Humans learn with practice. It’s one of the most amazing things about us. Learning occurs at a molecular level via LTP (glutamatergic) and at the neuronal/synaptic level, where practice or guided repetition strengthens the relevant pathways and, via LTD, weakens unused circuits--raising signal-to-noise. Our brains change dynamically based on what we use them for. The more regularly or intensely we do something, the more those specific pathways strengthen.

At first, thinking about SFM and focus, I assumed passive TikTok use “practiced” task-switching--getting better at jumping from topic to topic, like strengthening a rapid-reorientation muscle from so much scrolling. This doesn’t appear to be the case; the best studies find heavy social-media users actually worse at task-switching on classical tests. This really confused me at first. Aren’t our brains plastic? Don’t we get “fire together, wire together” learning (even if it’s not a prized skill)? My view now: there’s no learning even for task-switching because it’s too generic; there’s likely no single attentional intermediary we’re strengthening when we scroll. Instead, we get an almost infinite series of unique attentional shifts--one after another, never repeating--so they’re never reinforced and leave no LTP. We shift from a weight-lifting video to a keto lasagna taste test to a Tesla options-trading clip to an OnlyFans thirst trap within two minutes (TikTok recommends 21–34-second videos for optimal engagement).

Each of those context switches is wildly different. Our circuits try to process a new bench-press grip--past training, current routine, plans--then are jerked into processing a low-carb Italian meal, our last lasagna, the bad date at the Italian place, etc., all at once. Okay--those circuits get early-phase LTP signals; neurons fire together: this matters. We may even get AMPA upregulation and kinase activity in random neurons (connecting bench-press–to–lasagna regions). But two problems: First--this link is worthless. There’s no reason chest exercises and noodle-heavy entrees should be linked. Second--setting aside the uselessness of the link--given novelty/engagement algorithms, this connection will never be repeated (thankfully). So late-phase LTP never occurs: no gene transcription, no local protein synthesis, no cytoskeletal scaffold changes; no scaffolds rewire/reinforce the connection. The “efficiency” of this link just pinches off. Nothing gets neurally stronger via SFM: you’re constantly switching between unique context pairs. But things will get weaker. Idle dendritic spines retract. Low-frequency, modest calcium influx activates phosphatases that remove AMPA receptors, erasing unhelpful associations (bench press–lasagna) and quieting idle areas--like attention centers that fire when we remain on topic. Hours on SFM--or phones--constantly switching (chat → notification → IG → search) leave the focus center idle. If you don’t use it, you lose it--actively. It atrophies quickly as that cortical real estate gets repurposed. Even focusing on a TV show for 30 minutes is likely better than TikTok--you must track what’s happening and give attentional nuclei positive reinforcement.

So why call this the Zig-Zag Marathon? It’s the best metaphor I have for what SFM does to your brain. Let’s assume we run a marathon (42,195 meters) with an average stride length of 1.4 meters. Every 5 strides, instead of continuing straight, we turn in a random direction and run 5 more strides. Each change of direction is what we do to our minds when the next TikTok video scrolls up automatically. After running a marathon, how far are we from the start with random changes of direction? About 544 meters…after more than 42,000 meters run. And those 544 meters may not be toward the finish line. Each pivot pulls attention elsewhere; we burn mental energy and get nowhere. Random, abrupt changes don’t strengthen knees; they wear cartilage and risk ACL tears as fatigued legs keep moving despite getting nowhere. You aren’t repeating any movement; you’re not getting stronger--you’re getting weaker.