Home

asf: a simple framework

asf is a tool for presenting visual, auditory, and tactile stimuli in behavioural experiments under Windows, Linux and OSX. asf simplifies the experimenter’s task of programming such experiments using the Psychophysics Toolbox www.psychtoolbox.org and Matlab. Users create a text file with filenames for stimuli (.STD), a textfile with trial definitions (.TRD) concerning which image is shown for how long, and when to collect responses. A configuration structure (Cfg) determines appearance and how asf interfaces with hardware (MRI, TMS, EEG, MEG, tactile and auditory stimulators, eye trackers and response devices). Data for all experiments are stored in a standardised format.

## asf is a realtime slideshow player ## asf can be used as a slideshow player with precise timing. An experimental trial consists of showing a set of slides, each with its own specified duration, and a time-window within which you check for responses by the participant.

## asf is a realtime slideshow player with drawing capabilities of its own ## However, the slideshow aproach is limited. Sometimes an experiment would require too many slides to be prepared, for example in random dot kinematograms (see below). Preparing dedicated bitmaps for each single frame is not only tedious, but it can also lead to technical problems because fast graphics memory is limited and having to load many images can jeopardize all efforts of good timing because the computer has to move images between the graphics memory and standard memory.

For situations like this, asf allows you to plug-in your own code, which takes care of rendering the stimuli under program-control. You still have a simple slideshow going on, but your program adds items to each slide. Although this requires programming from the user, you are not left alone! asf comes with a template function, which is easy to enhance for your purposes. The [tutorial section](Tutorials.md) also contains examples for this.

asf scales with expertise

Finally, you can program some intelligence into your plugin-code. For example you want to program a gaze contingent window or you want to extinguish a stimulus if a participant makes a saccade. All of this is possible without having to start from scratch, and we hopefully will be able to put some example code about this on the webpage. Users are invited to contribute code, too.

After this intro, maybe you want to look at this presentation asfIntro for an overview.