AEPsych

AEPsych is a framework and library for adaptive experimetation in psychophysics and related domains.

Installation

AEPsych only supports python 3.8+. We recommend installing AEPsych under a virtual environment like Anaconda. Once you've created a virtual environment for AEPsych and activated it, you can install our requirements and then install AEPsych:

cd aepsych
pip install -r requirements.txt
pip install -e .

Eventually, AEPsych will be available on PyPI and pip-installable directly.

Usage

See the code examples here.

The canonical way of using AEPsych is to launch it in server mode.

python aepsych/server/server.py

(you can call python aepsych/server/server.py --help to see additional arguments). The server accepts messages over either a unix socket or ZMQ, and all messages are formatted using JSON. All messages have the following format:

{
     "type":<TYPE>,
     "version":<VERSION>,
     "message":<MESSAGE>,
}

Version can be omitted, in which case we default to the oldest / unversioned handler for this message type. There are five message types: setup, resume, ask, tell and exit.

Setup

The setup message prepares the server for making suggestions and accepting data. The setup message can be formatted as either INI or a python dict (similar to JSON) format, and an example for psychometric threshold estimation is given in configs/single_lse_example.ini. It looks like this:

{
    "type":"setup",
    "version":"0.01",
    "message":{"config_str":<PASTED CONFIG STRING>}
}

After receiving a setup message, the server responds with a strategy index that can be used to resume this setup (for example, for interleaving multiple experiments).

Resume

The resume message tells the server to resume a strategy from earlier in the same run. It looks like this:

{
    "type":"resume",
    "version":"0.01",
    "message":{"strat_id":"0"}
}

After receiving a resume message, the server responds with the strategy index resumed.

Ask

The ask message queries the server for the next trial configuration. It looks like this:

{
    "type":"ask",
    "version":"0.01",
    "message":""
}

After receiving an ask message, the server responds with a configuration in JSON format, for example {"frequency":100, "intensity":0.8}

Tell

The tell message updates the server with the outcome for a trial configuration. Note that the tell does not need to match with a previously ask'd trial. For example, if you are interleaving AEPsych runs with a classical staircase, you can still feed AEPsych with the staircase data. A message looks like this:

{
    "type":"tell",
    "version":"0.01",
    "message":{
        "config":{
                "frequency":100,
                "intensity":0.8
            },
        "outcome":"1",
    }
}

Exit

The exit message tells the server to close the socket connection, write strats into the database and terminate current session. The message is:

{
    "type":"exit",
}

The server closes the connection.

Data export and visualization

The data is logged to a SQLite database on disk (by default, databases/default.db). The database has one table containing all experiment sessions that were run. Then, for each experiment there is a table containing all messages sent and received by the server, capable of supporting a full replay of the experiment from the server's perspective. This table can be summarized into a data frame output (docs forthcoming) and used to visualize data (docs forthcoming).

Contributing

See the CONTRIBUTING file for how to help out.

License

AEPsych licensed CC-BY-NC 4.0, as found in the LICENSE file.

Citing

The AEPsych paper is currently under review. In the meanwhile, you can cite our preprint:

Owen, L., Browder, J., Letham, B., Stocek, G., Tymms, C., & Shvartsman, M. (2021). Adaptive Nonparametric Psychophysics. http://arxiv.org/abs/2104.09549