The aim of the study is to investigate perceived saturation by looking into individual observer's response. To achieve this, a psychophysical experiment was conducted in which 39 untrained British and Korean observers participated. According to the experimental results, British observers were classified into three subgroups. The three subgroups show different trends of perceived saturation against CIECAM02 values. Korean observers were also classified into three subgroups, each showing a distinct pattern of saturation response. It was found that among the 6 subgroups of observer, only one subgroup agreed well with the CIECAM02 saturation, i.e. only 10% of the observers agreed closely with the CIE definition of saturation. The other observers showed different understandings of saturation; some regarded white, a light grey or medium grey as the least saturated among all colour samples, while some regarded black as the most saturated among all colour samples. The results seem to imply an impact of background colour on the perceived saturation, which however will require further verification in future studies.