Negations in uncertainty lexicon affect attention, decision-making and trust

The Intergovernmental Panel on Climate Change (IPCC) currently communicates uncertainty using a lexicon that features four negative verbal probabilities to convey extremely low to medium probabilities (e.g., unlikely). We compare a positive probability lexicon with the IPCC lexicon in a series of psychology experiments. We find that although the positive and negative lexicons convey a similar level of probability, the positive lexicon directs more attention towards the outcome occurrence, and encourages more cautious decisions: in our role-playing experiment it reduced the number of Type 2 errors, i.e. failures to make needed precautionary interventions. Whilst participants considered the negative lexicon more useful in making a decision, they trusted the positive lexicon more and blamed information providers less after making an incorrect decision. Our results suggest that the negative verbal framing of probabilities used by the IPCC is not neutral and has implications for how climate information is interpreted by decision-makers

Control analysis of the TMT primary segment assembly

The primary mirror control system (M1CS) stabilizes the 492 segments of the Thirty Meter Telescope primary mirror in the presence of disturbances. Each Primary Segment Assembly (PSA) has three actuators and position sensors that control the piston, tip, and tilt of the mirror segment. Requirements for the PSA position controller are presented, with the main requirements being 10 Newton per micron stiffness below one Hertz, where wind is the primary disturbance. Bandwidths of the PSA position controller of about twenty Hertz, assuming a soft actuator, are needed to meet this requirement. A finite element model of the PSA was developed and used for a preliminary control design. PSA structural modes at 40, 90, and 120 impact the control design. We have studied control designs with different actuators, sensors, and structural filters in order to assess disturbance rejection properties and interactions with the PSA structural modes. The performance requirements are achieved using voice coil actuators with modal control architecture for piston, tip, and tilt. Force interactions with the underlying mirror cell are important, and we present the status of our studies of the control structure interaction effect (CSIE). A related paper presents further analysis of the CSIE and MICS global position control loop

Climate scientists’ wide prediction intervals may be more likely but are perceived to be less certain

The use of interval forecasts allows climate scientists to issue predictions with high levels of certainty even for areas fraught with uncertainty, since wide intervals are objectively more likely to capture the truth than narrow intervals. However, wide intervals are also less informative about what the outcome will be than narrow intervals, implying a lack of knowledge or subjective uncertainty in the forecaster. In six experiments, we investigate how lay people perceive the (un)certainty associated with wide and narrow interval forecasts, and find that the preference for accuracy (seeing wide intervals as “objectively” certain) vs. informativeness (seeing wide intervals as indicating “subjective” uncertainty) is influenced by contextual cues (e.g., question formulation). Most importantly, we find that people more commonly and intuitively associate wide intervals with uncertainty than with certainty. Our research thus challenges the wisdom of using wide intervals to construct statements of high certainty in climate change reports

Les manuels, un mode de textualisation scolaire du savoir savant

Comment dans la sphère scolaire, la transposition didactique transforme-t-elle un objet scientifique en objet d'enseignement? A cette question l'analyse des manuels scolaires permet de répondre de manière privilégiée, dans la mesure où ceux-ci, mettant en oeuvre programmes et instructions officielles, peuvent être considérés comme incarnant la forme scolaire du savoir. Les AA. ont considéré les manuels comme des « acteurs » de la transposition didactique car ils opèrent d'une part une sélection des objets de savoir, et d'autre part une textualisation. Trois aspects du fonctionnement de la transposition didactique du concept de respiration ont été retenus : 1) Quel savoir recouvre la notion de respiration dans les manuels? 2) Comment l'évolution des savoirs, et l'actualité scientifique sont-elles prises en compte? 3) Quel modèle de démarche scientifique est privilégié dans les manuels

Control analysis of the TMT primary segment assembly

The primary mirror control system (M1CS) stabilizes the 492 segments of the Thirty Meter Telescope primary mirror in the presence of disturbances. Each Primary Segment Assembly (PSA) has three actuators and position sensors that control the piston, tip, and tilt of the mirror segment. Requirements for the PSA position controller are presented, with the main requirements being 10 Newton per micron stiffness below one Hertz, where wind is the primary disturbance. Bandwidths of the PSA position controller of about twenty Hertz, assuming a soft actuator, are needed to meet this requirement. A finite element model of the PSA was developed and used for a preliminary control design. PSA structural modes at 40, 90, and 120 impact the control design. We have studied control designs with different actuators, sensors, and structural filters in order to assess disturbance rejection properties and interactions with the PSA structural modes. The performance requirements are achieved using voice coil actuators with modal control architecture for piston, tip, and tilt. Force interactions with the underlying mirror cell are important, and we present the status of our studies of the control structure interaction effect (CSIE). A related paper presents further analysis of the CSIE and MICS global position control loop

Analysis of the TMT mount control system

The TMT mount control system provides telescope pointing and tracking. Requirements include wind disturbance rejection, offsetting time and accuracy, control system robustness, and the magnitude of response at structural resonances. A finite element model of the complete telescope has been developed and the transfer functions used for the control designs are presented. Wind disturbance, encoder, and wave-front-sensor models are presented that are used for the control design. A performance analysis translates the requirements to a required bandwidth. Achieving this bandwidth is important for reducing telescope image motion due to wind-buffeting. A mount control design is presented that meets the demanding requirements by maximizing low frequency gain and using structural filters to roll-off structural modes. The control system analysis includes an outer guide loop using a wave front sensor. Offsetting time and accuracy requirements are satisfied using feed-forward control architecture

Structural mapping in statistical word problems: A relational reasoning approach to Bayesian inference

Presenting natural frequencies facilitates Bayesian inferences relative to using percentages. Nevertheless, many people, including highly educated and skilled reasoners, still fail to provide Bayesian responses to these computationally simple problems. We show that the complexity of relational reasoning (e.g., the structural mapping between the presented and requested relations) can help explain the remaining difficulties. With a non-Bayesian inference that required identical arithmetic but afforded a more direct structural mapping, performance was universally high. Furthermore, reducing the relational demands of the task through questions that directed reasoners to use the presented statistics, as compared with questions that prompted the representation of a second, similar sample, also significantly improved reasoning. Distinct error patterns were also observed between these presented- and similar-sample scenarios, which suggested differences in relational-reasoning strategies. On the other hand, while higher numeracy was associated with better Bayesian reasoning, higher-numerate reasoners were not immune to the relational complexity of the task. Together, these findings validate the relational-reasoning view of Bayesian problem solving and highlight the importance of considering not only the presented task structure, but also the complexity of the structural alignment between the presented and requested relations