We studied variations of all-cause human mortality during the weekly cycle, using deathdates collected from death notices published in regional or local newspapers in three distinct regions in Germany (South Baden, North Bavaria, Saarland), total database size N ≈ 44000. Probability distributions of death on different days of the week show significant ( P = 0.0155) departures from the uniformity hypothesis. The day of maximum mortality is Friday (probability of dying = 0.148), whereas minimum mortality is observed on Sundays and Mondays (probability of dying = 0.140 for both days). This ‘Friday excess’ effect seems to be a novel phenomenon, unrelated to other findings on weekly modulation of human mortality. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study did not receive any funding. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study used only openly available human data that were originally located on websites of daily or weekly German newspapers. Access information (URLs) of these websites are provided in the References section of the present paper. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors.

Destructured sensory fields, involving homogenous stimulation with little or no time-varying structure, provide a fertile ground for testing hypotheses about predictive coding in the human brain. Extended exposure to sensory patterns that deviate substantially from the statistics of natural environments can elicit a bewildering range of perceptual phenomena, up to and including vivid oneiric imagery. We illustrate how this large variety of perceptual effects can be understood as the experiential counterpart of auto-generated neuronal dynamics, unconstrained by parameters that tune the waking sensorium. We synthesize the literature on autonomous neuronal activity across multiple spatiotemporal scales with generative models of brain function and evidence from artificial neural architectures. Perception, we argue, emerges from a process of non-random sampling from an intrinsic distribution of hypotheses rather than a direct transfer of information from the world. The imagery that occurs in altered sensory environments is explained as the outcome of an iterative search through internal world models in which the structural typology of percepts reflects the brain's intrinsic functional architectures.

•Destructured sensory fields possess inadequate informational structure.•Exposure to such fields elicits autonomously generated perceptual effects.•Anomalous sensory fields provide a testing ground for predictive coding hypotheses.

Geometric-optical illusions (GOI) are a subclass of a vast variety of visual illusions. A special class of GOIs originates from the superposition of a simple geometric figure (target) with an array of non-intersecting curvilinear elements (context) that elicits a perceptual distortion of the target element. Here we specifically deal with the case of circular targets. Starting from the fact that (half)circles are geodesics in a model of hyperbolic geometry, we conceive of the deformations of the target as resulting from a context-induced perturbation of that base geometry. We present computational methods for predicting distorted shapes of the target in different contexts, and we report the results of a psychophysical pilot experiment with eight subjects and four contexts to test the predictions. Finally, we propose a common scheme for modeling GOIs associated with more general types of target curves, subsuming those studied previously.

We report results of an acoustic duration reproduction task with stimulus duration of 2, 4, and 6 s, using 45 emotionally negative, positive, and neutral sounds from the International Affective Digitized Sounds System, in a sample of 31 young healthy participants. To investigate the influence of induced emotions on perceived duration, the effects of emotional modulation were quantified in two ways: (1) via model-free indices (aggregated ratios of reproduced times), and (2) via dual klepsydra model (dkm)-based estimates of parameters of internal time representation. Both data-analytic approaches reveal an effect of emotional valence/arousal, namely, a significantly longer reproduction response for emotional stimuli than for the neutral stimuli. The advantage of the dkm-based approach is its ability to disentangle stimulus-related effects, which are represented by "flow intensities," from general effects which are due to the lossy character of temporal integration. We explain the rationale of the dkm-based strategy and interpret the observed effect within the dkm-framework as transient increase of internal "flows." This interpretation is in line with recent conceptualizations of an "embodiment" of time where the model-posited flows correspond to the ongoing stream of interoceptive (bodily) neural signals. Neurophysiological findings on correlations between the processing of body signals and the perception of time provide cumulative evidence for this working hypothesis.

Psychology should be a positive, empirically informed science of human existence; that is, a science of human experience of and acting in the world, in their unity. Therefore, psychology has to take human experience seriously. What does it mean for “psychology of time”?

Data from three experiments on serial perception of temporal intervals in the supra-second domain are reported. Sequences of short acoustic signals (“pips”) separated by periods of silence were presented to the observers. Two types of time series, geometric or alternating, were used, where the modulus 1+δ of the inter-pip series and the base duration Tb (range from 1.1 to 6s) were varied as independent parameters. The observers had to judge whether the series were accelerating, decelerating, or uniform (3 paradigm), or to distinguish regular from irregular sequences (2 paradigm). “Intervals of subjective uniformity” (isus) were obtained by fitting Gaussian psychometric functions to individual subjects' responses. Progression towards longer base durations (Tb=4.4 or 6s) shifts the isus towards negative δs, i.e., accelerating series. This finding is compatible with the phenomenon of “subjective shortening” of past temporal intervals, which is naturally accounted for by the lossy integration model of internal time representation. The opposite effect observed for short durations (Tb=1.1 or 1.5s) remains unexplained by the lossy integration model, and presents a challenge for further research.

