PsyPad User Manual Preamble
Contents
1. Each staircase terminates when its number of reversals is achieved or if the count of minimum maximum stimulus value correct incorrect reaches the specified number 10 Session Configurations A session is simply a list of enabled tests which are executed in order If you want different tests on different days of the week you should make sure that all the tests for all days are enabled and then each test is configured for the appropriate day Note that the practice session is separate from the test session and so if you want the same test to appear in both you need to duplicate the test and set the Is practice configuration option in the duplicate 11 Server Setup 11 1 The PsyPad net au Server Note that while http server psypad net au is password protected and under normal circumstances your log files are not available to any other users we are not providing a state of the art secure environment Any determined hacker will be able to get access to your logs in much the same way as they can access your personal computer iPad etc despite our best efforts We also have administrator access to your logfiles While we have procedures in place to limit the use of this access we may inadvertently view your logs while maintaining or updating the system As such do not include any private or unethical data in your participant identifiers or image file names that will appear in the log files Note that this standard level of security do2. 6 1 Participant list You can view a list of participants on the server by selecting the Participant tab From there you can create a new participant by clicking New Participant Choose a username and click Create Participant From the participant list you can click on the link in the Configurations column to access a participant s configurations and the link in the Logs column to access their test logs Section 6 2 You can click on Edit to change their username and Delete to delete them 6 2 Participant log list Clicking on a link in the Logs column in the participant list will take you to a list of the participant s logs From there you can View and Delete logs You can filter the log list using the filter options on the right and you can download the logs in various formats using the download links at the bottom left of the log list 6 3 Participant configuration list Clicking on a link in the Configurations column in the participant list will take you to a participant s configuration list From there you can Edit Delete Save to Gallery and Duplicate configurations You can also create a New Participant Configuration Section 7 or Import from Gallery Section 6 4 6 4 Importing configurations from the gallery Clicking Import from Gallery in a participant s configuration list will take you to the import screen From here select the configurations you would like to import from the gallery Se
3. Server Account Demo Mode Participants E E mass Configuration Configurations gt Image Public Gallery Private Gallery Figure 1 Overall structure of data in PsyPad Having a server account allows access to all of your own participants configurations and images in addition to Demo Mode and the Public Gallery of images and configurations Each entry in the image library is a zip file of images as per Section 8 Each participant has their own local copy of configurations named Config in this figure see Section 9 which may or may not be replicated in the either of the galleries Log files Section 12 are attached to participants or the Demo Mode and never feature in the galleries Each test configuration uses one of the image sets in the from either gallery 3 2 Private gallery Your private gallery can be accessed on the server by going to the Configuration Gallery for configurations or Image Sets for image sets tab and selecting the Private Configurations or Private Image Sets option Configurations and image sets you upload to your private gallery can not be seen by other PsyPad users see Section 11 for security disclaimers 4 Participant mode As opposed to Demo mode Participant mode allows you to configure experiments for participants where multiple experiments can be presented sequentially with the results uploaded to the server on completion You can switch to Participant m
4. 2 4 838 96ms 0 64 05 Correct Per Level gt 6 865 24ms 0 50 78 Reversals gt 8 859 10ms 0 66 44 Presentations Per Level gt 1 AEREA 16 1066 44ms 0 232 52 test_begin 30 09 2018 8 20 49 PM 18 exit_button_x 950 button2_y 700 num_buttons 2 staircase_max 20 831 52ms o 53 09 next_question 30 09 2013 8 20 49 PM 28 758 87ms 0 49 87 1 36 772 83ms 0 30 85 currentStaircase 30 09 2013 8 20 49 PM 44 4 s currentReversal 30 09 2013 8 20 49 PM 60 895 82ms 0 75 36 o presented_image 30 09 2013 8 20 49 PM 60 1_7 neacantad histtane aninaienaa a on aa DMA a b Correct Per Level Reversals UA Staircase 1 o 1 gt gt 2 6 100 00 2 8 66 67 4 12 80 00 Staircase 2 18 83 33 m S w l E 20 100 00 100 00 36 100 00 44 00 00 o m S 52 100 00 60 100 00 Y 8 o E 2 El E gt a Figure 4 Overall structure of data in PsyPad An administrator owns an image library and a list participants Each entry in the image library is a zip file of images as per Section 8 Each participant has a list of test configurations named Test in this figure see Section 9 and log files of previous tests Section 12 Each test configuration uses one of the image sets in the library The group of enabled test configurations for each participant make up a session 17
