The effect of surgical masks on identification decisions from masked and unmasked lineups.

While research has shown that wearing a disguise hinders lineup identifications, less is known about how to conduct lineups in cases of disguised perpetrators. We examined the influence of surgical masks, worn during a crime event (encoding) and within lineups (retrieval), on eyewitness identification accuracy. In our experiment, 452 participants watched a mock-crime video and identified the perpetrator from either a target-present or a target-absent simultaneous lineup.

How much time does it take to discriminate two sets by their numbers of elements?

The ability to evaluate the number of elements in a set-numerosity-without symbolic representation is a form of primitive perceptual intelligence. A simple binomial model was proposed to explain how observers discriminate the numerical proportion between two sets of elements distinct in color or orientation (Raidvee et al., 2017, Attention Perception & Psychophysics, 79[1], 267-282).

How are local orientation signals pooled?

Visual perception is capable of pooling multiple local orientation signals into a single more accurate summary orientation. However, there is still a lack of systematic inquiry into which summary statistics are implemented in that process. Here, the task was to recognize in which direction, clockwise or counter-clockwise, the mean orientation of a set of randomly distributed Gabor patches (N = 1, 2, 4, and 8) was rotated from the implicit vertical.

Proximity model of perceived numerosity.

The occupancy model (OM) was proposed to explain how the spatial arrangement of dots in sparse random patterns affects their perceived numerosity. The model's central thesis maintained that each dot seemingly fills or occupies its surrounding area within a fixed radius r and the total area collectively occupied by all the dots determines their apparent number. Because the perceptual system is not adapted for the precise estimation of area, it looks likely that the OM is just a convenient computational algorithm that does not necessarily correspond to the processes that actually take place in the perceptual system.

A method for detection of inattentional feature blindness.

In ensemble displays, two principal factors determine the precision with which the mean value of some perceptual attribute, such as size and orientation, can be discriminated: inefficiency and representational noise of each element. Inefficiency is mainly caused by biased inference, or by inattentional (feature) blindness (i.e.

The applicability of web-based solutions in headache epidemiology research.

Background: Epidemiological research of headache is vital but resource consuming prerequisite for evidence-based development in the field. Rapid evolution of information technology may provide new opportunities for population-based surveys. The aim of this study was to evaluate the applicability of web-based solutions in epidemiological studies of primary headaches.

Perception of means, sums, and areas.

In this age of data visualization, it is important to understand our perception of the symbols that are used. For example, does the perceived size of a disc correspond most closely to its area, diameter, circumference, or some other measure? When multiple items are present, this becomes a question of ensemble perception. Here, we compare observers' performance across three different tasks: judgments of (i) the mean diameter, (ii) the total diameter, or (iii) the total area of (N = 1, 2, 3, or 7) test circles compared with a single reference circle.

The prevalence of primary headache disorders in the adult population of Estonia.

Objective: To estimate the one-year prevalence of primary headaches, most importantly migraine and tension type headache, but also other primary headaches, in Estonia.

Methods: A population-based random sample of 2162 subjects in Tartu City and Tartu County were interviewed by telephone or face to face using a previously validated questionnaire.

Results: Of the 2162 contacted participants, 1215 (56%) fully completed the study.

Discrimination of numerical proportions: A comparison of binomial and Gaussian models.

Observers discriminated the numerical proportion of two sets of elements (N = 9, 13, 33, and 65) that differed either by color or orientation. According to the standard Thurstonian approach, the accuracy of proportion discrimination is determined by irreducible noise in the nervous system that stochastically transforms the number of presented visual elements onto a continuum of psychological states representing numerosity. As an alternative to this customary approach, we propose a Thurstonian-binomial model, which assumes discrete perceptual states, each of which is associated with a certain visual element.

3D Cinema and Headache: The First Evidential Relation and Analysis of Involved Factors.

Background: A possible link between 3D movies and headache (HA) has never been a target of specific and systematic investigations. The aim of this study was to investigate the relationship between 3D cinema and HA and to evaluate possible risk factors of developing HA during or after watching a 3D movie.

Methods: This was a prospective, non-randomized, observational study.

Obligatory averaging in mean size perception.

