___________________________________________________________________________________________________________________ DIGITAL FOOD DISPENSER - Spacebar operated ___________________________________________________________________________________________________________________ Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC Date: 07-07-2015 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 Digital Food Dispenser similar to the one described in: van Koningsbruggen, G.M., Veling, H., Stroebe, W. & Aarts, H. (2014). Comparing two psychological interventions in reducing impulsive processes of eating behaviour: Effects on self-selected portion size. British Journal of Health Psychology, 19, 767–782. ___________________________________________________________________________________________________________________ TASK DESCRIPTION ___________________________________________________________________________________________________________________ Participants view a food dispenser. By pressing the Spacebar down they "open" the Food Dispenser. By lifting the Spacebar they "close" the Food Dispenser and end the session. ___________________________________________________________________________________________________________________ DURATION ___________________________________________________________________________________________________________________ Max Duration: 2minutes ___________________________________________________________________________________________________________________ DATA FILE INFORMATION ___________________________________________________________________________________________________________________ The default data stored in the data files are: (1) Raw data file: 'digitalfooddispenser_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. stimulusitem: the presented stimuli in order of trial presentation response: the participant's response correct: the correctness of the response (1 = correct; 0 = incorrect) latency: the response latency (in ms) currentresponseduration: the amount of time the Spacebar was pressed (in ms) for the current food dispenser currentpoints: stores the points of the current food dispenser session (resets for each food dispenser) totalpoints: stores the points earned across food dispensers (2) Summary data file: 'digitalfooddispenser_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) maxpoints: the maximum number of points that can be gained for one food dispenser (default: 500) meanresponseduration: mean response duration in ms (how long Spacebar was pressed on average) across dispensers meanpoints: mean points gained across dispensers (Max: 500) ___________________________________________________________________________________________________________________ EXPERIMENTAL SET-UP ___________________________________________________________________________________________________________________ * 2 trials: 1 food dispenser with cherries and 1 food dispenser with bananas; order is randomly determined * Spacebar down: the dispenser "opens": fruit pieces "fall out" and a gray cover starts to cover the food dispenser to simulate that it empties out * Spacebar up: the dispenser "closes" -> trial comes to an end * every 100ms (default) of pressing the Spacebar earns the participant 1 point => max. 500 points can be earned (then the dispenser is empty) ___________________________________________________________________________________________________________________ STIMULI ___________________________________________________________________________________________________________________ provided by Millisecond Software ___________________________________________________________________________________________________________________ INSTRUCTIONS ___________________________________________________________________________________________________________________ provided by Millisecond Software; edit under 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: /increaseinterval: another point is added for every 100ms (default; Note: should not be set lower than vertical refreshrate of monitor which is ~17ms for a 60Hz monitor) that the Spacebar is NOT pressed /maxpoints: the maximum number of points that can be gained (default: 500) Note: the product of increaseinterval and maxpoints controls how long it takes to 'drain' the dispenser completely /finalcoverheight: the height of the final gray cover (Note: should only be messed with if different pictures are used)