STEP — Sequential Transmission Evaluation Pipeline

If you use STEP, please cite:

Lee, H., Çelen, E., Harrison, P. M. C., Anglada-Tort, M., Rijn, P. van, Park, M., et al. (2025). GlobalMood: A cross-cultural benchmark for music emotion recognition. In Proceedings of the International Society for Music Information Retrieval Conference (ISMIR). https://doi.org/10.48550/arXiv.2505.09539

STEP is a PsyNet plugin for running sequential transmission evaluation experiments online. Participants view stimuli (images, audio, video), rate existing tags with stars, flag irrelevant tags, and add new ones. Tags accumulate and converge across participants through an imitation-chain design.

The package ships with:

• step: the core Python module (trial makers, pages, controls, stimulus classes, i18n support for 36 languages)
• demos/STEP-Tag: a working PsyNet demo experiment

Quick Links

• Source code
• Issues
• PsyNet documentation

Installation

From PyPI

pip install psynet-step

The Python import name is step:

from step import StepTag, urls_to_start_nodes

From source (editable)

git clone https://github.com/pmcharrison/STEP.git
cd STEP
pip install -e .

Optional extras

• psynet — pulls in PsyNet and Dallinger (required at runtime; already present in any PsyNet experiment environment)
• dev — pytest
• publish — build, twine

Install an extra with, e.g.:

pip install -e ".[dev]"

Usage

from step import StepTag, urls_to_start_nodes
import psynet.experiment
from psynet.timeline import Timeline

class Exp(psynet.experiment.Experiment):
    timeline = Timeline(
        StepTag(
            start_nodes=urls_to_start_nodes(
                [
                    "https://mini-kinetics-psy.s3.amazonaws.com/emotional_prosody/03-01-08-02-02-02-24.wav",
                    "https://s3.amazonaws.com/generalization-datasets/vegetables/images/thaieggplant3.jpg",
                    "https://mini-kinetics-psy.s3.amazonaws.com/mini-kinetics-validation/cut_videos/[zumba]_dLE5YOEqBGs.mp4",
                ]
            ),
            expected_trials_per_participant=2,
            max_iterations=5,
        ),
    )

In your experiment's requirements.txt:

psynet-step==0.1.0

Running the Demo

cd demos/STEP-Tag
pip install -r constraints.txt
psynet debug local

License

MIT License