I was all smiles throughout this episode. Well, right up until the last 10 minutes when my facial expression more closely resembled the Doctor’s quizzical emoji, but no matter. I’m loving the student-teacher dynamic between Bill and the Doctor, and both actors are doing a fantastic job.
There’s a lot of talk about happiness in this episode, which as I learned last time can be associated with kindness. The Doctor and Bill find themselves on a planet inhabited by emojibots, which track emotions via badges, and the Vardy, which are tiny robots building a utopian colony for the last of humanity. We eventually learn that when the first human died of natural causes, the emojibots interpreted the resulting grief as “too unhappy to live” and responded accordingly, killing everyone. To survive on this planet, the Doctor and Bill must wear a constant smile in order to feign happiness.

DOCTOR: Smiles aren’t just smiles. Psychologically, they have a measurable effect on your mood states. (gif source)
A Smile is Kindness
Can smiling make us happy? From what I’ve learned, it may help. I found an intriguing response to this question in an essay on the Buddhist Eightfold Path. In Buddhism, the first noble truth is that all life is filled with suffering. The Path teaches us how views, thoughts, speech, action, livelihood, effort, mindfulness, and concentration can liberate us from suffering. One key aspect of our liberation is the ability to feel compassion. Nonverbal communication plays a role, as the author explains:
“A smile goes a long way; just contracting the facial muscles needed to smile helps change the biochemistry to make us feel better, feel like smiling. A smile is kindness, as it sends the message of approval to the other person and echoes inward.”
In the psychology world, the facial feedback hypothesis states that facial expression can influence emotion, by initiating or moderating the emotional experience. This hypothesis originated in the late 70’s and has been thoroughly tested since. In one such study, participants held a pencil in their mouth (apparently this reduces muscle effort?) and were instructed to do one of four degrees of a smile while watching funny videos. This study found that a true smile (you know, the full toothy grin) increased positive feelings in response to cartoons. It suggests that facial expression can have a stronger effect when it matches the emotional experience.

This works for frowning, too! Another study attached golf tees to participants’ eyebrows and asked them to furrow their brows until the two tees touched. When holding this expression, participants rated unpleasant pictures more negatively. So, frowning appears to increase negativity and may influence decision making. This study immediately reminded me of the somewhat grumpier Twelve we met in Season 8 and his attack eyebrows. We didn’t see a lot of smiles from him initially, but there was a lot of eyebrow furrowing. It’s certainly a stretch, but maybe those furrowed brows had an influence on his decision making?