Altered Time Perception Research Articles

Disrupted Time Perception Underlies Motivational Disturbances in Huntington’s Disease

Abstract Our sense of time is fundamental to interacting with the world in a goal-directed manner, with decisions underpinning goal pursuit utilising timing circuits in the seconds-to-minutes range. A reduction in goal-directed behaviour — apathy — is common in Huntington’s disease (HD), but no work has examined whether altered time perception could be a contributing mechanism. We investigated whether timing deficits were evident in HD apathy. Genetically confirmed carriers of the HD mutation (premanifest to mild manifest disease, n = 39) and healthy controls (n = 20) performed a time production task with active (press) and passive (wait) modes of production, alongside clinical and behavioural measures. Overall, people with HD underproduced target times whilst controls performed in near-optimal manner. In HD, there were significant interactions between condition (press/wait) and both apathy and impulsivity (apathy × condition: t = −3.8, p = 0.0002; impulsivity × condition: t = −3.3, p = 0.001). This was driven by people with either of these behavioural disturbances producing shorter times in the passive condition, relative to people without these behaviours. Whilst global timing deficits were evident in HD, further differences were evident as a function of apathy and impulsivity, whereby people thought more time had passed than really had, specifically when passively waiting. Altered time perception when passively waiting may alter estimation of environmental reward rates and subsequent decisions of when to act. Overall, and demonstrated in human neurological disease, we show that timing processes and motivated behaviours are fundamentally linked.

Phenomenological memory characteristics and impact of near-death experience in critically ill survivors: Observations at discharge and after a 1-year follow-up

BackgroundIt is not rare that intensive care unit (ICU) patients report unusual subjective experiences, ranging from a feeling of harmony with the environment to complex phenomena such as near-death experience (NDE). This 1-year follow-up study investigates the characteristics and potential global impact of the NDE memories recalled by ICU survivors. MethodWe prospectively enrolled 126 adult survivors of a prolonged (>7days) ICU stay (all etiologies), including 19 (15 %) who reported a NDE as identified by the Greyson NDE scale. The NDE group underwent a semi-structured interview one month later evaluating their memory characteristics and the associated life-threatening situation. One year after inclusion, all patients (regardless of whether they recalled an NDE) were contacted for a follow-up Greyson NDE scale assessment and questions about their ICU experience and opinions on death since discharge. ResultsThe Greyson NDE scale revealed that the most frequently reported features were altered time perception, heightened senses and life review, and the Greyson total scores did not evolve over time. NDE memories persisted, with a consequent number of phenomenological characteristics (e.g., visual details, emotions). One year post-ICU, two patients (18 %) of the NDE group and 12 (24 %) of the non-NDE group were less afraid of death. ConclusionsResults emphasize the clinical importance of interviewing all ICU patients to explore any memory after an ICU stay.

Trends in cannabis consumption: psychotic and anxiety symptoms among users

IntroductionDuring cannabis use, some individuals may experience psychotic symptoms, such as unusual perceptions or irrational thoughts, including mild hallucinations or temporary paranoia. Anxiety is also common, characterized by excessive worry or intense fear. The occurrence of these symptoms varies based on cannabis quantity, individual sensitivity, and surroundings. Although not all users experience these effects, the link between cannabis and psychotic or anxiety symptoms highlights the need for a thorough risk assessment.ObjectivesOur goal is to analyze trends in cannabis use, as well as the psychotic and anxiety symptoms experienced by users, and to examine whether cannabis use is associated with other substances consumption.MethodsWe collected demographic and substance consumption data from two groups: 29 individuals aged 18 to 28 who had tried cannabis at least once and 19 regular consumers through a structured questionnaire.ResultsRegular cannabis consumers had a higher proportion of males than those who had tried it once (X²(1)=4.81; p=0.028). There were no significant differences in age, alcohol or tobacco consumption between the groups. Notably, regular cannabis consumers had a history of using other illegal drugs, both in the past and within the last month (X²(1)=8.53; p=0.003). Regarding cannabis effects, regular users more frequently reported sensations like euphoria, relaxation, altered time perception, tachycardia, motor coordination difficulties, and impaired clear thinking compared to one-time users (X²(1)=10.12; p=0.001). Regarding anxiety symptoms during cannabis consumption, both groups experienced a similar frequency. Finally, regular cannabis consumers reported strange ideas or perceptions more often than one-time users (X²(1)=0.743; p=0.019). However, the associated discomfort level was similar in both groups.ConclusionsThis study highlights that regular cannabis use is associated with a greater likelihood of using other substances and experiencing more pronounced effects, including psychotic symptoms. However, it doesn’t necessarily lead to increased anxiety symptoms compared to one-time users. It’s important to acknowledge that the relationship between cannabis and psychosis is intricate and influenced by factors like consumption quantity and individual sensitivity. These findings stress the importance of understanding cannabis’s impact on mental health and its connection to the use of other substances.Disclosure of InterestNone Declared

