#31330 | AsPredicted

'Body Functionality and Weight Stigma'
(AsPredicted #31330)

Created:       11/18/2019 05:50 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?
Primary: Does focusing on the body functionality of another person (specifically, a woman considered to be 'fat' or 'overweight') lead to a reduction in weight stigma?
Secondary: Does functionality appreciation moderate the effects of the intervention technique?

3) Describe the key dependent variable(s) specifying how they will be measured.
Weight stigma, operationalised by fat attitudes (Fat Attitudes Assessment Toolkit; FAAT), social distance toward the target person (assessed from 1 to 5 on 6 items), and evaluation of the target person (assessed from -10 to +10 on 3 items). The FAAT will be assessed at Pretest and Posttest, and the other items will be assessed at Posttest only. The Functionality Appreciation Scale (FAS) will be used to assess participants' levels of functionality appreciation at Pretest.
Demographic items (age, gender orientation, sexual orientation, weight, height, self-classified body weight, and cultural background) will be assessed at Pretest.
At Posttest, participants will also rate the perceived weight of the target person, and indicate what they think the purpose of the study is.
At Pretest and Posttest, filler items will be included to disguise the true purpose of the study and align with the cover story (i.e., that the study concerns imagination skills).

4) How many and which conditions will participants be assigned to?
Two groups: Experimental (a writing exercise where participants will describe the body functionality of the target person) vs. Control (a writing exercise where participants will describe the house of the target person). The instructions for the Experimental group are based on Alleva, Veldhuis, and Martijn (2016).
Time: Pretest (a survey delivered online) and Posttest (a lab session to take place 5-9 days after the Pretest).

5) Specify exactly which analyses you will conduct to examine the main question/hypothesis.
To test our main hypothesis, we will conduct a series of AN(C)OVA analyses, with Group as independent variable and the respective measure of weight stigma as dependent variable. For the FAAT, Pretest will be included as a covariate.

To test our secondary hypothesis, concerning functionality appreciation as a moderator of intervention effects, we will conduct a series of regression analyses, with Group as predictor, and Functionality Appreciation as moderator. For the analyses concerning the FAAT, Pretest will also be included as a predictor.

6) Describe exactly how outliers will be defined and handled, and your precise rule(s) for excluding observations.
Outliers are defined as those values that are above or below 3SD from the group mean. The outlier values will be replaced with the boundary value identified (i.e., 3SD above or below the group mean).

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 will aim to recruit 100 participants who have correctly and fully completed the study (i.e., those who adhered to the instructions for the intervention technique, and who completed both Pretest and Posttest). The sample size is based on GPower calculations for testing the primary hypothesis, assuming an alpha of .05, power of 80%, and a medium-to-large effect size.

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

In a future study, we plan to analyse participants' written responses to the intervention technique using thematic analysis. In the present study, however, we will only read these responses to ensure that participants adhered to the instructions, but the data will not yet be analysed using thematic analysis.