5. 1 02 png 2_00 png 2_01 png v 3 1 002 01 png 1 01 png 1 02 png 2_00 png 2_01 png 1 01 png 1 02 png 2_00 png 2_01 png rrr 1 01 png 1 02 png 2_00 png 2_01 png 1 01 png 1 02 png 2_00 png 2_01 png d 1 01 png 1 02 png 2_00 png 2_01 png a b E E E E 5 E ie al ie fie gt 1 01 png 1 02 png 2_00 png 2_01 png rae ae ae y eaa aa 5 mia ia ia Y OO Ia a O ta ie 0 110 3 000 000 100 1 Figure 2 Folder and image filenames for a a staircase or MOCS procedure that has stimuli levels 0 5 10 15 b a MOCS with three levels low med and high and c a movie stimulus with levels 39 42 54 In a and b the prefix of the filenames give the button number for a correct response 1 or 2 and c the same is given by the prefix of the subfolder name In c files are movie frames that are presented in lexicographic sequence 2 Buttons What response buttons do you need for your test Up to four rectangular buttons are allowed Where should they be placed on the screen What color width and height should they be 3 Thresholding strategy MOCS or staircase If you choose a MOCS you must decide on the stimuli levels you want to test and how many trials per level see Section 9 1 For staircases you must decide how many to interleave and fo
6. image is replaced with the background color and background image if present Version 1 1 onwards and the buttons remain This option can interact strangely with movie stimuli If you have chosen Yes and have a movie stimuli that is not looping you will get the background color and background image if specified once the movie runs out of frames If you have chosen No and a value that is shorter than the movie number of frames x frame rate 60 then the movie will be truncated Infinite response window If Yes then PsyPad will wait until a button is pressed before proceeding to the next stimuli If No you must specify a time in seconds If a button is pressed within this time started from stimulus onset then PsyPad will proceed to the next stimuli checking the button number against the image file name for cor rect or incorrect If there is only one button and it is pressed within the window a correct response is recorded If No anda button is not pressed pressed within the time limit from stimulus onset then an incorrect response will be recorded Use specified seed If Yes the provided number is used to seed the random number generator handy for testing so that you get the same image se quences otherwise if No a random seed from dev urandon is used Attempt facial recognition If Yes then a picture is taken with the on board camera at the beginning of every stimulus pre
7. image set that contains a set of blanks which contains full size images all of one pixel level It might be easiest to annotate each corner of the image with the pixel value too You can then set up a MOCS or staircase using this image set to aid in calibration 8 5 Ramping Images are not ramped and are presented immediately after the inter stimulus interval expires If you want to ramp your stimuli on and or off make a movie style image that contains the ramp you require 8 6 Timing We do not have program access to the graphics clock on the iPad and so very precise frame presentation times are not supported If you require very fine timing control of stimuli presentations then PsyPad is probably not for you We have endeavoured to be as accurate as possible with presentation and inter stimulus interval timing and it should be sufficiently accurate for most tests 8 7 Uploading the images Image sets must be uploaded separately before you can associate them with a test configuration Once you have all the images you need for a single test named correctly you should zip them all into a single zipfile without an enclosing folder using zip on MacOS or Linux or winzip on Windows and upload them to the server by selecting the Image Sets tab and clicking Import Image Set They will then be automatically processed on the server and put in a suitable format a single big file with an index for transfer to the PsyPad iPad ap
8. questions per folder A comma separated list of pairs of the form s n where s is the stimulus level matching the filename of an image in the chosen image set and n is the number of trials For example 16 40 18 40 20 40 is a MOCS over three stimuli levels 16 18 and 20 using 40 trials for each level Display Configuration Background color An RGB hex string beginning with a For example FF0000 is red This is the color of the screen when the Begin button is displayed between stimuli if the Next button is used and also as the background for your images if they do not fill the entire screen or contain transparent pixels Show exit button If Yes then a small cross is displayed as per the exit position given below Exit button position x y width and height of the exit button All measurements are in pixels the top left of the screen is 0 0 and the bottom right is 1024 768 Exit button color Background and foreground colors as RGB hex strings For ex ample 00FF00 is green Ignored if Show exit button is No You can preview the position and colour of the exit button by clicking Show Preview at the bottom right of the browser win dow not 100 accurate Button Configuration Number of buttons The number of response buttons maximum 4 From Version 1 1 onwards if only one button is chosen if it is pressed within the response window this counts as a correc
