Original scientific paper

Comparison of three psychophysical methods for measuring displacement in frontal plane motion

Anja Podlesek
Luka Komidar

Abstract

Displacement is a phenomenon related to representations of dynamic stimuli. The final position of a target moving in the frontal plane is not remembered correctly, but is instead shifted in the direction of the motion. Previous studies of displacement have mostly used the constant-stimuli method and the adjustment method. Although both methods usually yielded forward displacements, the task of responding activates different processes in the two methods, which could result in different outcomes. The purpose of the present study was to examine whether the magnitude of displacement is affected by the measurement method. Three psychophysical methods were used: the constant-stimuli method, the staircase method, and the adjustment method. Direction and acceleration of the motion were also varied. The results showed that displacement is affected by motion acceleration (being the smallest for decelerated motion) and by motion direction (displacement was larger for motion to the right than for motion to the left). The constant-stimuli method and the staircase method gave comparable results, whereas the displacement obtained with the adjustment method was larger. Also, the variability of data differed between the methods, being the largest for the adjustment method. The results indicated that when experimenting with displacement a special consideration should be given to the selection of the psychophysical method, where as adjustment method should be used with caution.

Keywords

displacement; psychophysics; method of constant stimuli; staircase method; adjustment method

Hrčak ID:

9053

URI

https://hrcak.srce.hr/9053

Publication date:

5.2.2007.

Visits: 1.680 *