Base-rate neglect based on base-rates in experience-based contingency learning

Predicting criterion events based on probabilistic predictor events, humans often lend excessive weight to predictor event information and insufficient weight to criterion event base-rates. Using the matching-to-sample paradigm established in studies on experience-based contingency learning in animals, Goodie and Fantino (1996) showed that human judges exhibit base-rate neglect when sample cues are associated with response options through similarity relations. In conceptual replications of these studies, we demonstrated similar effects when sample cues resemble the response options in terms of base-rates skewed in the same direction rather than physical similarity. In line with the pseudocontingency illusion (Fiedler & Freytag, 2004), predictions were biased toward the more (less) frequently rewarded response option following the more (less) frequently presented sample cue. Thus, what is a demonstration of base-rate neglect from one perspective turns out to reflect the judges' sensitivity to the alignment of skewed base-rate distributions.

Vibrational phenomena in glasses at low temperatures captured by field theory of disordered harmonic oscillators

We investigate the vibrational properties of topologically disordered materials by analytically studying particles that harmonically oscillate around random positions. Exploiting field theory in the thermodynamic limit at $T=0$, we build up a self-consistent model by analysing the Hessian utilizing Euclidean Random Matrix theory. In accordance with earlier findings [1], we take non-planar diagrams into account to correctly address multiple local scattering events. By doing so, we end up with a first principles theory that can predict the main anomalies of athermal disordered materials, including the boson peak, sound softening, and Rayleigh damping of sound. In the vibrational density of states, the sound modes lead to Debye's law for small frequencies. Additionally, quasi-localised modes (QLMs), cause an excess in the density of states starting as $\omega^4$ in the low frequency limit.Comment: 6 pages, 5 figures; 7 pages of supplemental informatio

PD Trafficking of Potato Leaf Roll Virus Movement Protein in Arabidopsis Depends on Site-specific Protein Phosphorylation

Many plant viruses encode for specialized movement proteins (MP) to facilitate passage of viral material to and through plasmodesmata (PD). To analyze intracellular trafficking of potato leaf roll virus (PLRV) movement protein (MP17) we performed GFP fusion experiments with distinct deletion variants of MP17. These studies revealed that the C-terminus of MP17 is essential but not sufficient for PD targeting. Interestingly, fusion of GFP to three C-terminal MP17 deletion variants resulted in the accumulation of GFP in chloroplasts. This indicates that MP17 harbors hidden plastid targeting sequences. Previous studies showed that posttranslational protein phosphorylation influences PD targeting of MP and virus spread. Analysis of MP17-derived phospho-peptides by mass spectrometry revealed four phosphorylated serine residues (S71, S79, S137, and S140). Site-directed mutagenesis of S71/S79 and S137/S140 showed that the C-terminal serine residues S137/S140 are dispensable for PD targeting. However, exchange of S71/S79 to A71/A79 abolished PD targeting of the mutated MP17 protein. To mimic phosphorylation of S71/S79 both amino acids were substituted by aspartic acid. The resulting D71/D79 variant of MP17 was efficiently targeted to PD. Further deletion analysis showed that PD targeting of MP17 is dependent on the C-terminus, phosphorylation of S71 and/or S79 and a N-terminal domain

Base-rate neglect based on base-rates in experience-based contingency learning

Predicting criterion events based on probabilistic predictor events, humans often lend excessive weight to predictor event information and insufficient weight to criterion event base-rates. Using the matching-to-sample paradigm established in studies on experience-based contingency learning in animals, Goodie and Fantino (1996) showed that human judges exhibit base-rate neglect when sample cues are associated with response options through similarity relations. In conceptual replications of these studies, we demonstrated similar effects when sample cues resemble the response options in terms of base-rates skewed in the same direction rather than physical similarity. In line with the pseudocontingency illusion (Fiedler & Freytag, 2004), predictions were biased toward the more (less) frequently rewarded response option following the more (less) frequently presented sample cue. Thus, what is a demonstration of base-rate neglect from one perspective turns out to reflect the judges' sensitivity to the alignment of skewed base-rate distributions

