Daniel Lemire's blog

, 3 min read

Science and Technology links (March 2nd, 2018)

  1. Flashing lights might cure Alzheimer’s, according to Nature.
  2. There is no paradox: being obese is definitively bad for you.
  3. Class attendance predicts success in college.
  4. Barbara Streisan had her dog cloned, more than once.
  5. Contrary to what we have been told: stopping or reducing dietary fiber intake reduces constipation.
  6. Fasting can help prevent and treat cancer. Sadly, my wife would not let me fast if I wanted to (I’m quite thin as it is).
  7. If you cannot fast, maybe you can take aspirin: Aspirin mimics some of the effects of caloric restriction.
  8. Mitochondria, the power plants of your cells, run at a temperature of 50°C.
  9. Apparently, nobody knows how airplanes fly. (Credit: Leonid Boytsov)
  10. Another well-established psychology result bites the dust:

Dijksterhuis and van Knippenberg (1998) reported that participants primed with a category associated with intelligence (professor) subsequently performed 13% better on a trivia test than participants primed with a category associated with a lack of intelligence (soccer hooligans). (…) The procedure used in those replications served as the basis for this multilab Registered Replication Report. A total of 40 laboratories collected data for this project, and 23 of these laboratories met all inclusion criteria. Here we report the meta-analytic results for those 23 direct replications (total N = 4,493), which tested whether performance on a 30-item general-knowledge trivia task differed between these two priming conditions (results of supplementary analyses of the data from all 40 labs, N = 6,454, are also reported). We observed no overall difference in trivia performance between participants primed with the professor category and those primed with the hooligan category (0.14%) and no moderation by gender.

Psychology as a field is in big trouble.

  1. An old reference that should serve as a good reminder not to trust what you read:

Functional MRI (fMRI) is 25 years old, yet surprisingly its most common statistical methods have not been validated using real data. Here, we used resting-state fMRI data from 499 healthy controls to conduct 3 million task group analyses. Using this null data with different experimental designs, we estimate the incidence of significant results. In theory, we should find 5% false positives (for a significance threshold of 5%), but instead we found that the most common software packages for fMRI analysis (SPM, FSL, AFNI) can result in false-positive rates of up to 70%. (…) Our results suggest that the principal cause of the invalid cluster inferences is spatial autocorrelation functions that do not follow the assumed Gaussian shape.

I like this example because it is very common for statisticians to build into their model the assumption that the data must follow some prescribed distribution. Real-life is complicated and rarely behaves like our models.

  1. We are setting up a mobile phone network on the Moon.
  2. The state of California will authorize fully automated cars on its roads.
  3. The cells in your heart do not regenerate. Scientists have found that by turning four genes “on”, they can get the cells to divide and maybe regenerate your heart.
  4. PhD students face significant mental health problems.