No human being can build a sense of self if they do not have a "mirror" to reflect back their thoughts, behaviors and emotions in a meaningful manner.
That is particularly true in the case of children. Whatever they do, feel or say -the very fact that they exist!- needs to be genuinely acknowledged by their parents, educators and caregivers.
And yes, the key word here is genuinely. For acknowledging does not mean praising their every little move ad nausea, nor criticizing and correcting them continuously. Acknowledging means being fully, genuinely present with your child, and celebrating together with him/her the happiness of being. The miracle that, despite so many billions of variables, he or she appeared in the world. More precisely, in your world.
Of course, it is difficult to genuinely celebrate being if we learn to view life as some sort of inert mush that needs to be populated with "exciting" stuff. Being, without the obsessive need of doing, is generally considered "unproductive", "boring". However, there is a reason we are called Human Beings and not Human Doings.
Children are happy just to exist. They do not need to be continuously entertained, in fact it is precisely "boredom" what stimulates their imagination and creativity. By buying them stashes of toys, by scheduling every minute of their lives for "activities", by letting them stare for hours at various screens, we drag them further and further away from their own selves. We prevent them from creating, exploring and learning about who they are. We -in fact- deprive them from the most appropriate, most affordable and most reliable resources that they could have: the resources within themselves. We teach them to only look outwards, and define their identity in terms of what others believe and say about them.
When Identity and Sense of Self are defined mostly by external achievements, insecurity, fear, anxiety, and the possibility of being manipulated by others increase exponentially.
Initially (that is, before getting hooked on the endless Pleasure-Reward cycle built in certain technologies) when given the chance a child will always choose the validating, genuine presence and interaction with a carrying adult over staring at their new iPhone.
In fact, smartphones, tablets, computer and TV screens are nothing but pseudo-mirrors, which return (to children and adults alike) not an understanding of our own selves, but the subtle truth that we are stubbornly, unsuccessfully searching for belonging and mirroring in the wrong place. For it's only the intentional, authentic and empathetic human presence what creates a true mirror, allowing other humans to successfully build and sustain a healthy and meaningful identity (and not a merely functional, utilitarian identity, which often leads to confusion, cognitive and emotional dissonance, alienation and illness).
Many of us do not realize until late in life (if we ever do) that we have never truly been seen, and therefore no one in our family, culture or community reflected back to us glimpses of who we are, or who we want to be, or who we think we ought to be. It is that moment when we feel that our whole life has been nothing but a search for that initial, original (archetypal) reflection and acknowledgement. For that gaze in which we instinctively longed to reflect ourselves, so we can receive the absolutely necessary reassurance that we exist, that we are important, that we matter.
Narcissus (not unlike Instagram 'influencers') was somehow lucky: he could afford to just sit by the lake and admire his image in the water all day long. And let’s be honest, we all have inside us a little Narcissus who's chasing “likes” and ego-approval in the mirror of our 'social networks' accounts.
There are other lifetime, systemic implications of lack of mirroring, most of them represented by either withdrawal, either an obsession with being “first” or “best”, and an investment in titles and objects that are said to guarantee our visibility in an insanely fast paced society.
In their search for meaningful mirroring, humans exhibit a series of behaviors that often lead to unnecessary (even highly damaging) diagnostics and chemicals intake. Anxiety, attention deficit, fidgeting, irritability, anger and aggression, are often signals that they are struggling to make sense of who they are and what their place is in a world that reflects nothing -absolutely nothing!- back to them.