explained by the discrepancy between the sensation of active motion predicted by the efferent copy, and that of actual motion caused by the addition of the illusion. The findings of this study can guide the design of novel rehabilitation methods.


Subject(s)
Electromyography , Illusions , Movement , Vibration , Wrist , Humans , Illusions/physiology , Male , Female , Wrist/physiology , Young Adult , Adult , Movement/physiology , Hand/physiology , Healthy Volunteers , Motion , Proprioception/physiology , Muscle, Skeletal/physiology , Motion Perception/physiology , Psychomotor Performance/physiology , Sensation/physiology
13.
Curr Biol ; 34(8): 1801-1809.e4, 2024 04 22.
Article in English | MEDLINE | ID: mdl-38569544

ABSTRACT

Neural oscillations reflect fluctuations in the relative excitation/inhibition of neural systems1,2,3,4,5 and are theorized to play a critical role in canonical neural computations6,7,8,9 and cognitive processes.10,11,12,13,14 These theories have been supported by findings that detection of visual stimuli fluctuates with the phase of oscillations prior to stimulus onset.15,16,17,18,19,20,21,22,23 However, null results have emerged in studies seeking to demonstrate these effects in visual discrimination tasks,24,25,26,27 raising questions about the generalizability of these phenomena to wider neural processes. Recently, we suggested that methodological limitations may mask effects of phase in higher-level sensory processing.28 To test the generality of phasic influences on perception requires a task that involves stimulus discrimination while also depending on early sensory processing. Here, we examined the influence of oscillation phase on the visual tilt illusion, in which a center grating has its perceived orientation biased away from the orientation of a surround grating29 due to lateral inhibitory interactions in early visual processing.30,31,32 We presented center gratings at participants' subjective vertical angle and had participants report whether the grating appeared tilted clockwise or counterclockwise from vertical on each trial while measuring their brain activity with electroencephalography (EEG). In addition to effects of alpha power and aperiodic slope, we observed robust associations between orientation perception and alpha and theta phase, consistent with fluctuating illusion magnitude across the oscillatory cycle. These results confirm that oscillation phase affects the complex processing involved in stimulus discrimination, consistent with its purported role in canonical computations that underpin cognition.


Subject(s)
Visual Perception , Humans , Male , Adult , Female , Visual Perception/physiology , Young Adult , Illusions/physiology , Photic Stimulation , Electroencephalography , Discrimination, Psychological/physiology
14.
Vision Res ; 220: 108399, 2024 07.
Article in English | MEDLINE | ID: mdl-38603924

ABSTRACT

When a novel stimulus (oddball) appears after repeated presentation of an identical stimulus, the oddball is perceived to last longer than the repeated stimuli, a phenomenon known as the oddball effect. We investigated whether the perceptual or physical differences between the repeated and oddball stimuli are more important for the oddball effect. To manipulate the perceptual difference while keeping their physical visual features constant, we used the Thatcher illusion, in which an inversion of a face hinders recognition of distortion in its facial features. We found that the Thatcherized face presented after repeated presentation of an intact face induced a stronger oddball effect when the faces were upright than when they were inverted (Experiment 1). However, the difference in the oddball effect between face orientations was not observed when the intact face was presented as the oddball after repeated presentation of a Thatcherized face (Experiment 2). These results were replicated when participants performed both the intact-repeated and Thatcherized-repeated conditions in a single experiment (Experiment 3). Two control experiments confirmed that the repeated presentation of the preceding stimuli is necessary for the difference in duration distortion to occur (Experiments 4 and 5). The results suggest the considerable role of perceptual processing in the oddball effect. We discuss the discrepancy in the results between the intact-repeated and Thatcherized-repeated conditions in terms of predictive coding.


Subject(s)
Facial Recognition , Photic Stimulation , Humans , Female , Male , Young Adult , Adult , Photic Stimulation/methods , Facial Recognition/physiology , Illusions/physiology , Analysis of Variance , Pattern Recognition, Visual/physiology , Visual Perception/physiology
15.
J Health Commun ; 29(5): 327-339, 2024 May 03.
Article in English | MEDLINE | ID: mdl-38597612

ABSTRACT

Social media have become fundamental platforms for learning about health, including reproductive health knowledge. However, little is known about what specific user activity is conducive to learning about reproductive health and by what means. Drawing upon the cognitive mediation model, this study examines how different social media activities function in terms of elaboration and knowledge gain. Our hypothesized model was largely supported by a nationwide online survey with 1,000 Chinese women residing in both rural and urban areas. The results revealed the crucial role of information elaboration in bridging different social media activities with both subjective and factual reproductive health knowledge. Interestingly, public reposting of reproductive health information was found to be positively related to subjective knowledge but negatively related to factual knowledge, suggesting the emergence of an illusion of knowing among our participants. Multigroup SEM analyses revealed that the positive roles of scanning and private sharing in encouraging elaboration were more pronounced among users with lower levels of need for cognition. The findings are expected to contribute to a more nuanced understanding of health learning based on users' social media activities and intrinsic motivations for learning.


