PointLightLab Overview
Purpose
PointLightLab is a package of tools that can be used to create Point Light display style stimulus for psychological research purposes. The pack contains a general purpose editor for the various data files and a player which executes the display scripts and records the results.
The player can also be used to convert a script into a simple movie for use in other software systems that accept movie files.
The system will generate signals on the parallel port for integration with software that require this sort of input. Such as BioSemi
General Stimulus Features
The stimulus generated by PointLightLab can be composed of a range of complex generated elements. The basic element is a "point", which appears as a colored dot on the screen. These can be composed into recognisable structures such as biped figures, human faces, hands for sign language analysis, quadruped figures etc.
(Two figures doing starjumps at different speeds)
There are a huge range of parameters and options available for generating the stimulus and recording the subject responses.
Stimuli can be composed of:
- Animated point sets ( figures, faces etc )
- Animated noise point populations ( with the motion drawn from the same or different animation source.)
- Audio events
- Text
Each of these elements can be composed to form a single stimuli. Multiple different stimuli can be defined in the same test script.
Stimulus points can be textured with "freckles" to change the luminosity value of the points.
Recording of Subject Response
Test Subject responses can be captured from the keyboard into a comma delimited text file for analysis in spreadsheet programs or statistics packages. The data captured into the response file can include a rich set of information about the stimulus which triggered the response.
Parallel Port Integration
The PLLPlayer can generate outgoing signals on the Parallel Port for one way communication with other software. These signals are configurable and can be adapted to suit a number of software packages that accept parallel port event signals. The signals are generated at the start and end of the stimuli displays.
Easy Experiment Documentation
The system provides easy ways to capture screen shots and export stimulus Scripts as movies for straightforward documentation of your experiments. The movies are generated as image sequences for easy conversion to your format of choice.
Clear System information
Its easy to verify and document the system specification used for your experiment. Values like the frame rate, screen resolution and refresh rates are easily available so experiments can be duplicated across different computers reliably. This allows testing of large numbers of subjects using non standardised computers.
Usage
The PointLightLab package is composed of two programs and a set of data files.
The programs are:
- PLLEditor
- PLLPlayer
PLLEditor is the script authoring IDE. It supports the creation and editing of scripts and their sub files ( audio track files and model files). This program is only used by the origional script developer.
PLLPlayer is the script interpreter and can stand alone on computers seperated from the authoring environment. This allows the script to be developed on one machine and the experiment to be deployed to one or more computers in a dedicated "testing" area. In a networked environment the experiment can be administered from one computer and the results collated back to a single directory on that computer. This provides support for large scale experiments without the need to individually collate results from multiple locations.
Use case 1 - Single researcher working with a small number of subjects
PointLightLab is installed on a single computer where the script is developed. The script can then be run using PLLPlayer and the results collated to a single experiment directory for analysis. Additionally the experiment can be documented with screen captures and finally the script converted to a movie for display on a website.
Use Case 2 - Teaching research methods to students using PointLightLab
PointLightLab is installed on each workstation in the teaching lab. Students develop scripts in their allocated directories and use each other as test subjects. As the scripts are developed, they are executed from the PLLEditor interface. This removes the need for students to search through files and manage the execution of software from the OS file manager interface. Everything the students need is supplied by the PLLEditor interface. After the tests are run the result file can be imediatly loaded into Microsoft Excel ( or other software of choice ) from the PLLEditor Interface for easy analysis. The range of availible experimental methodologies provides a comprehensive set of experience for students exploring exerpimental methods.
Use Case 3 - Research team working with large number of research subjects
Similar to the first use case above, the script for the experiment would be developed on a single computer and tested as required. If the experiments will be conducted on a small LAN of computers, then a single shared directory can be configured as the repository for the script and data files and another for the collation of the results files. Indivudual copies of PLLPlayer will be required to be installed on each of the testing computers. From here the script can be run for each test subject and the results can be automatically returned to the network share directory. This permits easy backup and modification of the experiment from a single master script. Once the results have been collated, they are ready for analysis as required.
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