Brain mechanisms of temporal processing in impulsivity: Relevance to attention-deficit hyperactivity disorder.

In this article, we critique the hypothesis that different varieties of impulsivity, including impulsiveness present in attention-deficit hyperactivity disorder, encompass an accelerated perception of time. This conceptualisation provides insights into how individuals with attention-deficit hyperactivity disorder have the capacity to maximise cognitive capabilities by more closely aligning themselves with appropriate environmental contexts (e.g. fast paced tasks that prevent boredom). We discuss the evidence for altered time perception in attention-deficit hyperactivity disorder alongside putative underlying neurobiological substrates, including a distributed brain network mediating time perception over multiple timescales. In particular, we explore the importance of temporal representations across the brain for time perception and symptom manifestation in attention-deficit hyperactivity disorder, including a prominent role of the hippocampus and other temporal lobe regions. We also reflect on how abnormalities in the perception of time may be relevant for understanding the aetiology of attention-deficit hyperactivity disorder and mechanism of action of existing medications.

Frequency of Narcissistic Personality Disorder in Cannabis Consumer Engineering Students

IntroductionCannabis is the most widely used illicit drug, particularly by those in their adolescence to mid-adulthood. Its effects include altered time perception, decreased concentration, and learning impairment, as well as feelings of relaxation and euphoria. This study seeks to explore the possible correlation between cannabis use and the manifestation of narcissistic personality disorder. By identifying such a relationship, early detection, and treatment of patients with this disorder may prevent future substance abuse. MethodsIn this descriptive-cross-sectional study, a sample of 100 engineering students who were cannabis consumers at (Shahid Beheshti University in Tehran) was selected using snowball sampling. After confirming cannabis use and selecting individuals based on DSM-5 criteria, their status was described, and the NPI-16 questionnaire was administered to investigate narcissistic personality disorder. The frequency of narcissistic personality disorder and its association with demographic parameters were then statistically analyzed. ResultsBased on the results obtained in the present study, the prevalence of individuals with narcissistic personality disorder was estimated to be 15%, which is higher than the general population with a prevalence of around 2%. The frequency of cannabis use was higher in men, high school graduates, and in the age range of 24–25. Additionally, in individuals with narcissistic personality disorder, the frequency of men, high school graduates, age 24, and those residing in (XXX) was higher. ConclusionsThis study suggests that cannabis consumption may be linked to a higher incidence of narcissistic personality disorder compared to the general population. Given the potential impact on young people's mental health, particularly students, it is crucial to identify individuals who may be affected and offer appropriate therapeutic and counseling services. As there are existing treatments available for substance abuse and narcissistic personality disorder, taking proactive measures to address these issues can be crucial in mitigating their effects.

Autonomic nervous system modulation during self-induced non-ordinary states of consciousness

Self-induced cognitive trance (SICT) is a voluntary non-ordinary state of consciousness characterized by a lucid yet narrowed awareness of the external surroundings. It involves a hyper-focused immersive experience of flow, expanded inner imagery, modified somatosensory processing, and an altered perception of self and time. SICT is gaining attention due to its potential clinical applications. Similar states of non-ordinary state of consciousness, such as meditation, hypnosis, and psychedelic experiences, have been reported to induce changes in the autonomic nervous system. However, the functioning of the autonomic nervous system during SICT remains poorly understood. In this study, we aimed to investigate the impact of SICT on the cardiac and respiratory signals of 25 participants proficient in SICT. To accomplish this, we measured various metrics of heart rate variability (HRV) and respiration rate variability (RRV) in three conditions: resting state, SICT, and a mental imagery task. Subsequently, we employed a machine learning framework utilizing a linear discriminant analysis classifier and a cross-validation scheme to identify the features that exhibited the best discrimination between these three conditions. The results revealed that during SICT, participants experienced an increased heart rate and a decreased level of high-frequency (HF) HRV compared to the control conditions. Additionally, specific increases in respiratory amplitude, phase ratio, and RRV were observed during SICT in comparison to the other conditions. These findings suggest that SICT is associated with a reduction in parasympathetic activity, indicative of a hyperarousal state of the autonomic nervous system during SICT.