Subject(s)
Health Knowledge, Attitudes, Practice , Learning , Reproductive Health , Social Media , Humans , Female , Social Media/statistics & numerical data , Adult , Young Adult , Middle Aged , China , Surveys and Questionnaires , Adolescent , Illusions , Rural Population/statistics & numerical data
16.
Exp Brain Res ; 242(6): 1455-1467, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38676725

ABSTRACT

We explored how body movements influence illusory body motion intensity and their association with motion sickness. Twelve individuals who were seated in the back of a passenger car, performed a visual task and were subjected to continuous rotations followed by driving in a straight line. The body movements during and immediately after rotation were categorized as follows: (A) upright posture; (B) leaning the body in the yaw direction towards the rotation center, returning the yaw angle to zero upon transitioning to straight line travel, and tilting in the roll condition and gradually returning to upright; and (C) tilting in roll conditions towards the centripetal direction during rotation and becoming upright upon transitioning to straight line travel. In experiment-1, after spanning half a lap, participants reported the intensity of the illusory motion experienced during straight line travel immediately after rotation. In experiment-2, after travelling up to eight laps, the participants reported the symptom level of motion sickness experienced during two straight sections per lap using the MIsery SCale (MISC). Experiment-1 revealed that condition (C) had significantly larger illusions than Conditions (A) and (B). Experiment-2 revealed that motion sickness progressed significantly more in Condition (C) than in Condition (A). A significant positive correlation was found between the observed MISC and the illusion strength. Our findings suggest that body movements during and immediately after continuous rotation have a significant impact on the illusion strength. Additionally, illusory motion could serve as an indicator of impending motion sickness.


Subject(s)
Illusions , Motion Perception , Motion Sickness , Humans , Motion Sickness/physiopathology , Male , Female , Rotation , Adult , Illusions/physiology , Young Adult , Motion Perception/physiology , Movement/physiology , Automobile Driving , Posture/physiology
17.
Eur J Neurosci ; 59(11): 2979-2994, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38570828

ABSTRACT

Differences between autistic and non-autistic individuals in perception of the temporal relationships between sights and sounds are theorized to underlie difficulties in integrating relevant sensory information. These, in turn, are thought to contribute to problems with speech perception and higher level social behaviour. However, the literature establishing this connection often involves limited sample sizes and focuses almost entirely on children. To determine whether these differences persist into adulthood, we compared 496 autistic and 373 non-autistic adults (aged 17 to 75 years). Participants completed an online version of the McGurk/MacDonald paradigm, a multisensory illusion indicative of the ability to integrate audiovisual speech stimuli. Audiovisual asynchrony was manipulated, and participants responded both to the syllable they perceived (revealing their susceptibility to the illusion) and to whether or not the audio and video were synchronized (allowing insight into temporal processing). In contrast with prior research with smaller, younger samples, we detected no evidence of impaired temporal or multisensory processing in autistic adults. Instead, we found that in both groups, multisensory integration correlated strongly with age. This contradicts prior presumptions that differences in multisensory perception persist and even increase in magnitude over the lifespan of autistic individuals. It also suggests that the compensatory role multisensory integration may play as the individual senses decline with age is intact. These findings challenge existing theories and provide an optimistic perspective on autistic development. They also underline the importance of expanding autism research to better reflect the age range of the autistic population.


