Semi-orthogonal subspaces for value mediate a tradeoff between binding and generalization

When choosing between options, we must associate their values with the action needed to select them. We hypothesize that the brain solves this binding problem through neural population subspaces. To test this hypothesis, we examined neuronal responses in five reward-sensitive regions in macaques performing a risky choice task with sequential offers. Surprisingly, in all areas, the neural population encoded the values of offers presented on the left and right in distinct subspaces. We show that the encoding we observe is sufficient to bind the values of the offers to their respective positions in space while preserving abstract value information, which may be important for rapid learning and generalization to novel contexts. Moreover, after both offers have been presented, all areas encode the value of the first and second offers in orthogonal subspaces. In this case as well, the orthogonalization provides binding. Our binding-by-subspace hypothesis makes two novel predictions borne out by the data. First, behavioral errors should correlate with putative spatial (but not temporal) misbinding in the neural representation. Second, the specific representational geometry that we observe across animals also indicates that behavioral errors should increase when offers have low or high values, compared to when they have medium values, even when controlling for value difference. Together, these results support the idea that the brain makes use of semi-orthogonal subspaces to bind features together.Comment: arXiv admin note: substantial text overlap with arXiv:2205.0676

Naturalistic decision-making: continuous, open-world, and recursive

Real-world decisions take place over time, in dynamics contexts, and with frequently shifting choice sets. In contrast, most studies of decision making have focused on single, abstracted choices among small numbers of discrete options. Here, we advocate for a shift in emphasis to what we call continuous decisions, which better capture the complexity of decision-making in the wild. Continuous decisions involve a continuum of possible responses and take place over an extended period of time during which the response is continuously subject to modification. The range of options available at any time can fluctuate and is affected by recent responses, making consideration of feedback between choices and the environment essential. The study of continuous decisions emphasizes distinct questions not easily captured by discrete decisions, including questions about how the brain integrates choices with movement, bridges representations through time, and maintains hierarchically organized information. While microeconomic theory has proven invaluable for discrete decisions, we propose that engineering control theory may serve as a better foundation for continuous ones. And while the concept of value has proven foundational for discrete decisions, goal states and policies may prove more useful for continuous ones

Continuous Decisions

Humans and other animals evolved to make decisions that extend over time with continuous and ever-changing options. Nonetheless, the academic study of decision-making is mostly limited to the simple case of choice between two options. Here we advocate that the study of choice should expand to include continuous decisions. Continuous decisions, by our definition, involve a continuum of possible responses and take place over an extended period of time during which the response is continuously subject to modification. In most continuous decisions, the range of options can fluctuate and is affected by recent responses, making consideration of reciprocal feedback between choices and the environment essential. The study of continuous decisions raises new questions, such as how abstract processes of valuation and comparison are co-implemented with action planning and execution, how we simulate the large number of possible futures our choices lead to, and how our brains employ hierarchical structure to make choices more efficiently. While microeconomic theory has proven invaluable for discrete decisions, we propose that engineering control theory may serve as a better foundation for continuous ones. And while the concept of value has proven foundational for discrete decisions, goal states and policies may prove more useful for continuous ones

Subspace orthogonalization as a mechanism for binding values to space

When choosing between options, we must solve an important binding problem. The values of the options must be associated with other information, including the action needed to select them. We hypothesized that the brain solves this binding problem through use of distinct population subspaces. We examined responses of single neurons in five value-sensitive regions in rhesus macaques performing a risky choice task. In all areas, neurons encoded the values of both possible options, but used semi-orthogonal coding subspaces associated with left and right options, which served to link options to their positions in space. We also observed a covariation between subspace orthogonalization and behavior: trials with less orthogonalized subspaces were associated with greater likelihood of choosing the less valued option. These semi-orthogonal subspaces arose from a combination of linear and non-linear mixed selective neurons. By decomposing the neural geometry, we show this combination of selectivity achieves a code that balances binding/separation and generalization. These results support the hypothesis that binding operations serve to convert high-dimensional codes to multiple low-dimensional neural subspaces to flexibly solve decision problems.Comment: 45 pages, 4 figure

Trust in Institutions, Not in Political Leaders, Determines Covid-19 Public Health Compliance in Societies across the Globe

A core assumption often heard in public health discourse is that increasing trust in national political leaders is essential for securing public health compliance during crises like the Covid-19 pandemic (2019-ongoing). However, studies of national government trust typically are too coarse-grained to differentiate between trust in institutions versus more interpersonal trust in political leaders. Here, we present multiscale trust measurements for twelve countries and territories across the West, Oceania and East Asia. These trust results were used to identify which specific domains of government and social trust were most crucial for securing public health compliance (frequency of mask wearing and social distancing) and understanding the reasons for following the health measures (belief in effectiveness of public health measures). Through the use of linear regression and structural equation modeling, our cross-cultural survey-based analysis (N=3369 subjects) revealed that higher trust in national and local public health institutions were a universally consistent predictor of public health compliance, while trust in national political leaders was not predictive of compliance across cultures and geographical regions. Institutional trust was mediated by multiple types of transparency, including providing rationale, securing public feedback, and honestly expressing uncertainty. These results highlight the importance of distinguishing between components of government trust, to better understand which entities the public gives the most attention to during crises

Trust in Institutions, Not in Political Leaders, Determines Compliance in COVID-19 Prevention Measures within Societies across the Globe

A core assumption often heard in public health discourse is that increasing trust in national political leaders is essential for securing public health compliance during crises such as the COVID-19 pandemic (2019–ongoing). However, studies of national government trust are typically too coarse-grained to differentiate between trust in institutions versus more interpersonal trust in political leaders. Here, we present multiscale trust measurements for twelve countries and territories across the West, Oceania and East Asia. These trust results were used to identify which specific domains of government and social trust were most crucial for securing public health compliance (frequency of mask wearing and social distancing) and understanding the reasons for following health measures (belief in effectiveness of public health measures). Through the use of linear regression and structural equation modeling, our cross-cultural survey-based analysis (N = 3369 subjects) revealed that higher trust in national and local public health institutions was a universally consistent predictor of public health compliance, while trust in national political leaders was not predictive of compliance across cultures and geographical regions. Institutional trust was mediated by multiple types of transparency, including providing rationale, securing public feedback, and honestly expressing uncertainty. These results highlight the importance of distinguishing between components of government trust, to better understand which entities the public gives the most attention to during crises.Comp Graphics & Visualisatio