Publications by authors named "Javier Roca"

18 Publications

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Messages beyond the phone: Processing variable message signs while attending hands-free phone calls.

Accid Anal Prev 2021 Feb 17;150:105870. Epub 2020 Dec 17.

ERI-Lectura / Department of Developmental and Educational Psychology, University of Valencia, Valencia, Spain.

We examined the effects of different types of cognitive distraction coming from a hands-free phone conversation on the processing of information provided by variable message signs (VMS), on driving performance indicators, and on a physiological index of mental effort (heart rate). Participants drove a route in a driving simulator and had to respond to VMS messages under three conditions: no-distraction, visuospatial distraction (attending phone calls with questions inducing visuospatial processing), and conceptual distraction (attending phone calls with questions requiring semantic memory). Results showed more errors responding to VMS messages in the visuospatial distraction condition. In addition, both types of questions increased the intraindividual variability of response distances and the heart rate, as compared to the no-distraction condition. These results provide new evidence that talking on a hands-free phone entails costs in the processing of traffic information (in particular, text messages displayed on VMS) and it increases the driver's cognitive effort. Interestingly, the cognitive distraction had no effect on the driver's control of the vehicle speed or lateral position. Therefore, the effects of potential risk factors can critically vary among the different driving subtasks due to modulatory factors, such as the level of attentional task demands (relatively high in the processing of messages on VMS, but relatively low in controlling the speed and lateral position of the vehicle in quiet traffic conditions). In consequence, the current paper provides new evidence to discuss hands-free phone policies and highlights the importance of designing technological countermeasures to prevent drivers missing critical information displayed on VMS.
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http://dx.doi.org/10.1016/j.aap.2020.105870DOI Listing
February 2021

Phase-only modulation with two vertical aligned liquid crystal devices.

Opt Express 2020 Nov;28(23):34180-34189

Spatial Light Modulators (SLMs) are widely used in several fields of optics such as adaptive optics. SLMs based on Liquid Crystal (LC) devices allow a dynamic and easy representation of two-dimensional phase maps. A drawback of these devices is their elevated cost, preventing a massive use of the technology. We present a more affordable approach based on the serial arrangement of vertical aligned LC devices, with characteristics of phase modulation similar to a widely used parallel aligned LC device. We discuss the peculiarities of the approach, the performance and some potential areas of applications.
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http://dx.doi.org/10.1364/OE.410429DOI Listing
November 2020

Measuring attention and vigilance in the laboratory vs. online: The split-half reliability of the ANTI-Vea.

Behav Res Methods 2020 Sep 28. Epub 2020 Sep 28.

Department of Experimental Psychology, and Mind, Brain, and Behavior Research Center (CIMCYC), University of Granada, Campus de Cartuja S/N, CP 18011, Granada, Spain.

Over the past few years, there has been growing interest in using online methods for collecting data from large samples. However, only a few studies have administered online behavioral tasks to assess attention outside the lab. In the present study, we assessed the classic attentional functions and two vigilance components using two versions of the Attentional Networks Test for Interactions and Vigilance-executive and arousal vigilance components (ANTI-Vea): (1) a standard version, performed under typical experimental conditions (n = 314), and (2) an online version, completed outside the lab (n = 303). Both versions were equally effective in assessing (1) the main effects and interactions of phasic alertness, orienting, and executive control, and (2) the executive (i.e., a decline in the ability to detect infrequent critical signals) and the arousal (i.e., a progressive slowness and variability in responses to stimuli from the environment) vigilance decrement across time on task. Responses were generally slower in the online than in the standard version. Importantly, the split-half reliability observed for both tasks was (1) higher for executive control (~.67) than for phasic alertness and orienting (< .40), as observed in previous versions of the task, and (2) between .71 and .99 for the executive and arousal vigilance measures. We expect the present study will be of interest to researchers aiming to assess attentional functions with a valid and reliable method that, importantly, is publicly available on an open website ( https://www.ugr.es/~neurocog/ANTI/ ) and is easy to use in applied contexts.
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http://dx.doi.org/10.3758/s13428-020-01483-4DOI Listing
September 2020

Better read it to me: Benefits of audio versions of variable message signs in drivers with dyslexia.

Ann Dyslexia 2020 10 30;70(3):295-312. Epub 2020 May 30.

Departamento de Psicología Evolutiva y de la Educación/ERI Lectura, Facultad de Psicología, Universidad de Valencia, Avenida Blasco Ibáñez, 21 46010, Valencia, Spain.

