timeless PinkLetters, translated from our Spanish Substack for English-speaking readers.
December Makes Us Think Worse
December concentrates an absurd cognitive pressure: to evaluate, decide, and commit precisely when we are most tired and most biased. This is not deep introspection—it’s bad mental engineering.
December operates as an illusion of order. The calendar ends and, with it, we feel that everything should suddenly become evaluable: projects, decisions, relationships, habits, even internal states. As if the mere fact that the year is ending could retroactively give meaning to processes that are still open, immature, or simply poorly framed.
The problem is structural. Every process has its own temporal logic. Some need years to show clear signals. Others had already provided enough evidence long before December and should have been reviewed without waiting for any ritual of closure. The end of the year does not magically synchronize processes that began at different times, with different levels of complexity and deeply misaligned rhythms.
Forcing a simultaneous evaluation is not efficiency—it’s noise. It is taking asynchronous systems and demanding a synchronized report, even when the data is not ready. The result is not clarity, but premature conclusions that feel solid only because they arrive wrapped in a “year-end review” narrative.
Concentrated Introspection Is a Bad Idea
December also sells us a dangerous fiction: that deep reflection can be compressed into a few days. As if eleven months of decisions, contradictions, partial learnings, and context shifts could be distilled into a notebook, a walk, and a couple of well-phrased questions.
Real life does not work that way. We live second by second, conversation by conversation, adjustment by adjustment. Genuine understanding tends to emerge in a distributed way, at unexpected moments, once the system has processed enough information. Expecting everything to fall into place on demand—precisely when we are exhausted—is confusing introspection with paperwork.
Forced introspection tends to produce stories, not understanding. Clean narratives that soothe us, but often oversimplify processes that were ambiguous, erratic, or outright contradictory. Not because we lie, but because the brain hates disorder—and December offers the perfect excuse to close it.
We Think Worse Because We’re Full of Biases
It’s not just fatigue. It’s cognition under adverse conditions.
In December, we evaluate through a particularly toxic mix of biases. The recency effect makes us overweight what just happened, ignoring months of more relevant signals. Hindsight bias rewrites the past as if it had always been obvious, erasing the real uncertainty under which many decisions were made. Rosy retrospection softens experiences that, at the time, were confusing or painful. And the narrative fallacy does the rest, connecting dots that were never that well aligned.
On top of that comes the planning fallacy, just as we start projecting the year ahead. We underestimate time, overestimate energy, and commit to idealized versions of ourselves that rarely survive the first quarter. Believing that from this mental state we will extract fine-grained insights or design realistic commitments is, at best, optimistic.
December does not make us more reflective. It finds us tired, biased, and rushed to close stories we still don’t understand.
The Social Context Works Against Us
As if cognitive biases and fatigue were not enough, December adds another layer of interference: the social context. Accumulated gatherings, long dinners, family rituals repeated more out of inertia than desire, and implicit expectations to “have a good time” even when the conditions—or the willingness—are not there.
The atmosphere is one of mandatory celebration. We are expected to be grateful, upbeat, available. To show balance, show closure, show enthusiasm. All of this happens while the body is overstimulated: more alcohol than usual, excess food, less rest, broken routines. The damage is not always immediate or visible, but it is real—it alters emotional and cognitive states precisely when we are trying to think clearly.
It is no coincidence that this period concentrates friction. Many family conflicts do not start in December, but they become unavoidable there. Nor is it accidental that anxiety episodes, relationship crises, mental-health relapses, and even suicides increase during the so-called “holiday season.” The social narrative says celebration; the internal experience often says overload, comparison, and amplified loneliness.
Expecting that, in this context, we will arrive at fine evaluations of our lives or well-calibrated commitments for the year ahead ignores something basic: we think worse when we are socially and physiologically dysregulated.
Fewer Decisions, Better Evaluations
Perhaps the way out is not to think more in December, but to decide less. To resist the temptation to close, promise, or redefine everything precisely when we are more tired, more exposed to bias, and more constrained by the environment. Not every discomfort demands an immediate conclusion; many simply demand time.
Each area of life deserves to be evaluated when the process allows it. Work when there is enough data. Relationships when the noise subsides. The body when the rhythm stabilizes. Personal direction when we are not pushed by a symbolic date, but supported by some internal continuity. Evaluating well is, in large part, evaluating outside of December.
December can serve another role. Not that of the grand annual evaluation, but of enabling a different space: less reactive, less performative, less demanding. A month to set in motion a more logical, constant, lower-stress reflective practice—one that can then be sustained throughout the year.
Perhaps the best results do not come from deciding more forcefully in December, but from building a reflection system that does not depend on December to exist.
Thinking Better Starts With Choosing When to Think
Arriving in January without a closed narrative, without a perfect plan, and without total clarity is not a failure. In many cases, it may be the most honest signal that we are respecting the complexity of what we are living through.
Thinking better does not always mean thinking more—it means thinking at the right moment. And perhaps the first act of lucidity in the face of December is this: lowering the importance of the ritual, stopping the forced conclusions, and starting to design reflection cycles that serve real life, not an arbitrary date on the calendar.
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