A phone-movement task that measures automatic tendencies to approach or avoid pictures of one category: participants pull the phone toward themselves or push it away. Measures reaction time and response force.
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Include practice trials
Shown with feedback before the main task
Task parameters
BetaBeing validated on iOS and Android devices.
Phones only: the task reads the phone's accelerometer. The web preview simulates the movements with buttons or the ↑/↓ keys.
Participants should hold the phone with both hands, ideally standing.
The result stores reaction time, response force and validity per trial. As in Zech et al. (2020), a trial is valid with a movement in the required direction, an RT of at least 200 ms and a peak of at least 1 m/s²; participants with less than 80% valid trials are flagged.
Single-session test-retest reliability is low: ICC < .3 for one session, ICCk = .73 over 8 sessions for faces (Zech et al., 2023). The task suits repeated measurement.
This category is pushed and the other pulled in the first block; the rule reverses in the second. Random by default: Zech et al. (2020) counterbalanced the block order between participants.
8–120, even: half per category. Default 40 (Zech et al., 2020, 2023).
0 = no break. Default 20 (Zech et al., 2023).
Before each picture. Default 1500 ms (Zech et al., 2020); a black dot, as in the Zech app.
Then a clock shows that the trial timed out. Default 2000 ms (Zech et al., 2020).
2–20, before each block, with feedback (✓ / ✗). Default 10 (Zech et al., 2020). Drawn from the task's own pictures; Zech et al. used separate practice pictures of the same categories (no published value for this choice).
2 blocks × 40 = 80 trials, each block after 10 practice trials (about 4 min).
Pictures
Fixed: the acceleration perpendicular to the screen, corrected for gravity, requested at 100 Hz (Zech et al., 2020). A movement ends the trial once it exceeds +4 m/s² toward the participant (pull) or -6.5 m/s² away (push), and the trace runs until 1 s after it (Zech app). Each trace is then scored as in the preprocessing script of Zech et al.: the first acceleration peak gives the direction and the force, the RT is the last moment before it with less than 0.5 m/s². Practice feedback and the timeout clock stay 1500 ms (Zech app). Zech app = the task's published source code (osf.io/y5b32).
Outputs: RT bias per category (median push − pull RT) and the bias score A − B; force bias per category (median pull − push force) and its score A − B; median RT and force per category and direction; the share of valid trials; and, if stored, the acceleration trace per trial.
This is a researcher preview. No participant data is recorded.
Simulated participant view
A phone-movement task that measures automatic tendencies to approach or avoid pictures of one category: participants pull the phone toward themselves or push it away. Measures reaction time and response force.
No data is recorded
Phones only: the participant holds the phone with both hands, ideally standing. After a black dot for 1.5 s, a picture appears; the participant pulls the phone toward themselves for one category and pushes it away for the other, and the rule reverses in the second block. The phone's accelerometer (the acceleration perpendicular to the screen, corrected for gravity) detects the movement. After 2 s without a movement a clock shows that the trial timed out. The web preview cannot read a phone's motion and simulates the movements with buttons or the arrow keys.
Useful in addiction, eating, anxiety and health-behaviour research where automatic approach tendencies toward cue pictures are a target outcome, when a real arm movement and its force are wanted rather than a swipe. Suits repeated measurement: the bias score becomes reliable only when aggregated over several sessions (Zech et al., 2023).
Not a diagnostic instrument, and not for single-session individual scores: the test-retest reliability of one session was low (Zech et al., 2023). Not for tablets, computers or situations where participants cannot move the phone freely with both hands. Beta: the task is being validated on iOS and Android devices.
Upload a validated picture set with two matched categories, or pilot with the built-in drink pictures. The defaults follow the mobile AAT of Zech, Rotteveel, van Dijk & van Dillen (2020) and its published source code: the content rule (push one category and pull the other, then the reverse in a second block, the block order counterbalanced), 40 trials per block with a break after 20 (Zech et al., 2023), 10 practice trials with feedback before each block, a practice trial answered in the wrong direction shown again at the end of the practice block, a 1.5 s fixation and a 2 s time limit. Practice uses the task's own pictures; Zech et al. used separate practice pictures of the same categories (no published value for this choice). Ask participants to hold the phone with both hands, ideally standing, and plan several sessions per participant.
RT is the time from the picture's onset to the start of the movement, and force the peak acceleration of the first movement, both taken from the acceleration trace. A positive RT bias for a category means it is pulled faster than it is pushed; a positive force bias means it is pulled with more force than it is pushed. A trial counts as valid when it moves in the required direction, with an RT of at least 200 ms and a peak of at least 1 m/s²; Zech et al. (2020) excluded participants with less than 80% valid trials. The medians are a summary; Zech et al. analysed the trial-level data (1/RT and force) with mixed models. The test-retest reliability of one session was low (ICC < .3), and reached ICCk = .73 for faces when aggregated over 8 sessions (Zech et al., 2023). Force is measured on phones only; the web preview records which button was pressed and when.
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