'Garner effects in open-loop manual estimation' (AsPredicted #166531)
Author(s) Kriti Bhatia (University of Tuebingen) - kriti.bhatia@uni-tuebingen.de Angela Osenberg (University of Tuebingen) - angela.osenberg@student.uni-tuebingen.de Markus Janczyk (University of Bremen) - janczyk@uni-bremen.de Volker Franz (University of Tübingen) - volker.franz@uni-tuebingen.de
Pre-registered on 2024/03/16 - 01:50 AM (PT)
1) Have any data been collected for this study already? It's complicated. We have already collected some data but explain in Question 8 why readers may consider this a valid pre-registration nevertheless.
2) What's the main question being asked or hypothesis being tested in this study? Our experiment is a Garner experiment with very short decision amplitude (3 cm) and participants will perform manual (size) estimation. We expect the reaction time in the correlated condition to be fastest, then the baseline condition and the slowest reaction time in the filtering condition. Therefore, we expect a Garner facilitation (Correlated – Baseline) and Garner interference effect (Filtering – Baseline).
3) Describe the key dependent variable(s) specifying how they will be measured. We will measure RT (time to start the movement) calculated by data obtained from the Optotrak, calculated as the time point when the finger velocity exceeds 25 mm/s. We will also measure ManEstTime (time to complete manual estimate, measured with a button press at the time of estimation) and variability (within-subject SD) of manual estimate.
4) How many and which conditions will participants be assigned to? Participants will be presented the stimuli in three conditions: Correlated, Baseline and Filtering. They will be randomly assigned to one of six groups (BCF, BFC, CBF, CFB, FBC, FCB).
5) Specify exactly which analyses you will conduct to examine the main question/hypothesis. Our main analysis will include two paired t-tests (one-tailed, significance level = .05) on RTs: for a Garner facilitation effect (Correlated vs. Baseline), and for a Garner interference effect (Baseline vs. Filtering).
Based on previous research (Ganel & Goodale, 2003, 2014), we will also perform a one-tailed paired t-test to check for Garner interference (Baseline vs. Filtering) in ManEstTime and variability of manual estimate.
6) Describe exactly how outliers will be defined and handled, and your precise rule(s) for excluding observations. Trials with RTs < 100 ms or RTs > mean+2*SD of each participant in each condition will be excluded. Trials with missing Optotrak marker information before manual estimate will be excluded. Participants with more than 25% excluded trials will also be excluded.
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 want to compare the results of this experiment to a previous experiment with n = 32. Since we have 6 groups (see point 4), the final sample size should be a multiple of 6. Therefore, we aim for n = 30.
8) Anything else you would like to pre-register? (e.g., secondary analyses, variables collected for exploratory purposes, unusual analyses planned?) This experiment was part of a practical course and we already collected n = 19 for this experiment to adhere to time constraints of the course. The hypotheses for this study are determined by theory and previous research, therefore, we do not think it is a problem to pre-register after collecting partial data. As an exploratory analysis, we will check for Garner facilitation in ManEstTime and variability (within-subject SD) of manual estimate.
