___________________________________________________________________________________________________________________ FLICKER PARADIGM FOR CHANGEBLINDNESS (with mouse input) ___________________________________________________________________________________________________________________ Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC Date: 02-11-2014 last updated: 06-14-2023 by K. Borchert (katjab@millisecond.com) for Millisecond Software, LLC Script Copyright © 06-14-2023 Millisecond Software ___________________________________________________________________________________________________________________ BACKGROUND INFO ___________________________________________________________________________________________________________________ This script implements a Flicker Paradigm to investigate the role of attention in Change Blindness inspired by: Rensink, R.A., O'Regan, J.K. & Clark, J.J. (1997). TO SEE OR NOT TO SEE: The Need for Attention to Perceive Changes in Scenes. Psychological Science, 8, 368-373. NOTES: * This script runs with 6 example stimuli (ONLY intended for demonstration purposes). The original study ran with 48. * the variable "interest level of change" (central vs. marginal) is not included in this script as the example stimuli contain "marginal interest" changes only. * this script runs 2 cue conditions (cue vs. no cue) either in a mixed design (default) or in a blocked design. The script does not include an unreliable cue condition as tested by Rensink et al. * this script collects mouse input and stores images of the placed response Millisecond Software thanks Dr. Rensink for sharing his example stimuli for this script! ___________________________________________________________________________________________________________________ TASK DESCRIPTION ___________________________________________________________________________________________________________________ Participants are presented "flickering" presentations of original and altered pictures for a maximum cycle of 1 min (default). The task is to find the one difference between the two pictures. If participants find the difference they are instructed to click on the location of the change and are asked to describe the change in detail in a textbox. ___________________________________________________________________________________________________________________ DURATION ___________________________________________________________________________________________________________________ the default set-up of the script takes appr. 6 minutes to complete ___________________________________________________________________________________________________________________ DATA OUTPUT DICTIONARY ___________________________________________________________________________________________________________________ The fields in the data files are: (1) Raw data file: 'FlickerParadigm_raw*.iqdat' (a separate file for each participant) Note: by default, trial.savedata is the only trial that saves data to the raw data file build: The specific Inquisit version used (the 'build') that was run computer.platform: the platform the script was run on (win/mac/ios/android) date, time: date and time script was run subject, group, with the current subject/groupnumber session: with the current session id blockCode, blockNum: the name and number of the current block (built-in Inquisit variable) trialCode, trialNum: the name and number of the currently recorded trial (built-in Inquisit variable) Note: trialNum is a built-in Inquisit variable; it counts all trials run; even those that do not store data to the data file such as feedback trials. Thus, trialNum may not reflect the number of main trials run per block. flickerSame: the duration of the blank screen/flicker in between the 2 presentations of the original pictures (or altered pictures) (original: 80ms) Note: if set to 0 the presentation of the pictures appears continuous changeType: "location" (1), "presence/absence" (2), "color" changes (3) in the pictures cueCondition: 1 = a cue is given; 2 = no cue is given cue: the currently presented cue countTrials: counts the number of trials countCycles: counts the number of cycles started until a response occurs currentpic: the itemnumber of the currently presented (original/altered) pic stimulus: the image presented (StimA) responsePoint: determines the image in the response cycle (the cycle that participant made a positive response) that was presented when participant made response: "StimA1", "flicker_AA", "StimA2", "flicker_AB", "StimB1", "flicker_BB", "StimB2", "flicker_BA" or "N/A" (if no response was given) alternations: determines the number of alternations between original and altered pictures until response occurs Note: each switch between originals and altered pictures as well as each switch between altered pictures and original pictures is counted as an alternation. => for each completed cycle, participant go through 2 alternations; if the response occurs AFTER the change from original to altered pic in the last cycle, one more alternation is added to the count. cycleRt: stores the combined trial latencies across the entire cycle until response occurs (in ms) selectedChangeType: the selected observed change type ('location', 'presence/absence', 'color', or empty) accChangeType: 1 = the correct Change Type was selected 0 = in any other case currentChange: contains the correct description of the change changeDescription: stores the openended textbox response in regard to the observed change accChangeDescription: "needs to be evaluated" Note: script does NOT evaluate the correctness of the entered response automatically. Each openended response needs to be evaluated manually. changeReportRT: stores the time it took participant to work on the openended response until pressing the button (in ms) //placement of lbutton down response (in pixel): responseFieldCenterXPX: the pixel x-coordinate of the correct response field responseFieldCenterYPX: the pixel y-coordinate of the correct response field responseXPX: the pixel x-coordinate of the mouse lButtonDown response responseYPX: the pixel y-coordinate of the mouse lButtonDown response maxDistancePX: the max. allowed distance btw. center of correct response field and lButtonDown response (in px) distancePX: the calculated distance btw. center of correct response field and lButtonDown response (in px) accResponseCoordinates: 1 = the lButtonDown response was made within response circle 0 = the