9. server psypad net au free for your use but perhaps you want to run your own the server code is open source but this is not recommended or supported Section 11 discusses the server in more detail 2 Registration You will need an account on the server you are using All test configurations images and participants are associated with your login see Figure 1 You can create an account directly on the iPad app or at http server psypad net au 3 iPad app You can download the iPad app by searching for PsyPad on the App Store on your iPad or by visiting this link https itunes apple com al app psypad id735057966 After installing the app you will need to open it and log in with your PsyPad account 2 Demo mode The default mode on the iPad app is Demo mode Demo mode allows you to run pre built psychophysics experiments both your own and the demonstration experiments we provide and view their results on the iPad immediately In this mode three lists of test configurations are provided 1 Downloaded configurations Downloaded configurations can be run by pressing the Play button and deleted by pressing the Delete button only your local copy will be deleted 2 Updates available Configurations that have been updated on the server since you last downloaded them are presented here Press the Update button to download the updated configuration 3 Available configurations This is a list of test configurations available to
10. you from the server This will include the tests in the public gallery see Section 3 1 and the tests you have created Section 7 on the server which sit in your private gallery Section 3 2 Press the Download button to download a configuration Configurations including test parameters and images must be downloaded before they can be run Some tests have quite large image sets sometimes up to 100M and so consider downloading these before you need to use them live At the end of a test in Demo mode the test log will be displayed along with some options for automated log analysis see Section 13 The test log will also be uploaded to the server and is accessible by selecting the Demo Mode Logs tab on the server 3 Gallery Figure 1 shows the overall structure of the PsyPad server The collection of tests and stimuli are split into public and private galleries 3 1 Public gallery We provide a collection of test configurations and image sets in the public gallery that you can download and run in Demo mode see Section 2 or add to your own participants see Section 6 4 You can submit any configurations you create see Section 7 for consideration to be added to the public gallery see Section 7 2 The public gallery can be accessed on the server by going to the Configuration Gallery for public configurations or Image Sets for public image sets tab and selecting the Public Configurations or Public Image Sets option
11. PsyPad User Manual Introduction PsyPad 2 0 has two modes of operation Demo mode and Participant mode Demo mode allows you to run psychophysics experiments both your own and the demonstration experiments in the public gallery and view their results on the iPad immediately Participant mode allows you to configure experiments for participants where multiple experiments can be presented sequentially with the results uploaded to the server on completion Running experiments from the public gallery requires no psychophysics expertise though if you want to create your own tests this guide assumes you already know how to set up a psychophysics experiment For example you know the difference between MOCS and a staircase and you know about gamma correction Throughout we refer to a test as a sequence of stimuli either MOCS single or multiple staircases resulting in reversals or collection of correct results A collection of tests performed in sequence make up a session Document History The initial draft of this manual was written by Andrew Turpin David Lawson and Allison McKendrick in August 2013 Contact aturpin unimelb edu au for more information 21 March 2014 Added citation to JoV paper added Section 8 3 Infinite response window and one button doco added App Version 1 1 fixed a few typos 20 April 2015 Updated for PsyPad 2 0 Citation Please cite the following if you use PsyPad in your research PsyPad A platform
12. an image as per Section 8 Number of reversals A list of the number of reversals before terminating the staircase separated by a character one for each staircase Floor ceiling hits to finish A list of the number of times the minimum maximum stimuli are shown before terminating the staircase separated by a character one for each staircase Minimum level The minimum stimulus level separated by a character one for each staircase each must match a filename of an image as per Section 8 Maximum level The maximum stimulus level separated by a character one for each staircase each must match a filename of an image as per Section 8 A values The step sizes before each reversal as a comma separated list sep arated by a character one for each staircase must be the same number as in Number of reversals for each staircase 10 wrong to get easier The number of incorrect responses before the stimulus level is increased separated by a character one for each staircase Note that an incorrect response adds the current step size to the current stimuli level correct to get harder The number of correct responses before the stimulus level is reduced separated by a character one for each staircase Note that a correct response subtracts the current step size from the current stimuli level MOCS Parameters
