Patent and trademark experts Withers & Rogers say 64% of the people they interviewed rated colour as more important than a slogan, typeface or logo shape.
Interviewees were also asked to recall the colours used by a list of 20 brands. The brand colours most people recalled were the AA's, Easyjet's and Cadbury's.
The findings, which also saw the green BP and red Royal Mail score highly, have led Withers & Rogers to call for more companies to try and legally protect the colour of their brand with a patent.
Cadbury's is one of the few brands that scored highly in the research that has already protected the pantone reference of its purple, gaining a patent retrospectively when the history of its association with the colour was demonstrated.
Fiona McBride, partner and trademark attorney at Withers & Rogers, said: "Most marketers understand that people respond to brands emotionally and it is surprising that so few are aware that they can seek trademark protection for a brand's sensory attributes.
"With millions of pounds spent on brand development within global corporations and the influence of marketers ever growing at boardroom level, there is an opportunity to prioritise trade mark protection further."