Adults with dyslexia may find difficulties in reading the messages on variable message signs (VMS) while driving. These signs are an essential part of the traffic communication systems, aimed at informing road users of special circumstances, such as congestion, traffic diversion, or unexpected events. A driving simulation experiment was conducted to test if complementary audio versions of the VMS would be helpful for drivers with dyslexia. Twenty adults with dyslexia and 20 matched controls participated. They were asked to classify the messages displayed on VMS posted along a simulated route, which was completed twice: one with text VMS (visual condition), and another one with text VMS plus complementary audio messages (audio + visual condition). The results showed that in the ordinary, visual condition, the participants with dyslexia needed to be closer to the VMS than controls to correctly classify the message, but, crucially, these group differences vanished when the driver received an audio version of the message (audio + visual condition). Moreover, the availability of audio versions had positive effects for all participants, as shown by higher accuracy in the message classification task, as well as better driving performance. Therefore, technologies aimed at providing audio versions of VMS can help drivers with dyslexia. A mobile application, READit VMS, which is able to provide real-time complementary audio versions of VMS, is presented as an example.
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http://dx.doi.org/10.1007/s11881-020-00199-6DOI Listing
October 2020

The moderating effects of vigilance on other components of attentional functioning.

J Neurosci Methods 2018 10 29;308:151-161. Epub 2018 Jul 29.

Departamento de Psicología Experimental, Centro de Investigación Mente, Cerebro y Comportamiento (CIMCYC), Universidad de Granada, Campus Universitario Cartuja, s/n, 18071 Granada, Spain.

Background: Previous research suggested that vigilance may moderate the functioning of other attentional components. However, vigilance is usually neglected when comparing the attentional functioning between groups of clinical and/or healthy participants.

New Method: We combined data from several studies using the Attention Network Test for Interactions and Vigilance (ANTI-V), which includes a vigilance measure plus phasic alertness, orienting, and executive control scores. We estimated, for the first time, the reliability of the vigilance performance indices in the ANTI-V, by analyzing split-half correlations of 10,000 permutations of the trials. In addition, we tested whether a different attentional functioning would be found across the group of healthy participants varying in their vigilance performance, by using a considerably larger sample size (226 participants) than previous studies.

Results: Vigilance indices were the most reliable among the different attentional scores. Regression models show an inverse relationship between vigilance and phasic alertness and executive control.

Comparison With Existing Methods: No previous study has analysed the reliability of the vigilance performance indices in the ANTI-V. In comparison with other ANT variations, the ANTI-V provides a reliable measure of vigilance together with the typical phasic alertness, orienting and executive control scores. In addition, we provide estimates, based on a large sample size, of the magnitude of the link between vigilance and other attentional functions.

Conclusions: When assessing the multiple functions of attention, the current study highlights the importance of measuring vigilance, which may modulate the functioning of other attentional components, such as phasic alertness or executive control.
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http://dx.doi.org/10.1016/j.jneumeth.2018.07.019DOI Listing
October 2018

Executive and arousal vigilance decrement in the context of the attentional networks: The ANTI-Vea task.

J Neurosci Methods 2018 08 20;306:77-87. Epub 2018 May 20.

Department of Experimental Psychology, Mind, Brain, and Behavior Research Center (CIMCYC), University of Granada, Campus de Cartuja S/N, CP 18011, Granada, Spain. Electronic address:

Background: Vigilance is generally understood as the ability to detect infrequent critical events through long time periods. In tasks like the Sustained Attention to Response Task (SART), participants tend to detect fewer events across time, a phenomenon known as "vigilance decrement". However, vigilance might also involve sustaining a tonic arousal level. In the Psychomotor Vigilance Test (PVT), the vigilance decrement corresponds to an increment across time in both mean and variability of reaction time.

New Method: The present study aimed to develop a single task -Attentional Networks Test for Interactions and Vigilance - executive and arousal components (ANTI-Vea)- to simultaneously assess both components of vigilance (i.e., the executive vigilance as in the SART, and the arousal vigilance as in the PVT), while measuring the classic attentional functions (phasic alertness, orienting, and executive control).

Results: In Experiment #1, the executive vigilance decrement was found as an increment in response bias. In Experiment #2, this result was replicated, and the arousal vigilance decrement was simultaneously observed as an increment in reaction time.

