#50138 | AsPredicted

'A1IEToM-Beh: Altercentric and Egocentric Reaction Time Biases in Adults'
(AsPredicted #50138)


Author(s)
This pre-registration is currently anonymous to enable blind peer-review.
It has 2 authors.
Pre-registered on
10/20/2020 11:22 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?
The present study addresses the question whether two opposing biases (altercentric and egocentric) are involved in implicit and explicit Theory of Mind (ToM) tasks. To this end, two hypotheses are tested:
H1: Reaction times in an object detection task are modulated by the (task-irrelevant) belief of an agent (altercentric bias, implicit ToM).
H2: Reaction times in an action detection task are modulated by the (task-irrelevant) belief of the participant (egocentric bias, explicit ToM).

3) Describe the key dependent variable(s) specifying how they will be measured.
Button presses are recorded with the neurobehavioralsystems presentation software. Only left and right button presses that occur within frame 595 and frame 660 of a respective video are included into analysis (For implicit trials, from when a part of the object becomes visible until a curtain becomes visible that ends the scene. For explicit trials, from when the first eye movement of the agent can be seen that indicates the direction of her action until the curtain becomes visible.). Reaction times (RTs) are calculated relative to the occurrence of frame 595 in each respective video. Depending on the analysis (see details under question 5) we will use two dependent variables:
1) Average RTs: The RTs of all valid trials will be averaged within each experimental condition for each participant.
2) Individual RTs: The RTs of the individual valid trials of each experimental condition in each participant.

4) How many and which conditions will participants be assigned to?
During the experiment, participants watch 128 short video clips (test videos) in four consecutive experimental blocks. In the first two blocks, participants complete the implicit ToM task (one block TB, one block FB), in the last two blocks they complete the explicit ToM task (again: one block TB, one block FB). Each experimental block is preceded by a training that consists of two short training videos and two control questions concerning the belief of the agent. Training videos and control questions were repeated until the participant answered each one correctly.

Between-Subject Conditions: Participants will randomly be assigned to one of two experimental settings. In the TB-first setting, participants complete the True-Belief (TB) version of the tasks before the False-Belief (FB) version. In the FB-first setting, participants complete the FB version of the tasks before the TB version.

Within-Subject Conditions: The 128 test videos differ with respect to the following three factors:
I) Belief: In half of the test videos, the agent will wear an opaque mask while an object transfers from one box to another and will thus hold a false belief about the object’s location. In the other half, she will wear a transparent mask while the object switches place and will thus hold a true belief about the object’s location. These conditions will be presented block-wise, so that participants can experience the transparency of the mask themselves right before the mask occurs in the videos.
II) Task: During half of the test videos, participants complete an object detection task (implicit ToM). During the other half, they complete an action detection task (explicit ToM). A block-wise design is chosen for these conditions to assure that the explicit ToM task does not influence the performance in the implicit ToM task.
III) Congruency: In half of the videos, the outcome will be congruent to the real object location. In the other half, the outcome will be incongruent to the real object location.

5) Specify exactly which analyses you will conduct to examine the main question/hypothesis.
H1: Altercentric Bias, implicit ToM
Primary Analysis: To test H1, we will perform a mixed Bayesian ANCOVA using default priors with the two within-subject factors belief (true and false) and congruency (congruent and incongruent) and the between-subjects covariate belief-order (true or false belief first). We expect an interaction between belief and congruency and a main effect for the factor congruency. That is, we expect shorter RTs for congruent compared to incongruent trials. In addition, we expect that FB trials will be faster than TB trials in incongruent trials (planned comparison, directed Bayesian paired t-test with default priors). For congruent trials, we expect that TB trials will be faster than FB trials.

Secondary Analyses: The agent’s belief in the first experimental block might influence the interpretation of the second experimental block. We will therefore perform a mixed Bayesian ANOVA using default priors with the within-subjects factor congruency (two levels: congruent and incongruent) and the between-subjects factor belief (two levels: true and false) including only the data of the first experimental block. Expectations and planned comparison are analogous to above. To control for repetition effects, we will additionally analyze the individual responses using a Bayesian mixed linear model including the factors belief, congruency, subject, trial number and side of button press.

H2: Egocentric Bias, explicit ToM
Primary Analysis: To test H2, we will perform a mixed Bayesian ANCOVA using the same factors and parameters as for H1. We expect an interaction and a main effect for the factor belief (i.e., shorter RTs for TB compared to FB trials). In addition, we expect that reality incongruent trials will be faster than reality congruent trials in FB trials (planned comparison, directed Bayesian paired t-test with default priors). For TB trials, we expect that reality congruent trials will be faster than reality incongruent trials. There could also be an additional main effect for the factor congruency depending on whether the egocentric bias outweights the agent’s belief.

Secondary Analyses: Analogous to H1.

In case, the assumptions for the statistical tests are violated in the data, we will adjust our analyses accordingly.

6) Describe exactly how outliers will be defined and handled, and your precise rule(s) for excluding observations.
Responses will be excluded that were incorrect, that were given too early (before frame 595+150 ms) or too late (after frame 660), that followed any technical errors or that are more than three standard deviations above or below the participants overall mean.

The data of an entire experimental block will be excluded if more than 75% of the answers were excluded or if the participant answered wrong to more than one of the control questions preceding the block. If the implicit TB block was excluded, the implicit FB would also be excluded and vice versa. The same procedure will be applied to the explicit ToM blocks.

Participants that did not fulfill the inclusion criteria of this study (healthy right-handed adults between 18-50 years without any history of neurological/psychiatric disorders/substance abuse that were not under the influence of any drugs or alcohol) will 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 are going to collect data until the Bayes Factor of the interaction of the mixed ANCOVA reaches 4 or 0.25. To control false positives and negatives, we will collect a minimum of 68 participants. Within the process of sequential testing, we will monitor whether participants have to be excluded and increase our sample size in steps of four (counterbalancing the between-subject factors).

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

In addition, we will examine effects of age, gender and education, compute an item analysis and contrast subjects that were aware of the manipulation in the implicit task with those that were not aware of the manipulation.

Data collection has already started, but we have not analyzed any data yet. We have looked into the first five valid data sets (without any statistical data analyses) to assure that the presentation script is working and participants understood the task correctly. In addition, we collected 36 more data sets that we have not looked at at all.