A smile can speak a thousand words but those words may remain in the wilderness if the recipient doesn't speak human. Of course animals have many ways in which to interpret our emotions and intentions. They can listen to our voices, smell our bodily chemicals, touch us with their paws, hands and claws, taste us with their overworked tongues and they can see us with observant eyes.

They can see us.

This final sense is quite curious when we are thinking about animals watching us. What is it they are actually seeing? We know they understand many forms of visible body language but what about our faces? Is there any evidence they understand anything from our facial expressions and if there is, what would they be basing their understanding on? Is there anything we could do to aid their understanding of our facial expressions? Racing ahead, what would any inter-species facial communication between humans and animals mean for possible future meetings with extra-terrestrials?

Let's begin by looking at some of the evidence available. In 2004, the Journal of Comparative Psychology published the results of a study that showed dolphins instinctively comprehend human gazing to the extent that they understand the difference between what the study called static gazing and dynamic gazing. Static gazing being an idle stare with no action required and dynamic gazing meaning a gaze that prompted the dolphins to interact with an object. No verbal commands or prior training were needed for the dolphins to comprehend the difference.

If you think that's impressive, check out the work of Professor John Marzluff at the University of Washington in Seattle. In 2008, Professor Marzluff led a group of researchers for a walk in the park. He separated the group in to two teams with one team wearing a particular type of mask and the other team wearing another type. The park has a population of crows and one team were charged with trapping the crows while the second team were just asked to walk on by. In 2013, Marzluff led two teams with the same masks in to the same park. The team wearing the masks that were worn during the trapping of 2008 were ambushed by shrieking, hysterical crows, many of whom were not even present at the original trapping five years earlier.

Marzluff also worked with Dr. Barbara Clucas of Humboldt State University on a study that proved that American crows react differently to approaching people according to whether or not the person is gazing at them or away from them. If an approaching person is looking at them, they take off a lot faster. Interestingly, whether the person is smiling or scowling seemed irrelevant.

Dr. Clucas also has experience studying squirrels in unrelated studies. Aside from gazing, I asked Dr. Clucas if there was any evidence that some crows or squirrels interpret human facial expressions in a particular way.

"Apart from that study with crows, I have not done other studies on the topic. Anecdotally, I have noticed similar behaviour in other bird species (ravens, jays, etc). Although I haven't tested it in squirrels, I would suspect that because their vision is not as good as that of birds, they probably wouldn't be able to detect if a human eyes were looking at them versus looking the other way. They might react to a human whose face is facing them versus being turned away. Indeed there are many studies showing that mammals and reptiles react differently when a human face is facing them."

There was a study published earlier this year which showed some dogs understood the differences between human faces showing anger and those showing happiness. I wondered, regardless of what animals would understand from our facial expressions, what might their interpretations be based upon? Dr. Kun Guo of the University of Lincoln in the UK, has done a lot of research on interactions between animals and humans so I thought he would be a good man to ask.

"Very good question. 'Don't know' will be our current answer. If I have to guess, I will say 'based on the interaction between innate bias and prior learning from humans through experience / development'. You need to test wolf (evolutionary approach) and puppy (developmental approach) to answer this."

We have established that crows can recognize and remember human faces and they can also comprehend targeted and untargeted gazing. The evidence that they can decipher human facial expressions is limited but there are hints that this might be the case. I asked Dr. Clucas what might they be basing their interpretations of human facial expressions on?

"Well, I didn't find that the American crows responded differently to a smiling versus scowling face, however, laboratory studies have shown that a related species, jungle crows can discriminate male and female faces as well as a smiling face from a blank face. So I believe American crows likely are capable of learning to distinguish facial expressions. They are likely capable of such things because they are very social and use visual signals in their own conspecific communication (within species communication)."

While conducting the research for this article, I learned that the mere idea that our facial expressions represent emotions at all is not a universally accepted fact. Dr Eliza Bliss-Moreau of the University of California has done a lot of work with rhesus monkeys and people interacting together. I asked her some questions on her work but she had a question for me: "Are you familiar with the large human literature which calls into question the fact that faces represent emotions at all? Your questions are all predicated on the idea that emotions correspond to faces in a one-to-one way, and therefore emotions can be "read". But that's not the case."

Clearly, there are a lot of barriers between inter-species communication and this includes facial expressions. So is there anything we can do to help animals understand our faces better? Many domestic cats have an image of being cold in nature due to them consistently presenting straight faces but it has actually be proven that this usually means they are in a relaxed state. I asked Dr. Guo if mimicking their facial expressions be useful to relay our intentions?

"Very interesting thoughts. It could work if we can understand animal's emotion first and the relations between animal's emotion and their facial expression. Some animals, like cats, have limited ranges of facial muscle movements, which make their facial expressions less informative about their emotion / feeling / mood."