13. do ae See el Ee E NA Re O ee et ere ae Bea 8 2 Multiframe images movies oaa e 8 3 Background Image ww epee ete dh ok fl eh a ae eB Oh EA AAAS es Sod ae poh haa 8 4 Gamma correction and Auto brightness ee 8 9 Rampini viste St ae Se ee A OO Ee to ee ae Ae ea AA IA 4 8 6 WiMIN gs son Wye asd Sa Rei a ele ka a eG eed ag a ay ype hat ac dese ee ok e i 8 1 Uploading the images 3 06 4 dio be Hob Re a Pe A ee BOR ek a d 9 Test configuration options 9 1 MOCOS 2 AA O Bt ak EO ER DP eee OB AB ee eo Ss es a 952 Obalrcases ia a Ghat tale See a Gh ns eee Ri ee Sl ees See a oh 10 Session Configurations 11 Server Setup Tithe Psy Pad met server da ake A ee Pe A EA OEE AS Be SS 11 2 gt Your Own Servers sonn oneg a a De By De A ae a ee ee Bo E a LG 11 3 Communication with iPad a 2 a aa e a e a a e a a a a a a a a 11 3 1 Automatic session transfer from Server to iPad a a a 11 3 2 Log file transfer from iPad to Server e 12 Handling Logfiles 13 Checking test results on the iPad 14 iPad Settings 15 Upcoming features 16 Known Bugs D O Or or ot NID 0 OOO O C OC C WO 13 13 13 13 14 14 14 14 16 16 16 16 1 Before starting Before you begin you will need to make some decisions about your setup 1 Server location In order to send images for stimuli to the PsyPad app and to get test log files off the iPad running PsyPad a server is required We provide http
14. es not compromise your research as log files only contain sequences of image names and button responses There is no easy way for an outside observer to tell what the stimuli are or to which images filenames correspond While the server is currently backed up weekly do not rely on this for your data persistence Make your own backups of log files using the Export all logs regularly 11 2 Your Own Server The source code for the server implemented with Ruby on Rails is available at https www github com davidlawson PsyPad Server but it requires some technical expertise to deploy We do not plan to support you in running your own server 13 Identifier Data type Meaning button_press d String The number and text on the response button that was pushed currentReversal d The number of reversals seen so far Staircase only currentStaircase d The current staircase being presented Staircase only exit_test Last line in a single test log image hidden Time image was replaced with background next_question d The question number in the current test Staircase only next_question d d The question number in the current test numerator and the total number of questions denominator MOCS only presented_buttons String Labels of each button presented for this question presented_image String Filename of image that was presented at this time reaction_time d ddms Time between image presentation and button push reversal
15. eversal for staircase procedures For example Figure 4 d Presentations Per Level shows a bar graph of the number of times each stimulus level was presented in the test 14 Pad Settings There are several settings on the iPad that are not controlled by PsyPad Auto Brightness If contrast is important to your experiment you have to turn this off manually PsyPad sets the brightness to maximum at the beginning of each session Sounds You may like to set the Ringer and Alerts volume to 0 so that there is not a sound when PsyPad uses the camera Wi Fi Obviously if you want participant sessions pulled from the server to the iPad or want logfiles to upload you need to configure the Wi Fi connection so that the iPad is connected to the internet Notifications You probably want to make sure Do Not Disturb mode is active and that you are receiving Face Time calls from No One and that Repeated Calls are off Face Time Turn it off 15 Upcoming features Start screen to appear with begin button before each test Blocking of MOCS trials to ensure no two of the same level in a row Interactive screen preview during test configuration in the server Auto emailing of log files from server nominated email addresses Audio support 16 Known Bugs e On iPad analysis does not work for single button tests App Version 1 1 16 Current Log Reaction Time OS o 953 11ms 0 0 00 Reaction Time gt
16. for visual psychophysics on the iPad Andrew Turpin David J Lawson and Allison M McKendrick J Vis March 11 2014 14 3 16 doi 10 1167 14 3 16 as Bibtex article Turpin11032014 author Turpin Andrew and Lawson David J and McKendrick Allison M title PsyPad A platform for visual psychophysics on the iPad volume 14 number 3 year 2014 doi 10 1167 14 3 16 URL http www journalofvision org content 14 3 16 abstract eprint http www journalofvision org content 14 3 16 full pdfthtml journal Journal of Vision Contents 1 Before starting 2 Demo mode 3 Gallery 31 Publicegallery osa do gogo 4 deh hee oe Phos BG Wied da lee A ae SA A ce ee BG Gs 3 2 Private gallery nd ii A EEO RE AAA we owe Gu rae Gee wade aoe 4 Participant mode 4 1 Pre downloading participant configurations e 5 Internet connection 6 Adding and configuring participants 6 1 Participant list ac oe ey Glee ee A A A ve ee al al 6 2 Participant log list ad eevee a A Sed hd ce eee Bg o de ee a AP 6 3 Participant configuration list ooa ee 6 4 Importing configurations from the gallery o o e 000000000 6 5 Exporting configurations to the gallery 2 a ee 7 Creating your own test configurations 7 1 Things to consider for your test configurations 2 0 0 0 0 000020 e ee ee 7 2 Submitting to the public gallery 2 2 o 8 Image Stimuli 8 1 Single frame images i
