Return to the Redundant Signal Task page

Script Author: Katja Borchert, Ph.D. ( for Millisecond Software, LLC
Date: 10-02-2013
last updated: 01-25-2016 by K.Borchert ( for Millisecond Software LLC

Copyright © 01-25-2016 Millisecond Software


This script implements the Redundant Signal Task as described in:

Mark T. Fillmore, M.T. (2010). Processing Bimodal Stimulus Information Under Alcohol: Is There a Risk to Being Redundant?
Experimental and Clinical Psychopharmacology, 18, 429–435.

Participants perform a simple categorization task on 2 letters and/or 2 tones. The letters and/or tones
are presented at three random time intervals after a fixation cross disappears from the screen. Participants are 
asked to press one key for letter1/tone1 (here: O and high tone) and another key for letter2/tone2 (here: X and low tone).
There are 3 blocks: one block presents only the letters, one block presents only the tones, and one
block presents letters and tones simultaneously ("redundant" condition).

The default data stored in the data files are:

(1) Raw data file: 'RedundantSignalTask_raw*.iqdat' (a separate file for each participant)

build:							Inquisit build
computer.platform:				the platform the script was run on
date, time, subject, group:		date and time script was run with the current subject/groupnumber 
blockcode, blocknum:			the name and number of the current block
trialcode, trialnum: 			the name and number of the currently recorded trial
									(Note: not all trials that are run might record data; by default data is collected unless /recorddata = false is set for a particular trial/block) 
/practice:						0 = test trials; 1 = practice trials;
/SOA:							current SOA
/target:						1 = 0 and/or high tone; 2 = X and/or low tone
response:						the participant's response (scancode) (Note: 0 means trial timed out without a response)
correct:						the correctness of the response
latency: 						the response latency (in ms)
/valid:							1 = valid (latencies in acceptable range); 0 = invalid (latencies outside acceptable range)
/countinvalidtrials:			sums up the number of invalid trials
/countvalid_redundant:			count the number of valid trials in each condition
/countcorrect_redundant:		count the number correct responses (for valid trials only) in each condition
/sumrt_visualonly -
/sumrt_redundant:				sums up the latencies for correct responses (for valid trials only) in each condition

(2) Summary data file: 'RedundantSignalTask_summary*.iqdat' (a separate file for each participant)

script.startdate:				date script was run
script.starttime:				time script was started
script.subjectid:				subject id number
script.groupid:					group id number
script.elapsedtime:				time it took to run script (in ms)
computer.platform:				the platform the script was run on
/completed:						0 = script was not completed (prematurely aborted); 1 = script was completed (all conditions run)
/meanrt_visualonly -
/meanrt_redundant:				mean latency of correct responses (valid trials only) for the different condition (in ms)

/correctprop_visual -
/correctprop_redundant:			proportion of correct responses (valid trials only) for the different conditions

/percentinvalid:				percent invalid trials (latencies outside specified boundaries)

type of stimuli presented (visual only vs. audio only vs. both) tested within subjects in a blocked design

* Experimental Blocks:
- 3 blocks, order counterbalanced (latin square) by groupnumber 1-3
- 90 trials per block
- targets (e.g. O vs. X) randomly determined (=> 1/2 the trials with 0)

* Trial Sequence:
- Fixation cross (250ms) -> white screen (random SOA duration) -> target (response terminated of maximum presentation of 1000ms)-> ITI (2000ms)
- SOA is randomly determined. By default in this script: frequency of SOAs fixed at 1/3 for each of the 3 SOAs (=> see list.soas)
- pairings of letter and sound the same for all: O and high tone vs. X and low tone

* Practice:
- 3 practice blocks of 20 trials each (order always: visual -> audio -> redundant)
- errorfeedback

* visual: X vs. O
* audio: low tone (125Hz) vs. high tone (1000Hz); provided sound files were generated in Audacity, length: 5s, Amplitude: 0.8
see section Editable Stimuli

Instructions are not original can be edited under section Editable Instructions

check below for (relatively) easily editable parameters, stimuli, instructions etc. 
Keep in mind that you can use this script as a template and therefore always "mess" with the entire code to further customize your experiment.

The parameters you can change are:

Appearance of visual target:
/fontheight:								size of font (percentage of screen height) (default: 15%)

Appearance of audio target:
/volume_hightone:							volume adjustment for the high tone (default: -2000)
/volume_lowtone:							volume adjustment for the low tone (default: 0)

/fixationcrossduration:						duration of fixation cross in ms (default: 250ms)
/maxtargetduration:							max duration that target is on screen in ms (default: 1000ms)
											Note: if no response is given, trial expires after presenting the target for parameters.maxtargetduration
/iti:										intertrialinterval in ms (default: 2000ms)

/responsekey1:								scancode of responsekey 1 (default: 30)
/responsekey1_label:						label of responsekey 1 (default: "A")
/responsekey2:								scancode of responsekey 2 (default: 38)
/responsekey2_label = "L"					label of responsekey 2 (default: "L")
											Note: scancodes can be obtained via Tools->Keyboard Scancodes

/minRT:										minimum acceptable response latency in ms (default: 100ms)
/maxRT:										maximum acceptable response latency in ms (default: 1000ms)
											Note: outside these boundaries, the responses are counted as invalid trials

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