I think this is a subject worthy of further exploration, especially in an age when we are now putting some serious money into searching for extra-terrestrial life in the universe. What if some intelligent life in the universe does not use verbal language? Carl Sagan once made the valid point that dolphins have learned to understand many words in English but no human has ever learned one word of Dolphinese. Until we do that, it could be useful to study animal understanding of our facial expressions more, even if only to eliminate possibilities of facial communication between species.

And don't mess with the crows man.

Image: Wikipedia

In Of Mice and Men by John Steinbeck, one of the central characters is Lennie, a man with some form of mental development disability who enjoys petting mice and puppies. Only he enjoys it so much he can't stop and often ends up squashing them literally to death.

The thing is, evidence suggests that the mice and puppies were probably enjoying the petting before Lennie's fat fingers squashed them. In 2013 researchers from the California Institute of Technology published the results of a study done on mice that showed there is a specific type of sensory cell in skin that responds to careful stroking. The lead researcher on the study suggested we could one day have a skin lotion that makes us feel better.

It's all very well that mice enjoy being stroked, but why did Lennie — and why do many other people — derive pleasure from stroking soft animals? Numerous research studies suggest that during stroking, receptors in the skin send signals to various parts of the brain. This can be measured using MRI scans of the brain during stroking that show increased neuronal activity associated with increased blood flow. The affected areas of the brain light up even when the person involved is unconscious.

I think Lennie should have been given a stress ball or something to occupy him, although I've no idea if it would have been a sufficient alternative to petting mice. Sometimes such toys are not always what they seem:

As we know, there are plenty of materials that are lovely to touch. Silk, velvet, and polar fleece to name but a few. What factors affect whether or not our skin receptors will respond positively to such materials? I contacted Marilyn DeLong, a professor of apparel studies at the University of Minnesota. I wondered if personality might play a small part in how people respond to touching certain materials.

"Of course personality plays a part in how people respond to touching materials" she said. "When you have interest in touching, your prior experience in touching similar or different materials, your response to touching various materials — are all involved."

I was racking my brain, probably firing off all kinds of neuronal chaos, trying to think of other factors that might affect our reactions to touching materials. I was thinking about how people touch materials – for example, gently and slowly stroking materials as opposed to rubbing them quickly. I asked DeLong if this would have much effect on how people feel about a material?

"How people touch materials is critical. There are more ways to touch than fast and slow, however. In addition to stroking, a designer would likely pick up a material and squeeze gently to learn about its resiliency, lift it up and move it to determine drape, examine it visually for its perceptible tactile qualities, for example. Experience plays a large role in touch – experience is a good teacher and can result in shortcuts in the process of touching. One learns quickly that a material that feels soft upon first encounter could become scratchy and result in discomfort over time."

When one thinks about the materials that feel nice to the touch, plastic would probably not make many people's lists. However there is one plastic product that engages many of us in very pleasurable touching: that lovely stuff known as bubblewrap.

Why do so many people feel a sense of satisfaction when popping bubblewrap? Yes, it feels squidgy and makes a small bursting noise of air when the bubble is popped, but what is happening within us when we engage in such eccentric behavior? I got in, er, touch with Dr. Tiffany Field of the Touch Research Institute in Miami to briefly touch on the subject. I asked Dr. Field if she had any idea why people derived pleasure or contentment from popping bubblewrap or stroking animals.

"Both those activities involve stimulation of pressure receptors under the skin which leads to a relaxation state, e.g. slower heart rate and decreased stress hormones and the feedback from these activities is also pleasurable – the popping sound of the bubblewrap and the pleasurable sounds from the animal."

In 1992, psychology Professor Kathleen M. Dillon published a paper on her study about why people enjoy popping bubblewrap. She hypothesized that it may have something to do with your fingers releasing muscle tension when engaging in bubblewrap popping. She also noted in her paper that the ancient Greeks used to carry "worrybeads" (small smooth-surfaced stones or pieces of amber or jade) around with them to enjoy the calming effects of stroking them.

I also asked Dr. Field for her opinion on why evolution has resulted in many of us deriving pleasure from popping bubblewrap, stroking soft furry animals, velvet. etc? I haven't covered human-to-human touch here because I feel the benefits are more obvious but Dr. Field alluded to it in her answer: "In our "no touch" culture we find touch experiences as substitutes for human-to-human touch."

The central theme of Of Mice and Men is loneliness, so in light of what Dr. Field says, we can probably conclude that this at least partially explains why Lennie enjoyed petting mice so much. However, if his traveling partner George had bothered to take the time to invent bubblewrap, he might have saved Lennie and his animals a whole world of trouble. It turns out that there is evidence to suggest that cute animals make some people feel aggressive. At least that's according to two psychology graduates of Yale University in this paper. They found that if you show pictures of cute animals to people while they are popping bubblewrap, the subjects end up popping significantly more bubbles. I found out about this study via this site, which also features a photo of a teacup dog which is so cute, you might want to bite your screen.

Don't open it, I'm warning you.

Image: Shutterstock