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The ventromedial frontal lobe (VMF) is important for decision-making, but the precise causal role of the VMF in the decision process has not been fully established. Previous studies have suggested that individuals with VMF damage violate transitivity, a hallmark axiom of rational decisions. However, these prior studies cannot properly distinguish whether individuals with VMF damage are truly prone to choosing irrationally from whether their preferences are simply more variable. We had individuals with focal VMF damage, individuals with other frontal damage, and healthy controls make repeated choices across three categories-artworks, chocolate bar brands, and gambles. Using proper tests of transitivity, we find that, in our study, individuals with VMF damage make rational decisions consistent with transitive preferences, even though they exhibit greater variability in their preferences. That is, the VMF is necessary for having strong and reliable preferences, but not for being a rational decision maker. VMF damage affects the variability with which value is assessed, but not the consistency with which value is sought.

People use information flexibly. They often combine multiple sources of relevant information over time in order to inform decisions with little or no interference from intervening irrelevant sources. They adjust the degree to which they use new information over time rationally in accordance with environmental statistics and their own uncertainty. They can even use information gained in one situation to solve a problem in a very different one. Learning flexibly rests on the ability to infer the context at a given time, and therefore knowing which pieces of information to combine and which to separate. We review the psychological and neural mechanisms behind adaptive learning and structure learning to outline how people pool together relevant information, demarcate contexts, prevent interference between information collected in different contexts, and transfer information from one context to another. By examining all of these processes through the lens of optimal inference we bridge concepts from multiple fields to provide a unified multi-system view of how the brain exploits structure in time to optimize learning.

Across many studies, ventromedial prefrontal cortex (vmPFC) activity has been found to correlate with subjective value during value-based decision-making. Recently, however, vmPFC has also been shown to reflect a hexagonal gridlike code during navigation through physical and conceptual space, and such gridlike codes have been proposed to enable value-based choices between novel options. Here, we first show that, in theory, a hexagonal gridlike code can in some cases mimic vmPFC activity previously attributed to subjective value, raising the possibility that the subjective value correlates previously observed in vmPFC may have actually been a misconstrued gridlike signal. We then compare the two accounts empirically, using fMRI data from a large number of subjects performing an intertemporal choice task. We find clear and unambiguous evidence that subjective value is a better description of vmPFC activity in this task than a hexagonal gridlike code. In fact, we find no significant evidence at all for a hexagonal gridlike code in vmPFC activity during intertemporal choice. This result limits the generality of gridlike modulation as description of vmPFC activity. We suggest that vmPFC may flexibly switch representational schemes so as to encode the most relevant information for the current task.

Though the ventromedial frontal lobes (VMF) are clearly important for decision-making, the precise causal role of the VMF in the decision process has still not yet fully been established. Previous studies have suggested that individuals with VMF damage violate a hallmark axiom of rational decisions by having intransitive preferences (i.e., preferring A to B, B to C, but C to A), as these individuals are more likely to make cyclical choices (i.e., choosing C over A after previously choosing A over B and B over C). However, these prior studies cannot properly distinguish between two possibilities regarding effects of VMF damage: are individuals with VMF damage prone to choosing irrationally, or are their preferences simply more variable? We had individuals with focal VMF damage, individuals with other frontal damage, and healthy controls make repeated choices across three categories – artwork, chocolate bar brands, and gambles. Using sophisticated tests of transitivity, we find that, without exception, individuals with VMF damage made rational decisions consistent with transitive preferences, even though they more frequently exhibit choice cycles due to a greater variability in their preferences across time. That is, the VMF is necessary for having strong and reliable preferences across time and context, but not for being a rational decision maker. We conclude that VMF damage affects the noisiness with which value is assessed, but not the consistency with which value is sought. Significance statement The VMF is a part of the brain that is thought to be one of the most important for preference-based choice. Despite this, whether it is needed to make rational choices at all is unknown. Previous studies have not discriminated between different possibilities regarding the critical necessary role that the VMF plays in value-based choice. Our study shows that individuals with VMF damage still make rational decisions consistent with what they prefer, but their choices are more variable and less reliable. That is, the VMF is important for the noisiness with which value is assessed, but not the consistency with which value is sought. This result has widespread implications for rethinking the role of VMF in decision-making.

Excessive discounting of future rewards has been related to a variety of risky behaviors and adverse clinical conditions. Prior work examining delay discounting in schizophrenia suggests an elevated discount rate. However, it remains uncertain whether this reflects the disease process itself or an underlying genetic vulnerability, whether it is selective for delay discounting or reflects pervasive changes in decision-making, and whether it is driven by specific clinical dimensions such as cognitive impairment. Here we investigated delay discounting, as well as loss aversion and risk aversion, in three groups: schizophrenia (SZ), unaffected first-degree family members (FM), and controls without a family history of psychosis (NC). SZ had elevated discounting, without changes in loss aversion or risk aversion. Contrary to expectations, the FM group did not show an intermediate phenotype in discounting. Higher discount rates correlated with lower cognitive performance on verbal reasoning, but this did not explain elevated discount rates in SZ. Group differences were driven primarily by the non-smoking majority of the sample. This study provides further evidence for elevated discounting in schizophrenia, and demonstrates that steeper discounting is not necessarily associated with familial risk, cannot be wholly accounted for by cognitive deficits, and is not attributable to smoking-related impulsivity.

This event study of market efficiency found that prices of Treasury Inflation-Protected Securities (TIPS) adjust to inflation information without delay during the U.S. Consumer Price Index (CPI) survey period and even before the beginning of the survey period. The cumulative effect of unexpected inflation on the TIPS holding period returns peaks at the end of the survey period. After the CPI announcement, there is no discernible price adjustment.