Neuroscience/Psychology Experiments
in MATLAB Built on Psychtoolbox
MATLAB software built on Psychtoolbox for neuroscience/psychology experiments

Psychtoolbox is a popular MATLAB toolbox for neuroscience and psychology experiments. Building experiments in MATLAB with Psychtoolbox allows a degree of flexibility and precision that is essential in many research niches. However, it can be a technical process—tricky and time consuming even for experienced users. Redundancy is also a problem as code for stimuli and functionality needs to be continuously refactored across experiments and reinvented across labs.

PSYCHBENCH is software for MATLAB built on Psychtoolbox. It adds a layer to make building Psychtoolbox-based experiments faster, more accessible, and less redundant. It aims to do this while retaining all the precision. It also allows flexibility for custom stimuli and functionality that can plug into any experiment. The PsychBench library comes with a range of stimuli and functionality, including all the basics as well as niche stimuli possible only with Psychtoolbox.

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Download PsychBench beta (free)
for MATLAB – Windows/Mac/Linux

This link downloads the MATLAB function pb_install.m.
Put it in your MATLAB current folder and type help pb_install at the MATLAB command line.

See update history >

You'll also need...

MATLAB R2017a or later

Psychtoolbox (free)

Experiments

Build and run an experiment in PsychBench by writing a short script. Make objects of various types (.g. picture, text, sound, keyPress, etc.). For each object, you can specify parameters and options by setting properties using dot statements. Lots of properties are possible but for any given experiment you can omit most to leave them at default values.

With PsychBench

The script below would run a (very) simple experiment consisting of two repetitions of three distinct trials, all in random order. In each trial, a picture of an animal shows at a height of 10 degrees visual angle. The picture stops showing when the subject presses any key. Experiment results report which animal was shown (picture file name) and response latency for each trial.

Without PsychBench

Some compact Psychtoolbox code to run the same experiment—with the same timing precision and error handling, and assuming MATLAB imread loads the pictures with no fuss—would be:

The take-away is that with PsychBench you work mainly at the level of stimulus and experiment concepts while much of the technical lifting is automated underneath. Meanwhile the precision of Psychtoolbox is preserved because underneath is Psychtoolbox code.

PsychBench also facilitates modifying experiments and reusing stimuli and functionality across experiments. Changing something just means changing property values or swapping in different objects. Any object works anywhere in any experiment.

Core features

Make objects from a library of types and set their properties using dot statements in a simple script. Any object works anywhere in any experiment.
Set objects to start/end based on times or durations, or on flexible cues like other objects, responses from subject, triggers, etc. Further timing is available through object types like sequence (e.g. for change blindness experiments).
Precise timing and time measurement, including time-buffering stimulus onsets/offsets, and synchronizing across modalities (visual, auditory, etc.). The Reference Manual contains a technical summary of timing processes, with more detail available on request.
Sync experiments with external devices like scanners in each trial or for multiple (or all) trials. Set timing relative to sync with zero drift.
Properties all visual objects have allow setting position on screen, layering, rotation, flip, blur or other convolution filter, transparency/opacity, etc. More specific functionality is in each object type.
Default units of degrees visual angle for all values relating to distance on screen, including deg, deg/sec (e.g. speed), cycles/deg (e.g. spatial frequency), etc. Based on saved screen height and distance values, so you only need to reset those if they change. Optionally use px, wh, ww, cm units instead for any property.
Stereo display by most of the modes available in Psychtoolbox.
Sound playback and recording built on Psychtoolbox's high-precision PortAudio functions.
Core response functionality including recording responses, times and latencies, translating response values, scoring, and more. Device-specific functionality is in response handler object types (keyboard, mouse, button box, etc.).
Build any experiment design using MATLAB for loops to generate distinct trials across conditions. Sample one or multiple factors, from discrete or continuous distributions. Include one-off "trials" like intro, sync, breaks, etc.
Repeat, order, and block trials in any way. PsychBench includes little tools to help with replicating, randomizing, distributing, and balancing.
Method of adjustment experiments where the subject can adjust object properties in real time. Device-specific functionality is in adjuster object types (keyboard, mouse, etc.).
Staircase any property of any object using staircase objects (fixed step, QUEST, etc.). Set staircase parameters, interleave multiple staircases, exclude trials from staircases, etc.
Quit and save an experiment run and resume it later to split it across multiple sessions.
Customizable experiment results output drawing from any object properties and labels.

Open-source object type library

PsychBench comes with a library of open-source object types, including not just the basics but niche stimuli as well.

We add new object types regularly. Please contact us with requests.

Visual

Auditory

Response handlers

Adjusters

Other

Custom code

If the library doesn't have the stimuli or function you need for an experiment, you can write your own code in MATLAB + Psychtoolbox. The approach is to write it as a new object type—this allows you to use the code anywhere in any experiment by making objects of the type, as well as have it work with all core functionality (timing, degrees visual angle, core visual options, staircasing, etc.). All the standard types that come with PsychBench are open source, so you can use them as examples and/or build off them.

PsychBench's programming framework streamlines making a quick type for local use. Alternatively you can invest a bit more time to make a durable type with a fuller interface and error checking for an open range of future users.

Sharing object types

You can share a type you've made with other people by zipping the type's folder and sending it. To add a type you have received, just copy its folder into your "local element types folder", then call pb_addPath to refresh PsychBench.

You can also contribute a type to the standard library which comes with PsychBench. If you would like to do this, please email us. We would be happy to credit you. And thank-you!

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