Sequence Learning  Cue competition Documentation 

1: Data collection

Experiment code: SLSRT_Expt2_IMRM/04797/3

Research question:  To what extent would two cues (two trials preceding a third, and a coloured square) compete in terms of learning to make the next response faster and more accurate than controls?

Data collection:  The experiment was programmed using SuperLab version 4.0.7b on an iMac computer. The SuperLab files were used to present the stimuli and collect resultant data as .txt files.  We collected 3 groups of data: the “dual cue group” (both sequence and colour cues), a “colour only” control, and a “sequence only” control. 

Experiment context:  The experiment was run by Rossy McLaren (Associate Research Fellow) in Room 228-2 in the Washington Singer Building.  The blind over the window was closed to avoid participants from being distracted.  The overhead light was dimmed slightly (about 1/3 of dimmer switch) to enhance their view of the screen.  The experiment took place from October 2012 to January 2013.  The main experiment took about 45 minutes and this was followed by the experimenter asking each participant questions from a short questionnaire (about 10 minutes). Participants were either paid £5 or earned 1 course credit.  

Brief description of the experiment:  Once participants had read and filled in the Informed Consent form (Appendix 1), they were seated in front of the iMac computer with the experiment’s instructions displayed on screen.  After the participant had read the instructions, the experimenter briefly went through them again ensuring that the participant fully understood what was required of them (see Appendix 2 for the experimenter script).  In addition, participants were asked to either switch their mobile phone to ‘silent’ or ‘off’ to avoid disturbance during the experiment.  The experiment started once the participant pressed the spacebar and the experimenter observed them for the first block of trials.  Each trial consisted of an initial cue (blank circles either side of a square) presented for 250msec followed by the square filling with a colour and one of the circles filling (after a variable ISI from 250-500msec).  The participant had to press the corresponding response key as fast as they could (within 4000msec) whilst avoiding errors.  An error resulted in a ‘beep’ from the computer followed by the next trial.  If they were correct the next trial was presented after 250msec.  The experiment proceeds at a fast pace until the end of the block at which point there is an enforced 30 sec. break.  The participant was encouraged to rest their eyes and to look away from the screen during this period.  After the first block the experimenter checked that the participant was happy to continue and then left the room.  Each experimental block had 96 trials.  There were 20 blocks in the experiment (16 training blocks and 4 test blocks – indistinguishable to the participant).  Once the experiment was completed, the participant came to inform the experimenter who then went through the questionnaire (Appendix 3) with the participant.  At the end of the questionnaire, the experimenter briefly explained what the experiment was about, thanked and paid/credited the participant.

SuperLab Sequence and Colour learning file structure:

File groups
There are 3 groups of files as follows:

Group A (“colour only”) – colour predictive cues (sequences not predictive)
Group B (“sequence only”) – sequence predictive cues (colour cues not predictive)
Group C (“dual”) – both sequence and colour cues predictive

We did begin by running a fourth group in which neither sequence or colour were predictive, but decided to leave this out of the final experiment as A and B are the appropriate controls for C.

Group A Training Blocks
In the SuperLab files there are 16 training blocks (actually structured as 32 ‘half’ blocks) each of which is linked to 16 sequence trials in which all 8 sequences (xxx, xxy, xyx, xyy, yxx, yxy, yyx and yyy) are presented twice in random order.  This gives a total of 96 sequence trials for each of the 16 training blocks.

A new SuperLab file was created for each participant in which there were two predictive colours – one consistent for x (left) and one consistent for y (right) on the third trial of each sequence. (x and y were counterbalanced to right and left in additional SuperLab files appended “CB”).  The allocation of the colours to each trial in each SuperLab file was done on the basis of a semi-random selection process i.e. random numbers were used to select the predictive colour for x and the predictive colour for y (reselecting if the same colour came up).  The remaining two colours were the ‘controls’ (see Table 1).

