Information-Seeking Time: Only a Subset of Home Page Elements Matters

During goal oriented web navigation does the competition for web selection depend on all navigation options or only those options which are more likely to be functional for information seeking? Here we provide evidence in favour of the latter alternative. Within a representative set of real web sites of variable breadth, the time required to reach a goal located at the depth of two clicks from the home page is accounted for by C, an objective measure of the complexity of the start page, based on the number of links weighted by the number and type of embedding web elements. Our results demonstrate how focusing on links while ignoring other web elements optimizes the deployment of attentional resources necessary to navigation

Don’t worry, be active: how to facilitate the detection of errors in immersive virtual environments

The current research aims to study the link between the type of vision experienced in a collaborative immersive virtual environment (active vs. multiple passive), the type of error one looks for during a cooperative multi-user exploration of a design project (affordance vs. perceptual violations), and the type of setting in which multi-user perform (field in Experiment 1 vs. laboratory in Experiment 2). The relevance of this link is backed by the lack of conclusive evidence on an active vs. passive vision advantage in cooperative search tasks within software based on immersive virtual reality (IVR). Using a yoking paradigm based on the mixed usage of simultaneous active and multiple passive viewings, we found that the likelihood of error detection in a complex 3D environment was characterized by an active vs. multi-passive viewing advantage depending on: (1) the degree of knowledge dependence of the type of error the passive/active observers were looking for (low for perceptual violations, vs. high for affordance violations), as the advantage tended to manifest itself irrespectively from the setting for affordance, but not for perceptual violations; and (2) the degree of social desirability possibly induced by the setting in which the task was performed, as the advantage occurred irrespectively from the type of error in the laboratory (Experiment 2) but not in the field (Experiment 1) setting. Results are relevant to future development of cooperative software based on IVR used for supporting the design review. A multi-user design review experience in which designers, engineers and end-users all cooperate actively within the IVR wearing their own head mounted display, seems more suitable for the detection of relevant errors than standard systems characterized by a mixed usage of active and passive viewing

Large as being on top of the world and small as hitting the roof: A shared magnitude representation for the comparison of emotions and numbers

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Previous work on the direct Speed–Intensity Association (SIA) on comparative judgment tasks involved spatially distributed responses over spatially distributed stimuli with high motivational significance like facial expressions of emotions. This raises the possibility that the inferred stimulus-driven regulation of lateralized motor reactivity described by SIA, which was against the one expected on the basis of a valence-specific lateral bias, was entirely due to attentional capture from motivational significance (beyond numerical cognition). In order to establish the relevance of numerical cognition on the regulation of attentional capture we ran two complementary experiments. These involved the same direct comparison task on stimulus pairs that were fully comparable in terms of their analog representation of intensity but with different representational domain and motivational significance: symbolic magnitudes with low motivational significance in experiment 1 vs. emotions with rather high motivational significance in experiment 2. The results reveal a general SIA and point to a general mechanism regulating comparative judgments. This is based on the way spatial attention is captured toward locations that contain the stimulus which is closest in term of relative intensity to the extremal values of the series, regardless from its representational domain being it symbolic or emotiona

Segregation scheme of indium in AlGaInAs nanowire shells

Quaternary alloys enable the independent optimization of different semiconductor properties, such as the separate tuning of the band gap and the lattice constant. Nanowire core-shell structures should allow a larger range of compositional tuning as strain can be accommodated in a more effective manner than in thin films. Still, the faceted structure of the nanowire may lead to local segregation effects. Here, we explore the incorporation of indium in AlGaAs shells up to 25%. In particular, we show the effect of In incorporation on the energy shift of the AlGaInAs single-photon emitters present in the shell. We observe a redshift up to 300 meV as a function of the group-III site fraction of In. We correlate the shift with segregation at the nanoscale. We find evidence of the segregation of the group-III elements at different positions in the nanowire, not observed before. We propose a model that takes into account the strain distribution in the nanowire shell and the adatom diffusion on the nanowire facets to explain the observations. This work provides novel insights on the segregation phenomena necessary to engineer the composition of multidinary alloys