Comparison With Existing Method: The ANTI-Vea solves some issues observed in the previous ANTI-V task with the executive vigilance measure (e.g., a low hit rate and no vigilance decrement). Furthermore, the new ANTI-Vea task assesses both components of vigilance together with others typical attentional functions.

Conclusions: The new attentional networks test developed here may be useful to provide a better understanding of the human attentional system. The role of sensitivity and response bias in the executive vigilance decrement are discussed.
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http://dx.doi.org/10.1016/j.jneumeth.2018.05.011DOI Listing
August 2018

Increasing the default interletter spacing of words can help drivers to read traffic signs at longer distances.

Accid Anal Prev 2018 Aug 9;117:298-303. Epub 2018 May 9.

Departamento de Psicología Evolutiva y de la Educación / ERI Lectura, Universidad de Valencia, Facultad de Psicología, Avenida Blasco Ibáñez, 21, 46010, Valencia, Spain. Electronic address:

Would an increase in the default interletter spacing improve the legibility of words in traffic signs? Previous evidence on traffic sign design and recent studies on the cognitive processes involved in visual word recognition have provided conflicting results. The present work examined whether an increase in the default interletter spacing would improve the search of a word in direction traffic signs. To achieve this objective, twenty-two drivers participated in a driving simulation experiment. They followed a highway route and indicated whether a target place name was present among a set of distractors shown on direction traffic signs along the route. We compared the default interletter spacing of the Spanish "CC Rige" font (which is based on the internationally-used Transport font) and a 2.5-times expanded interletter spacing. The results revealed that the drivers were able to give a correct response at a distance to the traffic sign that was on average longer in the expanded than in the default spacing condition. This advantage in the legibility distance was observed in the absence of significant differences in reading accuracy, gaze behavior, or driving performance measures. Therefore, the evidence provided supports that drivers can benefit from a slight increase in interletter spacing relative to the standard spacing. Some of the design factors influencing this effect are discussed.
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http://dx.doi.org/10.1016/j.aap.2018.04.028DOI Listing
August 2018

Difficulties of Drivers With Dyslexia When Reading Traffic Signs: Analysis of Reading, Eye Gazes, and Driving Performance.

J Learn Disabil 2019 Jan/Feb;52(1):84-95. Epub 2018 Mar 14.

1 Universitat de València, Spain.

A group of adult individuals with dyslexia and a matched group of normally reading individuals participated in a driving simulation experiment. Participants were asked to read the word presented on every direction traffic sign encountered along a route, as far as possible from the sign, maintaining driving performance. Word frequency and word length were manipulated as within-subject factors. We analyzed (a) reading accuracy, (b) how far the sign was when the participant started to give the response, (c) where the participant looked during the time leading up to the response, and (d) the variability of the vehicle's speed during that time and during driving on similar segments of the route that did not present the traffic signs. Individuals with dyslexia showed lower levels of performance in the reading task, the roles of word frequency and word length were more influential for them, and there was larger variability of the vehicle's speed during the time they were attempting to read the traffic sign, which did not occur during their driving on similar segments that did not present the targeted traffic signs. Therefore, the specific needs of individuals with dyslexia on the road should be considered in plans aimed at increasing traffic safety and fluidity.
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http://dx.doi.org/10.1177/0022219418765766DOI Listing
April 2020

Legibility of Text and Pictograms in Variable Message Signs: Can Single-Word Messages Outperform Pictograms?

Hum Factors 2018 05 10;60(3):384-396. Epub 2018 Jan 10.

University of Valencia, Spain.

Objective: The current research shows the advantage of single-word messages in the particular case of variable message signs (VMSs) with a high aspect ratio.

Background: Early studies on traffic sign design proposed that pictorial information would advantage equivalent text messages in static signs.

Method: We used a driving simulator to present individually 36 VMSs, showing six words (e.g., "congestion") and six danger signs (e.g., congestion traffic sign). In Experiment 1, 18 drivers read aloud the text or orally identified the pictograms as soon as they could correctly do it. In Experiment 2, a different sample of 18 drivers gave a motor response, according to the meaning of the message. We analyzed the legibility distance and accuracy, driving performance (speed variability), and glance behavior.

Results: Our results show that single-word messages were associated with better performance (farther reading distances) and required less visual demands (fewer glances and less glancing times) than pictograms.

Conclusion: As typical configurations of VMSs usually have a high aspect ratio, and thus allow large character heights, single-word messages can outperform the legibility of pictograms. However, the final advantage of text or pictorial messages would depend on several factors, such as the driver's knowledge of the language and the pictogram set, the use of single or multiple words, the particular design and size of critical details in letters and pictograms, environmental factors, and driver age.