Table 1.  Predictive colour and control colour allocation for the third trial in each sequence for each participant in Group A

Participant	x 	y 	Control colours	
1	Red	Green	Blue and Yellow	
2	Blue	Red	Yellow and Green	
3	Blue	Green	Red and Yellow	
4	Blue	Yellow	Red and Green	
5	Yellow	Green	Red and Blue	
6	Yellow	Red	Green and Blue	
7	Green	Red	Blue and Yellow	
8	Yellow	Blue	Red and Green	
9	Green	Blue	Red and Yellow	
10	Red	Blue	Yellow and Green	
11	Green	Yellow	Red and Blue	
12	Red	Yellow	Green and Blue	
13	Blue	Red	Yellow and Green	
14	Yellow	Blue	Red and Green	
15	Green	Yellow	Red and Blue	

For the first 8 sequence trials in each half block, the predictive colours were allocated to the terminal (third) trial i.e. there were 3 occasions on which the colour predicting x was on the terminal trial and 3 occasions on which the colour predicting y was on the terminal trial.  These colours were then allocated to first and second trials in such a way that, in total, each predictive colour occurred 5 times on its’ consistent side and once on its’ inconsistent side.  The control colours were allocated in equal numbers to the remaining first and second trials.  See Table 2 below.

For the second 8 sequence trials in each half block, the predictive colours were allocated such that they occurred 3 times consistently on the terminal trials and then once consistently on a first or second trial.  In addition they were allocated on their inconsistent sides to two other first and second trials.  Again, the control colours were allocated in equal numbers to the remaining trials.  

Overall, the predictive colours occurred 75% of the time on their consistent side and 25% of the time on their inconsistent side.  The control colours occurred on both sides 50% of the time.

Table 2.  Colour allocation for each training block for Participant 1A.  

In this example, Red occurs 5 times with x and once with y in the first set of 8 sequences. In the second set, it occurs 4 times with x and twice with y.  In addition, Green occurs 5 times with y and once with x in the first set and 4 times with y and twice with x in the second set.

A total of 30 SuperLab files were created (15 with x=left/y=right and 15 counterbalanced with x=right and y=left).  Each had exactly the same structure, they simply varied in terms of the colours allocated to each trial.

Test blocks
Four test blocks, each consisting of 96 trials, were presented after the training blocks.  All 8 sequences occurred in random order.  The colours allocated to each trial during the test blocks were selected using random numbers in an Excel spreadsheet (Sequence colours-Test blocks. xls) to sort a column containing all the sequence/colour combinations.  This was done for all 4 test blocks until the colours had been allocated to all sequences in such a way that they were evenly distributed between x and y’s.  For the first 15 SuperLab files, the same test block colours were used for all participants.  The test block colours for the counterbalanced SuperLab files were different for each participant (see Sequence colours_Test blocks(new version).xls) .

Group B Training blocks
The same SuperLab programmes (including the colours allocated to each trial) for Group A participants 1-15 were used but the sequences were changed as follows:

(1 and 2 = third trial colours)
Group A sequences: xxx1, xxy2, xyx1, xyy2, yxx1, yxy2, yyx1, yyy2  

Group B sequences: xxx1, xxx2, xyy1, xyy2, yxy1, yxy2, yyx1, yyx2

The colours that had been allocated to each trial in Group A stayed the same which meant that the third trial colours (previously predictive of x or y in Group A) were more evenly spread between x and y and, therefore, not predictive of colour in Group B.  In Group B, the training was on the four sequences xxx, xyy, yxy and yyx.  

Group C Training blocks
The same SuperLab programmes as those for Group B were used i.e. only 4 sequences appeared in the Group C training blocks.  However, this time, the third trial colours were reallocated to be consistent with x and y.  This meant that participants were being trained in both colour consistency and sequence type.

Group C sequences: xxx1, xxx1, xyy2, xyy2, yxy2, yxy2, yyx1, yyx1

The colour allocation for the training sequences for the first participant in each group is shown in Table 3.  The sequences were presented in random order in each training and test block.  

