One-dimensional dynamics of attention and decision making in LIP

Where we allocate our visual spatial attention depends upon a continual competition between internally generated goals and external distractions. Recently it was shown that single neurons in the macaque lateral intraparietal area (LIP) can predict the amount of time a distractor can shift the locus of spatial attention away from a goal. We propose that this remarkable dynamical correspondence between single neurons and attention can be explained by a network model in which generically high-dimensional firing-rate vectors rapidly decay to a single mode. We find direct experimental evidence for this model, not only in the original attentional task, but also in a very different task involving perceptual decision making. These results confirm a theoretical prediction that slowly varying activity patterns are proportional to spontaneous activity, pose constraints on models of persistent activity, and suggest a network mechanism for the emergence of robust behavioral timing from heterogeneous neuronal populations.     

Consensus decision making in animals

Individual animals routinely face decisions that are crucial to their fitness. In social species, however, many of these decisions need to be made jointly with other group members because the group will split apart unless a consensus is reached. Here, we review empirical and theoretical studies of consensus decision making, and place them in a coherent framework. In particular, we classify consensus decisions according to the degree to which they involve conflict of interest between group members, and whether they involve either local or global communication; we ask, for different categories of consensus decision, who makes the decision, what are the underlying mechanisms, and what are the functional consequences. We conclude that consensus decision making is common in non-human animals, and that cooperation between group members in the decision-making process is likely to be the norm, even when the decision involves significant conflict of interest.     

Training in ethical decision making

Advances in biotechnology and evolving attitudes of biomedical professionals and members of the general public toward illness, medical care, and research generate topics for ethics discussions. The author offers advice for training animal care staff in ethical decision making.     

Causal role of dorsolateral prefrontal cortex in human perceptual decision making

The way that we interpret and interact with the world entails making decisions on the basis of available sensory evidence. Recent primate neurophysiology [1-6], human neuroimaging [7-13], and modeling experiments [14-19] have demonstrated that perceptual decisions are based on an integrative process in which sensory evidence accumulates over time until an internal decision bound is reached. Here we used repetitive transcranial magnetic stimulation (rTMS) to provide causal support for the role of the dorsolateral prefrontal cortex (DLPFC) in this integrative process. Specifically, we used a speeded perceptual categorization task designed to induce a time-dependent accumulation of sensory evidence through rapidly updating dynamic stimuli and found that disruption of the left DLPFC with low-frequency rTMS reduced accuracy and increased response times relative to a sham condition. Importantly, using the drift-diffusion model, we show that these behavioral effects correspond to a decrease in drift rate, a parameter describing the rate and thereby the efficiency of the sensory evidence integration in the decision process. These results provide causal evidence linking the DLPFC to the mechanism of evidence accumulation during perceptual decision making.     

Temporal decision making in complex environments

The basic hypothesis of the author is that under the influence of technological development and market pressure, situations take on temporal characteristics that are more and more difficult for the operator to control. The temporal strategies traditionally installed by the operator disappear, are transferred or transformed. Far from counterbalancing these phenomena, the displays, as they are designed in the workplace, obliterate the temporal dimension. The errors that are seen to appear are the product of a mismatch between the characteristics of the situation and the operator's resources. Four mechanisms of time estimation are discussed. Field study results on temporal strategies, such as anticipation, assessment of a process evolution and planning adjustment are developed.     

Independence and interdependence in collective decision making: an agent-based model of nest-site choice by honeybee swarms

Condorcet''s jury theorem shows that when the members of a group have noisy but independent information about what is best for the group as a whole, majority decisions tend to outperform dictatorial ones. When voting is supplemented by communication, however, the resulting interdependencies between decision makers can strengthen or undermine this effect: they can facilitate information pooling, but also amplify errors. We consider an intriguing non-human case of independent information pooling combined with communication: the case of nest-site choice by honeybee (Apis mellifera) swarms. It is empirically well documented that when there are different nest sites that vary in quality, the bees usually choose the best one. We develop a new agent-based model of the bees'' decision process and show that its remarkable reliability stems from a particular interplay of independence and interdependence between the bees.     