Application: Potential applications include the design of VMSs and other devices aimed at displaying text and/or pictograms with a high aspect ratio.
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http://dx.doi.org/10.1177/0018720817751623DOI Listing
May 2018

Impaired conflict resolution and vigilance in euthymic bipolar disorder.

Psychiatry Res 2015 Sep 27;229(1-2):490-6. Epub 2015 Jun 27.

Dipartimento di Psicologia, "Sapienza" Università di Roma, Italy. Electronic address:

Difficulty attending is a common deficit of euthymic bipolar patients. However, it is not known whether this is a global attentional deficit or relates to a specific attentional network. According to the attention network approach, attention is best understood in terms of three functionally and neuroanatomically distinct networks-alerting, orienting, and executive control. In this study, we explored whether and which of the three attentional networks are altered in euthymic Bipolar Disorder (BD). A sample of euthymic BD patients and age-matched healthy controls completed the Attention Network Test for Interactions and Vigilance (ANTI-V) that provided not only a measure of orienting, executive, and alerting networks, but also an independent measure of vigilance (tonic alerting). Compared to healthy controls, BD patients have impaired executive control (greater interference), reduced vigilance (as indexed by a decrease in the d' sensitivity) as well as slower overall reaction times and poorer accuracy. Our results show that deficits in executive attention and sustained attention often persist in BD patients even after complete remission of affective symptoms, thus suggesting that cognitive enhancing treatments programmed to improve these deficits could contribute to improve their functional recovery.
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http://dx.doi.org/10.1016/j.psychres.2015.06.026DOI Listing
September 2015

Phasic and tonic alerting in mild cognitive impairment: A preliminary study.

Exp Gerontol 2014 Jan 16;49:35-9. Epub 2013 Nov 16.

Departamento de Psicología Básica y Metodología, Facultad de Psicología, Universidad de Murcia, Campus de Espinardo, 30100 Murcia, Spain. Electronic address:

In this preliminary study we assessed the functioning of the different attentional networks in mild cognitive impairment (MCI) patients, taking as theoretical framework the Posner's cognitive neuroscience approach. Two groups of participants were tested in a single short experiment: 20 MCI patients (6 amnestic, 6 non-amnestic and 8 multiple-domain) and 18 healthy matched controls (HC). For attentional assessment we used a version of the Attention Network Test (the ANTI-V) that provided not only a score of the orienting, the executive, and the alerting networks and their interactions, but also an independent measure of vigilance (tonic alerting). The results showed that all subtypes of MCI patients exhibited a selective impairment in the tonic component of alerting, as indexed by a decrease in the d' sensitivity index, and their performance in executive network increased up to the HC group level when phasic alerting was provided by a warning tone. Our findings suggest that a core attentional deficit, especially the endogenous component of alerting, may significantly contribute to the behavioral and cognitive deficits associated with MCI.
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http://dx.doi.org/10.1016/j.exger.2013.11.001DOI Listing
January 2014

The influence of differences in the functioning of the neurocognitive attentional networks on drivers' performance.

Accid Anal Prev 2013 Jan 22;50:1193-206. Epub 2012 Oct 22.

Departamento de Psicología Experimental, Universidad de Granada, Campus Universitario Cartuja, s/n, 18071 Granada, Spain.

Considerable research efforts are currently being devoted to analysing the role that the attentional system plays in determining driving behaviour, with the ultimate objective of reducing the number of attention-related accidents. The present study aims to assess the influence of differences in the functioning of the three attentional networks (executive control, attentional orienting and alerting) when drivers have to deal with some common hazardous situations, for example, when an oncoming car or a pedestrian unexpectedly crosses their trajectory. Multiple measures of participants' attentional functioning were obtained from a computer-based neurocognitive test: the Attention Networks Test for Interactions and Vigilance (ANTI-V). These measures were compared to performance in a driving simulator where different types of hazardous situations were presented. Correlation and linear regression analyses revealed significant associations between individual attentional measures and driving performance in specific traffic situations. In particular, a higher attentional orienting score on the ANTI-V was associated with safer driving in situations where a single precursor anticipated the hazard source, whereas in complex situations with multiple potential hazard precursors, higher attentional orienting scores were associated with delayed braking. Additionally, partial evidence of a relationship between crash occurrence and the functioning of the executive control and the alerting networks was found. Overall, the current research would be helpful to better understand the role that each attentional network (executive control, attentional orienting and alerting) play in safe driving, and thus to develop efficient countermeasures to reduce attention-related crashes.
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http://dx.doi.org/10.1016/j.aap.2012.09.032DOI Listing
January 2013

The effects of sleep deprivation on the attentional functions and vigilance.