Table 3: Allocation of colours to training and test block trials for the first participant in each Group where x=left.  
The colour of the third trial in each sequence gives an indication of whether colour is predictive of x and y during training.

Table 4 shows the colours used in the Test Blocks for the counterbalance participants (where x=right)

Table 4: Colour allocation for Counterbalance test block trials for each participant.

Structure and content of data files:
Each .txt data file is labelled with the participant number and group (A-C) (and participant initials).  The column headings give the block name (Block number), trial name (sequence type), event name (Right/Left and Red/Green/Yellow/Blue), participant response (Left/Right), key (“x” or “.”), correct response (Right/Left), error code (C/E), reaction time (msec) and ISI duration (msec).

The files collected are in folders labelled A Participant Data, B Participant Data, and C Participant Data.  There are 30 .txt data files in each folder.  Those prefixed with “CB” are the counterbalanced files (where x=right). 

After collection, some data files were found to contain errors, SuperLab programming errors.  These files were replaced following correction of the programme (e.g. A13, A14, B14, CB5B2, CB6C2, CB7A3).  The data from these ‘discarded’ files is in the folder labelled ‘Discarded Data’. 

For further analysis each .txt file was opened as an Excel spreadsheet where it will be seen to consist of 1928 lines of data within 14 columns (A:N).  The contents of each of these files (A1:N1928) was copied and pasted into cell A1 of one of four analysis templates: 

“Group B _x_is_left_RTnoErrorsAnalysis Template.xls” (for Group B data files where x=left) 
“Group_B_CounterbalanceRTnoErrorsAnalysis Template.xls” (for Group B data files where x=right)
“Groups AandC_x_is_left_RTnoErrorsAnalysis Template.xls” (for Groups A and C data files where x=left)
“Groups_AandC_CounterbalanceRTnoErrorsAnalysis Template.xls” (for Groups A and C data files where x=right).

These templates allowed the extraction of the sequence (BV11:CC63) and colour (CF11:CM63) data for each training and test block.  The templates were set up to remove reaction times relating to error trials and the trial immediately following an error trial. 

Following analysis of the questionnaire data (Questionnaire data.xlsx), certain participants were re run (CB31A11 and CB40A14).  These were due to one failing to wear glasses during the experiment, which resulted in additional errors, and another participant started to repeatedly press the wrong keys during the test phase.  The original data files for these participants are in the folder ‘Discarded Data’.

Please see the paper: "Cue competition in incidental learning" for further details of the design and analyses.

Appendix 1: SLRT Experiment 2 INFORMED CONSENT FORM

EXPERIMENT CODE:

 IMRM/ 04797/ 3

Reaction Time Task

EXPERIMENT NAME:

PARTICIPANT NUMBER: ………..	     

Before you begin this experiment, I would like to let you know what to expect.

During the experiment you will see two circles (one on the left, one on the right) outlined in white on a black screen. The inside of each circle will flash up white periodically. Your task will be to press the “x” key if the left circle flashes white and the “>” key if the right circle flashes white. The idea is for you to respond as quickly as possible to the right and left circle flashes, whilst avoiding errors. 

In the centre of the screen there will be a square outlined in white on the black screen. Before each circle flashes white the square will fill with a colour. This is to warn you of the next trial. For optimal performance on the task it is important that you look at the square so you are prepared to make your response when the circle flashes.

If there is any reason why you feel that you may be unable to complete this study, you may withdraw from participation at any point and your data will be eliminated. The experiment involves flashes on screen, and if you have epilepsy you cannot take part.

