Dynamic Integration of Value Information into a Common Probability Currency as a Theory for Flexible Decision Making

Decisions involve two fundamental problems, selecting goals and generating actions to pursue those goals. While simple decisions involve choosing a goal and pursuing it, humans evolved to survive in hostile dynamic environments where goal availability and value can change with time and previous actions, entangling goal decisions with action selection. Recent studies suggest the brain generates concurrent action-plans for competing goals, using online information to bias the competition until a single goal is pursued. This creates a challenging problem of integrating information across diverse types, including both the dynamic value of the goal and the costs of action. We model the computations underlying dynamic decision-making with disparate value types, using the probability of getting the highest pay-off with the least effort as a common currency that supports goal competition. This framework predicts many aspects of decision behavior that have eluded a common explanation.     

Representation of spatial goals in rat orbitofrontal cortex

The orbitofrontal cortex (OFC) is thought to participate in making and evaluating goal-directed decisions. In rodents, spatial navigation is a major mode of goal-directed behavior, and anatomical and lesion studies implicate the OFC in spatial processing, but there is little direct evidence for coding of spatial or motor variables. Here, we recorded from ventrolateral and lateral OFC in an odor-cued two-alternative choice task requiring orientation and approach to spatial goal ports. In this context, over half of OFC neurons encoded choice direction or goal port location. A subset of neurons was jointly selective for the trial outcome and port location, information useful for the selection or evaluation of spatial goals. These observations show that the rodent OFC not only encodes information relating to general motivational significance, as shown previously, but also encodes spatiomotor variables needed to define specific behavioral goals and the locomotor actions required to attain them.     

Using conditional power of network meta‐analysis (NMA) to inform the design of future clinical trials

Clinical trials are typically designed with an aim to reach sufficient power to test a hypothesis about relative effectiveness of two or more interventions. Their role in informing evidence‐based decision‐making demands, however, that they are considered in the context of the existing evidence. Consequently, their planning can be informed by characteristics of relevant systematic reviews and meta‐analyses. In the presence of multiple competing interventions the evidence base has the form of a network of trials, which provides information not only about the required sample size but also about the interventions that should be compared in a future trial. In this paper we present a methodology to evaluate the impact of new studies, their information size, the comparisons involved, and the anticipated heterogeneity on the conditional power (CP) of the updated network meta‐analysis. The methods presented are an extension of the idea of CP initially suggested for a pairwise meta‐analysis and we show how to estimate the required sample size using various combinations of direct and indirect evidence in future trials. We apply the methods to two previously published networks and we show that CP for a treatment comparison is dependent on the magnitude of heterogeneity and the ratio of direct to indirect information in existing and future trials for that comparison. Our methodology can help investigators calculate the required sample size under different assumptions about heterogeneity and make decisions about the number and design of future studies (set of treatments compared).     

Resolution of uncertainty in prefrontal cortex

Making optimal decisions in the face of uncertain or incomplete information arises as a common problem in everyday behavior, but the neural processes underlying this ability remain poorly understood. A typical case is navigation, in which a subject has to search for a known goal from an unknown location. Navigating under uncertain conditions requires making decisions on the basis of the current belief about location and updating that belief based on incoming information. Here, we use functional magnetic resonance imaging during a maze navigation task to study neural activity relating to the resolution of uncertainty as subjects make sequential decisions to reach a goal. We show that distinct regions of prefrontal cortex are engaged in specific computational functions that are well described by a Bayesian model of decision making. This permits efficient goal-oriented navigation and provides new insights into decision making by humans.     

Prioritizing covariates in the planning of future studies in the meta‐analytic framework

Science can be seen as a sequential process where each new study augments evidence to the existing knowledge. To have the best prospects to make an impact in this process, a new study should be designed optimally taking into account the previous studies and other prior information. We propose a formal approach for the covariate prioritization, that is the decision about the covariates to be measured in a new study. The decision criteria can be based on conditional power, change of the p‐value, change in lower confidence limit, Kullback–Leibler divergence, Bayes factors, Bayesian false discovery rate or difference between prior and posterior expectation. The criteria can be also used for decisions on the sample size. As an illustration, we consider covariate prioritization based on genome‐wide association studies for C‐reactive protein levels and make suggestions on the genes to be studied further.     

An Analytically Solvable Model for Rapid Evolution of Modular Structure

Biological systems often display modularity, in the sense that they can be decomposed into nearly independent subsystems. Recent studies have suggested that modular structure can spontaneously emerge if goals (environments) change over time, such that each new goal shares the same set of sub-problems with previous goals. Such modularly varying goals can also dramatically speed up evolution, relative to evolution under a constant goal. These studies were based on simulations of model systems, such as logic circuits and RNA structure, which are generally not easy to treat analytically. We present, here, a simple model for evolution under modularly varying goals that can be solved analytically. This model helps to understand some of the fundamental mechanisms that lead to rapid emergence of modular structure under modularly varying goals. In particular, the model suggests a mechanism for the dramatic speedup in evolution observed under such temporally varying goals.     