Pseudocontingencies in stereotype formation : extending illusory correlations

Under the notion of illusory correlations, simple learning paradigms (e.g. Hamilton & Gifford, 1976) have been used to study the formation of stereotypes that discriminate between majorities and minorities. In the present paper, limitations of this approach in terms of theoretical explanations and empirical evidence are addressed. Theoretically, we propose pseudocontingencies (PCs, Fiedler, Freytag & Meiser, 2008) as a more robust mechanism behind illusory correlations. In contrast to previous explanations, PCs can explain illusory correlations when groups are never paired with valence. Empirically, we replicate earlier findings, i.e. that the more frequently observed group, the majority, is evaluated more in line with the more frequently observed valence. Crucially, we extend the empirical evidence in that illusory correlations prove robust over a very large number of observations (320) and under increasingly interactive task conditions, involving predictions of valence (Experiment 2) and reinforcement-learning conditions (Experiment 3). The latter provided evidence for illusory correlations on a new measure, participants’ predictions. These predictions reflect the expectations about the valence associated with majority and minority and might well affect real life behavior. The discussion focuses on possible reasons for why PCs are used in stereotypic judgments

The reproduction of base-rates promotes pseudocontingencies

Fiedler and Freytag (2004) proposed an alternative pathway to contingency assessment in terms of pseudocontingencies (PCs). PCs reflect the utilization of base-rate information in the formation of contingency judgments. Here, we introduce an instantiation of the phenomenon based on the mere reproduction of the base rates. Using a relationship-counseling scenario, participants in two experiments produced positive correlations on both indirect and direct measures of the contingency between partners’ responses to the subscales of a relationship inventory, although the objective contingency within each subscale had been negative in an initial learning phase. The magnitude of these effects was predicted accurately by computer simulations reproducing the base rate of ‘yes’ responses for each partner and domain. The findings are discussed within the PC framework

Zur Dynamik der Export- und Importbeteiligung deutscher Industrieunternehmen – Empirische Befunde aus dem Umsatzsteuerpanel 2001 – 2006

Im Jahr 2008 wurden erstmals die Querschnittsdatensätze der Umsatzsteuerstatistik zu einem Paneldatensatz verknüpft - zunächst für den Zeitraum 2001 bis 2005, seit Mitte 2009 steht nun die aktuelle Version des Umsatzsteuerpanels für den Zeitraum 2001 bis 2006 für Auswertungen zur Verfügung. Dieser Datensatz bietet die einzigartige Möglichkeit, alle in diesem Zeitraum umsatzsteuerpflichtigen Unternehmen über den Zeitverlauf hinweg zu betrachten. Da in den Daten auch Informationen über die Export- und Importaktivitäten der Unternehmen enthalten sind, kann das Umsatzsteuerpanel unter anderem dazu genutzt werden, Auskunft über die Verbreitung von Exportund Importaktivitäten sowie über die Dynamik der Export- und Importbeteiligung auf Unternehmensebene zu geben. In 2006 weisen gut 20 Prozent der westdeutschen Industrieunternehmen und knapp 14 Prozent der ostdeutschen Industrieunternehmen sowohl Export- als auch Importaktivitäten auf. Der Anteil der Industrieunternehmen die in 2006 weder exportiert noch importiert haben liegt bei 59 Prozent in Westdeutschland sowie bei 67 Prozent in Ostdeutschland. Eine Betrachtung der Muster der Export- und Importbeteiligung über die Jahre 2001 bis 2006 sowie Übergangsmatrizen für das Jahr 2001 auf 2006 zeigen, dass der überwiegende Teil der Unternehmen ihren Status (weder Exporteur noch Importeur, nur Exporteur, nur Importeur, sowohl Exporteur als auch Importeur) über die Zeit nicht ändert. Immerhin ein Drittel der in allen betrachteten Jahren im Datensatz enthaltenen Unternehmen haben jedoch mindestens einmal zwischen 2001 und 2006 ihren Status gewechselt.

A SAM analogue-utilizing ribozyme for site-specific RNA alkylation in living cells

Post-transcriptional RNA modification methods are in high demand for site-specific RNA labelling and analysis of RNA functions. In vitro-selected ribozymes are attractive tools for RNA research and have the potential to overcome some of the limitations of chemoenzymatic approaches with repurposed methyltransferases. Here we report an alkyltransferase ribozyme that uses a synthetic, stabilized S-adenosylmethionine (SAM) analogue and catalyses the transfer of a propargyl group to a specific adenosine in the target RNA. Almost quantitative conversion was achieved within 1 h under a wide range of reaction conditions in vitro, including physiological magnesium ion concentrations. A genetically encoded version of the SAM analogue-utilizing ribozyme (SAMURI) was expressed in HEK293T cells, and intracellular propargylation of the target adenosine was confirmed by specific fluorescent labelling. SAMURI is a general tool for the site-specific installation of the smallest tag for azide-alkyne click chemistry, which can be further functionalized with fluorophores, affinity tags or other functional probes