In today’s Academic Minute, Dr. Sophie Wuerger of the University of Liverpool explains how our perception of color remains constant even though our vision degrades with age.
Sophie Wuerger is a professor in the Institute of Psychology, Health, and Society at the University of Liverpool. Her research uses behavioral methods, EEG, and fMRI to understand how the human brain processes visual information with a focus on color vision.
Dr. Sophie Wuerger, University of Liverpool – Age and Color Perception
Our study suggests that the brain, not our eyes keep colour vision constant across lifespan. From our daily experience we know that colours don’t seem to change a lot over our life span. This is in fact quite surprising since, when we get older, our lens becomes yellowish and thereby filtering out most of the bluish light which should indeed affect the way we see colours.
To investigate this phenomenon we recruited 185 participants aged 18 to 75 years of age, with normal colour vision. We then tested them on two different tasks: in the first task, we measured their colour discrimination, that is, how well they could discern the difference between two hues. In the second task we measured how colours appeared to them, that is, we ask them to chose a patch of light that appeared neither red nor green, and neither yellow nor blue.
We found that colour discrimination deteriorates with age and this decline is most prevalent for yellowish-bluish hues (task 1). In contrast, how colours appeared to the observers (task 2) remained stable and there was no difference between the young and the old age groups.
How does the brain achieve stable colour perception? Researchers have suggested that the brain recalibrates itself across the life span by exploiting constancies in our visual environment (such as the sky or the sunlight), as an external calibration standard. This would also explain that – low and behold – different people perceive colours in a similar way although we now know that the number of light-sensitive red and green receptors in the human eye varies wildly between different people.