Most people are generous, but not toward everyone alike: generosity usually declines with social distance between individuals, a phenomenon called social discounting. Despite the pervasiveness of social discounting, social distance between actors has been surprisingly neglected in economic theory and neuroscientific research. We used functional magnetic resonance imaging (fMRI) to study the neural basis of this process to understand the neural underpinnings of social decision making. Participants chose between selfish and generous alternatives, yielding either a large reward for the participant alone, or smaller rewards for the participant and another individual at a particular social distance. We found that generous choices engaged the temporoparietal junction (TPJ). In particular, the TPJ activity was scaled to the social-distance-dependent conflict between selfish and generous motives during prosocial choice, consistent with ideas that the TPJ promotes generosity by facilitating overcoming egoism bias. Based on functional coupling data, we propose and provide evidence for a biologically plausible neural model according to which the TPJ supports social discounting by modulating basic neural value signals in the ventromedial prefrontal cortex to incorporate social-distance-dependent other-regarding preferences into an otherwise exclusively own-reward value representation.
Negative symptoms are a core feature of schizophrenia and have been grouped into 2 factors: a motivational factor, which we refer to as apathy, and a diminished expression factor. Recent studies have shown that apathy is closely linked to functional outcome. However, knowledge about its mechanisms and its relation to decision-making is limited. In the current study, we examined whether apathy in schizophrenia is associated with predecisional deficits, that is, deficits in the generation of options for action. We applied verbal protocol analysis to investigate the quantity of options generated in ill-structured real world scenarios in 30 patients with schizophrenia or schizoaffective disorder and 21 healthy control participants. Patients generated significantly fewer options than control participants and clinical apathy ratings correlated negatively with the quantity of generated options. We show that the association between measures of psychopathology and option generation is most pronounced in regard to apathy symptoms and that it is only partially mediated by deficits in verbal fluency. This study provides empirical support for dysfunctional option generation as a possible mechanism for apathy in schizophrenia. Our data emphasize the potential importance of predecisional stages in the development and persistence of apathy symptoms in neuropsychiatric disorders and might also inform the development of novel treatment options in the realm of cognitive remediation.
The prefrontal cortex houses representations critical for ongoing and future behavior expressed in the form of patterns of neural activity. Dopamine has long been suggested to play a key role in the integrity of such representations, with D2-receptor activation rendering them flexible but weak. However, it is currently unknown whether and how D2-receptor activation affects prefrontal representations in humans. In the current study, we use dopamine receptor-specific pharmacology and multivoxel pattern-based functional magnetic resonance imaging to test the hypothesis that blocking D2-receptor activation enhances prefrontal representations. Human subjects performed a simple reward prediction task after double-blind and placebo controlled administration of the D2-receptor antagonist amisulpride. Using a whole-brain searchlight decoding approach we show that D2-receptor blockade enhances decoding of reward signals in the medial orbitofrontal cortex. Examination of activity patterns suggests that amisulpride increases the separation of activity patterns related to reward versus no reward. Moreover, consistent with the cortical distribution of D2 receptors, post hoc analyses showed enhanced decoding of motor signals in motor cortex, but not of visual signals in visual cortex. These results suggest that D2-receptor blockade enhances content-specific representations in frontal cortex, presumably by a dopamine-mediated increase in pattern separation. These findings are in line with a dual-state model of prefrontal dopamine, and provide new insights into the potential mechanism of action of dopaminergic drugs.
Nervous systems must encode information about the identity of expected outcomes to make adaptive decisions. However, the neural mechanisms underlying identity-specific value signaling remain poorly understood. By manipulating the value and identity of appetizing food odors in a pattern-based imaging paradigm of human classical conditioning, we were able to identify dissociable predictive representations of identity-specific reward in orbitofrontal cortex (OFC) and identity-general reward in ventromedial prefrontal cortex (vmPFC). Reward-related functional coupling between OFC and olfactory (piriform) cortex and between vmPFC and amygdala revealed parallel pathways that support identity-specific and -general predictive signaling. The demonstration of identity-specific value representations in OFC highlights a role for this region in model-based behavior and reveals mechanisms by which appetitive behavior can go awry.
We examine how agents allocate attention between private and public signals to reduce the uncertainty about observation noises when coordination is an important concern. In this setting, the attention allocation may not be monotone in endowed attention capacity. Agents may decrease their attention on or even ignore the more accurate signal when capacity increases. As a result, social welfare may decrease when they have more attention to process information. And it can be even higher when agents possess a finite amount of capacity than when they have an infinite amount of capacity. We derive sufficient and necessary conditions under which multiple equilibria emerge and study the implications of equilibrium multiplicity for macroeconomic policies.
Often, economic policies are directed toward outcomes that are measured as counts. Examples of economic variables that use a basic counting scale are number of children as an indicator of fertility, number of doctor visits as an indicator of health care demand, and number of days absent from work as an indicator of employee shirking. Several econometric methods are available for analyzing such data, including the Poisson and negative binomial models. They can provide useful insights that cannot be obtained from standard linear regression models. Estimation and interpretation are illustrated in two empirical examples.
We estimate productivities at the sector level for 72 countries and 5 decades, and examine how they evolve over time in both developed and developing countries. In both country groups, comparative advantage has become weaker: productivity grew systematically faster in sectors that were initially at greater comparative disadvantage. These changes have had a signicant impact on trade volumes and patterns, and a non-negligible welfare impact. In the counterfactual scenario in which each country's comparative advantage remained the same as in the 1960s, and technology in all sectors grew at the same country-specic average rate, trade volumes would be higher, cross-country export patterns more dissimilar, and intra-industry trade lower than in the data. In this counterfactual scenario, welfare is also 1.6% higher for the median country compared to the baseline. The welfare impact varies greatly across countries, ranging from −1.1% to +4.3% among OECD countries, and from −4.6% to +41.9% among non-OECD countries.
The subjective values of choice options can impact on behavior in two fundamentally different types of situations: first, when people explicitly base their actions on such values, and second, when values attract attention despite being irrelevant for current behavior. Here we show with functional magnetic resonance imaging (fMRI) that these two behavioral functions of values are encoded in distinct regions of the human brain. In the medial prefrontal cortex, value-related activity is enhanced when subjective value becomes choice-relevant, and the magnitude of this increase relates directly to the outcome and reliability of the value-based choice. In contrast, activity in the posterior cingulate cortex represents values similarly when they are relevant or irrelevant for the present choice, and the strength of this representation predicts attentional capture by choice-irrelevant values. Our results suggest that distinct components of the brain’s valuation network encode value in context-dependent manners that serve fundamentally different behavioral aims.
