A case of colour-emotion synaesthesia?



Anger he smiles, towering in shiny metallic purple armour. Queen Jealousy, envy waits behind him, her fiery green gown sneers at the grassy ground. Blue are the life giving waters taken for granted, they quietly understand. Once happy turquoise armies lay opposite ready, but wonder why the fight is on.

My red is so confident he flashes trophies of war and ribbons of euphoria. Orange is young, full of daring, but very unsteady for the first go round. My yellow in this case is not so mellow, in fact I'm trying to say it's frightened like me. And all of these emotions of mine keep holding me from givin’ my life to a rainbow like you.


This post was chosen as an Editor's Selection for ResearchBlogging.orgHendrix fans amongst you will recognise the above as lyrics from Bold as Love, the title track of Jimi's second album. According to the sleevenotes (from a long-lost cassette, so you'll have to trust my memory on this), the concept for the song was the idea of using emotions to describe colours to a blind person. The more obvious interpretation is that Hendrix was using colours as a metaphorical device to describe his own conflicting emotions.



Earlier this week, I was reminded of Bold as Love when I came across an intriguing study reported in the journal, Neurocase [1]. The authors, VS Ramachandran and colleagues, described the case of TK, a young man with Asperger syndrome who was encouraged to use colours to help him understand emotions:
"Around the age of 10 his mother suggested that he attempt to label the feeling of each emotion (presumably based on context, social situation, and facial expressions) with a specific color, in an attempt to relay the appropriate emotions to his father and her. For example, while experiencing what he considered happiness he would tell his parents that he was feeling ‘green’." 
"Further, by comparing the color elicited by another person with the emotion that would be associated with the same color in his own mind, TK was able to ‘read’ the other individuals’ emotions more accurately."
"At about the same time that he began associating colors with emotions, he also began seeing colored halos around individuals. The color of these halos corresponds to TK’s emotional stance toward that particular person, and when a new individual is encountered a blue halo emerges de-nouveau and the color evolves progressively with repeated exposure."
Purple haze

To objectively measure the halo perception, Ramachandran et al asked TK to identify letters that were projected onto a white screen. An unfamiliar person, identified as having a blue halo, stood in front of the screen.

If the letters were blue and projected close to the person (i.e., within the halo) then TK was unable to identify the letters above chance levels - presumably because the letters and background appeared to be in the same colour. When the colour was changed or the letters moved to outside the halo, TK's performance was flawless.

It's a shame that the authors weren't able to test TK with a second person standing in front of the screen, whom he perceived as having a different coloured halo. Nonetheless, these results appear to provide some objective confirmation of TK's unusual subjective reports [2].

Love or confusion

In a second experiment, Ramachandran et al tested TK and 15 control subjects on a Stroop interference test.

Participants were given words printed in colour and had to say the colour of each word, ignoring what the word itself said. In the classic version of the test, the words are all themselves colour names.

In the congruent condition, the word matches the colour in which it's printed:

          RED BLUE YELLOW GREEN

In the incongruent condition, the word and its colour are mismatched

          RED BLUE YELLOW GREEN

People are generally faster to name the ink colours when the word matches the colour. Even though they're supposed to be ignoring what the word says, they can't help but read it, and this affects their response to the actual colour. As you can see from the graph below, TK was no exception. Like the control group, his reaction times were longer for the incongruent condition than for the congruent condition.


TK showed a similar effect when the words were emotions, being quicker to name the colour if the emotion word matched the colour he associated with that emotion (e.g., PRIDE and AGGRESSION) than when they were incongruent. When the control participants were given the same stimuli, they showed no such effect [3].



Ramachandran et al. interpret these findings as evidence of "emotion-colour synaesthesia" - the implication being that TK actually perceives emotions as colours. This is certainly one possibility, but it's worth noting that similar effects are commonly observed in typical adults using non-emotion words that have associations with colours. For example, it's easier and quicker to name the colours in FIRE GRASS LEMON SKY than it is in FIRE GRASS LEMON SKY.

Seeing the word SKY makes us think of the colour blue, which then affects our ability to name colours; but there's no suggestion that we actually perceive the colour blue every time we read SKY. By the same token, TK associates PRIDE with blue and this affects his colour naming, but the data from the Stroop task don't show that he experiences pride as the colour blue.

Crossbrain traffic

It's undoubtedly a fascinating case study. Ramachandran et al.'s data indicate that TK perceives a blue halo around certain people and it's safe to say that he has strong cognitive associations between colours and emotions. However, we are still relying on TK's subjective reports that the halos vary from person to person and that emotions are actually experienced as colours. This is not to cast doubt on TK's reports, merely to note that the objective evidence is not perhaps as strong as the authors claim.

Ramachandran et al. speculate that TK's experiences derive from increased connectivity between brain regions involve in vision (V4), face processing (FFA), and emotion (insula and amygdala). It would certainly be interesting to know whether this is supported by brain imaging.

I'd also like to know more about TK's Asperger's diagnosis and the extent to which his social and communication difficulties could be attributed to problems more specifically with face processing.

Finally, I'd be interested to know how common TK's reported experiences are, and whether other people on the autism spectrum have been able to use colours to help them understand or convey emotions.



Notes:

[1] Thanks to Michelle Dawson for the heads-up. Follow her on Twitter at @autismcrisis

[2] Ramachandran et al. begin the discussion by noting that the magician James Randi has offered a million dollar prize for anyone who can objectively demonstrate the existence of energy fields emanating from people. They then claim to have provided "the first evidence of the existence of this effect". You don't need me to tell you that Randi's million is safe. At best, the study demonstrates that a person genuinely perceives a halo. It doesn't show that the halo is actually there!

[3] Separate from the congruency effect, TK's responses were much slower for emotion words than for colour words. Control subjects didn't show this effect. Ramachandran et al don't discuss this finding and I'm not really sure what to make of it.


Slight return:




Reference:

ResearchBlogging.orgRamachandran VS, Miller L, Livingstone MS, & Brang D (2011). Colored halos around faces and emotion-evoked colors: A new form of synesthesia. Neurocase PMID: 22115465





Update [9/12/11]: 

Some really great comments below. Thanks to everyone for their insights.

This from Rohan, who's a member of the indie rock band Rudely Interrupted:
"our lead vocalist has Aspergers and was born without eyes. He's obsessed with colour. We wrote a song about it (Green Lights) Rory also has perfect and absolute pitch.
All being well, you should be able to listen to the song by clicking the Play button below:

RGreen Lights Green Lights