'Replication of Ganel & Goodale 2003 - February 2021' (AsPredicted #58774)
Author(s) Kriti Bhatia (University of Tuebingen) - kriti.bhatia@uni-tuebingen.de Markus Janczyk (University of Bremen) - janczyk@uni-bremen.de Volker H. Franz (University of Tuebingen) - volker.franz@uni-tuebingen.de
Pre-registered on 2021/02/19 - 04:10 AM (PT)
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 will replicate Ganel & Goodale 2003 (Ganel, T., & Goodale, M. A. (2003). Visual control of action but not perception requires analytical processing of object shape. Nature, 426(6967), 664–667.). Garner Interference is expected in reaction times for perceptual speeded-classification and manual estimation, but not grasping. We expect this for neither the open-loop nor closed-loop grasping.
3) Describe the key dependent variable(s) specifying how they will be measured. Grasping: reaction time to initiate movement (when finger and thumb leave the start position), reaction time to reach maximum grip aperture (MGA, the widest distance between finger and thumb that is reached when movement is approximately 70% completed), reaction time to complete the movement (when finger and thumb reach the object), and MGA. These will be measured using the trajectories tracked by the Optotrak.
Perceptual speeded-classification: reaction time to judge width of the object, measured by an analog button press.
Manual estimation: reaction time to initiate movement (measured by Optotrak) and reaction time to complete the movement (measured by button press).
4) How many and which conditions will participants be assigned to? There will be two conditions - baseline and filtering, performed by each participant for every task (open-loop grasping, closed-loop grasping, manual estimation and perceptual speeded-classification).
5) Specify exactly which analyses you will conduct to examine the main question/hypothesis. Paired samples t-test between the mean reaction times of all participants for the baseline and filtering conditions.
Repeated measures ANOVA with factors: task (perceptual speeded-classification, open-loop grasping, closed-loop grasping, manual estimation) and condition(baseline, filtering) on variable: reaction time.
6) Describe exactly how outliers will be defined and handled, and your precise rule(s) for excluding observations. Reaction times will be restricted between 100 ms - 1500 ms. Outliers with RTs greater than mean±2 SD will be excluded.
Furthermore, participants with greater than 10% error trials in the perceptual task will be eliminated (wrong response to the object width judgement).
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 collect data until 24 valid participant data-sets are available for analyses (after exclusions).
8) Anything else you would like to pre-register? (e.g., secondary analyses, variables collected for exploratory purposes, unusual analyses planned?) Secondary analyses: variability based Garner Interference, following the procedure of Ganel & Goodale 2014 (Ganel, T., & Goodale, M. A. (2014). Variability-based Garner interference for perceptual estimations but not for grasping. Experimental brain research, 232(6), 1751–1758.).
Within-subject standard deviation of the maximum grip aperture (measured by the Optotrak) will be computed for both conditions baseline and filtering in the grasping (open-loop and closed-loop) and manual estimation tasks. Paired samples t-tests will be computed.
