Distributed Coding of Evidence Accumulation across the Mouse Brain Using Microcircuits with a Diversity of Timescales.

The gradual accumulation of noisy evidence for or against options is the main step in the perceptual decision-making process. Using brain-wide electrophysiological recording in mice (Steinmetz et al., 2019), we examined neural correlates of evidence accumulation across brain areas. We demonstrated that the neurons with drift-diffusion model (DDM)-like firing rate activity (i.e., evidence-sensitive ramping firing rate) were distributed across the brain. Exploring the underlying neural mechanism of evidence accumulation for the DDM-like neurons revealed different accumulation mechanisms (i.e., single and race) both within and across the brain areas. Our findings support the hypothesis that evidence accumulation is happening through multiple integration mechanisms in the brain. We further explored the timescale of the integration process in the single and race accumulator models. The results demonstrated that the accumulator microcircuits within each brain area had distinct properties in terms of their integration timescale, which were organized hierarchically across the brain. These findings support the existence of evidence accumulation over multiple timescales. Besides the variability of integration timescale across the brain, a heterogeneity of timescales was observed within each brain area as well. We demonstrated that this variability reflected the diversity of microcircuit parameters, such that accumulators with longer integration timescales had higher recurrent excitation strength.

Desperation and inequality increase stealing: evidence from experimental microsocieties.

People facing material deprivation are more likely to turn to acquisitive crime. It is not clear why it makes sense for them to do so, given that apprehension and punishment may make their situation even worse. Recent theory suggests that people should be more willing to steal if they are on the wrong side of a 'desperation threshold'; that is, a level of resources critical to wellbeing. Below such a threshold, people should pursue any risky behaviour that offers the possibility of a short route back above, and should be insensitive to the severity of possible punishments, since they have little left to lose. We developed a multi-round, multi-player economic game with a desperation threshold and the possibility of theft as well as cooperation. Across four experiments with 1000 UK and US adults, we showed that falling short of a desperation threshold increased stealing from other players, even when the payoff from stealing was negative on average. Within the microsocieties created in the game, the presence of more players with below-threshold resources produced low trust, driven by the experience of being stolen from. Contrary to predictions, our participants appeared to be somewhat sensitive to the severity of punishment for being caught trying to steal. Our results show, in an experimental microcosm, that some members of society falling short of a threshold of material desperation can have powerful social consequences.

Non-instrumental actions can communicate roles and relationships, not just rituals.

Actions that do not have instrumental goals can communicate social goals that are not rituals. Many non-instrumental actions such as bowing or kissing communicate a commitment to or roles in dyadic relationships. What is unclear is when people understand such actions in terms of ritual and when they understand them in terms of relationships.

Advantages and limitations of representing groups in terms of recursive utilities.

Group representations based on recursive utilities can be used to derive the same predictions as Pietraszewski in conflict situations. Additionally, these representations generalize to non-conflict situations, asymmetric relationships, and represent the stakes in a conflict. However, both proposals fail to represent asymmetries of power and responsibility and to account for generalizations from specific observed individuals to collections of non-observed individuals.