Dot Numerosity Judgment Task

Perception Duration: ~8 minutes

System Requirements

🖥️

Screen Size:
Minimum: 800×600
Recommended: 1280×1024

⌨️

Keyboard required

Description

A perceptual numerosity judgment task using interleaved staircase procedures to estimate thresholds.

Measures: Numerosity discrimination, perceptual judgment

Perception Decision Making

About This Test

Participants view two groups of dots displayed briefly on screen and judge which group contains more dots. The task uses simultaneous interleaved staircase procedures to adaptively adjust difficulty, converging on the participant's discrimination threshold.

Test Details

Test ID:

dotjudgment

Main File:

dotjudgment.pbl

Parameters:

22 configurable parameters

22 configurable parameters available

Languages:

German English Spanish French Italian Dutch Portuguese

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📄 IRB Fact Sheet

Scientific Background

PEBL-Specific References:

These studies used the PEBL version of this task.

Mueller, S. T. (2011). The PEBL Dot Judgment Task. Computer software retrieved from http://pebl.sf.net/battery.html

Data Output

The task produces a trial-by-trial data file, a summary file with estimated thresholds, an aggregate file, and a session log.

Output File:

dots-{subnum}.csv

Format:

CSV

Scoring and Interpretation

Lower threshold values indicate better numerosity discrimination. Thresholds are estimated via staircase convergence across multiple interleaved procedures with different standard values.

Example Data

example-data.csv Primary

Trial-by-trial data recording each dot comparison judgment

subnum	block	trial	practice	standard	thresh	side	corr	abstime	rt
subnum	block	trial	practice	standard	thresh	side	corr	abstime	rt
111	1	1	1	50	4	1	1	3191	2739
111	1	2	1	6	4	1	1	6543	854
111	1	3	1	100	4	-1	0	8004	737
111	1	4	1	6	3.75	-1	1	9359	857
111	1	5	1	100	5	1	0	10825	877
111	1	6	1	6	3.5	-1	1	12318	922
111	1	7	1	50	3.75	1	0	13849	1198
111	1	8	1	6	3.25	-1	1	15655	1335

View full file (402 rows) →

example-summary.txt Summary

Text summary with estimated discrimination thresholds for each standard value and overall statistics

-----------------------------------------------
PEBL Dots Task, Version 1.0
http://pebl.sf.net
Shane T. Mueller
PEBL Version 2.2
LINUX
-----------------------------------------------
Subject code: 111
Time:         Wed Nov  5 14:33:43 2025
Reps per block: 25
Blocks:      4
fieldsize:   450
dotcolor:   red
dotfilled:   1
dotradius:   10
-----------------------------------------------
                      Thresholds  
Base value       Mean     Last half     Final 
-----------------------------------------------
6               2.5875      2.55882             3.75
20               4.875      5.44118             8.25
50               7.125      8.32353             15.25
100               11.15      13.7843             18.5
-----------------------------------------------
[0.7025, 743.755]

example-all.csv

Aggregated threshold estimates across all staircase procedures. One row per participant with final threshold values for each standard.

111	Wed Nov 5 14:33:43 2025	2.5875	4.875	7.125	11.15

example-log.csv

Session log tracking test events (initiation, practice, completion) with timestamps

111	EN	Wed Nov 5 14:24:08 2025	DOTS TASK	keyboard	INITIATED
111	EN	Wed Nov 5 14:24:09 2025	DOTS TASK	keyboard	PRACTICE BEGIN
111	EN	Wed Nov 5 14:33:43 2025	dots	keyboard	EXPERIMENT COMPLETE
1616	EN	Wed Nov 5 14:46:45 2025	DOTS TASK	keyboard	INITIATED
1616	EN	Wed Nov 5 14:46:47 2025	DOTS TASK	keyboard	PRACTICE BEGIN
1616	EN	Wed Nov 5 14:47:24 2025	DOTS TASK	keyboard	INITIATED
1616	EN	Wed Nov 5 14:47:25 2025	DOTS TASK	keyboard	PRACTICE BEGIN
1516	EN	Wed Nov 5 14:48:27 2025	DOTS TASK	keyboard	INITIATED
1516	EN	Wed Nov 5 14:48:29 2025	DOTS TASK	keyboard	PRACTICE BEGIN
51515	EN	Wed Nov 5 14:48:52 2025	DOTS TASK	keyboard	INITIATED

View full file (37 rows) →

Sample data showing typical output format. Actual values will vary by participant.

About This Test

A perceptual numerosity judgment task using interleaved staircase procedures to estimate thresholds.

Category: Perception
Estimated Duration: 8 minutes
Available Translations: 7 languages

Documentation Status: Complete