Assessment Strategies and the Effects of Fighting Experience on Future Contest Performance in the Green Anole (Anolis carolinensis)

Social experiences can be useful sources of information for animals charged with making fitness‐related decisions. Fighting experience can alter an animal's perception of its fighting ability possibly leading to changes in future contest decisions, which may increase/decrease their probability of winning future contests. Winner and loser effects have been revealed in a wide array of animals, but studies using reptilian models are rare. This study investigated the impact of fighting experience on future contest performance and outcome in the green anole lizard and investigated the assessment strategies used by anoles during contests of different intensities. To determine whether the green anole expresses winner or loser effects, focal animals engaged in a primary contest with a smaller (larger) opponent to gain a winning (losing) experience; opponent size asymmetries were a significant predictor of contest outcome. Focal individuals were isolated for 2 d before being given a secondary contest with a size‐matched, naïve opponent. We found no evidence of winner or loser effects 2 d following a previous contest. Although previous contest outcome did not dictate future contest success, dynamics of the previous contest did. Highly aggressive primary contest losers won a significant proportion of the secondary contests, while less aggressive losers were more apt to lose the secondary contest. Secondary contest success of prior winners was not influenced by earlier contest performance. Further analyses of contest dynamics reveal that individuals may use different assessment strategies depending on the intensity of the contest. Our results demonstrate that future contest success may be driven more by individual performance in a prior contest and less by prior contest outcome.     

Where is the Evidence for Assessing Evidence‐Based Restoration? Comments on Ntshotsho et al. (2010)

In their article “Assessing the evidence base for restoration in South Africa,” Ntshotsho et al. attempt to determine whether restoration in South Africa is evidence based by reporting on 10 projects' baseline data collection, goal setting, and monitoring. However, their contribution suffers from two major constraints. First, they confuse assessing the evidence base with assessing whether restoration is evidence based. Truly, assessing the evidence base would entail a systematic review of the quantity and quality of information available as well as the conclusions supported, perhaps in a meta‐analytical framework. Determining if restoration is evidence based would require a survey of project managers to evaluate if they take decisions based on scientific information. Second, Ntshotsho et al. do not clearly distinguish successfully achieving restoration project goals from successfully restoring ecosystems. They largely focus on projects' socioeconomic goals without emphasizing that these goals are, by definition, secondary to ecological goals in determining restoration success. Thus, Ntshotsho et al. provide neither a sound assessment of the evidence base for restoration nor whether restoration is evidence based. To evaluate and encourage evidence‐based restoration in South Africa, we recommend a simple assessment of the basis on which restoration managers make decisions, identification of factors precluding evidence‐based decision‐making, and development of platforms to evaluate the data collected in restoration programs to generate an evidence base from which to make defendable decisions.     

Decision accuracy in complex environments is often maximized by small group sizes

Individuals in groups, whether composed of humans or other animal species, often make important decisions collectively, including avoiding predators, selecting a direction in which to migrate and electing political leaders. Theoretical and empirical work suggests that collective decisions can be more accurate than individual decisions, a phenomenon known as the ‘wisdom of crowds’. In these previous studies, it has been assumed that individuals make independent estimates based on a single environmental cue. In the real world, however, most cues exhibit some spatial and temporal correlation, and consequently, the sensory information that near neighbours detect will also be, to some degree, correlated. Furthermore, it may be rare for an environment to contain only a single informative cue, with multiple cues being the norm. We demonstrate, using two simple models, that taking this natural complexity into account considerably alters the relationship between group size and decision-making accuracy. In only a minority of environments do we observe the typical wisdom of crowds phenomenon (whereby collective accuracy increases monotonically with group size). When the wisdom of crowds is not observed, we find that a finite, and often small, group size maximizes decision accuracy. We reveal that, counterintuitively, it is the noise inherent in these small groups that enhances their accuracy, allowing individuals in such groups to avoid the detrimental effects of correlated information while exploiting the benefits of collective decision-making. Our results demonstrate that the conventional view of the wisdom of crowds may not be informative in complex and realistic environments, and that being in small groups can maximize decision accuracy across many contexts.     

The neural systems that mediate human perceptual decision making

Perceptual decision making is the act of choosing one option or course of action from a set of alternatives on the basis of available sensory evidence. Thus, when we make such decisions, sensory information must be interpreted and translated into behaviour. Neurophysiological work in monkeys performing sensory discriminations, combined with computational modelling, has paved the way for neuroimaging studies that are aimed at understanding decision-related processes in the human brain. Here we review findings from human neuroimaging studies in conjunction with data analysis methods that can directly link decisions and signals in the human brain on a trial-by-trial basis. This leads to a new view about the neural basis of human perceptual decision-making processes.     