lButtonDown response was made outside of response circle Note: this script collects screencaptures of the location of the lButtonDown response coordinates (2) Summary data file: 'FlickerParadigm_summary*.iqdat' (a separate file for each participant) inquisit.version: Inquisit version run computer.platform: the platform the script was run on (win/mac/ios/android) startDate: date script was run startTime: time script was started subjectId: assigned subject id number groupId: assigned group id number sessionId: assigned session id number elapsedTime: time it took to run script (in ms); measured from onset to offset of script completed: 0 = script was not completed (prematurely aborted); 1 = script was completed (all conditions run) runCueCondition: by default, the cuecondition (cue vs. no cue) is run in a "mixed" design; to run the cuecondition in a blocked design, set value.runcuecondition = "blocked" countPracticeRuns: counts how often the practice round was repeated countResponses: counts how often participants clicked the mouse/touched the screen to report the change propCorrectChangeTypeSelections: proportion correct selection of Change Type (across all trials) rtCorrSelections: the mean latency (in ms) of cycles when participant selected the correct change rtAll: the mean latency (in ms) of cycles when participant responded (regardless of accuracy) countL: number of LOCATION trials run countNRL: number of no responses in LOCATION trials propCorrectChangeTypeSelectionsL: proportion correct selection of Change Type in LOCATION trials (based on responses made) rtCorrSelectionsL: the mean latency (in ms) of cycles when participant selected the correct change in LOCATION trials countP: number of PRESENCE trials run countNRP: number of no responses in PRESENCE trials propCorrectChangeTypeSelectionsP: proportion correct selection of Change Type in PRESENCE trials (based on responses made) rtCorrSelectionsP: the mean latency (in ms) of cycles when participant selected the correct change in PRESENCE trials countC: number of COLOR trials run countNRC: number of no responses in COLOR trials propCorrectChangeTypeSelectionsC: proportion correct selection of Change Type in COLOR trials (based on responses made) rtCorrSelectionsC: the mean latency (in ms) of cycles when participant selected the correct change in COCATION trials //Accuracy evaluation of response placement: //Note: this script uses a response circle placed around the predetermined center of the correct response //with responseCircleRadius (this works reasonably well for COLOR and PRESENCE changes but might //miss LOCATION changes - check screencaptures if in doubt) propCorrectResponsePlacement: proportion correct placement of mouse response across all trials propCorrectResponsePlacementL: proportion correct placement of mouse response across LOCATION trials propCorrectResponsePlacementP: proportion correct placement of mouse response across PRESENCE trials propCorrectResponsePlacementC: proportion correct placement of mouse response across COLOR trials ___________________________________________________________________________________________________________________ EXPERIMENTAL SET-UP ___________________________________________________________________________________________________________________ 3 (change types: location, color, presence/absence) x 2 (cue conditions: no cue, cue); tested within Change types are tested by default in a mixed design. To run them in a blocked design: change parameters.runcuecondition (editable parameter). If the conditions are run in a blocked design, the order of the cue conditions is determined randomly in this script. Cues in this script alert participants to the type of change: color, location or the addition/removal of an object (a) Blocks: 1. Practice: by default, the script runs as many practice trials as specified under parameters.max_numberoftrials_practice (default: 1) and selects the stimuli randomly from item.practice_stimA. NOTE: Rensink et al ran 6 (=3 changetypes x 2 interest levels; interest levels are not tested in this script by default) 2. Flicker_MixedCue: by default, the script runs 6 trials 3. Flicker_Cue/Flicker_NoCue: by default, the script runs 3 trials per block (stimuli are randomly assigned to either one of them) (b) Trial Sequences: 1. cue-field screen: 3000ms -> the cue condition is selected at random 2. blank screen: 1000ms 3. Cycle: the selection of the individual pictures is random original (240ms) -> flicker (80ms) -> original (240ms)-> flicker (80ms) -> altered (240ms) -> flicker (80ms) -> altered (240ms) -> repeat of cycle if noResponse (maximum cycle duration: ~1 min) Note: all durations are editable parameter. They can be changed under EDITABLE CODE -> Editable Values 4. Change Description: if a change was reported (by clicking the mouse): a) a screenshot is saved with the response coordinates c) a forced-choice question with 3 answer choices asks participants to select the type of change observed c) a textbox asks participants to describe the observed change in detail ___________________________________________________________________________________________________________________ STIMULI ___________________________________________________________________________________________________________________ The provided stimuli are example stimuli generously shared by Dr. Rensink under http://www2.psych.ubc.ca/\nensink/flicker/download/index.html They are only intended for demonstration purposes. Substitute your own stimuli under EDITABLE CODE -> Editable Stimuli and follow instructions Use script 'flickerparadigm_determinechangelocations.iqjs' to determine the new areas of change for each of your images. ___________________________________________________________________________________________________________________ INSTRUCTIONS ___________________________________________________________________________________________________________________ The instructions used in this script are not original. They are provided by Millisecond Software in html-format. To change the instructions, simply change the html files in a simple Text Editor (e.g. in 'Notepad' in Win or 'textEdit' in Mac) ___________________________________________________________________________________________________________________ EDITABLE CODE ___________________________________________________________________________________________________________________ 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: