Free, Python-based software--with a graphical user interface--for building and running behavioral experiments. There is some coding involved (if you want to provide participants with accuracy or response-time feedback, for example).
You can also use it to collect data online. There's a modest charge for collecting data online (about $0.30 per participant in 2021). The charge does not include recruiting fees such as Amazon Mechanical Turk fees.
PsychoPy (and the Python programming language more generally) can also be used for experiments in animal behavior if interfaced with hardware appropriate for detecting animal responses. See: Cook, P. F., Prichard, A., Spivak, M., & Berns, G. S. (2016). Awake canine fMRI predicts dogs' preference for praise vs food. Social Cognitive and Affective Neuroscience, 11(12), 1853-1862. doi:10.1093/scan/nsw102
A free, scripting-based, web application for creating and running online experiments. It is not as flexible as PsychoPy3. Researchers need to arrange their own recruiting (e.g., Amazon Mechanical Turk fees).
A menu-driven system for creating and running online experiments. It is not free, but costs $240 per year (2021 price). It is not as flexible as Psychopy3. Recruiting costs (e.g., Amazon Mechanical Turk fees) are not included.
For running web-based surveys and experiments.
Classic software for building and running laboratory-based experiments. It has recently added an option to run experiments online. E-Prime costs about a thousand dollars (2021).
Free, open-source software for building and running laboratory-based experiments. It is similar to E-prime. Open Sesame has recently added an option to run experiments online.
Program for merging data files, generated for individual participants, into a single file.
A very simple, example experiment (Stroop Task)
Complex experiment structure: An example of block randomization. [Tags: random; randomize; block; sequence; OpenSesame]
Allows the creation of online experiments. It costs a little over $1 per participant. Recruiting costs (e.g., Amazon Mechanical Turk fees) are not included.
For running online experiments. Very nice looking. Costs about $400 for 3 months of use (2021 price).