Hand amputees have distorted vision

The space immediately surrounding the hands, where objects are grasped, touched, and manipulated, is called “action space” by psychologists. It is distinct from the wider spatial field because there is evidence that visual perception of an object is affected by the object’s proximity to the hands—i.e., its ability to be touched.

A new study has shown that hand amputees have distorted visual perception in the action space:

The space within reach of our hands—where actions such as grasping and touching occur—is known as the “action space.” Research has shown that visual information in this area is organized in hand-centered coordinates—in other words, the representation of objects in the human brain depends on their physical location with respect to the hand. According to new research in Psychological Science amputation of the hand results in distorted visuospatial perception (i.e., figuring out where in space objects are located) of the action space….

Volunteers were instructed to look at a central cross on a screen as two white squares were briefly shown to the left and right side of the cross. The volunteers had to indicate which of the squares was further away from the cross. The results reveal that hand amputations affect visuospatial perception. When the right square was slightly further away from the center, participants with right-hand amputations tended to perceive it as being at the same distance from the center as the left square; this suggests that these volunteers underestimated the distance of the right square relative to the left. Conversely, when the left square was further away, participants with left-hand amputations perceived both squares as being equally far away from the center—these participants underestimated the left side of near space. Interestingly, when the volunteers were seated farther away from the screen, they were more accurate in judging the distances, indicating that hand amputations may only affect perception of the space close to the body.

The findings suggest that losing a hand may shrink the action space on the amputated side, leading to permanent distortions in spatial perception. According to the researchers, “This shows that the possibility for action in near space shapes our perception—the space near our hands is really special, and our ability to move in that space affects how we perceive it.

Perceptual chauvinism

I read two articles in a row today that use unnecessary quotation marks, which expose that strange discomfort with writing about touch I have written about before. As humans we hold our feelings dear, so we don’t like to say that any other beings can feel. Especially plants, for chrissake:

Plants are incredibly temperature sensitive and can perceive changes of as little as one degree Celsius. Now, a report shows how they not only “feel” the temperature rise, but also coordinate an appropriate response—activating hundreds of genes and deactivating others; it turns out it’s all about the way that their DNA is packaged.

The author can’t simply say that plants can feel, so instead he writes “feel,” indicating a figurative sense of the word. Why? Because the word ‘feel’ implies some amount of consciousness. (In fact I have argued that ‘feeling’ signifies a baseline for the existence of a subject.) Only the animal kingdom gets feeling privileges.

And then, in another article posted on Science Daily, we have a similar example, but this one is even more baffling. The context is that research has shown that playing Mozart to premature infants can have measurable positive effects on development:

A new study… has found that pre-term infants exposed to thirty minutes of Mozart’s music in one session, once per day expend less energy—and therefore need fewer calories to grow rapidly—than when they are not “listening” to the music

In the study, Dr. Mandel and Dr. Lubetzky and their team measured the physiological effects of music by Mozart played to pre-term newborns for 30 minutes. After the music was played, the researchers measured infants’ energy expenditure again, and compared it to the amount of energy expended when the baby was at rest. After “hearing” the music, the infant expended less energy, a process that can lead to faster weight gain.

Not allowing plants to feel is one thing. And I can even understand the discomfort with writing that newborns are listening to music, because that may imply they are attending to it, which is questionable. But why can’t human babies be said to hear music? This is the strangest case of perceptual chauvinism I have yet come across.

Meet physical addiction with physical destruction

Smokers who crushed computer-simulated cigarettes… had significantly reduced nicotine dependence and higher rates of tobacco abstinence than smokers participating in the same program who grasped a computer-simulated ball…

Other notable findings include the following: smokers who crushed virtual cigarettes tended to stay in the treatment program longer (average time to drop-out > 8 weeks) than the ball-grasping group (< 6 weeks). At the 6-month follow-up, 39% of the cigarette crushers reported not smoking during the previous week, compared to 20% of the ball graspers.