DirectRT Features

The following outlines most of the features and functions that DirectRT provides. Where useful, links are provided to related "how to.." documentation.

Response Times

•Timing resolution of 1 millisecond.
•Response timing is synchronized with the screen display so timing always begins when the screen first begins to draw (eliminates 10-17 milliseconds of random error).
•Works with Windows to reduce the impact of system events while timing is taking place.
•Uses Microsoft's DirectX to gain the fastest access possible to input events from the keyboard, mouse, joystick and soundcard.
•Optionally define minimum and maximum response times and deliver custom message screens for each when violated.
•Collect multiple response times on a single trial.
•Collect key release response times in addition to key press times.
•Define valid keys for any response.
•Define correct key for any response. Optionally require a correct response.

Input Options

•Keyboard, mouse, and joystick input for discrete responses.
•Short open ended (fill-in-the-blank) responses.
•Voice responses via microphone connected to your soundcard.
•Option of saving voice responses as wav files on your hard drive.
•Continuous joystick motion.
•TTL signals can be read from a defined port to gather data from external equipment.

Stimulus Presentation

•Create simple or complex visual displays with single or multiple images and text.
•Create as many different displays as you need for any given trial.
•Play sound, video or animation files with tremendous precision.
•Can handle multiple simultaneous and/or sequential sound files, with control over left/right panning and frequency (Hz). Easily synchronized with visual stimuli.
•Send precisely synchronized TTL signals to communicate with external equipment (e.g., another computer controlling physiological equipment).
•Present subject's own responses to open ended questions as stimuli in the same session.
•Easily create full screens of instructions with formatted text.
•Create multiple style settings with choices of fonts and display colors.
•Present full colour graphics that can be as large as full screen and in any resolution from 640x480 to 1600x1200 and beyond.
•Present multiple images and/or text in succession or simultaneously.
•Superimpose custom graphics you make (e.g., special rating scales) over any other image or text. Great for pretesting and rating visual stimuli.
•Capture screens from Microsoft PowerPoint and other presentation software and present them as stimulus or instruction screens in your experiment.
•Precisely locate images and text with flexible and easy to use alignment options.
•Display of stimulus screens is synchronized with the monitor's refresh rate resulting in highly controlled presentation rates.
•Enter stimulus presentation times in milliseconds. DirectRT will determine the screen refresh rate and will present the stimulus for the number of screen refreshes that will comes closest to your specified interval. All actual display times are written to a log file for each session.

Randomization & Trial Structure

•Randomize trials within a single block.
•Randomize the order that blocks of trials are presented.
•Randomly select which items from a set are presented.
•Extremely flexible trial design which can change from one trial to the next.
•Define stimuli directly in the input file or refer to stimulus lists.
•Access stimuli from lists sequentially, randomly, or randomly without replacement.
•Create scale responses and multiple choice questions in any format.
•Skip pattern capability when a particular key is pressed on any trial.
•Jump capability -Depending on which key is pressed you can have DirectRT jump to different events (e.g., such as a feedback sequence) and then resume where it left off.
•Option of self-paced or time-limited responses.
•Repeat trials for which stimuli were randomly selected at run-time.

Data

•Writes data to an easy-to-analyze ASCII file.
•Add optional variables to the data file that identify within subject trial conditions-makes for much easier analysis.
•Writes all data into a single file that can be imported straight into Excel or SPSS.
•Includes a utility to easily merge data files collected on different computers.
•Produces two data files per run-one that is simplified and easy to use for most purposes and a more detailed "log" version that records everything including actual stimulus presentation times so you can ensure that your system is capable of achieving the timing you need.

Other Features

•Easily modify and re-use your input files experiments.
•You don't have to learn a new editor! Do everything from your favourite spreadsheet application (e.g., Excel, Lotus, Quattro). If you know how to use one of these, then you already know how to edit DirectRT input files.
•Also works great in combination with MediaLab (versions 2000 and later). Just drop a DirectRT session into any MediaLab questionnaire. MediaLab will ask DirectRT to execute the session and will pass along the current subject and condition IDs. When DirectRT is finished, MediaLab will resume where it left off. This is a great way to assign multiple DirectRT input files as a function of between subject factors.
•Runs easily from a command line prompt so you can call the session and execute it seamlessly from your within own programs. You would never know you left your own program.
•Context sensitive help such that pressing F1 at any time will help you with what you are currently doing.
•Easy-to-use intuitive interface–no programming code necessary.