Subject(s)
Speech Perception , Visual Perception , Humans , Adult , Middle Aged , Male , Female , Adolescent , Aged , Speech Perception/physiology , Young Adult , Visual Perception/physiology , Autistic Disorder/physiopathology , Autistic Disorder/psychology , Acoustic Stimulation/methods , Photic Stimulation/methods , Illusions/physiology , Age Factors , Auditory Perception/physiology
18.
Conscious Cogn ; 121: 103684, 2024 05.
Article in English | MEDLINE | ID: mdl-38613994

ABSTRACT

To what degree human cognition is influenced by subliminal stimuli is a controversial empirical question. One striking example was reported by Linser and Goschke (2007): participants overestimated how much control they had over objectively uncontrollable stimuli when masked congruent primes were presented immediately before the action. Critically, however, unawareness of the masked primes was established by post hoc data selection. In our preregistered study we sought to explore these findings while adjusting prime visibility based on individual thresholds, so that each participant underwent both visible and non-visible conditions. In experiment 1, N = 39 participants engaged in a control judgement task: following the presentation of a semantic prime, they freely selected between two keys, which triggered the appearance of a colored circle. The color of the circles, however, was independent of the key-press. Subsequently, participants assessed their perceived control over the circle's color, based on their key-presses, via a rating scale that ranged from 0 % (no control) to 100 % (complete control). Contrary to Linser and Goschke (2007)'s findings, this experiment demonstrated that predictive information influenced the experience of agency only when primes were consciously processed. In experiment 2, utilizing symbolic (arrow) primes, N = 35 participants had to rate their feeling of control over the effect-stimulus' identity during a two-choice identification paradigm (i.e., they were instructed to press a key corresponding to a target stimulus; with a contingency between target and effect stimulus of 75 %/25 %). The results revealed no significant influence of subliminal priming on agency perceptions. In summary, this study implies that unconscious stimuli may not exert a substantial influence on the conscious experience of agency, underscoring the need for careful consideration of methodological aspects and experimental design's impact on observed phenomena.


Subject(s)
Unconscious, Psychology , Humans , Female , Male , Adult , Young Adult , Subliminal Stimulation , Perceptual Masking/physiology , Repetition Priming/physiology , Illusions/physiology , Psychomotor Performance/physiology , Adolescent , Awareness/physiology
19.
Am J Psychoanal ; 84(1): 94-110, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38454110

ABSTRACT

This article focuses on the prevailing aspiration to reach a "good-enough ending" in analysis, a concept that is partly realistic and partly illusional. I discuss some of the obstacles that interfere with achieving this yearned for goal, and lead to endings that are far from the misleading illusion of the good-enough termination, that many of us believe we have achieved and are many more than it is commonly reported. I describe characteristics, obstacles, blockages, dreads within the analysand, within the analyst and in the space in between, which lead to endings which are far from good enough, by any criteria we might choose. These obstacles include the failure to distinguish between "real" versus "similar to"; emotional excess; emptying out of internal resources and toxemia of therapy/analysis; a fascination with certain levels of mind versus a neglect of others; osmotic pressure for oneness and the terror of perfection; and malignant nostalgia. Reflecting on such complex facets in the analytic process is relevant not only for a deeper understanding of illusions that we and our analysands hold with regard to endings, but also, implicitly, to the understanding of illusions, beliefs, and myths we and our patients have regarding beginnings.


Subject(s)
Illusions , Psychoanalytic Therapy , Humans , Emotions
20.
Proc Natl Acad Sci U S A ; 121(12): e2315758121, 2024 Mar 19.
Article in English | MEDLINE | ID: mdl-38489383

ABSTRACT

Grid cells in the entorhinal cortex (EC) encode an individual's location in space, integrating both environmental and multisensory bodily cues. Notably, body-derived signals are also primary signals for the sense of self. While studies have demonstrated that continuous application of visuo-tactile bodily stimuli can induce perceptual shifts in self-location, it remains unexplored whether these illusory changes suffice to trigger grid cell-like representation (GCLR) within the EC, and how this compares to GCLR during conventional virtual navigation. To address this, we systematically induced illusory drifts in self-location toward controlled directions using visuo-tactile bodily stimulation, while maintaining the subjects' visual viewpoint fixed (absent conventional virtual navigation). Subsequently, we evaluated the corresponding GCLR in the EC through functional MRI analysis. Our results reveal that illusory changes in perceived self-location (independent of changes in environmental navigation cues) can indeed evoke entorhinal GCLR, correlating in strength with the magnitude of perceived self-location, and characterized by similar grid orientation as during conventional virtual navigation in the same virtual room. These data demonstrate that the same grid-like representation is recruited when navigating based on environmental, mainly visual cues, or when experiencing illusory forward drifts in self-location, driven by perceptual multisensory bodily cues.


Subject(s)
Grid Cells , Illusions , Spatial Navigation , Humans , Entorhinal Cortex/physiology , Grid Cells/physiology , Consciousness , Illusions/physiology , Touch , Spatial Navigation/physiology
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