Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com), Millisecond
Created: January 20, 2014
Last Modified: June 06, 2023 by K. Borchert (katjab@millisecond.com), Millisecond
Script Copyright © Millisecond Software, LLC
This script implements the ADJUSTMENT METHOD to estimate the difference threshold for a particular color red
Ehrenstein, W.H. & and Addie Ehrenstein, A. (1999). Psychophysical Methods. In U. Windhorst & H. Johansson, Hakan (Eds.), Modern Techniques in Neuroscience Research (pp.1211-1241). Heidelberg: Springer. (->https://uni-leipzig.de/~isp/isp/history/texts/PSYPHY-M.PDF)
2 minutes
Participants are asked to adjust a red Target color until the red color of the Target is as red as the given red Base color. Adjustments are made with keyboard input (D = decrease red target color; L = increase red target color)
By default this scripts estimates the Difference Thresholds for 1 Base color (-> editable values),
with 2 sequences (one where the targets starts out lighter and one where the target starts out darker,
order randomly determined).
The thresholds are the red color components of the target when participants decide that they are the same (aka press 'ENTER').
The overall threshold is the mean of the "up" and "down" thresholds.
see section Editable Instructions
File Name: adjustmentmethod_redcolor_summary*.iqdat
| Name | Description |
|---|---|
| inquisit.version | Inquisit version number |
| computer.platform | Device platform: win | mac |ios | android |
| startDate | Date the session was run |
| startTime | Time the session was run |
| subjectId | Participant ID |
| groupId | Group number |
| sessionId | Session number |
| elapsedTime | Session duration in ms |
| completed | 0 = Test was not completed 1 = Test was completed |
| step | The decrease in target value everytime participants adjusts (default: 1) |
| adjustcycles | Stores the number of adjustment cycles run |
| parameters.baselineValue1 | The default baseline value for the first adjustment cycle |
| diffThreshold1 | Mean difference threshold for the first adjustment cycle (both up and down) |
File Name: adjustmentmethod_raw*.iqdat
| Name | Description |
|---|---|
| build | Inquisit version number |
| computer.platform | Device platform: win | mac |ios | android |
| date | Date the session was run |
| time | Time the session was run |
| subject | Participant ID |
| group | Group number |
| session | Session number |
| blockCode | Name of the current block |
| blockNum | Number of the current block |
| trialCode | Name of the current trial |
| trialNum | Number of the current trial |
| adjustcycles | Stores the number of adjustment cycles run |
| baselineValue | Stores the color of the current base |
| targetValue | Stores the color of the current target |
| direction | 1 = Down (sequence starts with targetvalue > baseline value) 2 = Up (sequence starts with targetvalue < baseline value) |
| sequenceCount | Counts how many adjustment sequences have been run |
| response | The participant's response |
| latency | The response latency in ms |
| diffThresholdUp | The estimated Difference threshold for the current UP sequence (= starting with target value < baseline value) |
| diffThresholdDown | The estimated Difference threshold for the current DOWN sequence (= starting with target value > baseline value) |
| meanDiffThreshold | Mean difference threshold for one adjustment cycle (up and down) |
The procedure can be adjusted by setting the following parameters.
| Name | Description | Default |
|---|---|---|
| baselineValue1 | The baseline red value for the first adjustment cycle (0 -> black, 255 -> brightest red) to add adjustment cycles with different basevalues add a value for each new baseline value you want to test and go to BLOCKS for further instructions. | |
| step | The decrease in target value everytime participants adjusts | 1 |
| initialdifference | Initial difference in the red component of target and base | 50 |
| interAdjustmentPause | Pause after an adjustment sequence | 500ms |