Book Review: Sight Unseen (part III). Are frogs conscious?

As I indicated in part II, although she has no conscious experience of the presence of a pencil, Dee Fletcher is able to catch a pencil using the same hand orientation as would a person with unimpaired vision.

As it turns out, some people have brain damages that cause the opposite effect: They can see and describe a pencil (they are consciously aware of the presence of a pencil) but they are unable to make the necessary movements to grasp it (Balint's syndrome). What these people have is not a motor problem. Balint "...could deduce that from asking the patient to point to different parts of his own body using his right hand with his eyes closed: there was no problem."

From the analysis of Dee Fletcher's case, it seems that when we are reaching for a pencil, we think that we need to be aware of the presence of the pencil, but actually not. We do not need to be aware of its presence. Dee Fletcher is not aware of its presence, but she can catch it. Reaching for objects is an ability that has been hard wired in our brain far back in our evolutionary history and it did not require consciousness. For this kind of motor acts at least, we are not better than "zombies".

A further indication that it is indeed so comes from experiments on animals:

When frogs catch preys, they use a different brain module from the one that guides them around visual obstacles blocking their path. This has been demonstrated in the following experiment:

First of all, they are two things that you need to know about frogs:

1) frogs’ brains can regenerate new connections when damaged.

2) the right eye of a frog is connected to the left hemisphere of its brain (and vice versa).

In these experiments, the optic nerves that brought information from the right eye to the "prey catching part" of the brain were cut. A few weeks later, however, the cut nerves re-grew and connected with the "prey catching part" of the brain but on the wrong side of the brain. As a result, when these frogs were brought in presence of a pray on their right side, they tried to catch it on their left side. However, when brought in presence of an obstacle on their right side, the frog correctly avoided the obstacle (this because the "obstacle avoiding part" of their brain had not been rewired.

The "prey catching part" in these frogs was now wired up the wrong way around.

But this did not mean that their entire visual world was reversed. It was as though the frogs saw the world correctly when skirting around an obstacle, but saw the world mirror-imaged when snapping at prey. Hence, frogs do not experience a global visual world created for all purposes. Frogs have specialized parts of their brain using visual information independently to perform different tasks.

Does that mean that frogs do not experience a visual world at all? Maybe they do, but as a matter of fact, they do not need one for catching prey or avoiding obstacles. By the way, we also do not need one for catching objects or avoiding obstacles. But we do experience a global visual world. This conscious visual experience might only be present in animals needing to communicate and/or to plan ahead...

For a long time I thought that any animal with a memory was conscious. Maybe frogs are conscious to some extend but it seems that they can function without experiencing a visual world as we do. Their kind of consciousness, if it exists, might be very different from ours.