17. gt This response caused a reversal Staircase only test_begin String Description of all test parameters in JSON format test_finished 7 Time the test finished distance_detection String Result of face detection if turned on An example string is Question 5 Detected facial features left eye 733 75 443 75 right eye 932 50 482 50 mouth 876 25 236 25 where each number pair is the x y coordi nate of the preceding feature Table 2 An example logfile for a staircase procedure right and a summary of that logfile left d indicates an integer and d dd indicates a decimal number 11 3 Communication with iPad 11 3 1 Automatic session transfer from Server to iPad When a participant logs on and an internet connection is available to PsyPad their session information is checked against the server and if updated the new version is downloaded This allows remote altering of session configurations 11 3 2 Log file transfer from iPad to Server This happens automatically at the end of a session if there is an internet connection and is never repeated if successful The admin user on the iPad can force the sending of all log files by pressing Upload logs to server on the Admin Panel 12 Handling Logfiles Logfiles contain lines of text with three columns delimited by a vertical bar pipe symbol The fields are 1 time stamp in number of seconds since 1 1 1970 2 identifier that describes the line and 3 the data rela
18. images www libpng org pub png which are presented without alteration in the centre of the screen You can generate these any way you like ImageMagick Photoshop Matlab R custom C code etc but their folder directory location and filenames are important PsyPad will also faithfully display 32 bit RGBA PNG images if you want to make use of the Alpha channel for transparency The thresholding algorithms in PsyPad identify stimuli using folder names not image filenames This allows for different random images of the same stimulus level to be used by PsyPad For example when PsyPad is asked to present a stimulus of level 33 it randomly selects an image from the folder named 33 Each stimuli folder must be named in the correct format for the thresholding algorithm that you chose e any alphanumeric text if a MOCS is to be used or e an integer corresponding to stimulus level if a staircase thresholding algorithm is to be used Note that because PsyPad s staircases work on integer stimuli levels you may have to be a little creative in mapping your thresholding domain onto an integer domain For example if you are thresholding in log units with a step size of 0 2 log units you might convert a stimulus level to the integer 1000 x 1074 giving stimuli levels of 6 10 15 25 39 63 100 158 251 398 630 1000 Inside each folder the images themselves must be named in a specific format as described in Sections 8 1 and 8 2 8 1 Si
19. lect whether or not you want to overwrite existing configurations then click Import From Gallery Selecting Yes for Overwrite existing configurations will mean that any configurations that the participant already has with the same name as a configuration you are importing will be overwritten This allows you to update a configuration in your gallery see Section 3 2 and import the changes you make to multiple participants 6 5 Exporting configurations to the gallery Clicking Save to Gallery in a participant s configuration list will take you to the export screen You may be presented with the option to overwrite existing configurations if there are any configurations in your private gallery with the same name To perform the export simply click the Save to Gallery button To copy configurations from one participant to another you should use the gallery as a clipboard Copying to the gallery also allows the configuration to be used in Demo mode 7 Creating your own test configurations Configurations can either be created in your private configuration gallery see Section 3 2 or created for an individual participant Note that you can save participant configurations to your gallery and you can import configurations to a participant from the gallery This mechanism allows you to create a configuration in your gallery that can be imported and used by multiple participants Only configurations in the gallery will be acce
20. ngle frame images Within the folder individual images must be named as b_n png where b is the button number that would correspond to a correct response for this stimuli and n is an integer See Figure 2 a for an example The button numbers are used to generate a test summary on the iPad for the admin user see Section 13 and to determine correctness for each step in staircase procedures If you do not follow this naming convention staircases will not work and on iPad analysis will not work While folder names in the format for a staircase also match the requirements for a MOCS the folder names for a MOCS can be more general for example as in Figure 2 b 8 2 Multiframe images movies Dynamic stimuli are achieved using a sequence of frames that are also 24 bit RGB PNG images or 32 bit RGBA but in a subfolder named as for the single images without the png suffix with the individual frames named in lexicographic order for example 11 comes before 2 If you want numeric order make sure you pad with leading zeroes as in Figure 2 c which shows stimulus level 48 consisting of 11 frames where a button press of 1 would be correct The time that each frame of the movie is displayed before the next frame is presented and the looping behaviour is set as part of the test configuration see Section 9 8 3 Background Image As of Version 1 1 of the PsyPad app you can also include a background image that is displayed cent
