Risk Patterns and Correlated Brain Activities. Multidimensional Statistical Analysis of fMRI Data in Economic Decision Making Study

Decision making usually involves uncertainty and risk. Understanding which parts of the human brain are activated during decisions under risk and which neural processes underly (risky) investment decisions are important goals in neuroeconomics. Here, we analyze functional magnetic resonance imaging (fMRI) data on 17 subjects who were exposed to an investment decision task from Mohr, Biele, Krugel, Li, and Heekeren (in NeuroImage 49, 2556–2563, 2010b). We obtain a time series of three-dimensional images of the blood-oxygen-level dependent (BOLD) fMRI signals. We apply a panel version of the dynamic semiparametric factor model (DSFM) presented in Park, Mammen, Wolfgang, and Borak (in Journal of the American Statistical Association 104(485), 284–298, 2009) and identify task-related activations in space and dynamics in time. With the panel DSFM (PDSFM) we can capture the dynamic behavior of the specific brain regions common for all subjects and represent the high-dimensional time-series data in easily interpretable low-dimensional dynamic factors without large loss of variability. Further, we classify the risk attitudes of all subjects based on the estimated low-dimensional time series. Our classification analysis successfully confirms the estimated risk attitudes derived directly from subjects’ decision behavior.     

Interactive context integration in children? Evidence from an action memory study

Action–object phrases (e.g., “lift the bottle”) are remembered better if they have been enacted rather than learned verbally. This enactment effect is largest in free recall for phrases with objects (e.g., “bottle”) present because these phrases can be interactively encoded with those context objects (interactive context integration) that serve as retrieval cues. The current study investigated whether 6- and 8-year-olds are already capable of interactive context integration. Experiment 1 demonstrated interactive context integration with 8-year-olds. This was hindered in a condition where attention was directed away from context objects. Experiment 2 demonstrated interactive context integration with 6-year-old kindergartners. Taken together, our findings show that even 6-year-olds are capable of incidental context integration through enactment and that this process is attention based.