Faster but less careful prehension in presence of high, rather than low, social status attendees

5noAmple evidence attests that social intention, elicited through gestures explicitly signaling a request of communicative intention, affects the patterning of hand movement kinematics. The current study goes beyond the effect of social intention and addresses whether the same action of reaching to grasp an object for placing it in an end target position within or without a monitoring attendee’s peripersonal space, can be moulded by pure social factors in general, and by social facilitation in particular. A motion tracking system (Optotrak Certus) was used to record motor acts. We carefully avoided the usage of communicative intention by keeping constant both the visual information and the positional uncertainty of the end target position, while we systematically varied the social status of the attendee (a high, or a low social status) in separated blocks. Only thirty acts performed in the presence of a different social status attendee, revealed a significant change of kinematic parameterization of hand movement, independently of the attendee's distance. The amplitude of peak velocity reached by the hand during the reach-to-grasp and the lift-to-place phase of the movement was larger in the high rather than in the low social status condition. By contrast, the deceleration time of the reach-to-grasp phase and the maximum grasp aperture was smaller in the high rather than in the low social status condition. These results indicated that the hand movement was faster but less carefully shaped in presence of a high, but not of a low social status attendee. This kinematic patterning suggests that being monitored by a high rather than a low social status attendee might lead participants to experience evaluation apprehension that informs the control of motor execution. Motor execution would rely more on feedforward motor control in the presence of a high social status human attendee, vs. feedback motor control, in the presence of a low social status attendee.openopenFantoni, Carlo; Rigutti, Sara; Piccoli, Valentina; Sommacal, Elena; Carnaghi, AndreaFantoni, Carlo; Rigutti, Sara; Piccoli, Valentina; Sommacal, Elena; Carnaghi, Andre

Navigating within a web site: the webstep model

Web navigation is a complex activity in which users interact with a system to achieve their goals. Current webnavigatio

Web party effect: a cocktail party effect in the web environment

In goal-directed web navigation, labels compete for selection: this process often involves knowledge integration and requires selective attention to manage the dizziness of web layouts. Here we ask whether the competition for selection depends on all web navigation options or only on those options that are more likely to be useful for information seeking, and provide evidence in favor of the latter alternative. Participants in our experiment navigated a representative set of real websites of variable complexity, in order to reach an information goal located two clicks away from the starting home page. The time needed to reach the goal was accounted for by a novel measure of home page complexity based on a part of (not all) web options: the number of links embedded within web navigation elements weighted by the number and type of embedding elements. Our measure fully mediated the effect of several standard complexity metrics (the overall number of links, words, images, graphical regions, the JPEG file size of home page screenshots) on information seeking time and usability ratings. Furthermore, it predicted the cognitive demand of web navigation, as revealed by the duration judgment ratio (i.e., the ratio of subjective to objective duration of information search). Results demonstrate that focusing on relevant links while ignoring other web objects optimizes the deployment of attentional resources necessary to navigation. This is in line with a web party effect (i.e., a cocktail party effect in the web environment): users tune into web elements that are relevant for the achievement of their navigation goals and tune out all others

