Evaluative Progressive Ratio Button Press Task

Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com), Millisecond

Created: January 27, 2020

Last Modified: January 12, 2025 by K. Borchert (katjab@millisecond.com), Millisecond

Script Copyright © Millisecond Software, LLC

Background

This script implements a 'Progressive Ratio Button Press Task' to investigate approach-avoidance behavior towards different stimulus categories. The implemented template is based on the procedure described by Driscoll et (2018).

References

Driscoll, R., Quinn de Launay, K. & Fenske, M.J. (2018). Less approach, more avoidance: Response inhibition has motivational consequences for sexual stimuli that reflect changes in affective value not a lingering global brake on behavior. Psychon Bull Rev (2018) 25:463–471 DOI 10.3758/s13423-017-1291-y

the implemented procedure is Millisecond's best guess effort

Duration

12 minutes

Description

Participants view images of two different categories (here: images depicting a positive or a negative scene). The images are originally somewhat blurry. Participants get the option to press one button to 'see more' of the image (aka make them more clear) or press another button to 'see less' of the image (aka make them more blurry).

At the beginning of each round it will take few button presses to get to the extremes (aka 'fully clear' or 'fully obscured'). However, as time goes one more and more button presses will be needed to reach one of the extremes.

For example, if a participant has selected to see a fully clear picture of a 'positive' image, the next time the participant wants to see a fully clear view of a positive image DOUBLE the number of button presses are required. And so on and so on.

Any button press is acceptable and participants can always change their minds, but they will eventually have to reach one of the extremes to move on the next image.

Procedure

In this script:
- 2 categories of images tested (here: positive vs. negative)
- 8 block/rounds (editable parameter) each presenting 12 images (6 positive, 6 negative)

Each round:
- the order of the positive (category1) and negative (category2) images is selected at random
- the image for each category is selected randomly WITHOUT replacement from the pool of available items*
• This script only provides 6 images per category, so each round presents the same 12 images
To add additional images per category, simple go to section Editable Stimuli and add the stimuli to
item.category1Images/item.category2Images. The script will automatically adapt to the increased
pool of items.


Trial Sequence:

- the base image is presented with an overlay of noise (noise itemnumber of 33 is used for first presentation)
- participant has to make a decision via key presses: 'see less of image' vs. 'see more of image'
=> depending on key choice and depending on how many key presses are necessary to show
the extreme of this choice, the participant sees a more blurry image or a more clear image and is either
done with this trial or has to make more selections.

Algorithm implemented:
1. At the start of each trial scripts notes the number of key presses required to get to
the extreme view of an image category in either direction.
Based on this number, the noise itemnumber stepsize is calculated that is needed to jump
through the progressive noise filters (e.g. for the first trial this stepsize is 32, that is
the script would jump from 33 to either 1 or 65 - the extremes- with one key press)

2. Participants makes choice to either see more or less of the image.
Depending on the number of key presses required to see one of the extremes view and the number of
key presses already made in a specific direction, two outcomes are possible:

1) the trial is over: participant sees selected extreme and can move to the next image.
At this point, the script doubles the number of presses needed for this category of images to
reach this particular extreme view again during the next presentation of this category.

2) the key press count was not enough to reach the extreme of the selected direction yet
and results in the selection of a new noise filter (either more blurry or more clear, depending on choice)
for the image.
At this point, the participant can choose to select the same direction again or change
her directional choice.
Again, the script will update the key press count and compare the number of key presses made to the
number of key presses required to see the directional extreme view of the image.


Example:

First Category1 Trial of a round:
Participant needs to use 1 key press in either direction to see one of the extremes.
Participant chooses the 'clear' key, sees the extremely clear view of the image (noise filter 1:
transparent overlay with no noise) and moves on to the next trial.

Second Category1 Trial of the round:
The script determines that participant needs 2 key presses to see the clear-extreme view of the image
but still requires only 1 key press to see the blurry-extreme view of the image.
Participant chooses 'clear' key and sees a more clear image (reduced noise filter: 17)-
however, one more key press is required to see the clear-extreme view of the image, so the trial hasn't ended yet.
At this point, participant changes direction and selects the 'blurry' key. Since one key press is enough
to reach the blurry-extreme (noise filter 65), the trial ends and participant moves to the next trial.

Third Category1 Trial of the round:
Participant now requires 2 key presses in either direction to see one of the extremes.
Participant chooses - clear-blurry-clear and reaches the clear-extreme as 2 key presses towards the clear-extreme
were made. End of Trial.
For the next category1 Trial, participants needs 4 key presses to the clear-extreme view and
2 key presses to the blurry-extreme view.

...and so on and on...

If a participant only wants to see the clear-extreme of positive images:
1) Trial1: 1 key press required
2) Trial2: 2 key presses required
3) Trial3: 4 key presses required
4) Trial4: 8 key presses required
5) Trial5: 16 key presses required
6) Trial6: 32 key presses required
( this script offers 65 noise filters, 32 noise filters going in either direction from starting point 33)

Stimuli

Category1/Category2 Stimuli:

6 category1 images (positive images) and 6 category2 images (negative images)
are provided by Millisecond as example stimuli.
The images can be edited under section Editable stimuli. Additional images can be edited to
item.category1Images/item.category2Images. The script will automatically adapt to the
increased pool of stimuli.

Example: to run 8 blocks with 6 positive images each => 48 different positive images
would be required. Thus, if item.category1Images contains 48 images, each image would
only presented once.

Noise Filters:
This script provides 65 noise filters.
Noise Filter 33 is the starting noise filter that is superimposed over the target image at the start of each
trial sequence. There are 32 increasing noise filters to get to 65 (most blurry) and 32 decreasing noise filters
to get to 1 (no noise at all = completely transparent noise image).
32 noise filters in either direction are necessary for 6 trials per category
with a doubling ratio of key presses.
If more trials should be run, increase the number of noise filters accordingly and change parameters.numberTrials_perblock.
For example, for 7 trials per category, use 129 noise filters; for 8 trials per category use 257 noise filters etc.
(the scripts will automatically adapt the starting noise filter).

noise images: created in paint.net with added plugin
Millisecond attempted to evenly space the noise on a transparent background across 65 noise images.
Exchange filter images under section Editable Stimuli

Instructions

provided by Millisecond - can be edited
in script "progressiveratio_driscoll_instructions_inc.iqjs"

Summary Data

File Name: progressiveratio_driscoll_summary*.iqdat

Data Fields

Raw Data

File Name: progressiveratio_driscoll_raw*.iqdat

Data Fields

Parameters

The procedure can be adjusted by setting the following parameters.