Posts in Category: experiment

experimental and empirical research

Paper: The echo in flu-vaccination echo chambers


Helge Giese, Hansjörg Neth, Mehdi Moussaïd, Cornelia Betsch, Wolfgang Gaissmaier

The echo in flu-vaccination echo chambers: Selective attention trumps social influence

Immune to influence


Online discussions may impact the willingness to get vaccinated. This experiment tests how groups of individuals with consistent and inconsistent attitudes towards flu vaccination attend to and convey information online, and how they alter their corresponding risk perceptions.

Out of 1859 MTurkers, we pre-selected 208 people with negative and 221 people with positive attitudes towards flu vaccinations into homogeneous or heterogeneous 3-link experimental diffusion chains. We assessed (i) which information about flu vaccinations participants conveyed to the subsequent link, (ii) how flu-vaccination related perceptions were altered by incoming messages, and (iii) how participants perceived incoming information.

Participants (i) selectively conveyed attitude-consistent information, but exhibited no overall anti-vaccination bias, (ii) were reluctant to alter their flu-vaccination related perceptions in response to messages, and (iii) evaluated incoming information consistent with their prior attitudes as more convincing.

Flu-vaccination related perceptions are resilient against contradictions and bias online communication. Contrary to expectations, there was no sign of amplification of anti-vaccine attitudes by online communication.

Keywords: Amplification of risk; Diffusion chain; Opinion dynamics; Vaccine hesitancy; Social media; Polarization

Press release

Reference:  Giese, H., Neth, H., Moussaïd, M., Betsch, C., & Gaissmaier, W. (2020).  The echo in flu-vaccination echo chambers: Selective attention trumps social influence.  Vaccine, 38 (8), 2070–2076.   doi: 10.1016/j.vaccine.2019.11.038

Related:  Social influence and collective opinion formation

Resources:  Download_PDFGoogle Scholar

Paper: Visual working memory resources as item activation

To understand visual intelligence is to understand, in large part, who we are.
Donald D. Hoffmann (1998), p. XII


The body’s movements at this time scale provide an essential link between processes underlying elemental perceptual events
and those involved in symbol manipulation and the organization of complex behaviors.
Ballard et al. (1997), p. 723


Bella Z. Veksler, Rachel Boyd, Christopher W. Myers, Glenn Gunzelmann, Hansjörg Neth, Wayne D. Gray

Visual working memory resources are best characterized as dynamic, quantifiable mnemonic traces

An example stimulus used in the paradigm of repeated serial search.

An example stimulus used in the paradigm of repeated serial search.

Abstract:  Visual working memory (VWM) is a construct hypothesized to store a small amount of accurate perceptual information that can be brought to bear on a task.  Much research concerns the construct’s capacity and the precision of the information stored.  Two prominent theories of VWM representation have emerged: slot-based and continuous-resource mechanisms.  Prior modeling work suggests that a continuous resource that varies over trials with variable capacity and a potential to make localization errors best accounts for the empirical data.  Questions remain regarding the variability in VWM capacity and precision.  Using a novel eye-tracking paradigm, we demonstrate that VWM facilitates search and exhibits effects of fixation frequency and recency, particularly for prior targets.  Whereas slot-based memory models cannot account for the human data, a novel continuous-resource model does capture the behavioral and eye tracking data, and identifies the relevant resource as item activation.

Paper: Foraging for alternative options

Should I stay or should I go now?
If I go there will be trouble,
and if I stay it will be double…
The Clash

Hansjörg Neth, Neele Engelmann, Ralf Mayrhofer

Foraging for alternatives: Ecological rationality in keeping options viable

Abstract:  Do we invest irrational amounts of effort into keeping options viable, or do we manage available and threatened options in an adaptive fashion? 

Paper: Social influence and collective opinion formation

The rule is perfect: in all matters of opinion our adversaries are insane.
Mark Twain, Christian Science (1907, Book 1, Ch. 5)

Mehdi Moussaïd, Juliane E. Kämmer, Pantelis P. Analytis, Hansjörg Neth

Social influence and the collective dynamics of opinion formation

Abstract:  Social influence is the process by which individuals adapt their opinion, revise their beliefs, or change their behavior as a result of social interactions with other people. In our strongly interconnected society, social influence plays a prominent role in many self-organized phenomena such as herding in cultural markets, the spread of ideas and innovations, and the amplification of fears during epidemics. Yet, the mechanisms of opinion formation remain poorly understood, and existing physics-based models lack systematic empirical validation. Here, we report two controlled experiments showing how participants answering factual questions revise their initial judgments after being exposed to the opinion and confidence level of others.