Questions From Curious Minds

No. This myth has been around for over a century and starred in films like Lucy (2014), but brain imaging shows activity across virtually the whole brain over the course of a day. Damage to almost any region produces noticeable effects, and the brain uses around 20% of the body's energy, an expensive organ to leave 90% idle.

Not in the popular sense. Some functions are lateralised (language tends to rely more on the left hemisphere in most people), but a 2013 University of Utah study led by Jared Nielsen analysed over 1,000 brain scans and found no evidence that individuals are dominated by one side overall. Creative and logical thinking both recruit networks across both hemispheres.

In 2015 the Open Science Collaboration, coordinated by Brian Nosek, tried to repeat 100 published psychology studies. Only about 36% produced statistically significant results again. Since then psychologists have adopted pre-registration, larger samples and open data. On this site we flag findings that have struggled to replicate, such as ego depletion. See our habits shelf.

Not at all. Biases are side effects of efficient shortcuts and affect experts and highly intelligent people too. Daniel Kahneman, who helped discover many of them, often said he was no less prone to them himself. More on the biases shelf.

Researchers aren't fully certain, but a leading explanation is a familiarity signal firing without a matching memory. Anne Cleary's lab at Colorado State University has triggered déjà vu-like feelings using virtual scenes whose layout resembled ones participants had seen before but couldn't recall. It is common and usually harmless.

Rarely. A 2006 meta-analysis by Charles Bond and Bella DePaulo, covering more than 200 studies, found people correctly classify lies and truths about 54% of the time, barely better than a coin toss. Averted gaze and fidgeting are not reliable signs of lying.

Longer than 21 days for most of us. In Phillippa Lally's UCL study the median was 66 days, ranging from 18 to 254 depending on the person and behaviour. Missing one day didn't spoil progress.

Yes. They are simple puzzles, word lists and everyday observations. They are designed for curiosity, not diagnosis, so don't read anything personal into your "score".

No. Pandavikrhythmfx is educational. If you are struggling with your mental health, please speak to a qualified professional or your local health service. In an emergency, contact your local emergency number.