3-2-1, action! A combined motor control-temporal reproduction task shows intentions, motions, and consequences alter time perception

3-2-1, action! A combined motor control-temporal reproduction task shows intentions, motions, and consequences alter time perception

State and trait dissociation in pathological skin picking

Dissociative experiences like trance or depersonalization may play a prominent role in pathological skin picking (PSP). However, trait and state dissociation and their relation to skin picking have hardly been studied in those with PSP. By means of an anonymous online survey, we recruited 323 adults with PSP defined by Skin Picking Scale-Revised (SPS-R) scores ≥ 7 as well as Skin Picking Impact Scale (SPIS) scores ≥ 7. Participants were administered the Dissociative Experiences Scale-Taxon (DES-T) to determine trait dissociation as well as the modified Peritraumatic Dissociative Experiences Questionnaire (PDEQ) to assess state dissociation during a typical episode of PSP. Sixty-three participants (19.5%) were assigned to the pathological dissociative taxon, that is, were high in trait dissociation. State dissociation during episodes of skin picking was reported by 221 individuals (68.4%) with the feeling of being on “automatic pilot” (49.6%) and alterations in time perception (33.1%) being the most frequent phenomena. Both trait and state dissociation were significantly associated with skin picking-related impairment, but effect sizes were small. Dissociation conceived as trait and state might be an important psychopathological dimension in skin picking. Its systematic detection and recognition may hold therapeutic implications as dissociation is a negative predictor of treatment outcome.

Time perception in astronauts on board the International Space Station

We perceive the environment through an elaborate mental representation based on a constant integration of sensory inputs, knowledge, and expectations. Previous studies of astronauts on board the International Space Station have shown that the mental representation of space, such as the perception of object size, distance, and depth, is altered in orbit. Because the mental representations of space and time have some overlap in neural networks, we hypothesized that perception of time would also be affected by spaceflight. Ten astronauts were tested before, during, and after a 6–8-month spaceflight. Temporal tasks included judging when one minute had passed and how long it had been since the start of the workday, lunch, docking of a vehicle, and a spacewalk. Compared to pre-flight estimates, there is a relative overestimation for the 1-min interval during the flight and a relative underestimation of intervals of hours in duration. However, the astronauts quite accurately estimated the number of days since vehicle dockings and spacewalks. Prolonged isolation in confined areas, stress related to workload, and high-performance expectations are potential factors contributing to altered time perception of daily events. However, reduced vestibular stimulations and slower motions in weightlessness, as well as constant references to their timeline and work schedule could also account for the change in the estimation of time by the astronauts in space.

The Silence Is Deafening: Commentary on an article by Stephanie A. Kwan, DO, et al.: "Risk of Noise-Induced Hearing Loss for Orthopaedic Surgeons".

Commentary In his book Flow: The Psychology of Optimal Experience1, Mihaly Csikszentmihalyi described a state of mind that the surgeon achieves while in the operating room. He described the state of flow as an “order of awareness” that allows the person to be able to concentrate entirely on the task at hand—which for surgeons is the operative field. There are 8 elements that define the flow state. Three of these are a high level of concentration on a limited field, an altered perception of time, and a melding of action and consciousness during which there is no room for distraction. In the flow state, there is likely a disregard for the noise level in the operating room, yet the time and dose of the sound remain present and affect our sensory organs. In this eye-opening (or ear-closing) analysis of background noise in the operating room, the authors assess the noise doses endured by surgeons in the operating room, which have rarely been analyzed heretofore. This analysis gives us pause as to how we are exposing ourselves, our highly skilled teams, and our patients to a potentially damaging level and sustained dose of sound during the operating day. So many sounds—some obvious, some not so obvious—have been assessed by the authors during some 300 recordings in attempt to quantify both baseline preoperative, maximum operative, and projected mean surgical noise levels. A total dose of sound was described as the time-weighted average of decibels. The authors compare these values to known sound exposure levels that are considered by occupational health experts to be detrimental to hearing health. I thank the authors for their first pass at gathering data to start the discussion and research necessary to make our operating rooms safer for surgeons. More and more bells and whistles, powered equipment, blowers, pumps, beeps, and chirps have crowded the sound space of the operating room, possibly to the detriment of its inhabitants. Further study is necessary that utilizes the defined measurements introduced by the authors. There is hope; electrically powered drills and burrs are quieter than nitrogen-powered turbines. Anesthesia machines are becoming smaller and quieter. Hopefully we surgeons can enjoy some peacefulness outside of the flow state.