21. ode from Demo mode by pressing Configure PsyPad and pressing the green toggle next to Demo Mode When doing this ensure you know the admin password if it is set so you can return to the admin panel later To return to the admin panel from Participant mode enter admin as the participant name followed by the password of it has been set in the admin panel If you forget this password you will need to uninstall and reinstall the iPad app Participants need to be configured on the server see Section 6 To run a test in Participant mode close the admin panel if it is open enter the participant username then press Login From there you will be able to press Begin Test or Begin Practice Test visible if any practice tests are configured Once the test is completed the logs will be automatically uploaded to the server if there is an internet connection available When you press the Login button the latest version of the participant configuration will be downloaded if there is an internet connection available 4 1 Pre downloading participant configurations It is recommended to download participant configurations before beginning tests especially if the configuration uses large image sets It is also necessary if there will be no internet connection available where the test is run To pre download a participant s configurations open the admin panel press Load server participant list then press the Download button ne
22. p When PsyPad is next started with an internet connection to the server and a participant using the image set logs in the images will be transferred and stored on the iPad This might take a while so it is recommended that you log in as at least one participant using the image set so that this download is already done before the actual participants use the app 9 Test configuration options In order to define a test you need to choose an image set already uploaded to the server see Section 8 and then choose several options as described in this table This table lists the options in the order they appear on the server interface To preview the background colour exit button and response buttons as they will appear on the iPad not 100 accurate click Show Preview at the bottom right of the browser window General Settings Name Simply identifies the test configuration for your organisational use only Does not have to be unique but might be easier for you if it is When importing configurations from the gallery or exporting to the gallery this name affects the optional overwriting behaviour see Section 6 4 Title This text appears on the iPad along with a Begin button before the test You might like to put something here that reminds the participant of the task Description For your organisational use Be descriptive here if you are consid ering submitting this to the public gallery Enabled If tr
23. r each the starting values the number of reversals and the step sizes between each reversal See Section 9 2 for more information 4 How many tests in a session Does a session from participant login on the iPad to completion of all tests consist of just one test a thresholding run for one stimuli type or do you want more than one test in a session What order do you want the tests Do you want different tests on different days of the week Do you want a different random seed for each test See Section 10 for information on how to set up tests 5 Do you want a practice session If you mark some test configurations as Practice configurations then once a participant logs in to PsyPad there are options to Begin Test and Begin Practice Test The practice test session can be configured separately from the main test session but otherwise shares all features with main test sessions Practice sessions are identifiable as such in log files 7 2 Submitting to the public gallery We would love to let you share configurations image sets that you think would be helpful for other people to use If you would like to submit a configuration and its image set for consideration to be added to the public gallery simply click on Share to Public Gallery on a configuration list We will review any submitted configurations and let you know via email if we add them to the public gallery 8 Image Stimuli All stimuli in PsyPad are 24 bit RGB PNG
24. red on the screen throughout the entire test with stimuli and buttons written over the top of that image This is useful for fixation targets in particular but could also be used in many creative ways The background image must be a PNG and must be named background png in the top directory folder of images The screen is always set to the background color and overlaid with the centered background image so if no background png is present the screen appears as the background color To avoid apparent flickering of buttons the background image should either contain the buttons in the actual image or be small enough to not overwrite the buttons when the display is refreshed 8 4 Gamma correction and Auto brightness There is no Gamma correction or look up table LUT capabilities in PsyPad You need to do your own gamma correction and luminance determination offline and then choose the pixel values in your images accordingly For example there is no guarantee that RGB 127 127 127 is mean luminance on every device If exact luminance is important to you you should use a photometer and measure different pixel levels and make your images accordingly PsyPad sets the iPad to maximum brightness at the beginning of a test session but cannot control the Auto Brightness setting You should make sure this is off and instruct participants never to turn it on if luminance levels are important to your test For calibration you can create an
