Monday, August 20, 2007

Can You Directly Will Sensory Experiences?

You can will changes in your sensory visual experience indirectly, of course, by deliberately looking one direction, or closing your eyes, or pressing on your eyelids. And you can directly will visual imagery experiences by, for example, deciding to form the image of your house as seen from the street. But normally we don't think we can directly will sensory experience: We don't think we can will ourselves simply to see red or see a cross-shaped figure.

In 1894, the eminent psychologist George Ladd asserted, to the contrary, that he and his students could form visual experiences by direct willing.

What they were asked to do was briefly this: to close the eyes, allow the after-images completely to die away, and then persistently and attentively to will that the color-mass caused by the Eigenlicht [that is, the dark or chaotic visual field one supposedly experiences with one's eyes closed] should take some particular form, - a cross being the most experimented with.... Of the sixteen persons experimenting with themselves, four only reported no success; nine had a partial success which seemed to increase with practice and which they considered undoubtedly dependent directly upon volition; and with the remaining three the success was marked and really phenomenal. It should be said, however, that of the four who reported 'no success,' only one appears to have tried the experiment at all persistently.

As far as I am aware no one has ever published an attempted replication of Ladd's experiment.

What do you think? Can you make a cross -- not just an image of a cross but a sensory experience of a cross -- by closing your eyes and trying hard? Ladd recommends a few trials of no more than 5-7 minutes.

6 comments:

Pete Mandik said...

Here are my results.

I did it twice. Both times I was trying for a cross, but I wasn't trying for a cross of any particular color. I was also trying for a stationary cross.

On both occasions I wound up with a black cross. And on both occasions I was surprised to find that the cross rotated counter-clockwise. Weird!

Jonathan Ichikawa said...

I'm worried about methodology, here; by what criterion are we distinguishing imagery from sensory experience? I'm often tempted to think that what it is for an experience to be imagistic is for it to be produced by an expression of will. (I think one can dig this idea out of some remarks from Wittgenstein and Sartre, if one cares to.)

Tanasije Gjorgoski said...

Hi Eric,

I got similar results with Pete (didn't read his comment before trying).
Though I got a fluorescent green first, and I got the black cross later. The black cross borders were I think defined by kind of light coming from behind of the cross.

I believe as Jonatan that this is in fact imagery.

One idea is that what imagination does is pick out information in the noise already present, makes some parts of information more salient and in that way 'draws' using noise.
Wildly speculation, that's why I got green cross when the afterimage hasn't already disappeared. Now about the black cross... I'm not sure if I was motivated by this previous speculation, but when I closed my eyes, and covered them to make it as black as possible, it still seemed to me as if it is not black, but that noise of some kind is present.
Of course that might have been product of my imagination, same as the cross was!

BTW, two or three times, the cross was moving away from the center, and when i tried to focus my eyes on it, it was starting to move even faster eventually going out of the visual field.
I think this also relates to idea that what is picked out is something objective, which rotates when the eyes rotate.

Pete Mandik said...

In response to Jonathan and Tanasije, I'd say that subordination to the will doesn't automatically make it imagery. As for what criterion makes it experience, I'd offer something along the lines of Humean vividness. I can imagine a cross with no problem, but willing into existence a cross with the requisite vividness took additional effort.

Consider some cases that I think are a bit clearer. One can look at a three-hole wall outlet and will it to look like a face. Similarly, one can look at ambiguous figures and whether they look like ducks vs. rabbits or upward vs. downward facing Necker cubes is under some degree of volitional control. But in all these cases there's a vividness that distinguishes them from imagery.

Anibal said...

Memory factors permeate our visual perception, and how we recollect those past events related to visual scenes in some sense structure and construct our visual perception, or so said stucturalists theorists in the debate about the mechanisms of visual perception against the "gestaltic" theorists view.

We have cognitive penetrability in memory access for past events most of the time, unless we have a memory impairment (see Daniel L. Schacter´s seven sins of memory) , then, i think it is reasonable to think or even wonder, why not we could have cognitive penetrability and control-hand of our phenomenal contents at will.

For instance, modern scientists have been made susbstantial advances in the objective study of sensory experience, helping to resolve, one day, the puzzle that intrigue Ladd.

I refer to the experimental study made by P. Read Montague and collaborators traslated into a paper entitled: "Vividness of mental imagery: individual variability can be measured objectively"

In that paper they discuss the neural mechanisms responsible for visual imaginery, individual differences in visual skills, some physiological indexes pointing to the private mental experience or visual imagery making it objective to be measured, how some individuals are more prone to visualize scenes than others by factors of personality and finally, the legal implications of the findings in forensic cases involving eyewitness.

Eric Schwitzgebel said...

Thanks, folks, for the interesting and thoughtful comments!

I'm inclined to agree with Pete against Jonathan and Tanasije about imagery experience vs. sensory experience. Although typically imagery experience is under control and sensory experience is not, I don't see the motivation to make this definitional of the distinction. People sometimes report images they have no control over; and on the other side, here Pete and Ladd report experiences like sensory experiences except that they are amenable to direct control -- shall we say that such things are simply a priori impossible?

Rather, I'd characterize the sensory/imagery distinction ostensively: There's something phenomenally it's like to imagine my house and something quite different it's phenomenally like to see it. And when I close my eyes and see afterimages and darkness and the like, the phenomenology is more like sensory phenomenology than it is like imagery. Although typically things with the sensory phenomenal character aren't under my control, maybe here's a case where they are.

Tanasije: I like your suggestion that it has something to do with interpreting noise.

Anibal: Thanks especially for the tip on the Montague study. I'm printing it out now! I don't know it, but in 2002 I published an essay skeptical of the validity of studies of individual differences in imagery. At the time, I don't recall finding any brain data supporting purported differences in imagery skill.

I like your point, Pete, about the three-hole outlet.

And thanks to all for the phenomenal reports!