Raggiungere gli assenti:usi del podcast e auto-regolazione nello studio

I mutamenti economici e l\u2019orizzonte formativo in una prospettiva di lifelong education toccano da un quinquennio in modo evidente l\u2019Universit\ue0 italiana, in cui la partecipazione degli studenti lavoratori \ue8 una realt\ue0 in costante crescita. L\u2019offerta accademica si \ue8 differenziata facendo delle diverse tecnologie di rete uno strumento inizialmente pi\uf9 necessario che voluto, fino a valorizzarne potenzialit\ue0 e applicazioni rispetto a diversi contesti formativi e domini di apprendimento. Questo studio \ue8 un\u2019indagine conoscitiva e descrittiva che si concentra sulle esperienze svolte nel contesto dell\u2019Universit\ue0 di Trieste, in cui dal 2005 si \ue8 introdotto l\u2019utilizzo di materiale multimediale (audio e slide) a supporto e integrazione della didattica in presenza. In questo Ateneo dall\u2019a.a. 2008-2009 la Facolt\ue0 di Psicologia offre un corso interamente on-line rivolto agli studenti lavoratori. L\u2019indagine che abbiamo realizzato si \ue8 focalizzata su questo corso on-line. E\u2019 stato analizzato l\u2019uso da parte degli iscritti dei materiali visivi ed audio messi a loro disposizione mediante una piattaforma open source. I risultati ottenuti indicano che gli studenti lavoratori non considerano il testo d\u2019esame come unica risorsa per la propria preparazione ma fanno anche uso dei materiali on-line. E\u2019 stata inoltre valutata l\u2019efficacia dell\u2019uso di queste risorse in termini di rendimento agli esami di profitto trovando una correlazione positiva tra uso delle risorse audio on-line e rendimento dello studente. L\u2019indagine svolta pu\uf2 essere considerata una fase di un progetto pi\uf9 ampio che prevede di sperimentare una repository di podcasting per gli studenti a distanza, che si svolger\ue0 presso l\u2019universit\ue0 di Trieste

Bodily action penetrates affective perception

Fantoni & Gerbino (2014) showed that subtle postural shifts associated with reaching can have a strong hedonic impact and affect how actors experience facial expressions of emotion. Using a novel Motor Action Mood Induction Procedure (MAMIP), they found consistent congruency effects in participants who performed a facial emotion identification task after a sequence of visually-guided reaches: a face perceived as neutral in a baseline condition appeared slightly happy after comfortable actions and slightly angry after uncomfortable actions. However, skeptics about the penetrability of perception (Zeimbekis & Raftopoulos, 2015) would consider such evidence insufficient to demonstrate that observer’s internal states induced by action comfort/discomfort affect perception in a top-down fashion. The action-modulated mood might have produced a back-end memory effect capable of affecting post-perceptual and decision processing, but not front-end perception. Here, we present evidence that performing a facial emotion detection (not identification) task after MAMIP exhibits systematic mood-congruent sensitivity changes, rather than response bias changes attributable to cognitive set shifts; i.e., we show that observer’s internal states induced by bodily action can modulate affective perception. The detection threshold for happiness was lower after fifty comfortable than uncomfortable reaches; while the detection threshold for anger was lower after fifty uncomfortable than comfortable reaches. Action valence induced an overall sensitivity improvement in detecting subtle variations of congruent facial expressions (happiness after positive comfortable actions, anger after negative uncomfortable actions), in the absence of significant response bias shifts. Notably, both comfortable and uncomfortable reaches impact sensitivity in an approximately symmetric way relative to a baseline inaction condition. All of these constitute compelling evidence of a genuine top-down effect on perception: specifically, facial expressions of emotion are penetrable by action-induced mood. Affective priming by action valence is a candidate mechanism for the influence of observer’s internal states on properties experienced as phenomenally objective and yet loaded with meaning

Supporting presentation techniques based on virtual humans in educational virtual worlds

Educational Virtual Worlds (EVWs) allow one to circumvent physical, safety, and cost constraints that often affect real-world training and learning scenarios. Virtual humans can improve the effectiveness of an EVW e.g., by explaining and demonstrating to the user procedural tasks and communicating with learners in a natural way by exploiting both verbal and nonverbal communication. However, choosing how the learning material has to be presented to the learner and how to employ the virtual human is influenced by different factors, ranging from available technology (e.g., bandwidth, graphics hardware, installed software) to learner’s profile (e.g., physical and/or cognitive disabilities, spatial abilities, 2D/3D navigation expertise). The system we present in this paper flexibly supports different presentation techniques employing a virtual human into an EVW. The different capabilities of the system are illustrated, motivated and discussed