Preface It is pleasure and honor to host this year’s Annual Meeting of the International Society for Psychophysics, Fechner Day 2013, in Freiburg. We feel that it is a well-deserved honor for Freiburg. Indeed, in spite of its somewhat eccentric geographic location, Freiburg occupies an important place in the map of Germany’s academic and intellectual life. Freiburg University has a long record of famous names and significant contributions to scholarship and science of not only German, but truly international dimensions. Let us mention, first of all, Edmund Husserl’s phenomenology, a direction of thought that profoundly influenced European philosophy, but also adjacent fields of study such as psychology, anthropology, aesthetics, and finds a comeback in merging with cognitive science and conscious- ness studies. Freiburg has its place in the history of mathematics, with Ernst Zermelo and his significant contributions to the foundations of the set theory, and in natural sciences—e. g. in physics with Gustav Mie, known for his works in optics and fundamental theory of matter and gravitation; and in chemistry with Georg von He ve sy, the founding father of nuclear medicine. Again on the side of humanities, we should also name the late Friedrich von Hayek, who is known mostly for his economical and philosophical writings, but whose original contribution to theoretical psychology, The Sensory Order, should not remain unmentioned. Closer to and more specifically for the fields of psychophysics and sensory physiology, at least two names should be mentioned, those of Hugo Mu nsterberg and Johannes von Kries. Hugo Munsterberg (1863–1916), after his studies with Wundt in Leipzig, and then in Heidel- berg, spent four years in Freiburg before he moved (by invitation of William James) to Harvard University, USA, where he stayed until his untimely death. His Freiburg years were filled with creative research in experimental psychology and psychophysiology, as he built up his own labo- ratory which, at that time, was only the fourth experimental psychology laboratory in Germany1. If E. G. Boring named Munsterberg the “founder of applied psychology” 2, it may seem a little bit high-pitched, but not unjustly exaggerated. Johannes von Kries (1853–1928), who studied physiology and medicine at several universities in Germany and Switzerland, and spent a year with Helmholtz in Berlin, had a chair for physiology in Freiburg since 1880 for the rest of his life. He worked not only in his own fields of specialisation, muscle physiology and physiology of color vision; being a person of broad intellectual and philosophical interests, he was occupied with foundational problems of natural sciences, including theory of measurement and probability theory. On the same basis, von Kries had to become one of the most severe critics of Fechner’s concept of “measurement of sensa- tions.”3 Surely the list of illustrious names could be continued—omissions do not imply less impor- tance!—but let us turn from historical dimensions to actual present. *** Thematic diversity is a constant feature of Fechner Day conferences, and this is true for this year’s Fechner Day again. We envisage a rich program, consisting of about fifty oral and more than forty poster presentations—experimental reports, theoretical developments, and philosophi- cal or historical investigations—, authored and co-authored by no less than 160 colleagues from eighteen countries world-wide. The topics of five theme sessions range from novel treatments of traditional psychophysical problems up to recently opening fields of research. We are pleased to see contributions from the fields of applied and clinical psychophysics, and strengthening links to related disciplines of psychophysiology, neurophysiology, and cognitive neuroscience. This rich scientific program is highlighted by two invited lectures: by Professor Gunnar Borg (University of Stockholm), discussing methodological problems of measurement of subjective ex- perience, and by Professor Gary Hatfield (University of Pennsylvania), presenting philosophical perspective on sensory experience and problems of perception in general. A special symposium is dedicated to the intellectual legacy of Ernst Mach, the Austrian physi- cist, to commemorate the 175th anniversary of his birth (1838). Mach’s contributions to psycho- physics are well-known, but there is more. The aim of the symposium is not only to remember Mach’s experimental research in optics and acoustics, and his discoveries in the field of sensory physiology, but also to acknowledge his impact on philosophy of science and to evaluate his influence on other fields, such as Gestalt psychology, pedagogy, and didactics of science. *** We wish to thank all those who helped us in conceptualizing and organizing this conference: members of the Executive Committee of the ISP (p. iii) for their ideas and suggestions, and also organizers of earlier Fechner Days for sharing their experience with us. Special thanks to our assistants for their help: Oksana Gutina, Hanna Lehnen, Anna Sarikaya, and Jakob Pacer. Also, a financial donation and administrative-technical support from the Institute for Frontier Areas of Psychology and Mental Health in Freiburg are to be thankfully acknowledged. We wish all participants an interesting meeting, thought-provoking discussions, inspiring ex- change of ideas, and enjoyable social events. Welcome to Freiburg! Program committee Fechner Day 2013: Jiˇr i Wackermann, Marc Wittmann, and Wolfgang Skrandies

