Estimating the impact of COVID-19 self-test availability and modifications in test-strategy on overall test uptake using an experimental vignette study.

To inform future Dutch COVID-19 testing policies we did an experimental vignette study to investigate whether inclusion of the less reliable lateral flow tests (self-tests) would change test-uptake sufficiently to improve population-level test sensitivity. A representative sample (n = 3,270) participated in a 2-by-2 online experiment to evaluate the effects of test-guidelines including self-testing advice (IV1), and the effects of self-test availability (IV2) on expected test uptake (PCR test, self-test or no test) and sensitivity of the overall test strategy (primary outcome). Across four scenarios, changing test advice did not affect expected testing behaviour.

An experimental investigation of breaking learnt habits with verbal implementation intentions.

The interplay between inflexible habits and flexible goal-directed control can be modelled in lab-settings using the slips-of-action task. In this task, participants are required to selectively respond to still-valuable outcomes while suppressing responding towards no-longer valuable outcomes, thereby overriding learned stimulus-response associations. Here we examined in the slips-of-action task whether learnt habits can be changed using a planning technique - so-called implementation intentions - whereby people instruct themselves to enact a certain behaviour (or not) in the presence of a specific critical stimulus.