25. rrentReversal 5 1378869891 presented_image 52 1_002 png 1378869891 presented_buttons Concentric Radial 1378869891 image_hidden null 1378869892 reaction_time 1424 79ms 1378869892 button_press 1 Concentric 1378869893 next_question 17 1378869893 currentStaircase 0 1378869893 currentReversal 5 1378869893 presented_image 52 1_001 png 1378869893 presented_buttons Concentric Radial 1378869893 image_hidden null 1378869895 reaction_time 1773 27ms 1378869895 button_press 2 Radial 1378869895 reversal null 1378869895 test_finished null 1378869895 exit_test null Figure 3 An example logfile for a staircase procedure right and a summary of that logfile left 15 13 Checking test results on the iPad Figure 4 a shows the four choices and the actual log file for a participant s test which can be reached by logging in as admin tapping the participant s login name View Logs and then the log in which you are interested The choices reveal the following Reaction Time shows a bar graph of the mean reaction time for each of the stimuli levels shown in the test The mean is in text in the bar and the standard deviation of each reaction time is show in parentheses as o For example Figure 4 b Correct Per Level shows a bar graph of the correct for each of the stimuli levels shown in the test For example Figure 4 c Reversals shows a bar graph of the stimulus level at each r
26. sentation beware of the camera noise that can be turned off on the iPad Settings The image is processed to locate two eyes and a mouth The three coordinates are saved into the log file If No no picture is taken and nothing is logged This option is not used in Psy Pad App Version 1 0 After choosing all of your settings don t forget to save the configuration using the appropriate button at the bottom of the screen 91 MOCS To set up a MOCS procedure you need the stimuli levels to test and the number of trials per level Once you have chosen your image set to use as the basis for your test the levels are defined by the folder names in your image set For example if you used the image set from Figure 2 b the test levels are low med and high On the server the number of trials per level to use is specified in a comma separated list as ly n1 l2 na Kaci where 4 is the stimulus level matching the folder names n is the number of trials at that level On the iPad the interface for specifying these is a bit nicer as it lists all available levels and you enter the number of trials next to each level leave blank for no trials Remember if you alter tests on the iPad to upload them to the server before a participant logs in otherwise the server version will overwrite your changes if an internet connection is present For the example in Figure 2 c if you want 10 trials per level you would
27. ssible from Demo mode see Section 2 To create a configuration in your gallery click on the Configuration Gallery tab then click New Gallery Configuration To create a configuration for an individual participant click on New Participant Configuration in a participant s configuration list Section 6 3 There are two parts to creating your own test configurations Firstly you need to create or select an image set to use Secondly you need to specify the test parameters There are pre made image sets available in the public gallery Section 3 1 that you can use though you will first need to understand the image set folder structure For an explanation of the folder structure and instructions on how to create your own image sets see Section 8 For a breakdown of the test configuration options see Section 10 Once you have selected the image set and set the configuration options click Create configuration at the bottom of the page to create the configuration 7 1 Things to consider for your test configurations 1 Stimuli All stimuli in PsyPad are precomputed 24 or 32 bit PNG images that are presented centred on the screen and written over a background image that is also a PNG Dynamic stimuli are a sequence of frames that are also PNG images The filenames of the images must be in a specific format see Section 8 If you cannot precompute all the stimuli you might need in a test then PsyPad will not work for you 1 01 png
28. t response otherwise it counts as an incorrect response Button text The text to appear on each button Button presentation delay The amount of time in seconds before the buttons appear after the stimuli has been presented does not have to be an integer Button backgrounds RGB hex string specifying the background color of each button For example 0000FF is blue Button text colours RGB hex string specifying the text color of each button For example 888888 is grey Button positions For each button x y width and height All measurements are in pixels and the top left of the screen is 0 0 and the bottom right is 1024 768 even on iPad III You can preview the position colour and text of the buttons by clicking Show Preview at the bottom right of the browser window not 100 accurate General Test Parameters Next button after each response If Yes then a Next button appears after each response and must be pressed before the next trial begins Time between each question Specify the mean time between response button press and the variation The next stimuli is presented after mean where 6 is sampled uniformly at random from variation variation 11 Infinite presentation time If Yes stimuli are presented until a button is pressed otherwise if No you must specify the presentation time in seconds In the No case the
