___________________________________________________________________________________________________________________ CONTINUOUS PERFORMANCE TASK - IDENTICAL PAIRS (CPT-IP) (4-digit numbers, 2 visual distraction conditions optional) ___________________________________________________________________________________________________________________ Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC script is in part based on Millisecond Software's IMTDMT.iqx by David Nitz Date: 12-06-2013 last updated: 02-21-2022 by K. Borchert (katjab@millisecond.com) for Millisecond Software, LLC Script Copyright © 02-21-2022 Millisecond Software ___________________________________________________________________________________________________________________ BACKGROUND INFO ___________________________________________________________________________________________________________________ This script implements a subset of the CPT-IP, a test of sustained and selective attention. Reference: Cornblatt, B. A., Risch ,N. J., Faris,G., Friedman,D.& Erlenmeyer- Kimling, L. (1988). The continuous performance test, identical pairs version (CPT-IP): I. New findings about sustained attention in normal families. Psychiatry Research 26, 223-238. The default variant of the CPT-IP implemented: 4-digit numbers without distractions (default) 2 number distraction conditions are optional: 4-digit number overlapping/4-digit number surrounded by stars Adjustments to z-scores as described by: Gregg, A. & Sedikides, C. (2010). Narcissistic Fragility: Rethinking Its Links to Explicit and Implicit Self-esteem, Self and Identity, 9:2, 142-161 (p.148) ___________________________________________________________________________________________________________________ TASK DESCRIPTION ___________________________________________________________________________________________________________________ Participants work through several conditions of a Continuous Performance Task with the task to identify identical pairs. Participants are presented a continuous stream of 4-digit numbers, one at a time, in the middle of the screen at a fairly fast presentation rate. The task is to press a response key any time a number is repeated (=target; Go trials). For non-repeating stimuli, including lures that look similar to the previous stimulus (= catch stimulus), participants are instructed to wait for the next target (NoGo trials). 2 visual distraction conditions can be added: (A) using overlapping 4-digit numbers and (B) using stars around the the 4-digit numbers ___________________________________________________________________________________________________________________ DURATION ___________________________________________________________________________________________________________________ the default set-up of the script takes appr. 3 minutes to complete ___________________________________________________________________________________________________________________ DATA FILE INFORMATION ___________________________________________________________________________________________________________________ The default data stored in the data files are: (1) Raw data file: 'cpt_ip_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) 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. trialtype: stores the type of the trial: 1 = target; 2 = catch; 3 = filler stim: the currently presented 4-digit number response: the participant's response (scancode of response code or 0 = no response) correct: the correctness of the response (1 = correct; 0 = otherwise) latency: the response latency in ms (measured from onset of stimulus) (2) Summary data file: 'cpt_ip_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) Note: N = Numbers Condition list.hit_N.itemCount: the number of target (signal) trials run in the N = Numbers condition H_N: Hit rate in the N = Numbers condition M_N: Miss rate in the N = Numbers condition list.FAcatch_N.itemCount: the number of catch (noise) trials run in the N = Numbers condition FAc_N: False Alarm catch rate in the N = Numbers condition CRc_N: Correct Rejection catch rate in the N = Numbers condition RandomError_N.itemCount: the number of filler trials run in the N = Numbers condition (filler = obviously different numbers) RandomErrors_N: Error-Response Rate to filler trials in the N = Numbers condition CRf_N: Correct Rejection filler rate in the N = Numbers condition meanrt_hit_N: mean reaction time of hits in the N = Numbers condition meanrt_fa_N: mean reaction time of false alarms in the N = Numbers condition meanrt_randomerrors_N: mean reaction time of random errors (Filler trials) in the N = Numbers condition Note: z-score calculations: adjustments (see Gregg & Sedikides, 2010, p.148) If the hit rate / FA rate is 0 => 0.005 is used instead (aka 0.005 is added to the hit/FA rate) IF the hit rate / FA rate is 1.0 => 0.995 is used instead (aka 0.005 is subtracted fro m the hit/FA rate) zhits_N: z-score of the hit rate zFAs_N: z-score of the false alarm rate dprime_N: stores d' (parametric measure of discriminability) for Numbers condition (expressions.z_Hit-expressions.z_Fa) beta_N: stores ß (beta) (parametric measure of bias) for Numbers condition IF distractor conditions are to be run: add the corresponding values for the remaining distractor conditions: NO = overlapping numbers NS = starred numbers ___________________________________________________________________________________________________________________ EXPERIMENTAL SET-UP ___________________________________________________________________________________________________________________ By default, this script runs 1. 1 Practice Block of 50 trials 2. 1 Number Block (no distractions) of 150 trials target trials: 30 catch trials: 28 filler trials: 92 !!!Note: This script can also run 2 distraction conditions: (A) degraded numbers: numbers are partly overlapping (block.numbers_overlap) (B) starred numbers: numbers are surrounded by a circle of 5 randomly placed stars (block.numbers_stars) To add distraction conditions, go to section EXPERIMENT Trials: 3 types 1. Filler trials: not repeating, look different (at least 2 digits differ) from previous stimulus 2. Target trials: repeat previous stimulus 3. Catch trials: similar to previous stimulus (only 1 digit differs) - Target and Catch trials call filler items => at least one filler item in between targets - the numbers are presented for 50ms (editable value) and then blacked-out for 950ms => SOA = 1000ms Participants have the entire 1000ms to respond Notes: If distractor conditions are run, summary statistics need to be added to data files accordingly ___________________________________________________________________________________________________________________ STIMULI ___________________________________________________________________________________________________________________ white 4-digit numbers (can repeat digits) on a black background in monospaced 'Courier New'. (a monospaced font was chosen to ensure that all digits get the same screen space) Size can be adjusted via Editable Parameters - > parameters.height_digits ___________________________________________________________________________________________________________________ INSTRUCTIONS ___________________________________________________________________________________________________________________ Instructions are provided by Millisecond Software LLC. They are not original to Cornblatt et al (1988). -> section Editable Instructions ___________________________________________________________________________________________________________________ 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: response key (default: spacebar as " ") /height_digits: defines the fontsize of the digits in screen height percentage (default: 20%) Note: Cornblatt et al (1988) used the following sizes on their machine Numbers: - ~each letter 1.5cm wide - ~each letter 2.2 cm high - ~8cm wide altogether (on a 15inch monitor, 20% roughly translates into the suggested sizes) /height_stars: defines the size of the distractor stars in screen height percentage (default: 10%) /getreadyduration: the duration (in ms) of the get-ready trial (default: 2000ms) /stimulusduration: presentation duration (in ms) of the targets (default: 50ms) /blackoutduration: interstimulusduration in ms (default: 950ms) => note: stimulusduration and interstimulusduration together provide a stimulus onset asynchrony (SOA) = 1000ms /minhdist: minimum number of digits that need to differ between a new filler stimulus and a previous stimulus -comparison is done by comparing digits at the same position (default: 2) /debugmode: 1 = runs debugmode; 0 = runs test mode