Laura Otis & Krish Sathian
Images in the Mind
Otis spoke of work towards a book to be titled, Thirty Thinkers, which draws from
interviews with a range of creative people about the phenomenology of their
mental imagery. Inquiry into the
phenomenology of mental imagery is nothing new in itself, even if it is only in
the last forty years that the study of mental imagery has been taken seriously
as a subject of scientific research.
Continental phenomenologists like Sartre, Husserl, and Merleau-Ponty
pioneered the systematic study of the phenomena of imagination in the first
half of the twentieth century. However,
they did so according to the methodology of classical phenomenology – by
describing what they took to be the essential
structures of the formation of mental imagery by conscious subjects. In contrast, the interest and promise of
Otis’ empirical approach lies in what
it reveals about the range of ways in
which people form mental images. The diversity of mental image formation from
individual to individual emerged as one of the key take-aways from the lunch.
If you close your eyes and think of the word “bridge,” what
do you see? As you read fiction, what
sorts of images do you form in your mind?
These are the sorts of questions that Otis asked the participants in her
book research, and she posed them to the lunch participants as well. The latter reported bridge images ranging
from “a covered bridge in Indiana” (absent color) to “the river that runs under
a bridge” to less specific, more generic images. No one reported no images at all, but one
participant testified to knowing someone who claims never to form mental
images. The range of responses at lunch was
in line with the findings of Otis’ book research. In response to queries about images formed
while reading fiction, some participants in Otis’ study said that they read fiction
because forming images is intrinsically pleasant; others reported not seeing
anything at all and enjoying simply following the play of language.
In the 1970s it became popular to distinguish people who are
more verbal in their thinking from those who are more visual or spatial on the
grounds of functional differences between the brain’s hemispheres. While it might seem that participants’
reports in Otis’ study reinforce this dichotomy – with those who read for the
words, on the left side, as it were, and those who read for images, on the
right – Otis urged that the situation is in fact more complicated, citing Maria
Kozhevnikov (Radiology, Harvard Medical School), whose research has challenged
the old linear spectrum (from verbal to spatial), and who will speak on the
subject of differences between object and spatial imagery at a CMBC-sponsored
event on October 10th.
Sathian posed the question of mental imagery from the neuroscientific
perspective: what are the neural substrates of image formation? How much overlap is there between the neural
pathways involved in mental imagery with those involved in visual perception? Evidence suggests that the overlap is substantial,
as might be expected. PET scans and functional
MRIs show that visual cortical areas are active in the formation of mental
images. Damage to these cortical areas,
moreover, interferes not only with perception but also with image formation:
patients with right parietal stroke, for example, who suffer from neglect of
the left side of the spatial field, not only can’t see the field, but they fail to mention anything on the left side
when asked simply to imagine a
familiar, remembered scene.
Although visual perception and mental imagery share neural
substrates, Sathian underscored important differences: while visual cortex
subtends the images of both visual perception and mental imagery, the neural
pathways that lead to image formation in each case are very different. Mental imagery stems – in “top-down” fashion –
from the frontal cortex, while what we see is received through the eyes. Sathian was careful to qualify this
dichotomy, however, pointing out that in actual cases of perception, and
especially in cases of perceiving unfamiliar objects, the activity of mental
image formation plays an important role in “interpreting” the data, and
therefore in determining the images we actually see.
One of Sathian’s most intriguing points concerned non-visual imagery. Object properties are encoded in multi-sensory
representations, not just visual ones.
One interesting question of on-going debate is whether spatial imagery
is specifically visual, or rather “amodal”?
The question of the relationship between different kinds of sensory
imagery is a fascinating one. In this
regard, Sathian left off with a reference to Oliver Sack’s recent book, The Mind’s Eye, in which Sacks discusses
the phenomenon of blind people actually becoming more visual in their image formation after the loss of vision. This would seem to underscore the connection
between the tactile and the visual (along with providing an interesting
variation on the famous problem of Molyneaux, who in a letter to John Locke
asked whether a person born blind, able to distinguish a sphere and cube by
touch, would be able, with vision restored, to distinguish the objects with
sight alone).
What about a friend who claims never to form images? Is it possible that images could never appear
in someone’s mind? I must admit, being
someone who forms images easily and takes the delight in them that I do in
vivid dreams, it is (somewhat ironically?) hard to imagine an inner life
without them. Perhaps those who report
no images are merely misreporting their
inner world? Perhaps they are merely
less conscious of the images they are
forming than others? In response to this
line of questioning, Sathian pointed out that there is some tendency for brain
scans to correlate with reports of the vividness of imagery, suggesting that if
someone reports a lack of imagery, there may well be some neural basis to the
claim. In addition, Sathian explained,
even if someone lacks vivid visual imagery, they most likely form other kinds
of sophisticated sensory image, such as auditory or spatial. For her part, Otis offered the image-less
friend her vote of confidence, cautioning against the presumption that others’
inner worlds need be akin to our own. In
illustration, she drew an analogy that elicited laughs from the audience: we
don’t talk to one another about our bathroom routines, and in consequence just
imagine that everyone’s is just like our own.
We cannot know, however, whether this is the case. Likewise, since we never see what is going on
in other people’s minds, we naturally imagine it to be just like our own. This is hasty.
The discussion of the image-less friend nicely encapsulated
what were perhaps the chief upshots of the lunch: on the phenomenological side,
there is increasing appreciation of the diversity of ways in which and degrees
to which people form images in the mind;
on the neural side, advances in brain imaging techniques, and, more
generally, advances in the understanding of the interplay of distinct neural
functions are helping to make neuroscientific sense of the range of
phenomenological reports. Because of the
need to reconcile the phenomenology with the neuroscience, and because of the
importance of image formation for the work of both humanists and scientists
alike, the study of mental imagery is an apt poster child for collaboration
across traditional disciplinary boundaries. In other words, it was a perfect subject for a
CMBC lunch.
Here is a link to the podcast: https://itunes.apple.com/us/itunes-u/images-in-the-mind/id503937750?i=122583440
Here is a link to the podcast: https://itunes.apple.com/us/itunes-u/images-in-the-mind/id503937750?i=122583440