Swarm Intelligence in Animal Groups: When Can a Collective Out-Perform an Expert?

An important potential advantage of group-living that has been mostly neglected by life scientists is that individuals in animal groups may cope more effectively with unfamiliar situations. Social interaction can provide a solution to a cognitive problem that is not available to single individuals via two potential mechanisms: (i) individuals can aggregate information, thus augmenting their 'collective cognition', or (ii) interaction with conspecifics can allow individuals to follow specific 'leaders', those experts with information particularly relevant to the decision at hand. However, a-priori, theory-based expectations about which of these decision rules should be preferred are lacking. Using a set of simple models, we present theoretical conditions (involving group size, and diversity of individual information) under which groups should aggregate information, or follow an expert, when faced with a binary choice. We found that, in single-shot decisions, experts are almost always more accurate than the collective across a range of conditions. However, for repeated decisions - where individuals are able to consider the success of previous decision outcomes - the collective's aggregated information is almost always superior. The results improve our understanding of how social animals may process information and make decisions when accuracy is a key component of individual fitness, and provide a solid theoretical framework for future experimental tests where group size, diversity of individual information, and the repeatability of decisions can be measured and manipulated.     

Group decision making in fission-fusion societies: evidence from two-field experiments in Bechstein's bats

Group decisions are required when group coordination is beneficial, but individuals can choose between alternatives. Despite the increased interest in animal group decision making, there is a lack of experimental field studies that investigate how animals with conflicting information make group decisions. In particular, no field studies have considered the influence of fission-fusion behaviour (temporary splitting into subgroups) on group decisions. We studied group decision making in two wild Bechstein's bat colonies, which are fission-fusion societies of stable individual composition. Since they frequently switch communal roosts, colony members must regularly make group decisions over where to roost. In the two-field experiments, we provided marked individuals with conflicting information about the suitability of potential roosts. We investigated whether conflicting information led to group decisions that followed a 'unanimous' or a 'majority' rule, or increased colony fission. Individual behaviour suggests that bats considered both their own information and the behaviour of others when deciding where to roost. Group decisions about communal roosts reflected the information available to a majority of the bats roosting together, but conflicting information led to an increased fission in one colony. Our results suggest that fission-fusion societies allow individuals to avoid majority decisions that are not in their favour.     

Laboratory studies on surface sampling of Bacillus anthracis contamination: summary,gaps and recommendations

This article summarizes previous laboratory studies to characterize the performance of methods for collecting, storing/transporting, processing and analysing samples from surfaces contaminated by Bacillus anthracis or related surrogates. The focus is on plate culture and count estimates of surface contamination for swab, wipe and vacuum samples of porous and nonporous surfaces. Summaries of the previous studies and their results were assessed to identify gaps in information needed as inputs to calculate key parameters critical to risk management in biothreat incidents. One key parameter is the number of samples needed to make characterization or clearance decisions with specified statistical confidence. Other key parameters include the ability to calculate, following contamination incidents, the (i) estimates of B. anthracis contamination, as well as the bias and uncertainties in the estimates and (ii) confidence in characterization and clearance decisions for contaminated or decontaminated buildings. Gaps in knowledge and understanding identified during the summary of the studies are discussed. Additional work is needed to quantify (i) the false‐negative rates of surface‐sampling methods with lower concentrations on various surfaces and (ii) the effects on performance characteristics of: aerosol vs liquid deposition of spores, using surrogates instead of B. anthracis, real‐world vs laboratory conditions and storage and transportation conditions. Recommendations are given for future evaluations of data from existing studies and possible new studies.     

Identity economics and the brain: uncovering the mechanisms of social conflict

Social contexts can have dramatic effects on decisions. When individuals recognize each other as coming from the same social group, they can coordinate their actions towards a common goal. Conversely, information about group differences can lead to conflicts both economic and physical. Understanding how social information shapes decision processes is now a core goal both of behavioural economics and neuroeconomics. Here, we describe the foundations for research that combines the theoretical framework from identity economics with the experimental methods of neuroscience. Research at this intersection would fill important gaps in the literature not addressed by current approaches in either of these disciplines, nor within social neuroscience, psychology or other fields. We set forth a simple taxonomy of social contexts based on the information content they provide. And, we highlight the key questions that would be addressed by a new 'identity neuroeconomics'. Such research could serve as an important and novel link between the social and natural sciences.     

