___________________________________________________________________________________________________________________ INSPECTION TIME TASK ___________________________________________________________________________________________________________________ Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC Date: 12-05-2014 last updated: 02-23-2022 by K. Borchert (katjab@millisecond.com) for Millisecond Software, LLC Script Copyright © 02-23-2022 Millisecond Software ___________________________________________________________________________________________________________________ BACKGROUND INFO ___________________________________________________________________________________________________________________ This script runs an Inspection Time task; a task used to study the early stages of visual processing. The implemented task is based on: Deary, I.J., Enrico Simonotto, E., Meyer, M., Marshall, A., Ian Marshall, I., Goddard, N. & Wardlawf, J.M. (2004). The functional anatomy of inspection time: an event-related fMRI study. NeuroImage, 22, 1466– 1479. ___________________________________________________________________________________________________________________ TASK DESCRIPTION ___________________________________________________________________________________________________________________ Participants see stimuli that have one long and one short arm. The stimuli are presented for variable durations before they are covered by a mask. Participants have to decide whether the short arm was left or right and press corresponding response keys. Participants are told that reaction time is unimportant. ___________________________________________________________________________________________________________________ DURATION ___________________________________________________________________________________________________________________ the default set-up of the script takes appr. 18 minutes to complete __________________________________________________________________________________________________________________ DATA FILE INFORMATION ___________________________________________________________________________________________________________________ The default data stored in the data files are: (1) Raw data file: 'inspectiontimetask_raw*.iqdat' (a separate file for each participant) build: The specific Inquisit version used (the 'build') that was run computer.platform: the platform the script was run on (win/mac/ios/android) display.refreshrate: the vertical refresh rate of the current monitor NOTE: Deary et al (2004) used the following durations: 6, 12, 19, 25, 31, 37, 44, 50, 62, 75, 87, 100, 125, 150, 200 ms on a monitor with a vertical refresh rate = 160Hz !!! Most monitors have a vertical refresh rate of 60Hz and therefore it won't be possible to present any stimuli at 6 or 12 ms. One these computers it takes about 17ms (minimum) to refresh the screen (thus 17ms is the minimum that can be used on 60Hz monitors). 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 counttrials: counts all stim trials stimduration: duration (in ms) of current stim stimduration_condition1-15 (depending on stimduration) location: 1 = left shorter arm; 2 = right shorter arm stimulusitem: the presented stimuli in order of trial presentation response: the participant's response (scancode of response buttons) 30 = A 38 = L correct: accuracy of response: 1 = correct response; 0 = otherwise latency: the response latency (in ms); measured from: onset of stims (2) Summary data file: 'inspectiontimetask_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) display.refreshrate: the vertical refresh rate of the current monitor NOTE: Deary et al (2004) used the following durations: 6, 12, 19, 25, 31, 37, 44, 50, 62, 75, 87, 100, 125, 150, 200 ms on a monitor with a vertical refresh rate = 160Hz !!! Most monitors have a vertical refresh rate of 60Hz and therefore it won't be possible to present any stimuli at 6 or 12 ms. One these computers it takes about 17ms (minimum) to refresh the screen (thus 17ms is the minimum that can be used on 60Hz monitors). 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) propcorre:ct_stim1: proportion correct responses for stim duration 1 (here: 6ms) (the same for all 15 stim durations) __________________________________________________________________________________________________________________ EXPERIMENTAL SET-UP ___________________________________________________________________________________________________________________ (1) 15 stimulus presentation durations tested with 20 repetitions (default). Deary et al (2004) used the following durations: 6, 12, 19, 25, 31, 37, 44, 50, 62, 75, 87, 100, 125, 150, 200 ms on a monitor with a vertical refresh rate = 160Hz !!! Most monitors have a vertical refresh rate of 60Hz and therefore it won't be possible to present any stimuli at 6 or 12 ms. One these computers it takes about 17ms (minimum) to refresh the screen. (set durations under section EDITABLE CODE -> Editable Values) (2) The stimuli duration times are selected randomly without replacement (method of constant stimuli). (3) The short arm is located on the left for 50% of the trials (4) Practice block for 25 randomly durations (number of trials can be edited) Trial Sequence: (1) Cue ('+') for 500ms (editable) (2) Interstimulus interval: Blank screen for 600ms (editable) (3) Stimulus for variable duration (4) Mask for 500ms (editable) (5) Trial continues until response is made (6) Intertrial interval (blank screen) for 500ms (editable) ___________________________________________________________________________________________________________________ STIMULI ___________________________________________________________________________________________________________________ Stimuli are provided by Millisecond Software. They can be replaced under section EDITABLE CODE -> Editable stimuli. The target stimulus was created in such a way, that the long arm is twice the length of the short arm (which equals the length of the crossbar) Note: The size of the target stimulus in this script is coded in terms of canvas screen %. In order to achieve, a size that is roughly equal to the one used by Deary et al (2004), edit parameters.skip_stimsizecalibration under section EDITABLE CODE -> Editable Values (default: true -> stim size calibration routine is not run). ___________________________________________________________________________________________________________________ INSTRUCTIONS ___________________________________________________________________________________________________________________ Instructions are provided by Millisecond Software in the form of htm pages. Instructions can be edited directly in file "IT_intro.htm" or replaced entirely. ___________________________________________________________________________________________________________________ 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: /responsekey_left: the left response key (default: 'A') /responsekey_right: the right response key (default: 38) /trials_perduration: number of trials per stimulusduration (default: 20) !!!Note: if that number is changed, list.stimdurations/list.stimduration_condition (section Editable Lists) need to be changed accordingly => 15 stimdurations x 20 trials/stimduration = 300 trials total /nr_practicetrials: number of practice trials in this script. Note: the durations are selected at random. /fontsize_cue: default height (in screen height %) of the cue (default: 10%) /skip_stimsizecalibration: false: the picture stimulus can be sized to 5cm (Deary et al, 2004) prior to start of experiment on current monitor true: the calibration routine is skipped (default) /stimpic_height: default height (in screen height %) (default: 26%) Note: Deary et al (2004): long arm = 5cm (short arm and cross bar = 2.5cm) Note: absolute sizing requires calibration for the current monitor which is run if parameters.skip_stimsizecalibration = false (see below) /stimpic_height_in_mm: default height of stimulus in mm (default: 5cm = 50mm) will be used if 'skip_stimsizecalibration = false' / readyDuration: duration in ms of get-ready-trial (default: 2000) /cueduration: duration of cue in ms (default: 500) /cue_ISI: cue(offset)-stim(onset) Interstimulus Interval in ms (default: 600) /maskduration: duration of mask in ms (default: 500) /iti: inter trial interval in ms (measured from response to onset of cue) (default: 500ms) /stimduration1- /stimduration15: stores the 15 stimulus presentation durations in ms Note: Deary et al (2004) used: 6, 12, 19, 25, 31, 37, 44, 50, 62, 75, 87, 100, 125, 150, 200 ms on a monitor with a vertical refresh rate = 160Hz !!! Most monitors have a vertical refresh rate of 60Hz and therefore it won't be possible to present any stimuli at 6 or 12 ms. One these computers it takes about 17ms to refresh the screen.