It seems as if touch doesn’t merely increase your good feelings, but it also decreases your bad feelings.

For many years, researchers believed that the nerves of our skin could recognize just four kinds of stimulation: touch, heat, pain and itch. But there is growing evidence that cutaneous senses include another one that conveys information not just about touch, but about the pleasant properties of touch.

Animals that are social by nature, such as many birds and mammals, have areas that can’t be reached by their own design and must be addressed either by rubbing against objects or by grooming by others. These areas — largely the head and neck — appear to be endowed with extra nerves that feel good when stimulated.

Consciousness and Sentience

Understanding the evolution of consciousness will not come from looking for intelligent behavior in other animals, but rather from understanding the fundamental mechanisms that support subjective awareness and selective attention, which we now know insects have.

Consciousness is a summary, produced by the non-conscious brain, and tossed up for us to view. Consciousness requires extra brain work to produce. The hard parts of thinking all happen below the level of consciousness, and we must make an effort to tap what is going on. The thinking that our brain does below consciousness, or before we are consciously aware of what it is doing, is the important part. All animals have the general capabilities of that most important part, and whether they are conscious or not doesn’t much matter.

The Mind of Your Horse

The brains of mammals are very similar, and differ in degree rather than kind.

The human desire to believe that we are the most intelligent species has led to a number of comparisons of brains. Brain size must matter, but our brains are smaller than those of the elephant or whale. Some researchers find pleasure in noting that some parts of our brain are much bigger than the same parts in other animals. For instance, our friend Cowboy Bob reports that “the brain cavity of a horse is filled with a lot more than what we usually think of as the “brain.” Although the space would, in fact, hold a small grapefruit, the cerebral hemisphere — or “thinking” portion of the brain cavity is a lot smaller.”

If horses could talk, though, they might point out that the brain cavity of their skulls is about the size of ours, and that lots of preprocessing happens between the nostrils and the brain, and between the eyes and the brain. If we compare head size of Mr. Horse and Mr. Man, Mr. Horse does just fine.

Early Learning and Imprinting

Early research focused on the following reaction of precocial birds, something that is now called “filial imprinting”. Filial imprinting is useful in fostering a mother-offspring bond, and makes perfect sense. Even if a bird could learn to follow a man in boots or follow a toy train, in nearly every case the big moving thing nearby is mom, and learning to follow her is a key to survival. We can be comfortable believing that such a feat did not originate with birds, but that young dinosaurs of many species might have also followed their moms.

Filial imprinting seems to have been found in every species of bird that has been studied. We are all familiar with pictures of ducklings following a human or a dog that they have imprinted on. Whether filial imprinting occurs in other species is an open question. While there is a huge amount of early learning in mammals, it is not clear that any of this learning should be called “imprinting.” While the general public is comfortable with the word “imprinting” when talking about young mammals such as foals, scientists don’t use the term. Scientists don’t use the term “imprinting” when discussing mammals because mammals don’t imprint the way birds do. I don’t think it is appropriate to talk about imprinting in horses, but I’ll need to account for the positive effects of early exposure, so keep reading.