Acta Psychol (Amst) 2012 Jun 23;140(2):164-76. Epub 2012 May 23.

Departamento de Psicología Experimental, Facultad de Psicología, Universidad de Granada, Campus Universitario Cartuja, Spain.

The study of sleep deprivation is a fruitful area of research to increase our knowledge of cognitive functions and their neural basis. In the current work, 26 healthy young adults participated in a sleep deprivation study, in which the Attentional Networks Test for Interactions and Vigilance (ANTI-V) was performed at 10a.m. after a night of normal sleep and again at 10 a.m. after 25.5-27.5 h of total sleep deprivation. The ANTI-V is an experimental task that provides measures of alerting, orienting and executive control attentional functions. Compared with previous versions, the ANTI-V includes a vigilance task, more reliable auditory alerting signals, non-predictive peripheral orienting cues, and also a neutral no-cue condition allowing the analysis of reorienting costs and orienting benefits. Thus, new evidence to evaluate the influence of sleep deprivation on attentional functioning is provided. Results revealed differences in both tonic and phasic alertness after sleep deprivation. Vigilance performance was deteriorated, while a warning tone was more helpful to increase participants' alertness, resulting in slightly faster RT and, in particular, fewer errors. The reorienting costs of having an invalid spatial cue were reduced after sleep loss. No sleep deprivation effect on the executive control measure was found in this study. Finally, since no control group was used, particular precautions were taken to reduce the influence of potential practice effects.
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http://dx.doi.org/10.1016/j.actpsy.2012.03.007DOI Listing
June 2012

Attentional networks functioning, age, and attentional lapses while driving.

Traffic Inj Prev 2011 Oct;12(5):518-28

Departamento de Psicología Experimental y Fisiología del Comportamiento, Universidad de Granada, España.

Objective: Based on Posner's (1994) model of attentional functions, the relationship between age and personal proneness to attention-related errors while driving and the functioning of the 3 attentional networks were explored by means of attentional behavioral measures and self-report data.

Methods: A sample of 55 drivers was drawn from the general population of Mar del Plata, Buenos Aires, Argentina. The Attention Network Test for Interactions (ANTI) (Callejas et al. 2004) task was used to obtain behavioral measures of the attentional networks, and we used the Attention-Related Driving Error Scale (ARDES) (Ledesma et al. 2010) questionnaire to obtain a self-report measure of attention-related driving errors.

Results: Drivers reporting the greatest propensity to experience attention-related errors showed an overall slowdown in performance, less endogenous preparation for high = priority warning signs, and a better response to conflict in the presence of valid cues than drivers less prone to attention-related errors while driving. Older participants showed a slowdown in performance, less endogenous preparation for high-priority warning signs, and worse cognitive control when solving conflict in comparison with younger drivers.

Conclusions: We suggest that each group variable, attention-related error proneness and age, shows a particular combination of attentional network functioning that implies different ways of being distracted, which have different practical implications for safe driving. It can be inferred that drivers who are more prone to commit attentional errors while driving run less risk in situations in which they can deal with response conflict in the presence of valid cues because of the particular way in which their attentional networks are combined when a valid cue is present, could serve to compensate, with a better response conflict, their general slowdown and less endogenous preparedness for high-priority signs. It can be inferred that older drivers might show a reduction of the general state of alertness to signs that indicate the presence of a dangerous driving situation and in solving conflict in traffic circumstances.
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http://dx.doi.org/10.1080/15389588.2011.588295DOI Listing
October 2011

Measuring vigilance while assessing the functioning of the three attentional networks: the ANTI-Vigilance task.

J Neurosci Methods 2011 Jun 15;198(2):312-24. Epub 2011 Apr 15.

Departamento de Psicología Experimental y Fisiología del Comportamiento, Facultad de Psicología, Universidad de Granada, Campus Universitario Cartuja, s/n, 18071 Granada, Spain.

