#53503 | AsPredicted

'Self-regulation and nudge acceptability'
(AsPredicted #53503)

Created:       12/04/2020 04:46 AM (PT)

This is an anonymized version of the pre-registration.  It was created by the author(s) to use during peer-review.
A non-anonymized version (containing author names) should be made available by the authors when the work it supports is made public.

1) Have any data been collected for this study already?
No, no data have been collected for this study yet.

2) What's the main question being asked or hypothesis being tested in this study?
We want to investigate how self-regulation relates to nudges’ acceptability. We will measure a variety of self-regulation constructs such as trait self-control, proactive coping competence, autonomous motivation, controlled motivation, and amotivation for eating a healthy/sustainable diet, self-efficacy, perceived behavioral control and perceived difficulty of performing the desired behavior. The goal of this study is to relate these self-regulation constructs to acceptability of nudges. This is an exploratory study and no hypotheses are formulated.

3) Describe the key dependent variable(s) specifying how they will be measured.
The key dependent variable is the extent to which people welcome the implementation of three different nudges, which will be measured with three items pertaining to acceptability (“How much would you accept the implementation of this measure?”), appreciation (“How much would you appreciate the implementation of this measure?”), and support (“How much would you support the implementation of this measure?”), all measured on a continuous slider ranging from 0% to 100%.
Other dependent variables are: Intrusiveness (“How intrusive do you find this measure?”), perceived effectiveness (“How effective do you think this measure would be?”), and goal alignment (“To what extent is this measure in line with your own goal?”), which will be measured with 1 item each on a continuous slider ranging from 0% to 100%.

4) How many and which conditions will participants be assigned to?
There are two conditions in a 1 factor (behavioral domain: healthy eating vs. sustainable eating) between subjects design. For each behavioral domain we will have three scenarios, describing a default nudge, a portion size nudge, and a rearrangement nudge.

5) Specify exactly which analyses you will conduct to examine the main question/hypothesis.
The study is exploratory. We will report descriptives for key (in)dependent variables and run correlations between those variables. We will use frequentist statistics for the main (exploratory) analyses.

6) Describe exactly how outliers will be defined and handled, and your precise rule(s) for excluding observations.
We have two attention check questions. If participants fail both attention checks, we will exclude them from all analyses.
We will use 3SDs above or below the mean as a standard for detecting outliers for all relevant (in)dependent variables. Outliers will initially be set missing. Analyses will be run with inclusion and exclusion of outliers. If this does not affect the results (i.e., significance and/or direction of effect), we will report on the entire sample with inclusion of outliers.

7) How many observations will be collected or what will determine sample size?
No need to justify decision, but be precise about exactly how the number will be determined.

We aim to recruit 300 participants (150 per condition), which should be adequate to detect a medium-sized effect with 80% power, and substantial enough to explore the data with enough flexibility.

8) Anything else you would like to pre-register?
(e.g., secondary analyses, variables collected for exploratory purposes, unusual analyses planned?)

To assess our assumption that eating a healthy diet is more of a pro-self behavior than eating a sustainable diet, we will ask participants to rate one statement (“Eating a healthy diet is something I do for…”) on a continuous slider ranging from 0 (myself) to 100 (society).

We will measure age, gender, trustworthiness of the employer, the frequency of going to work, and the frequency of buying food at work.
For all questionnaires, we will first do reliability analyses and will use Cronbach’s alpha > .7 as acceptable. Next, we will create variables for these constructs according to the official scoring instructions for each questionnaire.