Perception and stimulus statistics: any good experiments?
Posted Aug 16 2009 10:11pm
As part of a series on consciousness I am writing, I am presently writing up some notes on the Necker Cube. I have a question perhaps some of the more historically minded readers could answer.
Most of you are familiar with the Necker Cube (see one to the left), a line-drawing that can appear as a cube facing down to the left, or up to the right. People's experience of the stimulus switches every few seconds between these two percepts.
There are quite a few studies of the effects on perception of the Necker cube when you first show subjects a disambiguated picture of a cube. If the disambiguated version is shown for a fairly short time, then they will see the same perspective when you switch over to the ambiguous Necker. However, if shown a disambiguated version for a long time (e.g., minutes) then the opposite perspective is seen after the switch (this is usually interpreted as some kind of low-level adaptation effect).
My question is, has there been research on much longer
time scales, with extensive exposure to disambiguated cubes? For
instance, show subjects the same disambiguated cube over weeks or
months, every day (for example, pictures with many down-left cubes and
zero up-right cubes). Perhaps the disambiguated cubes could be used in
some attention task unrelated to bistable perception. After N days of such training what happens on day N+1 if we show the
ambiguous cube? Will perception be biased toward one or the other perspective?
During training, would the brain change its statistical estimation of the frequency of
the two cubes in the world? If so, what would our prediction be for the percept? Would
subjects be more likely to see the Necker cube as the disambiguated version shown during training? Or would the brain be primed
to see the less probable cube, the
cube that offers a higher surprise value?
Does anyone know if this has been done with Necker cubes, or similar long-term studies have
been done with other ambiguous stimuli? I know there is tons of work on adaptation effects in which stimuli bias perception in the short term (e.g., show a bunch of
lines slanted to the left, then vertical lines will appear
slanted to the right). I am asking about longer-term effects.
For the research on short-term effects of disambiguated Necker-cube like stimuli, see Gerald Long's work such as: Long G M, Moran C J, 2007, "How to keep a reversible figure from
reversing: Teasing out top – down and bottom – up processes" Perception
36(3) 431–445 .