Archive for May, 2021

Rava Azeredo da Silveira

Rava Azeredo da Silveira, Head, Theoretical & Computational Neuroscience Group, Institute of Molecular and Clinical Ophthalmology Basel, will give a presentation via Zoom in this week’s Social, Economic, and Decision Psychology research seminar (Thursday 3 June).

Cognitive biases and costly mental representations

While the faculty of rational thinking defines, at least to an extent, our human nature, it suffers from a remarkably long list of so-called “cognitive biases”—systematic deviations from rational information processing. Human behavior is also variable, even when an optimal observer would behave in a deterministic fashion. Biases and variability are particularly salient in situations in which humans update their beliefs as a function of a stream of stochastic observations, and cannot be explained on the basis of a sound, Bayesian manipulation of probabilities. In this talk, I will introduce a theoretical framework in which biases and variability emerge from a trade-off between Bayesian inference and the cognitive cost of carrying out probabilistic computations. After discussing the theoretical implications of this framework, I will present data from behavioral experiments in humans and their analysis in the context of our framework. If time allows, I will contrast this approach and predictions with those of an alternative framework in which cognitive costs impose limits on the precision of memory. The various theoretical approaches I will outline point to the fact that biases and variability in human cognition can reflect optimality under constraints—”resource-rational cognition”—rather than ad hoc erroneous beliefs or heuristics.

Stephan Lewandowsky

Stephan Lewandowsky, University of Bristol, will give a presentation via Zoom in this week’s Social, Economic, and Decision Psychology research seminar (Thursday 20 May).

Resisting the knowledge dementors: The truth about “post-truth”

We are said to live in a “post-truth” era in which “fake news” has replaced real information, denial has compromised science, and the ontology of knowledge and truth has taken on a relativist element. I argue that to defend evidence-based reasoning and knowledge against those attacks, we must understand the strategies by which the post-truth world is driven forward. I depart from the premise that the post-truth era did not arise spontaneously but is the result of a highly effective political movement that deploys a large number of rhetorical strategies. I focus on three strategies: The deployment of conspiracy theories, the use of “micro-targeting” and “bots” online, and agenda-setting by attentional diversion. I present evidence for the existence of each strategy and its impact, and how it might be countered.

Isabella Kooij

Isabella Kooij, University of Zurich Department of Banking and Finance will give a presentation via Zoom in this week’s Social, Economic, and Decision Psychology research seminar (Thursday 6 May).

Social Trading – Skill, performance and trading behavior

Using data from the social trading platform Wikifolio, we analyze the performance, characteristics and risk-return profile of professional and non-professional traders managing virtual portfolios. In line with the literature traders are not able to earn significant positive returns. Portfolios earning positive returns before they become investable for other users mostly cannot maintain their performance afterwards. In line with findings from the mutual fund industry, persistence in performance is generally low. Supporting previous findings on social trading, we find that risk and return of portfolios are not generally positively correlated. Trader and trading characteristics such as high confidence, high turnover and low diversification tend to negatively influence portfolio returns. Social trading platforms allow their users to exchange information and trade real world securities in an online setup. Some users are thereby invested with actual money, while others use it as a learning opportunity.