Integrating biodiversity into decision making

The prominent theme in the debates concerning biodiversity has been the integration of biodiversity into social and economical processes. Integration has meant two different but related things: on one hand, biological phenomena have been contextualized in social and economical processes; on the other hand, biological issues have been incorporated into decision making. These two aspects of integration are related: knowing the context of biodiversity helps in assessing its worth for decision making. In what follows we will first look at the ramifications of decision making, on how to proceed when dealing with apparently incommensurable dimensions. Secondly, we will highlight some key issues in both biological and social impact assessment. Finally, we will propose a process model which takes into account the multiple aspects of biodiversity.     

Behavior-analytic approaches to decision making

Behavior analysis has much to offer the study of phenomena in the area of judgement and decision making. We review several research areas that should continue to profit from a behavior-analytic approach, including the relative merit of contingency-based and rule-governed instruction of solving algebra and analogy problems, and the role of conditioned reinforcement and the inter-trial interval in a type of Prisoner's Dilemma Game. We focus on two additional areas: (1) the study of base-rate neglect, a notorious reasoning fallacy and (2) the study of the sunk-cost effect, which characterizes ill-conceived investment decisions. In each of these two cases we review studies with humans and pigeons as subjects.     

Aging and consumer decision making

Research on consumer decision making and aging is especially important for fostering a better understanding of ways to maintain consumer satisfaction and high decision quality across the life span. We provide a review of extant research on the effects of normal aging on cognition and decision processes and how these age-related processes are influenced by task environment, meaningfulness of the task, and consumer expertise. We consider how research centered on these topics generates insights about changes in consumption decisions that occur with aging and identify a number of gaps and directions for future research.     

Involving the motor system in decision making

The control of behaviour is usually understood in terms of three distinct components: sensory processing, decision making and movement control. Recently, this view has been questioned on the basis of physiological and behavioural data, blurring the distinction between these three stages. This raises the question to what extent the motor system itself can contribute to the interpretation of behavioural situations. To investigate this question we use a neural model of sensory motor integration applied to a behaving mobile robot performing a navigation task. We show that the population response of the motor system provides a substrate for the categorization of behavioural situations. This categorization allows for the assessment of the complexity of a behavioural situation and regulates whether higher-level decision making is required to resolve behavioural conflicts. Our model lends credence to an emerging reconceptualization of behavioural control where the motor system can be considered as part of a high-level perceptual system.     

Speed versus accuracy in collective decision making

We demonstrate a speed versus accuracy trade-off in collective decision making. House-hunting ant colonies choose a new nest more quickly in harsh conditions than in benign ones and are less discriminating. The errors that occur in a harsh environment are errors of judgement not errors of omission because the colonies have discovered all of the alternative nests before they initiate an emigration. Leptothorax albipennis ants use quorum sensing in their house hunting. They only accept a nest, and begin rapidly recruiting members of their colony, when they find within it a sufficient number of their nest-mates. Here we show that these ants can lower their quorum thresholds between benign and harsh conditions to adjust their speed-accuracy trade-off. Indeed, in harsh conditions these ants rely much more on individual decision making than collective decision making. Our findings show that these ants actively choose to take their time over judgements and employ collective decision making in benign conditions when accuracy is more important than speed.     

Selective attention and host-plant specialization

The importance of attentional processing is summarized, and the different ways in which selective attention is maintained, explained. Examples from arthropods are highlighted. The significance of selective attentiveness for insect herbivores is discussed. In the finding and selecting of host plants, insects should adopt the strongest or most clear-cut cues that override noise, and they should channel the appropriate sensory information efficiently. It is argued that achieving this end is difficult and costly because the information capacity of the sensory system is far greater than the capacity of the central nervous system to process it. It is suggested that the need to obtain a clear signal quickly and efficiently may be one of the factors favoring reduced diet breadth, and that the existence of highly specific and sensitive receptor neurons is an adaptation to the information-processing problem.