From anticipation to impulsivity in Parkinson’s disease

Anticipatory actions require to keep track of elapsed time and inhibitory control. These cognitive functions could be impacted in Parkinson’s disease (iPD). To test this hypothesis, a saccadic reaction time task was used where a visual warning stimulus (WS) predicted the occurrence of an imperative one (IS) appearing after a short delay. In the implicit condition, subjects were not informed about the duration of the delay, disfavoring anticipatory behavior but leaving inhibitory control unaltered. In the explicit condition, delay duration was cued. This should favor anticipatory behavior and perhaps alter inhibitory control. This hypothesis was tested in controls (N = 18) and age-matched iPD patients (N = 20; ON and OFF L-DOPA). We found that the latency distribution of saccades before the IS was bimodal. The 1st mode weakly depended on temporal information and was more prominent in iPD. Saccades in this mode were premature and could result of a lack of inhibition. The 2nd mode covaried with cued duration suggesting that these movements were genuine anticipatory saccades. The explicit condition increased the probability of anticipatory saccades before the IS in controls and iPDON but not iPDOFF patients. Furthermore, in iPD patients the probability of sequences of 1st mode premature responses increased. In conclusion, the triggering of a premature saccade or the initiation of a controlled anticipatory one could be conceptualized as the output of two independent stochastic processes. Altered time perception and increased motor impulsivity could alter the balance between these two processes in favor of the latter in iPD, particularly OFF L-Dopa.

Distorted time perception in patients with transient global amnesia: time perception task and imaging analysis.

Transient global amnesia (TGA) is defined as a sudden and transient episode of memory loss and accompanied by temporal disorientation. However, the mechanism by which time distortion occurs is not clearly elucidated yet. Between March 2019 and November 2020, we subjected 30 TGA patients to several time perception tasks and analyzed their magnetic resonance image (MRI) scans and compared the results with age- and sex-matched control group. Among the 60 recruited subjects (64.5 ± 6.3years), 70% were women. Fourteen patients had only anterograde amnesia. Furthermore, 46% of the patients with TGA (n = 14) had a history of Valsalva maneuver, and 70% of the patients (n = 21) had a pre-attack stress factor. The MRI scans of 14 patients (46.67%) showed hippocampal hyperintensity. With regard to the time production task, patients with TGA exhibited shorter times in all trials compared with their counterparts (5s, 4.90 ± 1.16 vs. 5.53 ± 0.87; p value = 0.02: 15s, 12.18 ± 4.55 vs. 14.42 ± 2.54; p value = 0.021). For the time comparison task, the number of correct answers given by patients with TGA was significantly lesser than that given by the control group (6.07 ± 1.23 vs. 6.90 ± 1.24; p value = 0.006). This is the first study to invesgating an altered time perception in patients with TGA. Although the exact neurophysiological mechanism remains unclear, our findings could aid in the elucidation of brain function across specific time frames.

Provider Perception of Time During Trauma Resuscitation: A Prospective Quantitative Trauma Video Review Analysis.