29. ted to the identifier Figure 3 shows an example log file for a staircase procedure and Table 2 describes each identifier The log file format has been designed for processing with script languages such as awk Perl Python and so on The http server psypad net au server offers the summary text Example Python scripts for processing logfiles can be found in the Gallery at http server psypad net au 14 Summary Test date 11 9 2013 13 24 11 Glass stairc Practice no Staircase 0 Not seen Seen min Reversal Reversal Reversal Reversal Reversal Reversal Start time 11 9 2013 13 24 11 11 9 2013 13 24 55 O minutes 44 seconds End time Duration ase max oP WN BE 6 58 54 58 52 54 52 1378869851 test_begin 1378869851 next_question 1 1378869851 currentStaircase 0 1378869851 currentReversal 0 1378869851 presented_image 50 2_005 png 1378869851 presented_buttons Concentric Radial 1378869852 image_hidden null 1378869859 reaction_time 7711 23ms 1378869859 button_press 1 Concentric 1378869860 next_question 2 1378869860 currentStaircase 0 1378869860 currentReversal 0 1378869860 presented_image 58 2_003 png 1378869860 presented_buttons Concentric Radial 1378869860 image_hidden null 1378869861 reaction_time 1820 66ms 1378869861 button_press 2 Radial 1378869890 reversal null 1378869891 next_question 16 1378869891 currentStaircase 0 1378869891 cu
30. ue then this test is part of a participant s session Is Practice Configuration If true then this test is part of a participant s practice session if also Enabled Practice configurations are started by pressing Begin Practice Tests instead of Begin Tests on the iPad Order This specifies the order in which this test will appear in the session if enabled Any integer is fine the tests are sorted by this number to get their order for a session Days of the week The test configuration will only be enabled on the selected days of the week Image Sets Image Set Choose from the image sets in the public and private image set gallery Loop animations Only relevant for images that are a sequence of frames movie If true then the frames loop until a button is pressed Animation frame rate This is the number of frame refreshes on the iPad for which each image in the movie sequence should be displayed Currently iPads have a frame rate of 60Hz For example if you want a movie of 8 images to display for 400 ms you would enter 3 here 3 60 x 8 0 4 Staircase Method Parame ters Use staircase method If Yes then staircase is used otherwise MOCS Number of staircases The number of staircases you wish to interleave should be at least one Start level A list of start levels separated by a character one for each staircase each must match a filename of
31. use the following string low 10 med 10 high 10 The order of levels is chosen at random and images within each level are chosen at random without replace ment unless the number of trials exceeds the number of images in which case some images will be repeated images trials times 12 9 2 Staircase A correct response as determined by matching the first character of the filename of the stimulus with the button number pressed will cause the current step size to be subtracted from the current stimulus level to determine the next stimulus level to display An incorrect response will cause the current step size to be added to the current stimulus level Thus PsyPad assumes hard to see stimuli have higher folder numbers than easy to see stimuli If you prefer working in a reverse scale eg dB where a low number is easy and a high number hard you can always reverse the button labels on your images so that when the participant press the correct button you treat it as incorrect for the purposes of the staircase A reversal is registered whenever the number of wrong correct in a row is recorded followed by the number of correct wrong in a row For example in a 1 up 1 down staircase wrong 1 correct 1 a correct followed by an incorrect or vice versa is a reversal In a 1 up 2 down staircase 4wrong 1 correct 2 then reversals would be triggered by responses incorrect correct correct and correct correct incorrect
32. xt to a participant You can also simply log in as a participant to ensure their configuration is downloaded 5 Internet connection All tests undertaken are logged in both Demo and Participant mode If there is an internet connection present at the end of a session the the log file for that session and any previous sessions that have not been uploaded will be uploaded to the server If an internet connection was not present at the end of a session you can upload the logs at a later date by pressing Upload logs to server in the admin panel or wait until the end of another session performed by that participant when an internet connection is present See Section 12 for more information on logs If an internet connection is present when a participant logs in to PsyPad their configurations are downloaded from the server If there are new configurations that use images sets that are not already on the iPad these are also downloaded This allows remote altering of participants testing parameters when an iPad is in the field You may want to consider using an iPad with a SIM card on an active data plan if you need to ensure internet connectivity 6 Adding and configuring participants When the iPad app is in Participant mode participants will need to enter in their username before each session You might want to choose usernames that are easy to type on the iPad Participants have both configurations and logs associated with them
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