A subdivided path in the visual field appears longer than an empty path of the same length. This effect may be attributed to the division of the path into multiple segments, or to an influence of the visual elements used to mark the subdivision, and thus filling-up the estimated space. To address this question, we used two series of stimuli, in which the spatial distribution of the filling optical mater, or the form of the dividers, was varied while the relative coverage of the filled space was kept constant. We found significant dependence of the effect magnitude on a number of filling elements as well as on their form. These results indicate that the illusory space expansion is not merely an effect of "filling-up" the space, but it also depends on the filling pattern. Consequences of these findings for the theory of the Oppel-Kundt phenomenon are briefly discussed.

The “dual klepsydra model” (DKM) of internal time representation successfully models duration reproduction data, but relations between the DKM-based parameter κ (“loss rate”) and procedural variables (presentation modality) or individual characteristics (cognitive indices, age, sex) remained as yet unexplored. For that purpose, we re-analyzed data from an earlier time reproduction study ( N = 100), using visually or acoustically presented intervals of 1–5 sec. duration. Typical values of parameter κ were ≈0.03–0.04 sec.−1, corresponding to relaxation times of internal “lossy integrators” of ≈30 sec. Significant effects of presentation modality (smaller κ values for the visual reproduction task) and of age (greater κ in acoustic reproduction with increasing age) were observed. Cognitive variables (working memory, general fluid reasoning, attention) and sex of participants were not associated with κ. Cognitive functions seem to play only a minor, if any, role at the level of time representation addressed by the DKM.

Subjective estimates of lengths or areas in the visual field depend on the visual contents of the estimated space (filled/empty or Oppel-Kundt illusion). We studied the dependence of this phenomenon on the presentation mode (white on black vs. black on white background), and on the figure/ground contrast. We found, as expected, overestimation of the filled part of the figure for both contrast polarities. The expansion effect was found to be an increasing function of the absolute luminance contrast, and was consistently higher for the negative (luminant figures on a dark background) than for the positive polarity. The contrast factor contributes from one-fifth to one-third of the total effect. Possible interpretations in terms of known sensory phenomena (irradiation, lateral interactions) or higher, integrative functions are discussed.

BACKGROUND:Parkinson's disease (PD) patients are deficient in time estimation. This deficit improves after dopamine (DA) treatment and it has been associated with decreased internal timekeeper speed, disruption of executive function and memory retrieval dysfunction.METHODOLOGY/FINDINGS:The aim of the present study was to explore the neurophysiologic correlates of this deficit. We performed functional magnetic resonance imaging on twelve PD patients while they were performing a time reproduction task (TRT). The TRT consisted of an encoding phase (during which visual stimuli of durations from 5 s to 16.6 s, varied at 8 levels were presented) and a reproduction phase (during which interval durations were reproduced by a button pressing). Patients were scanned twice, once while on their DA medication (ON condition) and once after medication withdrawal (OFF condition). Differences in Blood-Oxygenation-Level-Dependent (BOLD) signal in ON and OFF conditions were evaluated. The time course of activation in the brain areas with different BOLD signal was plotted. There were no significant differences in the behavioral results, but a trend toward overestimation of intervals ≤11.9 s and underestimation of intervals ≥14.1 s in the OFF condition (p<0.088). During the reproduction phase, higher activation in the precuneus was found in the ON condition (p<0.05 corrected). Time course was plotted separately for long (≥14.1 s) and short (≤11.9 s) intervals. Results showed that there was a significant difference only in long intervals, when activity gradually decreased in the OFF, but remained stable in the ON condition. This difference in precuneus activation was not found during random button presses in a control task.CONCLUSIONS/SIGNIFICANCE:Our results show that differences in precuneus activation during retrieval of a remembered duration may underlie some aspects of time perception deficit in PD patients. We suggest that DA medication may allow compensatory activation in the precuneus, which results in a more accurate retrieval of remembered interval duration.

