This task looks at identification of Attneave shapes (random polygons) with foils.
This test was described in Mueller, S. T. (2010), and the attneave figure based on an algorithm published by Collin and Mcmullen, 2002.
There are two scripts in the objectjudgment folder, objectjudgment.pbl and objectjudgment-inv.pbl. The first asks for absolute judgments between shapes--participants must decide which of two shapes is exactly like the other shape. The second asks this question, but the choices are made regardless of its size or orientation (i.e., invariance).
 Data Output
Data are saved in a file called objjudge-X.csv in the data\ directory, where X is the participant code.
The columns for object-judgment-inv.pbl are:
participant code, judgementtype, trial,cond,angle, size,shapepert, -1,response, correct, rt
Here, judgmenttype is always 'inv', and shapepert describes the maximum amount of perterbation (in pixels)that the foil shape has.
The columns of object-judgment.pbl are:
participant code, judgementtype, trial, condition, parameter,-1,shapepert, order,response, correct, rt
here, judgmenttype is always 'abs' condition is either 1,2, or 3, where 1=angle, 2=size, 3=shape parameter depends on which condition; for 1 it is the angle of deviation, for size it is the proportional size, and for 3 it is the number of vertices perturbed. shapepert is again the maximum amount of deviation in pixels, which is set to 10.
In both conditions, angle is in radians. the -1 column is used as a placeholder so each data file produces similar output.
Mueller, S. T. (2010). A partial implementation of the BICA Cognitive Decathlon using the Psychology Experiment Building Language (PEBL). International Journal of Machine Consciousness, 2, 273–288.
Collin, C. A., & Mcmullen, P. A. (2002). Using Matlab to generate families of similar Attneave shapes. Behavior Research Methods Instruments and Computers, 34(1), 55-68.