A species commonly found around humans is one group that illustrates this idea. Although often unnoticed, we are able to understand dogs to a much greater extent compared to other animals; domesticity probably has an impact on this.
A human is able to interpret a dog’s emotional state based on its tail, even if they do not own one. Dr. Stanley Coren (2011) describes tail wags “like any other language” as he focuses on the “tail’s pattern of movement and its position”. The tail’s position is the first factor to pay attention to, “specifically the height at which it is held, [it] can be considered a sort of emotional meter” (Coren 2011). Here are three different examples of possible tail positions dogs exhibit:
Speed of Tail Wag
The position of a simple muscle alone can play such a large role in human-animal interaction. Along with tail position, the speed of the tail wag can also help reveal a dog’s emotional state. A common idea is quicker wags indicate a dog’s level of excitement, while slow wags are a sign of sadness or insecurity.
Positive or Negative Emotions
Furthermore, one can hypothesize that positive and negative emotions corresponds to the side of the body the tail wags (Coren 2011). “When a dog feels generally positive about something or someone, their tails wag more to the right side of their rear ends” (Coren 2011). For example, if an owner or another familiar person approaches the dog, it’s wag is expected to be more biased to the right side. If a complete stranger approaches the dog, on the other hand, it’s wag is expected to be more biased to the left side.
To demonstrate this biased tail wag here is a video of a dog welcoming home it’s owner.
Similar to a dog’s tail position, human posture can help show a person’s emotions. Generally, the most common feature one notices about posture is shoulder position: pushed back shoulders indicates pride and self-confidence, while slouched shoulders communicates sadness and low self-esteem.
Another common expression involves hands and feet: fidgety hands reflect anxiety or boredom, while stiff hands indicate anger (Whitbourne 2012). Foot movements act in a similar way as hands, as feet tapping usually shows someone is nervous or in a rush. While some responses are harder to control than others, the range in abilities our body has to express emotions is a unique characteristic to humans.