Parents’ Agendas in Paediatric Clinical Trial Recruitment Are Different from Researchers’ and Often Remain Unvoiced: A Qualitative Study

Ensuring parents make an informed decision about their child’s participation in a clinical trial is a challenge for practitioners as a parent’s comprehension of a trial may differ from that intended by the practitioners responsible for recruitment. We explored what issues parents consider important when making a decision about participation in a paediatric clinical trial and their comprehension of these issues to inform future recruitment practice. This qualitative interview and observational study examined recruitment in four placebo-controlled, double-blind randomised clinical trials of medicines for children. Audio-recorded trial recruitment discussions between practitioners and parents (N = 41) were matched with semi-structured interviews with parents (N = 41). When making a decision about trial entry parents considered clinical benefit, child safety, practicalities of participation, research for the common good, access to medication and randomisation. Within these prioritised issues parents had specific misunderstandings, which had the potential to influence their decisions. While parents had many questions and concerns about trial participation which influenced their decision-making, they rarely voiced these during discussions about the trials with practitioners. Those involved in the recruitment of children to clinical trials need to be aware of parents’ priorities and the sorts of misunderstandings that can arise with parents. Providing trial information that is tailored to what parents consider important in making a decision about a clinical trial may improve recruitment practice and ultimately benefit evidence-based paediatric medicine.     

Whole-genome re-sequencing

DNA sequencing can be used to gain important information on genes, genetic variation and gene function for biological and medical studies. The growing collection of publicly available reference genome sequences will underpin a new era of whole genome re-sequencing, but sequencing costs need to fall and throughput needs to rise by several orders of magnitude. Novel technologies are being developed to meet this need by generating massive amounts of sequence that can be aligned to the reference sequence. The challenge is to maintain the high standards of accuracy and completeness that are hallmarks of the previous genome projects. One or more new sequencing technologies are expected to become the mainstay of future research, and to make DNA sequencing centre stage as a routine tool in genetic research in the coming years.     

Monkeys monitor human goals in a nonmatch-to-goal interactive task

We designed a new task, called nonmatch-to-goal, to study the ability of macaque monkeys to interact with humans in a rule-guided paradigm. In this task the monkeys were required to choose one of two targets, from a list of three. For each choice, they were required to switch from their choice on the previous trial to a different one. In a subset of trials the monkeys observed a human partner performing the task. When the human concluded his turn, the monkeys were required to switch to a new goal discarding the human's previous goal. We found that monkeys were very skillful in monitoring goals, not only of their own choice by also those of their human partner. They showed also a surprising ability to coordinate their actions, taking turns with the human partner, starting and stopping their own turn following the decision of the human partner in the task.     

Weight Goals in a College‐age Population

Objective: Although a growing body of literature has found unrealistic weight loss goals to be common among older, primarily female, subjects, little is known about weight loss goals of younger adults. Research Methods and Procedures: Three hundred seventy‐nine college students had their height and weight taken and reported their “goal,” “dream,” “happy,” “acceptable,” and “disappointed” weights. A series of 2 (gender) × 2 (nonoverweight vs. overweight) ANOVAs were conducted with both absolute weight goals and percentage of weight loss needed to obtain those goals as dependent variables. Results: When examined in terms of absolute weight goals, women generally had lower body mass index (BMI) goals than men, and nonoverweight participants had lower BMI goals than overweight participants. Surprisingly, most overweight participants would accept a weight loss that would still place them in the overweight BMI range. When examined in terms of percentage loss needed to reach those goals, only overweight women chose goal and dream weights that would require a loss greater than can be expected from nonsurgical weight‐loss treatments, and all overweight participants chose happy and acceptable weights within 15% of current weight. Discussion: Participants in this study had generally reasonable weight‐loss goals, and even the most extreme weight loss goals were much more moderate than those found in previous studies. These results are surprising given the extreme social pressures for thinness facing young adults. Future studies should examine the variables that influence selection of goal weights and how goal weights affect actual dieting behavior.     

Adaptive management of coastal ecosystem restoration projects

There is a clear need to apply better and more effective management schemes to coastal ecosystem restoration projects. It is very common for aquatic ecosystem restoration projects not to meet their goals. Poor performance has led to a high degree of uncertainty about the potential success of any restoration effort. Under adaptive management, the knowledge gained through monitoring of the project and social policies is translated into restoration policy and program redesign. Planners and managers can utilize the information from the monitoring programs in an effective way to assure that project goals are met or that informed and objective decisions are made to address both ecological and societal needs. The three main ingredients of an effective adaptive management plan in a restoration project are: (1) a clear goal statement; (2) a conceptual model; and (3) a decision framework. The goal ‘drives’ the design of the project and helps guide the development of performance criteria. The goal statement and performance criteria provide the means by which the system can be judged. With the conceptual model, the knowledge base from the field of ecological science plays an active and critical role in designing the project to meet the goal. A system-development matrix provides a simple decision framework to view the alternative states for the system during development, incorporate knowledge gained through the monitoring program, and formulate a decision on actions to take if the system is not meeting its goal.