In this chapter, we describe how risk and ambiguity impact the value of choice options, how this impact can be modelled formally and how it is implemented in the brain. In particular, we give an overview of two distinct ways of how risky choice options can be decomposed – either into outcomes and probabilities as proposed in economics or into statistical moments of the probability distribution like mean, variance, or skewness, as proposed in finance theory. The components of either approach appear to be represented in common and, at least to some extent, in separate brain regions, which include the dopaminergic midbrain, striatum and the orbitofrontal cortex. Activity in different (prefrontal and striatal) brain regions also supports the distinction between decisions from experience, when knowledge about risk is learned through trial and error versus decisions from description, when it is described symbolically. The fact that the principal components of formal models from economics and finance theory and their behavioral versions that provide better descriptive fit are represented in the brain provides converging support for these models.
In order to choose advantageously in many circumstances, the values of choice alternatives have to be learned from experience. We provide an introduction to theoretical and experimental work on reinforcement learning, that is, trial-and-error learning to obtain rewards or avoid punishments. We introduce one version, the temporal-difference learning model, and review evidence that its predictions relate to the firing properties of midbrain dopamine neurons and to activity recorded with functional neuroimaging in humans. We also present evidence that this computational and neurophysiological mechanism affects human and animal behavior in decision and conditioning tasks.
In this chapter, we present a set of concepts and tools for defining and examining strategic choice that are drawn from behavioral economics and discuss how they can be applied to and tested with neuroscience techniques. The standard language for studying strategic choice in economics is game theory. Game theory provides concrete mathematical formulas for linking strategic actions to rewarding payoffs. After outlining the four components necessary to make predictions about strategic social behavior, we present recent evidence that the computations predicted by game theory in specific strategic choice contexts are reflected in the brain. In addition, we discuss links between strategic decision making and the psychological concept of theory of mind. We conclude by suggesting that developing mathematical models of social and strategic actions may aid in the understanding of how the brain implements typical choice behavior as well as categorizing dysfunctions that lead to aberrant behavior in psychiatric disorders.
All known human societies have maintained social order by enforcing compliance with social norms. The biological mechanisms underlying norm compliance are, however, hardly understood. We show that the right lateral prefrontal cortex (rLPFC) is involved in both voluntary and sanction-induced norm compliance. Both types of compliance could be changed by varying the neural excitability of this brain region with transcranial direct current stimulation, but they were affected in opposite ways, suggesting that the stimulated region plays a fundamentally different role in voluntary and sanction-based compliance. Brain stimulation had a particularly strong effect on compliance in the context of socially constituted sanctions, whereas it left beliefs about what the norm prescribes and about subjectively expected sanctions unaffected. Our findings suggest that rLPFC activity is a key biological prerequisite for an evolutionarily and socially important aspect of human behavior.
Wachstum vermehrt die verfügbaren Güter und lindert dadurch die Not. Mit steigendem Wohlstand verliert diese Expansion der bestehenden Produktion an Nützlichkeit. Worauf aber gründet sich dann die Bedeutung von Wachstum? “The desire of food is limited in every man by the narrow capacity of the human stomach; but the desire of the conveniencies and ornaments... seems to have no limit or certain boundary” formuliert Adam Smith in einer berühmten Stelle des Wealth of Nations.1) Die Verbesserung und die Verschönerung der Produkte stellen also eine wichtige Funktion dar, der sich das Wachstum zuwendet. Die andere wichtige Funktion ist, durch immer neue Produkte den Wunsch nach Vielfalt und Unterscheidung zu erfüllen. “The wants of the savage are few; but civilization brings with it a desire for variety for its own sake”, und “Man’s capacity for food is limited, but not his craving for distinction” lautet (in Anlehnung an Senior) Marshalls Kurzcharakteristik dieses Sachverhalts.2)
