In a Harvard paper published in 2021, researchers were interested in whether the way we talk to ourselves — kindly or critically — changes how our brain works and how well we think and problem-solve.
In simple terms, they wanted to know: Does positive self-talk help the brain work better? And what about negative self-talk?
How the study was done
Participants were divided into two groups:
- One group practised positive self-talk (speaking to themselves with respect and encouragement)
- The other group practised negative self-talk (self-criticism).
Before and after this self-talk exercise, participants:
- Completed a reasoning task (a problem-solving test).
- Had their brains scanned using fMRI to see how different brain regions were communicating.
What they found (in everyday language)
1. Self-talk really does change the brain
Both positive and negative self-talk altered how different parts of the brain talked to each other — especially areas involved in motivation, focus, and control of thinking.
So this isn’t “just in your head” in a metaphorical sense — it’s visible in brain activity.
2. Negative self-talk slightly improved performance in the short term
People who used critical self-talk did a bit better on the reasoning test immediately afterwards.
The researchers think this may be because self-criticism temporarily:
- Reduced overconfidence
- Increased effort, vigilance, or urgency
In other words, being hard on yourself can sometimes make you try harder in the moment.
3. Positive self-talk affected the brain differently
Positive self-talk also changed brain connectivity, but in a way more related to:
- Motivation
- Self-regulation
- Confidence and emotional balance
It didn’t boost test scores as much in this short experiment, but it still produced meaningful brain changes.
A really important caution
This study only looked at short-term effects in a lab setting.
It does not suggest that negative self-talk is healthy or beneficial in the long run.
Decades of psychological research show that chronic self-criticism is linked to:
- Anxiety
- Depression
- Lower resilience
The study simply shows that different types of self-talk have different immediate effects on the brain.
The take-home message
- The way you talk to yourself matters neurologically.
- Self-talk alters brain networks involved in thinking and motivation.
- Negative self-talk may boost short-term effort, but it’s not a strategy for long-term wellbeing.
- Positive self-talk appears more aligned with emotional regulation and sustainable mental health.
This study supports the idea that self-talk is a real psychological tool, not just a feel-good concept.