 
I understand that:
•	Participation in this study is entirely voluntary and that I can withdraw from the study at any time without giving a reason.
•	Non-participation or withdrawal from the study will not be of any disadvantage to my university career [Students only.]
•	If I prematurely withdraw from the study I will still be appropriately compensated for my participation.
•	I can instruct the researchers carrying out this study at any time to delete  data obtained from me from their records. 
•	I am free to ask any questions at any time and that I can arrange to discuss any concerns with the lead researcher (see below).
•	At the end of the study I will be provided with additional information and feedback about the purpose of the study. 
•	No data will be published in which I can be identified individually. In accordance with the Data Protection Act, I can have access to my information at any time.
•	The data provided by me in this experiment will be used for research purposes only. They will not be shared in any manner which would allow identification of my individual responses. 
•	Anonymised research data will be archived at the Economic and Social Data Service (ESDS), and might also be uploaded onto other digital data repositories, such as Figshare and the Exeter Data Archive, in line with current data sharing practices.

Name: ____________________________					Age: _______________

Date: _____________________________					Gender: ____________

Signature: _________________________					R/L handed: _________

Degree course: ____________________________________

Prof. Ian McLaren

If you require more information about this study, please contact                                                   (Lead Researcher)

i.p.l.mclaren @ex.ac.uk

	   
									Email:	 								

Appendix 2: SLRT Experiment 2  Experimenter Script

The first thing to say about this experiment is that it’s not related to any other research you might have done with other people in the department, so if you could try not to guess what is going on that would be great!

The experiment is very simple, it’s all about the effect of practice on your ability to respond quickly to stimuli.  During the experiment the screen will be black and two white circle outlines will appear on screen.  These will fill in white, one at a time, and you should respond to these as quickly as possible by pressing the “x” key if it comes up on the left hand side of the screen, or the “>.” key if it comes up on the right.  In the centre of the screen will be a white square outline, which will fill up before each circle flash with a colour.  It will fill up with different colours to draw your attention back to the centre of the screen, so that your eyes are equidistant from both circles, and you are ready for the next trial.  This will make you faster overall, and also means you aren’t looking at one circle rather than the other.

If you make a mistake the computer will beep at you to tell you that you have pressed the wrong key and move on to the next trial.  This will also happen if you press any other key on the keyboard or do not make a response within about 4 seconds.  While I know it’s frustrating to make a mistake, especially when the computer beeps at you, the experiment as I said is about your reaction times so please try and respond as quickly as possible whilst avoiding too many errors.

This session will last around one hour, and comprises of twenty blocks of the same length.  In between each block there is an enforced 30 second break, which you can use to rest your eyes and hands.  Please feel free to take longer than this to rest if you like.  I will ask you some questions at the end about the experiment and then pay you.

I will sit with you for the first block to make sure everything is working fine, and in summary your task is to look at the coloured square when it flashes and then respond as quickly as possible to the circle.  Have you got any questions?

If you could try and keep the way that you respond the same throughout the experiment that would be great.  Please use your index fingers on the response keys and keep your hands flat on the table.  Also, if you have a mobile phone, please either have it on ‘silent’ or switch it off to avoid being disturbed during the experiment.

When you are ready to start you should press the ‘spacebar’ and then press the ‘spacebar’ again to start the experiment.

Appendix 3: SLRT Questionnaire

Sequence/Colour Experiment 3–Structured Questionnaire

Please ask the following questions verbally and note down any responses.

Do you have any comments about the experiment?

  
How do you think your speed and accuracy changed as the experiment progressed? 

Why do you think this was?

Did you look at the coloured square before each trial?

How do you think the coloured square affected your responding?

Did you notice any relationship between the coloured square and the location of the circles?

Would it surprise you if there was a relationship between some of the colours and locations, or did you have some idea that was happening?

Some of the colours may or may not have had a predictive relationship with whether the circle came up on the right or the left. Could you describe the relationship between all, or any of the colours and where the circles flashed?

Did you notice any patterns in the way the circles flashed or do you think the circles in fact followed a random pattern?

If you did notice patterns, can you describe them?

And when did you become aware of them?

Were there any patterns you noticed more obvious than the others?

How did noticing the sequences and patterns (or deciding it was random) affect your responding?