The perception of ensemble characteristics is often regarded as an antidote to an established bottleneck in focused attention and working memory, both of which appear to be limited in capacity to a few objects only. In order to test the associative law of summation, observers were asked to estimate the mean size of four circles relative to a reference circle. When there was no time to scrutinize each individual circle, observers discriminated the mean size difference identically, irrespective of whether the same summary size increment or decrement was added to or subtracted from the size of only one, two, or all four circles.

Visual evoked potentials to change in coloration of a moving bar.

In our previous study we found that it takes less time to detect coloration change in a moving object compared to coloration change in a stationary one (Kreegipuu etal., 2006). Here, we replicated the experiment, but in addition to reaction times (RTs) we measured visual evoked potentials (VEPs), to see whether this effect of motion is revealed at the cortical level of information processing.

Unintentionality of affective attention across visual processing stages.

Affective attention involves bottom-up perceptual selection that prioritizes motivationally significant stimuli. To clarify the extent to which this process is automatic, we investigated the dependence of affective attention on the intention to process emotional meaning. Affective attention was manipulated by presenting affective images with variable arousal and intentionality by requiring participants to make affective and non-affective evaluations.

Unattended and attended visual change detection of motion as indexed by event-related potentials and its behavioral correlates.

Visual mismatch negativity (vMMN) is a negative-going component amongst cognitive event-related potentials. It reflects an automatic change-detection process that occurs when an infrequent stimulus is presented that is incongruent with the representation of a frequent (standard) event. In our research we use visual motion (more specifically motion direction changes) to study vMMN.

An almost general theory of mean size perception.

A general explanation for the observer's ability to judge the mean size of simple geometrical figures, such as circles, was advanced. Results indicated that, contrary to what would be predicted by statistical averaging, the precision of mean size perception decreases with the number of judged elements. Since mean size discrimination was insensitive to how total size differences were distributed among individual elements, this suggests that the observer has a limited cognitive access to the size of individual elements pooled together in a compulsory manner before size information reaches awareness.

Visibility versus accountability in pooling local motion signals into global motion direction.

The human observer is surprisingly inaccurate in discriminating proportions between two spatially overlapping sets of randomly distributed elements moving in opposite directions. It was shown that observers took into account an equivalent of 74 % of all moving elements when the task was to estimate their relative number, but only an equivalent of 21 % of the same elements when the task was to discriminate between opposite directions. It was concluded that, in the motion direction discrimination task, a large proportion of the signal from all of the elements was inaccessible to the observers, whereas the majority of the signal was accessible in a numerosity task.

A new approach for assessment of mental architecture: repeated tagging.

A new approach to the study of a relatively neglected property of mental architecture-whether and when the already-processed elements are separated from the to-be-processed elements-is proposed. The process of numerical proportion discrimination between two sets of elements defined either by color or by orientation can be described as sampling with or without replacement (characterized by binomial or hypergeometric probability distributions respectively) depending on the possibility to tag an element once or repeatedly. All empirical psychometric functions were approximated by a theoretical model showing that the ability to keep track of the already tagged elements is not an inflexible part of the mental architecture but rather an individually variable strategy which also depends on conspicuity of perceptual attributes.

Pooling elementary motion signals into perception of global motion direction.

Six observers were asked to indicate in which of two opposite directions, to the right or to the left, an entire display appeared to move, based on the proportion of right vs leftward motion elements, each of which was distinctly visible. The performance of each observer was described by Thurstone's discriminative processes and Bernoulli trial models which described empirical psychometric functions equally well. Although formally it was impossible to discriminate between these two models, treating observer as a counting device which measures a randomly selected subsample of all available motion elements had certain advantages.

Reaction time to motion onset and magnitude estimation of velocity in the presence of background motion.

Reaction times (RT) to motion onset of a target grating moving at 0.4, 0.6, 0.

Health-related quality of life in patients with hereditary spastic paraplegia in Estonia.

Study Design: Observational population-based cohort study.

Objectives: The main aim of this study was to examine the relative effect of hereditary spastic paraplegia (HSP) on the health-related quality of life (HRQoL).

Methods: HRQoL was evaluated using a RAND 36-Item Health Survey 1.