Wednesday, November 16, 2011

Empirical Evidence Against My View of Dream Reports

Nowadays, most Americans report dreaming in color. In the 1950s, most Americans reported dreaming in black and white. In a series of articles I have argued that the reason for this change is not that people used to dream in black and white and now dream in color. Rather, I argue, people over-analogize dreams to movies. Thus, as movie technology shifts, people's dream reports shift, though their dreams themselves remain the same.

(Two pieces of evidence for this view: (a.) The use of color terms ("brown", "orange", etc.) in dream diaries seems to have been consistent since the 1950s. (b.) Color dream reporting correlates with group history of black-and-white media exposure across socioeconomic groups in China.)

A new study by Hitoshi Okada and colleagues in Japan calls my research into doubt. In 1993, Okada and colleagues had found that young Japanese respondents tended to report colored dreaming while older respondents tended to report not dreaming in color -- a result entirely in accord with my hypothesis, due to respondents' presumably different histories of black-and-white vs. colored media exposure. Now in 2011, Okada at al. find almost exactly the same pattern of responding. Thus, the cohort of respondents that was in their 20s and 30s in 1993, and who reported mostly colored dreaming back then, reports relatively infrequent color dreaming now. Twenty years of (presumably) colored media exposure appears not to have shifted them toward reporting more colored dreaming -- if anything, the opposite.

Maybe these results can be reconciled with my view. For example, maybe older Japanese regard as the archetypal movie the old-fashioned high-art black-and-white movies of Kurosawa and others. But that doesn't seem especially likely.

Another possibility (as always!) is that Okada's research is open to interpretations other than its face-value interpretation.

The following is Okada et al.'s entire description of their questionnaire:

The participants were required to check one of five categories describing the frequency with which color occurred in their dreams during the past year: 1 (always), 2 (sometimes), 3 (occasionally), 4 (seldom), or 5 (never) (p. 216).
In English, I don't know that "sometimes" implies higher frequency than "occasionally", but I trust that this is just an infelicity of translation from the original Japanese.

One worry is that this measure has no denominator. So here's one possible explanation of the Okada et al. results: Older Japanese people report dreaming less in general than do younger Japanese, so they report less frequent colored dreaming too. This would be consistent with their self-reported ratio of black-and-white to colored dreaming being about the same. (In my own work on the issue, I ask some respondents about absolute frequency or colored dreaming and others about the proportion of colored to black-and-white dreams.)

Another potential concern is non-response bias. Okada et al. state that their participants were "students in Bunkyo University, Jissen Women’s University, and Iwate University, or members of their families" (p. 215). They don't indicate the response rates of the family members, but it's possible that only a minority of family members who heard about the questionnaire chose to respond. If so, those family responders would mostly be people with higher-than-average interest in the issue of black-and-white vs. colored dreaming. And we might reasonably worry that such people would not have views on that question that are representative of the population as a whole. (This is, of course, the notorious problem with online polls.)

I'd be very interested to see a follow-up study addressing these concerns.


steve02476 said...

I wonder if people will start dreaming in 3D now? Will they be wearing special glasses in their dreams?

Eric Schwitzgebel said...

Yes! That would be cool to study. We should probably get reports of the relative flatness or not of dream experiences now, while we can, before 3D takes over (assuming that it will, eventually).

clasqm said...

Not something I've given much thought to, but now that you've raised it, all sorts of questions arise. Why do we think of dreams as exclusively visual experiences?

I, for one, definitely have an audio component to my dreams, but touch, smell & taste are conspicuously absent. Yet these are considered the first sense to evolve. Does this imply that dreaming is a recent development in evolutionary history?

And what about the senses beyond the classical five? Proprioception, nociception etc?

Eric Schwitzgebel said...

@ clasqm: There are some descriptions of dreams as soundless -- especially in the early to mid-twentieth century (comparing dreams to silent movies). But interestingly, I've never seen dreams compared to radio broadcasts. Also, feeling a pinch is often thought to be indicative of waking.

So: Why this preference for the visual? Are dreams really more visual than sensory in other modalities? Or is this slant toward visuality only a feature of our biases or misconceptions in reporting? I can't recall any studies of this issue that aren't just uncritical catalogs of people's subjective reports.

L. Edgar Otto said...


I wrote something inspired by your contemplations and in relation to what is light and color in general- and what is such information. It will be posted shortly on my blog:

I think there may be a way to set up an experiment or survey for the data, by such considerations.


clasqm said...

One possible way to find out would be to study the dreams of people blind from birth and/or deaf from birth.

Did Helen Keller dream?

Eric Schwitzgebel said...

Thanks, ThePeSla and clasqm. Clasqm: My understanding is that people blind from birth do not report visual experiences in their dreams. There's interesting research on the question of the extent to which people who go blind in adulthood still experience visuality in their dreams (see, e.g., Oliver Sacks).

L. Edgar Otto said...

Oh, and as I recall there is evidence that long into blindness we may have visual dreams but lose the ability to recall color...

Pinker shows that we can orient things in three space in our minds (a product of our evolving seeing) as we do in two space. I think we see like nature is made so that we imagine things in 4 and more space.

I found it a lot harder to imagine a three by three by three lattice in my mind but it was worth the effort, than it was a smashed down shadow of a 4D cube into three space. I mention also the studies of synaethesia in regards to color as philosophy or science- can we imagine higher color which to color would be as color is to black and white?


Silk said...

Just thinking that the issue could be one related to memory or recall of dreams, as it seems to me to be more difficult to remember a dream scene in colour (if colour is not important to the dream), well a dream that isn't based on memory anyway...

I'm rambling but my point is it could be that the black and white group are older and more likely to have memory issues.

Eric Schwitzgebel said...

Silk: That certainly might be part of the story. Eva Murzyn and Michael Schredl both discuss the possibility in 2008 papers on the topic.