Measuring AgeDependence Of Colour Afterimage Perception

Abstract

Afterimages are common and frequent perceptual phenomena of everyday life. A typical appearance is the negative УghostФ image of a bright light source when we turn away from it. In the case of significant colour contrast, the afterimage can be coloured. The perceived false imageТs strength decreases gradually and completely disappears in a (10-100) s timescale. The underlying processes have multiple components: a quick adaptation on the retinal level, and a slower adaptation on the neural level. Several studies discuss these mechanisms, but there are still important questions to be answered. In our research, we apply the toplevel, blackbox style approach: instead of focusing on the inner details, we ask human test subjects to test and measure the duration and Уstrength scoreФ of the same lighttransitions. Our goal is to find the main features that affect the duration and subjective strength of the colour afterimages. Specifically, we examine whether the age and gender of the test subjects or the colourimetry parameters affect these parameters. Two set of experiments were performed: colourcolour transitions with 41 and colourgrey transitions with 16 test subjects between 19 and 62. We found that gender has no measurable influence, but age makes a difference in high significance. Both experiment types confirmed that over 40 years the average duration of colour afterimages decreases.

On the relationship between afterimages and a simple sensorimotor reaction

“…The phenomenon of the difference in the behavior of slow relaxation is similar to the manifestation of an afterimage on different backgrounds: the afterimage from light irritation is seen on a dark background as light, and on a light background as dark. A similar pattern is observed when stimulated by chromatic light – in one case, the afterimage has a direct color, in the other – a color in an additional color [8-12].…”

“…When considering chromatic afterimages, then, depending on the intensity of the background, the afterimages had a direct color, or a color of an additional color, as different as possible from the additional color of the object [8][9][10][11][12]. At the same time, the authors [12] did not notice the influence of age on the effect.…”

“…The relaxation time of the afterimage is known to be 4-8 seconds [17,18]. The authors [12] did not notice the influence of age on the rate of disappearance of the afterimage. At the same time, the destruction began with the disappearance of the contour and further blurring of the afterimage [19].…”

Szemelvények a BGE kutatásaiból (II. kötet)

“…Each subject's saftim,norm and taftim,norm values were transformed to separate nine dimensional vectors (according to the nine colour transitions used in Colour-Colour test series), and cluster analysis of strength and duration of colour afterimage results was run separately. For clustering, we implemented the Apache Commons Math 3.6 API in our Java application developed for test result processing in (Garai, Horvath, 2021;Garai, Horvath, 2022). Using the elbow method (Figure 8) and some natural criteria, like every cluster should have at least 10 members, 50-75% of males and no centroid has "0" value, we found that the most probable number of afterimage strength clusters is 3.…”