Neural Responses to Truth Telling and Risk Propensity under Asymmetric Information

This research was supported by the Laureate Institute for Brain Research and the William K. Warren Foundation. The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.Trust is multi-dimensional because it can be characterized by subjective trust, trust antecedent, and behavioral trust. Previous research has investigated functional brain responses to subjective trust (e.g., a judgment of trustworthiness) or behavioral trust (e.g., decisions to trust) in perfect information, where all relevant information is available to all participants. In contrast, we conducted a novel examination of the patterns of functional brain activity to a trust antecedent, specifically truth telling, in asymmetric information, where one individual has more information than others, with the effect of varying risk propensity. We used functional magnetic resonance imaging (fMRI) and recruited 13 adults, who played the Communication Game, where they served as the “Sender” and chose either truth telling (true advice) or lie telling (false advice) regarding the best payment allocation for their partner. Our behavioral results revealed that subjects with recreational high risk tended to choose true advice. Moreover, fMRI results yielded that the choices of true advice were associated with increased cortical activation in the anterior rostral medial and frontopolar prefrontal cortices, middle frontal cortex, temporoparietal junction, and precuneus. Furthermore, when we specifically evaluated a role of the bilateral amygdala as the region of interest (ROI), decreased amygdala response was associated with high risk propensity, regardless of truth telling or lying. In conclusion, our results have implications for how differential functions of the cortical areas may contribute to the neural processing of truth telling.Yeshttp://www.plosone.org/static/editorial#pee

Variability of dense water formation in the Ross Sea

The paper presents results from a model study of the interannual variability of High Salinity Shelf Water (HSSW) properties in the Ross Sea.Salinity, potential temperature and volume of HSSW formed in the western Ross Sea show oscillatory behaviour at periods of 5-6 and 9 years superimposed on long-term fluctuations.While the shorter oscillations are induced by wind variability, variability on the scale of decades appears to be related to air temperature fluctuations.At least part of the strong decrease of HSSW salinities deduced from observations for the period 1963-2000 is shown to be an aliasing artefact due to an undersampling of the periodic signal.While sea ice formation is responsible for the yearly salinity increase that triggers the formation of High Salinity Shelf Water, interannual variability of net freezing rates hardly affects changes in the properties of the resulting water mass.Instead, results from model experiments indicate that the interannual variability of dense water characteristics is predominantly controlled by variations in the shelf inflow through a sub-surface salinity and a deep temperature signal.The origin of the variability of inflow characteristics to the Ross Sea continental shelf can be traced into the Amundsen and Bellingshausen Seas.The temperature anomalies are induced at the continental shelf break in the western Bellingshausen Sea by fluctuations of the meridional transport of Circumpolar Deep Water with the eastern cell of the Ross Gyre.Upwelling in the centre of this gyre carries the signal into the surface layer where it causes anomalies of brine release near the sea ice edge in the Amundsen Sea, which results in a sub-surface salinity anomaly.With the westward flowing coastal current, both the sub-surface salinity and deep temperature signals are advected onto the Ross Sea continental shelf.Convection carries the signal of salinity variability into the deep ocean, where it interacts with Modified Circumpolar Deep Water upwelled onto the continental shelf as the second source water mass of HSSW.Sea ice formation on the Ross Sea continental shelf thus drives the vertical propagation of the signal rather than determining the signal itself