We exploit Italian law DPR 81/2009, which determines class composition, as an instrument to identify the causal effect of grouping students of different grades into a single class (multigrading) on children cognitive achievement. This article focuses on 7-year-old students—those at the beginning of their formal education. Results suggest that attendance in multigrade classes versus single-grade classes increases students’ performance on standardized tests by 15–20 percent of a standard deviation. The positive impact of multigrading only appears for children sharing their class with peers from higher grades and is relatively stronger for students from disadvantaged backgrounds.
Having chosen an item typically increases the subjective value of the chosen item, and people generally enjoy making choices from larger choice sets. However, having too many items to choose from can reduce the value of chosen items—for example, because of conflict or choice difficulty. In this study, we investigated the effects of choice set size on behavioral and neural value updating (revaluation) of the chosen item. In the scanner, participants selected items from choice sets of various sizes (one, two, four, or eight items). After they chose an item, participants rerated the chosen item, and we quantified revaluation by taking the difference of postchoice minus prechoice ratings. Revaluation of chosen items increased up to choice sets of four alternatives but then decreased again for items chosen from choice sets of eight alternatives, revealing both a linear and a quadratic effect of choice set size. At the time of postchoice rating, activation of the ventrolateral pFC (VLPFC) reflected the influence of choice set size on parametric revaluation, without significant relation to either prechoice or postchoice ratings tested separately. Additional analyses revealed relations of choice set size to anterior cingulate and insula activity during actual choice and increased coupling of both regions to revaluation-related VLPFC during postchoice rating. These data suggest that the VLPFC plays a central role in a network that relates choice set size to updating the value of chosen items and integrates choice overload with value-enhancing effects of larger choice sets.
We analyze social mobility of decennial citizenry cohorts of Zurich born between 1780 and 1870. We categorize individuals according to their occupations and use different measures to show the level, change, and components of intergenerational mobility. Mobility was imperfect and weakly decreasing over time. Both level and change are driven by intergenerational persistence of occupations with a low socioeconomic position and low transition between low and high socioeconomic position.
Unternehmer braucht das Land, sagt der Ökonom Fabrizio Zilibotti: Sie sorgen
für Innovationen und wirtschaftliche Entwicklung. Zilibotti erforscht den Esprit
des Unternehmertums und wie dieser weitergegeben wird.
Many researchers seek factors that predict the cross-section of stock returns. The standard methodology sorts stocks according to their factor scores into quantiles and forms a corresponding long-short portfolio. Such a course of action ignores any information on the covariance matrix of stock returns. Historically, it has been difficult to estimate the covariance matrix for a large universe of stocks. We demonstrate that using the recent DCC-NL estimator of Engle et al. (2017) substantially enhances the power of tests for cross-sectional anomalies: On average, 'Student' t-statistics more than double.
Einkommensungleichheiten führen zu einer ungleichen Verteilung der meisten auf dem Markt käuflichen Güter. Es ist allerdings unklar, wie sich das Einkommen auf den Konsum von sozialen Gütern wie Freundetreffen oder Vereinsaktivitäten auswirkt. Marktgüter und Sozialgüter unterscheiden sich konzeptuell, indem der Konsum Ersterer vor allem Geld, der Konsum Letzterer hingegen vor allem Zeit benötigt. Eine Untersuchung hat deshalb den Zusammenhang zwischen den verschiedenen Arten von Gütern, Einkommen, Arbeitszeit und Wohlbefinden untersucht. Sie zeigt: Sowohl Marktgüter als auch soziale Güter spielen eine zentrale Rolle für die Lebenszufriedenheit. Menschen mit hohem Einkommen besitzen zwar mehr Marktgüter, aber nicht mehr oder weniger soziale Güter. Hingegen besitzen Menschen mit langen Arbeitszeiten weniger soziale Güter. Die Ungleichheit in der Arbeitszeit führt somit zu Ungleichheit beim Konsum von sozialen Gütern.
Adaptation facilitates neural representation of a wide range of diverse inputs, including reward values. Adaptive value coding typically relies on contextual information either obtained from the environment or retrieved from and maintained in memory. However, it is unknown whether having to retrieve and maintain context information modulates the brain’s capacity for value adaptation. To address this issue, we measured hemodynamic responses of the prefrontal cortex (PFC) in two studies on risky decision-making. In each trial, healthy human subjects chose between a risky and a safe alternative; half of the participants had to remember the risky alternatives, whereas for the other half they were presented visually. The value of safe alternatives varied across trials. PFC responses adapted to contextual risk information, with steeper coding of safe alternative value in lower-risk contexts. Importantly, this adaptation depended on working memory load, such that response functions relating PFC activity to safe values were steeper with presented versus remembered risk. An independent second study replicated the findings of the first study and showed that similar slope reductions also arose when memory maintenance demands were increased with a secondary working memory task. Formal model comparison showed that a divisive normalization model fitted effects of both risk context and working memory demands on PFC activity better than alternative models of value adaptation, and revealed that reduced suppression of background activity was the critical parameter impairing normalization with increased memory maintenance demand. Our findings suggest that mnemonic processes can constrain normalization of neural value representations.