Vigilance could be a crucial aspect of attention that may modulate the functioning of the attentional system. Some behavioural tests, such as the Attention Network Test (ANT), have been developed to obtain an individual index of the three attentional networks (alertness, orientation, and executive control). However, alerting network measures are usually inferred using a phasic alertness task, and some indirect indexes of tonic alertness or vigilance have been proposed but not properly evaluated. The general aim for the present study is to provide the ANT with a direct measure of vigilance and then to analyse the relationship between this measure and other alternative indirect indexes. The obtained results suggest that the proposed new test (ANTI-Vigilance or ANTI-V) is useful to achieve a direct measure of vigilance and could be considered as a new tool available in cognitive, clinical or behavioural neurosciences for analysing vigilance in addition to the usual ANT scores. Other alternative indexes (such as global reaction time and global accuracy averaged across conditions) are only moderately correlated to a direct vigilance measure. As a consequence, although they may be to some extent related to the participants' vigilance level, they could not be used isolatedly as appropriate indexes of vigilance. Also, the role played by these global measures in the ANT task, which have been previously associated with some performance measures in applied areas (such as driving performance), is discussed.
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http://dx.doi.org/10.1016/j.jneumeth.2011.04.014DOI Listing
June 2011

A driving-emulation task to study the integration of goals with obligatory and prohibitory traffic signs.

Appl Ergon 2012 Jan 22;43(1):81-8. Epub 2011 Apr 22.

Departamento de Psicología Experimental y Fisiología del Comportamiento, Universidad de Granada, Campus Cartuja s/n, 18011 Granada, Spain.

This research aims to analyse how drivers integrate the information provided by traffic signs with their general goals (i.e. where they want to go). Some previous studies have evaluated the comparative advantages of obligatory and prohibitory traffic signs using a judgement task. In this work, a new experimental task with greater similarity to driving situations is proposed. Participants imagine they are driving a vehicle and must make right or left turn manoeuvres according to a previously indicated objective and the information from obligatory and prohibitory traffic signs. Eighty-two participants took part in two different experiments. According to the results, an obligatory traffic sign is associated with faster and more accurate responses only when the participant's initial objective is allowed. When the initial objective was not allowed, an advantage in accuracy was observed with prohibitory traffic signs and there was no significant difference in reaction time between the two types of sign. These results suggest that having an obligatory traffic sign may facilitate a correct response when the driver's goal is effectively allowed, whereas a prohibitory traffic sign could be more effective in preventing error when the driver has a not-allowed goal in mind. However, processing a prohibitory sign requires an extra inference (i.e. deciding which is the allowed manoeuvre), and thus the potential advantage in reaction time of the prohibitory sign may disappear. A second experiment showed that the results could not be explained by a potential congruency effect between the location (left or right) of the road signs and the position of the key or the hand used to respond (such as the Simon effect or the spatial Stroop effect). Also, an increase in the difficulty of the task (using an incongruent hand to respond) affected performance more strongly in experimental conditions that required making inferences. This made the advantage of the obligatory sign over the prohibitory sign in this condition more noteworthy. The evidence gathered in the current study could be of particular interest in some applied research areas, such as the assessment of road traffic signalling strategies or the ergonomic design of GPS navigation systems.
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http://dx.doi.org/10.1016/j.apergo.2011.03.010DOI Listing
January 2012

High-performance electron tomography of complex biological specimens.

J Struct Biol 2002 Apr-May;138(1-2):6-20

Departamento de Arquitectura de Computadores, Universidad de Almería, 04120 Almería, Spain.

We have evaluated reconstruction methods using smooth basis functions in the electron tomography of complex biological specimens. In particular, we have investigated series expansion methods, with special emphasis on parallel computation. Among the methods investigated, the component averaging techniques have proven to be most efficient and have generally shown fast convergence rates. The use of smooth basis functions provides the reconstruction algorithms with an implicit regularization mechanism, very appropriate for noisy conditions. Furthermore, we have applied high-performance computing (HPC) techniques to address the computational requirements demanded by the reconstruction of large volumes. One of the standard techniques in parallel computing, domain decomposition, has yielded an effective computational algorithm which hides the latencies due to interprocessor communication. We present comparisons with weighted back-projection (WBP), one of the standard reconstruction methods in the areas of computational demand and reconstruction quality under noisy conditions. These techniques yield better results, according to objective measures of quality, than the weighted backprojection techniques after a very few iterations. As a consequence, the combination of efficient iterative algorithms and HPC techniques has proven to be well suited to the reconstruction of large biological specimens in electron tomography, yielding solutions in reasonable computation times.
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http://dx.doi.org/10.1016/s1047-8477(02)00017-5DOI Listing
July 2003