Delays in transition to the next phase of care result in increased mortality. Prehospital literature suggests emergency medical service technicians underestimate transport times by as much as 20%. What remains unknown is clinician perception of time during the trauma resuscitation. We sought to determine if clinicians have an altered perception of time. We hypothesized that clinicians underestimate time, resulting in delay of care. Clinicians at a large level 1 trauma center completed a post-trauma activation survey on the perceived elapsed time to complete three specific resuscitation endpoints. The primary study endpoint was the time to the next phase of care, defined as leaving the trauma bay to go to the operating room, interventional radiology, computerized tomography or time of death. The data from the surveys were linked and compared with recorded videos of the resuscitations. The difference in perceived versus actual time, along with confounding variables, was used to assess the impact of perception of time on the time to the next phase of care using a stepwise multivariate linear model. There were 284 complete surveys and videos, culminating in 543 time points. The median perceived versus actual time (minutes [interquartile range]) to the next phase of care was 20 [10-25] versus 26 [19-40] (P<0.001). Overall, clinicians underestimated time by 28%, such that if the resuscitation lasted 20min, the clinician's perception was that 14.4min elapsed. Differences in the perceived versus actual time in the procedure group impacted time to the next phase of care (P=0.01). Clinicians have significant gaps in the perception of time during trauma resuscitations. This misperception occurs during procedures and correlates with an increase in the length of time to the next phase of care.

Examining the underlying structure of after-class boredom experienced by English majors

Learning a second and/or a foreign language (L2) is accompanied by both positive and negative emotions which influence the quality, dynamics and efficiency of this process. One of the achievement emotions that has only recently been recognized by second language acquisition (SLA) researchers as an important individual difference (ID) factor is boredom. The study reported in this paper aimed to identify factors constituting the structure of after-class boredom, a negative emotion that learners experience in out-of-class situations, whether completing tasks and activities assigned by the teacher or such that they choose of their own accord. It was also intended to examine the extent to which the intensity of boredom is affected by general boredom proneness and attainment, and to develop and validate a domain-specific scale tapping into this negative experience in after-class contexts. The study involved 107 English majors in Poland who filled out the Boredom in Learning English Outside of School Questionnaire (BLEOS). Using the Boredom Proneness Scale (BPS) and end-of-the-year examination grades, participants were divided into more and less susceptible to boredom as well as into high- and low-achievers. Exploratory factor analysis allowed extraction of three factors underlying after-class boredom: (F1) unwillingness to learn English and inability to find (interesting) tasks, (F2) lack of creativity, focus and involvement and (F3) altered time perception, underused language abilities and monotony. Statistically significant differences were detected between more and less boredom-prone students for all three factors.

Adrift in time: the subjective experience of circadian challenge during COVID-19 amongst people with mood disorders

ABSTRACT Social distancing/lockdown policies during the coronavirus (COVID-19) pandemic may alter social rhythms of people through imposition of restrictions on normal daily activities. This may in turn challenge circadian function, particularly in people with mood disorders. Although objective data describing the relationship between circadian disturbances and mood disorders exist, data regarding the subjective experience of circadian challenge is sparse, and its association with mood symptoms is unclear. The present qualitative study was one component of a mixed-methods multi-national project, which took advantage of widespread disruption to daily routines due to Government COVID-related lockdowns during 2020. The Behavior Emotion and Timing during COVID-19 (BEATCOVID) survey study included three open questions generating qualitative data on participants’ subjective experience of social disruption due to social distancing/lockdown policies, two of which asked about the barriers and opportunities for stabilizing routines. Responses were coded and analyzed using Thematic Analysis. A total of N = 997 participants responded to at least one of the free-text questions. Four themes were identified: 1) loss of daily timed activities, 2) role of social interaction, 3) altered time perception and 4) disruption to motivation and associated psychological effects. Themes were organized into a provisional heuristic map, generating hypotheses for future research centered on the new concept of ‘psychological drift.’

Is the scalar property of interval timing preserved after hippocampus lesions?

Time perception is fundamental for decision-making, adaptation, and survival. In the peak-interval (PI) paradigm, one of the critical features of time perception is its scale invariance, i.e., the error in time estimation increases linearly with the to-be-timed interval. Brain lesions can profoundly alter time perception, but do they also change its scalar property? In particular, hippocampus (HPC) lesions affect the memory of the reinforced durations. Experiments found that ventral hippocampus (vHPC) lesions shift the perceived durations to longer values while dorsal hippocampus (dHPC) lesions produce opposite effects. Here we used our implementation of the Striatal Beat Frequency (SBFML) model with biophysically realistic Morris-Lecar (ML) model neurons and a topological map of HPC memory to predict analytically and verify numerically the effect of HPC lesions on scalar property. We found that scalar property still holds after both vHPC and dHPC lesions in our SBFML-HPC network simulation. Our numerical results show that PI durations are shifted in the correct direction and match the experimental results. In our simulations, the relative peak shift of the behavioral response curve is controlled by two factors: (1) the lesion size, and (2) the cellular-level memory variance of the temporal durations stored in the HPC. The coefficient of variance (CV) of the behavioral response curve remained constant over the tested durations of PI procedure, which suggests that scalar property is not affected by HPC lesions.

