OK, I admit this picture is a bit dark, but don't give up texting quite yet, the relationship between movement and posture isn't quite that causal (2). That said, the comic does reminds us that our postures (and behaviours) are not just a single event, but the end product of movement and choices expressed over a lifetime.
Each time you text, each step you take, how you move at work or at the gym; over time, you are shaped in the ways in which you consistently perform these acts. It’s an incredible and continuous act of learning that occurs between you and your environment, with and without your awareness and attention (3).
The opportunity lies here: With each and every movement you're offered a fresh chance to observe, learn, and develop how you interact in the world. This can include expressing new movement, positions, and behaviours that taken over time, can positively influence how you perform and experience the things you do; including how you use and shape your 'body'.
The opportunity is for the taking.
Resources/ People/ Ideas related to the Alexander Technique in this post
2. Krakauer, J. W., & Mazzoni, P. (2011). Human sensorimotor learning: adaptation, skill, and beyond. Current opinion in neurobiology. 21(4), 636-644.