How feedback boosts motivation and play in a brain-training game

AbstractGames are important vehicles for learning and behavior change as long as players are motivated to continue playing. We study the impact of verbal feedback in stimulating player motivation and future play in a brain-training game. We conducted a 2 (feedback valence: positive vs. negative)×3 (feedback type: descriptive, comparative, evaluative) between-subjects experiment (N=157, 69.4% female, Mage=32.07). After playing a brain-training game and receiving feedback, we tapped players’ need satisfaction, motivation and intention to play the game again. Results demonstrate that evaluative feedback increases, while comparative feedback decreases future game play. Furthermore, negative feedback decreases players’ feeling of competence, but also increases immediate game play. Positive feedback, in contrast, satisfies competence and autonomy needs, thereby boosting intrinsic motivation. Negative feedback thus motivates players to repair poor short-term performances, while positive feedback is more powerful in fostering long-term motivation and play

Designing context-aware systems: A method for understanding and analysing context in practice

NWO438-13-60Past research project

Knowledge Graph of Design Rules for a Context-Aware Cognitive Design Assistant

[Context] The design of a system shall comply with many design rules that help industrial designers to create high quality design in an efficient way. Nowadays, design rules try to consider all product lifecycle’s phases leading to an ever-increasing growth. This context makes the management of design rules a difficult but essential task. This is why many research and industrial works try to automate this task [1, 3, 4]. [Problem] The processing of design rules, which are natural language sentences stored in unstructured documents, requires expert software. Moreover, existing tools interrupt the design workflow and slow down the design process. [Proposition] We propose a Context-Aware Cognitive Design Assistant (CACDA) to support designers who have to satisfy some design rules among “Big Data”. First, we describe the CACDA from the user’s perspective. Second, we detail the process for modelling unstructured design rules into a com-putable knowledge graph that will feed the cognitive design assistant. [Future Work] Once our knowledge graph of design rules will be operational, we will concentrate on its processing to retrieve, recommend, and verify design rules. Experiments will also help to determine pros and cons of the design assistant.En partenariat avec Capgemini DEM

Re-evaluating a vision-related quality of life questionnaire with item response theory (IRT) and differential item functioning (DIF) analyses

Background: For the Low Vision Quality Of Life questionnaire (LVQOL) it is unknown whether the psychometric properties are satisfactory when an item response theory (IRT) perspective is considered. This study evaluates some essential psychometric properties of the LVQOL questionnaire in an IRT model, and investigates differential item functioning (DIF). Methods: Cross-sectional data were used from an observational study among visually-impaired patients (n = 296). Calibration was performed for every dimension of the LVQOL in the graded response model. Item goodness-of-fit was assessed with the S-X2-test. DIF was assessed on relevant background variables (i.e. age, gender, visual acuity, eye condition, rehabilitation type and administration type) with likelihood-ratio tests for DIF. The magnitude of DIF was interpreted by assessing the largest difference in expected scores between subgroups. Measurement precision was assessed by presenting test information curves; reliability with the index of subject separation. Results: All items of the LVQOL dimensions fitted the model. There was significant DIF on several items. For two items the maximum difference between expected scores exceeded one point, and DIF was found on multiple relevant background variables. Item 1 ‘Vision in general’ from the “Adjustment” dimension and item 24 ‘Using tools’ from the “Reading and fine work” dimension were removed. Test information was highest for the “Reading and fine work” dimension. Indices for subject separation ranged from 0.83 to 0.94. Conclusions: The items of the LVQOL showed satisfactory item fit to the graded response model; however, two items were removed because of DIF. The adapted LVQOL with 21 items is DIF-free and therefore seems highly appropriate for use in heterogeneous populations of visually impaired patients. (aut.ref.

LsrR-Mediated Quorum Sensing Controls Invasiveness of Salmonella typhimurium by Regulating SPI-1 and Flagella Genes

Bacterial cell-to-cell communication, termed quorum sensing (QS), controls bacterial behavior by using various signal molecules. Despite the fact that the LuxS/autoinducer-2 (AI-2) QS system is necessary for normal expression of Salmonella pathogenicity island-1 (SPI-1), the mechanism remains unknown. Here, we report that the LsrR protein, a transcriptional regulator known to be involved in LuxS/AI-2-mediated QS, is also associated with the regulation of SPI-1-mediated Salmonella virulence. We determined that LsrR negatively controls SPI-1 and flagella gene expressions. As phosphorylated AI-2 binds to and inactivates LsrR, LsrR remains active and decreases expression of SPI-1 and flagella genes in the luxS mutant. The reduced expression of those genes resulted in impaired invasion of Salmonella into epithelial cells. Expression of SPI-1 and flagella genes was also reduced by overexpression of the LsrR regulator from a plasmid, but was relieved by exogenous AI-2, which binds to and inactivates LsrR. These results imply that LsrR plays an important role in selecting infectious niche of Salmonella in QS dependent mode

Analysis of the Expression, Secretion and Translocation of the Salmonella enterica Type III Secretion System Effector SteA

Many Gram-negative pathogens possess virulence-related type III secretion systems. Salmonella enterica uses two of these systems, encoded on the pathogenicity islands SPI-1 and SPI-2, respectively, to translocate more than 30 effector proteins into eukaryotic host cells. SteA is one of the few effectors that can be translocated by both systems. We investigated the conditions affecting the synthesis of this effector, its secretion to culture media and its translocation into host cells. Whereas steA was expressed under a wide range of conditions, some factors, including low and high osmolarity, and presence of butyrate, decreased expression. SteA was efficiently secreted to the culture media under both SPI-1 and SPI-2 inducing conditions. The kinetics of translocation into murine macrophages and human epithelial cells was studied using fusions with the 3xFLAG tag, and fusions with CyaA from Bordetella pertussis. Translocation into macrophages under non-invasive conditions was mainly dependent on the SPI-2-encoded type III secretion system but some participation of the SPI-1 system was also detected 6 hours post-infection. Interestingly, both type III secretion systems had a relevant role in the translocation of SteA into epithelial cells. Finally, a deletion approach allowed the identification of the N-terminal signal necessary for translocation of this effector. The amino acid residues 1–10 were sufficient to direct translocation into host cells through both type III secretion systems. Our results provide new examples of functional overlapping between the two type III secretion systems of Salmonella