London Judgement and Decision Making seminars
The LJDM seminar series is supported by
University College London
City University London
Originally established at UCL in the early 1970’s as a weekly Cognition and Reasoning seminar, it later became an intercollegiate seminar on Language and Cognition in the early 1980’s.
The name LJDM was finally coined in 1990, and the group has been running seminars under this name ever since, with lecturers and researchers in and around the UK meeting on a regular basis to discuss judgment and decision making, judgments of likelihood, reasoning, thinking, problem solving, forecasting, risk perception and communication, and other related topics.
If you would like to present your research to the group or to suggest a speaker, please contact the organizer, Neil Bramley (firstname.lastname@example.org).
Unless specified otherwise, all seminars take place on Wednesdays at 5pm, in Room 313 at the Psychology Department, University College London (on the corner of Bedford Way, Gordon Square and Torrington Place, London WC1H 0AP). Map.
To get updates on the current schedule and weekly reminders of the seminars, please subscribe to the Risk and Decision mailing list.
All are welcome to attend.
Term 1 Seminar Schedule
October – December 2017
Neural Mechanisms of Hierarchical Planning in a Virtual Subway Network
University of Oxford
Planning allows actions to be structured in pursuit of a future goal. However, in natural environments, planning over multiple possible future states incurs prohibitive computational costs. To represent plans efficiently, states can be clustered hierarchically into “contexts”. For example, representing a journey through a subway network as a succession of individual states (stations) is more costly than encoding a sequence of contexts (lines) and context switches (line changes). Here, using functional brain imaging, we asked humans to perform a planning task in a virtual subway network. Behavioral analyses revealed that humans executed a hierarchically organized plan. Brain activity in the dorsomedial prefrontal cortex and premotor cortex scaled with the cost of hierarchical plan representation and unique neural signals in these regions signaled contexts and context switches. These results suggest that humans represent hierarchical plans using a network of caudal prefrontal structures.
Omissions and Expectations
Ruhr University Bochum, Germany
What is the difference between a friend’s not showing up to meet you at a café and any other person not coming? In some sense, all people who did not come show the same kind of behaviour, but most people would be willing to say that the absence of a friend who you expected to see is different in kind. In this talk, I will spell out this difference by investigating laypeople’s conceptualisation of absences of actions in four experiments. In languages such as German, French, Italian, or Polish, people consider a friend’s not coming an omission. Any other person’s not coming, in contrast, is not considered an omission at all, but just a mere nothing. This use of the term omission differs from the usage in English, were ‘omission’ refers to all kinds of absences. In addition, ‘omission’ is not even an everyday term, but invented by philosophers for the sake of philosophical investigation. In other languages, ‘omission’ (and its translates) is part of an everyday vocabulary. Furthermore, I will discuss how this folk concept of omission could be made fruitful for philosophical questions about negative causation.
In the second part of the talk, I will sketch an outline of a new research project that aims to provide a better understanding of how causal judgments about omissions work. I will present preliminary results of two experiments.
The role of mood in reward learning: function and dysfunction
University College London, UK
Unexpected rewards impact our mood, which may in turn impact our evaluation of subsequent rewards. I will show how this two-way interaction between mood and reward learning may serve an adaptive role, ‘correcting’ learning to account for general changes in reward availability in the environment. I will then present evidence indicating that this mechanism can also have maladaptive consequences, in particular by engendering mood instability, which may contribute to psychiatric mood disorders.
Compositional inductive biases in human function learning
University College London, UK
Function learning lies at the core of everyday cognition. From learning which stimulus will lead to reward all the way to how other people's intentions influence their actions, almost any task requires the construction of mental representations that map inputs to outputs. Since the space of such mappings is infinite, inductive biases are necessary to constrain plausible inferences. What is the nature of the human inductive biases over functions? How do people deal with complex functions that are not easily captured by standard learning algorithms?
Insight into this question is provided by the observation that many complex functions encountered in the real world can be broken down into compositions of simpler form. We pursue this idea theoretically and experimentally, by first defining a hypothetical compositional grammar for intuitive functions and then investigating whether this grammar quantitatively predicts human learning, pattern completion, and memory and change detection performance. We end by speculating that compositionality is a necessary requirement for intelligent behaviour.
Risk taking and information aggregation in groups: Reverse confirmation bias
We conducted a controlled laboratory experiment examining information aggregation in groups facing a common risk. The experiment allows us to examine how subjects respond to new information, in the form of both privately observed signals and signals reported by others. Our specific interest is in situations where Bayesian updating predicts no change in risk taking after receiving new information from others, but confirmation bias predicts that people's risk taking will tend towards the direction of their private signal. We find considerable heterogeneity in responses. Most surprising, we find that the majority of non-Bayesian subjects exhibits ‘reverse confirmation bias’: they place less weight on information from others that agrees with their private signal and more weight on conflicting information. This tendency is only significant when signal sharing is structured as a group discussion - without a discussion, non-Bayesian deviations do not follow a systematic pattern.
University of Essex
London School of Economics
King's College London
Reward and decision making
University of Oxford, UK
Internally driven strategy shifts