Visual distortions of perceived lengths, angles, or forms, are generally known as “geometric–optical illusions” (goi). In the present paper we focus on a class of gois where the distortion of a straight line segment (the “target” stimulus) is induced by an array of non-intersecting curvilinear elements (“context” stimulus). Assuming local target–context interactions in a vector field representation of the context, we propose to model the perceptual distortion of the target as the solution to a minimization problem in the calculus of variations. We discuss properties of the solutions and reproduction of the respective form of the perceptual distortion for several types of contexts. Moreover, we draw a connection between the interactionist model of gois and Riemannian geometry: the context stimulus is understood as perturbing the geometry of the visual field from which the illusory distortion naturally arises. The approach is illustrated by data from a psychophysical experiment with nine subjects and six different contexts.

Several studies provide empirical evidence for the association between impulsivity and time perception. However, little is known about the neural substrates underlying this function. This investigation examined the influence of impulsivity on neural activation patterns during the encoding and reproduction of intervals with durations of 3, 9 and 18s using event-related functional magnetic resonance imaging (fMRI). Twenty-seven subjects participated in this study, including 15 high impulsive subjects that were classified based on their self-rating. FMRI activation during the duration reproduction task was correlated with measures of two self-report questionnaires related to the concept of impulsivity (Barratt Impulsiveness Scale, BIS; Zimbardo Time Perspective Inventory, ZTPI). Behaviorally, those individuals who under-reproduced temporal intervals also showed lower scores on the ZTPI future perspective subscale and higher scores on the BIS. FMRI activation revealed an accumulating pattern of neural activity peaking at the end of the 9- and 18-s intervals within right posterior insula. Activations of brain regions during the reproduction phase of the timing task, such as those related to motor execution as well as to the 'core control network' - encompassing the inferior frontal and medial frontal cortices, the anterior insula as well as the inferior parietal cortex - were significantly correlated with reproduced duration, as well as with BIS and ZTPI subscales. In particular, the greater activation in these regions the shorter were the reproduced intervals, the more impulsive was an individual and the less pronounced the future perspective. Activation in the core control network, thus, may form a biological marker for cognitive time management and for impulsiveness.

OPINION article Front. Integr. Neurosci., 12 August 2011 | https://doi.org/10.3389/fnint.2011.00037

OBJECTIVES Supplementary motor area (SMA) was suggested to have a dominant role in the temporal control of behavior by many neuroimaging studies. The aim of this study was to support this hypothesis by influencing time estimates with theta burst transcranial magnetic stimulation (TMS) over the SMA. METHODS Nineteen healthy volunteers with a mean age 25.9±3 (SD) years performed the time reproduction task (TRT) before and after 190 seconds of intermittent theta-burst TMS over SMA and the precuneus (total 600 pulses). The TRT consisted of an encoding phase (during which visual stimuli with durations of 5, 10 and 16.82 seconds were presented pseudorandomly) and a reproduction phase (during which interval durations were reproduced by pressing a button). Mean subjects' interval estimates as a measure of accuracy and standard deviation as a measure of variability pre-TMS and post-TMS were compared. RESULTS Theta-burst TMS over both areas had no effect on the accuracy of duration estimates. An increased variability of interval reproduction was present after stimulation of the precuneus (p<0.01) with the biggest effect on the five second interval. Stimulation of SMA caused a decrease of variability in the ten second interval only (p<0.05). CONCLUSION It is likely that increased variability of time estimates is a non-specific result of impaired attention and working memory after theta-burst TMS. Decreased variability after stimulation over the SMA could be explained in terms of enhanced activity of the physiological oscillator with a frequency close to 0.1 Hz.

Flickering light induces visual hallucinations in human observers. Despite a long history of the phenomenon, little is known about the dependence of flicker-induced subjective impressions on the flicker frequency. We investigate this question using Ganzfeld stimulation and an experimental paradigm combining a continuous frequency scan (1-50 Hz) with a focus on re-occurring, whole percepts. On the single-subject level, we find a high degree of frequency stability of percepts. To generalize across subjects, we apply two rating systems, (1) a set of complex percept classes derived from subjects' reports and (2) an enumeration of elementary percept features, and determine distributions of occurrences over flicker frequency. We observe a stronger frequency specificity for complex percept classes than elementary percept features. Comparing the similarity relations among percept categories to those among frequency profiles, we observe that though percepts are preferentially induced by particular frequencies, the frequency does not unambiguously determine the experienced percept.