Visual continuity during blinks and alterations in time perception.

Eye blinks strongly attenuate visual input, yet we perceive the world as continuous. How this visual continuity is achieved remains a fundamental and unsolved problem. A decrease in luminance sensitivity has been proposed as a mechanism but is insufficient to mask the even larger decrease in luminance because of blinks. Here we put forward a different hypothesis: visual continuity can be achieved through shortening of perceived durations of the sensory consequences of blinks. Here we probed the perceived durations of the blackouts caused by blinks and visual stimuli interrupted by blinks. We found that the perceived durations of blackouts because of blinks are about half as long as artificial blackouts immediately preceding or following the blink. Stimuli interrupted by blinks were perceived as briefer than uninterrupted stimuli, by about the same duration as the interruption-but so were stimuli interrupted by optically simulated blinks. There was a difference between real and simulated blinks, however: The decrease in perceived duration depended on the duration of the interruption for simulated, but not for real, blinks. These profound modifications in time perception during blinks show a way in which temporal processing contributes to the solution of an essential perceptual problem. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Supplemental Material for Visual Continuity During Blinks and Alterations in Time Perception

Supplemental Material for Visual Continuity During Blinks and Alterations in Time Perception

Effect of Exercise-Related Factors on the Perception of Time.

The concept of time whether considered through the lenses of physics or physiology is a relative measure. Alterations in time perception can have serious implications in sport, fitness and work. Accurate perception of time is an important skill with many time constrained sports (i.e., basketball, North American football, tennis, gymnastics, figure skating, ice hockey, and others), and work environments (i.e., workers who need to synchronize their actions such as police and military). In addition, time distortions may play a role in exercise adherence. Individuals may be disinclined to continue with healthy, exercise activities that seem protracted (time dilation). Two predominant theories (scalar expectancy theory and striatal beat frequency model) emphasize the perception of the number of events in a period and the role of neurotransmitters in activating and coordinating cortical structures, respectively. A number of factors including age, sex, body temperature, state of health and fitness, mental concentration and exercise intensity level have been examined for their effect on time perception. However, with the importance of time perception for work, sport and exercise, there is limited research on this area. Since work, sports, and exercise can involve an integration of many of these aforementioned factors, they are interventions that need further investigations. The multiplicity of variables involved with work, sport, and exercise offer an underdeveloped but fruitful field for future research. Thus, the objective of this review was to examine physiological and psychological factors affecting human perception of time and the mechanisms underlying time perception and distortion with activity.

Time perception in childhood absence epilepsy: Findings from a pilot study

ObjectivesWith this explorative study, we aimed to examine time perception in children with childhood absence epilepsy (CAE) and to compare those children with a matched control group. The study also investigated the association between the neuropsychological performance of the group with CAE and time judgment. We hypothesize that children with CAE could fail in time perception and that this may be because of a common underlying substrate with executive impairments. MethodsThirteen children with CAE, aged 6–13 years, and 17 healthy children were recruited. All children performed the time bisection task; the children with CAE also performed a cognitive and neuropsychological assessment. We performed a univariate analysis using each parameter of the bisection task (bisection point [BP]) and Weber ratio (WR) as dependent variables, the group (patients vs. controls) as fixed factors and age at evaluation and vocabulary scores as covariates. In the subgroup of patients, we correlated bisection task parameters with neuropsychological tests using a nonparametric partial correlation; the analysis has corrected for age at evaluation. ResultsThe BP and WR measures differed between controls and patients with CAE. In the subgroup of patients also performing a neuropsychological assessment, we found a correlation between the WR measure and performance on the inhibition test (r = −0.641, p = .025), coding test (r = −0.815, p = .014), and Trail Making Test B (TMT B) (r = 0.72, p = .042). ConclusionsWe found an altered time perception in a pilot study of a small group of children with CAE. A neurophysiological mechanism underlying CAE seems to influence cognitive and behavioral deficits and time sensibility.