Pupil diameter tracks changes in control state predicted by the adaptive gain theory of locus coeruleus function

An important dimension of cognitive control is the adaptive regulation of the balance between exploitation (pursuing known sources of reward) and exploration (seeking new ones) in response to changes in task utility. Recent studies have suggested that the locus coeruleus-norepinephrine system may play an important role in this function and that pupil diameter can be used to index locus coeruleus activity. On the basis of this, we reasoned that pupil diameter may correlate closely with control state and associated changes in behavior. Specifically, we predicted that increases in baseline pupil diameter would be associated with decreases in task utility and disengagement from the task (exploration), whereas reduced baseline diameter (but increases in task-evoked dilations) would be associated with task engagement (exploitation). Findings in three experiments were consistent with these predictions, suggesting that pupillometry may be useful as an index of both control state and, indirectly, locus coeruleus function.     

Dissecting the genetic architecture of human personality

The first candidate gene studies of human personality promised much but, in the fifteen years since their publication, have delivered little in the way of clear evidence for the contribution of specific genetic variants to observed variation in personality traits. This is most likely due to the very small effects conferred by individual loci. The advent of genome-wide association studies has brought growing awareness that high levels of statistical stringency, very large sample sizes, and independent replication will be minimum requirements for future genetic studies of personality. At the same time, evidence from other fields indicates that the genetic architecture of personality is likely to consist of the combined effect of many hundreds, if not thousands, of small effect loci.     

Intuitions in physics

This paper is an exploration of the role of intuition in physics. The ways in which intuition is appealed to in physics are not well understood. To the best of my knowledge, there is no analysis of the different contexts in which we might appeal to intuition in physics, nor is there any analysis of the different potential uses to which intuition might be put. In this paper I look to provide data that goes some way to giving a sense of the different contexts in which intuition is appealed to in physics. As I note in the conclusion, there is still much work to be done but I hope that the work here provides us with a first step in the journey to properly understand the use to which intuitions are put in physics and science more generally.     

Probabilism Today: Permissibility and Multi-Account Ethics

In ethics, ‘probabilism’ refers to a position defended by a number of Catholic theologians, mainly in the sixteenth and seventeenth centuries. They held that, when one is uncertain which of a range of actions is the right one to perform, it is permissible to perform any which has a good chance of being the right one—even if there is another which has a better chance. This paper considers the value of this position from the viewpoint of modern ethical philosophy. The unusual nature of probabilism as a theory focusing upon permissibility, rather than right-making properties, is explored and related to some modern attempts to set out ‘satisficing’ and ‘hybrid’ ethical theories. Such theories try to distinguish between what is best and what is permissible, and probabilism can be understood as an alternative way of supplementing a theory of right-making properties by adding to it a theory of permissibility. But a more radical version is also possible, where one abandons any attempt to identify right actions or right-making properties, and instead considers permissibility alone. Accordingly, a ‘multi-account theory’ of permissibility is proposed and defended as a model of how many people actually make moral decisions.     

Explaining the Instrumental Principle

The Wide-Scope view of instrumental reason holds that you should not intend an end without also intending what you believe to be the necessary means. This, the Wide-Scoper claims, provides the best account of why failing to intend the believed means to your end is a rational failing. But Wide-Scopers have struggled to meet a simple Explanatory Challenge: why shouldn't you intend an end without intending the necessary means? What reason is there not to do so? In the first half of this paper, I argue that the Wide-Scope view struggles to meet this challenge because it takes the principles of instrumental reason to have unlimited application—to apply to all agents, in all circumstances. I then go on to offer a new account of these principles. The new account is very much in the spirit of the Wide-Scope view, and shares its central advantages, but lacks its unlimited application. This view should, therefore, find the Explanatory Challenge more tractable. In the second half of the paper, I argue that this prediction is confirmed. If the requirements of instrumental reason apply only when a means is, or is believed to be, necessary for your end, then plausible independent claims, about reasons, rationality, and intentions, explain why failing to intend the necessary means to your ends is a rational failing.     

PandaEPL: A library for programming spatial navigation experiments

Recent advances in neuroimaging and neural recording techniques have enabled researchers to make significant progress in understanding the neural mechanisms underlying human spatial navigation. Because these techniques generally require participants to remain stationary, computer-generated virtual environments are used. We introduce PandaEPL, a programming library for the Python language designed to simplify the creation of computer-controlled spatial-navigation experiments. PandaEPL is built on top of Panda3D, a modern open-source game engine. It allows users to construct three-dimensional environments that participants can navigate from a first-person perspective. Sound playback and recording and also joystick support are provided through the use of additional optional libraries. PandaEPL also handles many tasks common to all cognitive experiments, including managing configuration files, logging all internal and participant-generated events, and keeping track of the experiment state. We describe how PandaEPL compares with other software for building spatial-navigation experiments and walk the reader through the process of creating a fully functional experiment.     

Eastern Europe 1997-2000: A Review of Church Life

A decade after the collapse of communist rule, Christian life in Eastern Europe continues to be a complex mixture of satisfaction and disappointment. This survey of the last four years illustrates the recent successes and failures, and sets out to highlight the many challenges which still await effective responses.