Return to the Visual Statistical Learning (Fisher & Aslin) page

Script Author: Katja Borchert, Ph.D. ( for Millisecond Software, LLC
last updated: 07-22-2019 by K.Borchert ( for Millisecond Software LLC

Script Copyright © 07-22-2019 Millisecond Software

Millisecond Software LLC thanks Turk-Browne et al (2005) for providing the 12 original shapes used in this study!


The script "Visual Statistical Learning I"  adapts the procedure used by Fiser & Aslin (2002) to study the unprompted statistical learning of 
temporal relationships inherent in a visual presentation of moving shapes:

Fiser, J. & Aslin, R.N. (2002). Statistical Learning of Higher-Order Temporal Structure from Visual Shape Sequences. Journal of 
Experimental Psychology: Learning, Memory, and Cognition, 28, 458-467.

Participants are presented with a 5-6min "movie", in which 12 basic shapes moved one after the other 
across the monitor from, seemingly "changing" from one shape into another when they cross a black bar in the center of the screen. 
The "change", however, is not random as the 12 shapes were grouped into 4 triplets with strict rules regarding to which shape can
follow another, e.g. triplets haveto stay together and have to be presented always in the same order (A->B->C). To test whether participants
have learned the inherent temporal shape relationships, the movie-triplets (=familiar) are pinned against "novel" triplets in a balanced 
forced-choice task, in which participants are asked to decide which of the two triplet pairs are more familiar to them.									  

The default data stored in the data files are:

(1) Raw data file: 'VSL_Fiser_raw*.iqdat' (a separate file for each participant)

build:								Inquisit build
computer.platform:					the platform the script was run on
date, time, subject, group:			date and time script was run with the current subject/groupnumber 
blockcode, blocknum:				the name and number of the current block
trialcode, trialnum: 				the name and number of the currently recorded trial
										(Note: not all trials that are run might record data; by default data is collected unless /recorddata = false is set for a particular trial/block) 
list.tripletsequence.currentindex:	the index of the selected tripletsequence (e.g. the third sequence in the list)
values.selectedletter:				the letter presented in the shape presentation sequence
values.index:						the letter position in the shape presentation sequence										
values.A-values.L:					the indices of the shapes (from the item list shapes) that are assigned to shapes A-L
values.novel11-values.novel43:		the indices of the shapes (from the item list shapes) that are assigned to novel triplets
values.pairing:						determines which familiar and which novel triplets were compared and in which order
															(e.g. 15 -> triplet pair ABC against novel triplet 1, familiar first)
values.shape1-values.shape6:		the shapes presented during the forced-choice trials with shape 1 being the first
response:							the key-response of the participant
correct:							whether this is a correct response (1= correct; 0 = error)
latency:							how long the participant took to make response (in ms)

(2) Summary data file: 'VSL_Fiser_summary*.iqdat' (a separate file for each participant)

script.startdate:					date script was run
script.starttime:					time script was started
script.subjectid:					subject id number
script.groupid:						group id number
script.elapsedtime:					time it took to run script (in ms)
computer.platform:					the platform the script was run on
/completed:							0 = script was not completed (prematurely aborted); 1 = script was completed (all conditions run)
/prop_correct:						proportion correct familiar triplet identifications
/meanRT_correct:					mean latency (in ms) of correct familiar triplet identifications
/SD_correct:						standard deviation of correct familiar triplet identification latencies

PART I: Shape Sequence "Movie":
This script implements a simple imitation of the original movie used by Fiser & Aslin (2002). In Fiser and Aslin's study, participants watched a shape
appear from under a black bar that was positioned in the middle of the screen. The shape then moved to the left  of the screen, 
changed direction and  moved back towards the bar, behind which it disappeared once more. When it "reappeared", the shape had 
"morphed" into the next shape, which stayed on the same trajectory and moved to the right side of the screen, changed direction and 
moved back towards and behind the bar again (and so on). Each shape was presented for 1s.

The underlying shape sequence in this script meets the same criteria used by Fiser & Aslin (2002):
 	(1) 12 shapes divided into 4 triplets
	(2) Triplets stay together
	(3) Each triplet is presented 24 times (=288 shape presentations)
	(4) No immediate repeats of triplets (e.g. ABCABC)
	(5) No repeat of triplet pairs (e.g. ABCDEFABCDEF)
	(6) Each triplet appears the same number of times in each third of the sequence (8times)

In addition, this script offers the opportunity to randomly
	(1) select from a pool of 10 possible sequences that all meet these criteria. (=> vary sequence across participants)
	(2) assign the 12 shapes to the 4 triplet pairs (=> triplet pairs are not constant across participants)

PART II: Forced-Choice
In the Forced-Choice part of the experiment, the script pins the 4 familiar triplet pairs (ABC, DEF, GHI, JKL - from the sequence) against  4 
novel triplets (AEI, DHL, GKC, JBF)*. These novel triplets are made up of shapes that had never directly followed each other
during the sequence presentation - changes to these triplets can be made under trial.assignments (e.g. change triplets to 
partial triplets as used in Fiser & Aslin (2002), Experiment2).

Participants get to view 2 sequences of 3 shapes. Each shape is presented for default=500ms** with a break of 1s (s. Fiser & Aslin).
Shapes appear in a left- right-left sequence (s. Fiser & Aslin). Participants are asked to decide which one is more familiar.
(default TASK: press "1" for first, press "2" for second -> change keys to press under values).
Each of the 16 triplet-pairings is presented twice, once with the familiar sequence being presented first and once with the familiar sequence
being presented second. The resulting 32 possible forced-choice tasks are selected at random.

*Fiser & Aslin (2002) do not specify the novel triplet combinations used. The triplet combinations used in this script are taked from 
Turk-Browne et al (2005). The automaticity of visual statistical learning. Journal of Experimental Psychology: General, 134, 552-564.

**Fiser & Aslin (2002) do not specify the screen duration of the individual shapes in the forced-choice task.

are not original, see section Editable Instructions

Millisecond Software LLC thanks Turk-Browne et al (2005) for providing the 12 original shapes used in this study!
See section Editable Stimuli

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:

waitforcedchoice:										determines the pretrialpause before the first shape triplets are shown in the forced-
																choice task (default is 1s)
leftkey:												the scancode of the left key used to respond if the first sequence is more familiar
																(default = 2 -> letter "1")
rightkey:												the scancode of the right key used to respond if the second sequence is more familiar
																(default = 3 -> letter "2")

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