priceonomics:

The speakers at TED conferences give the type of presentations that public speaking coaches use as examples of effective presentation skills. They open with arresting images or stories that engage the audience, speak clearly and passionately, and illustrate each of their points with concise evidence or examples.

TED Talks are also slick productions. The lighting is as well done as a rock concert’s, cameras film from a variety of angles to keep viewers visually engaged, and the length is never so long as to drain an audience’s attention span.

At the end of a TED talk, this author often feels inspired and enlightened, patting himself on the back for spending 10 minutes improving his mind instead of watching sitcom reruns. But according to a study performed by a group of psychologists, the degree to which a TED audience feels newly educated may be partly illusory – the result of showmanship as much as actual learning.

In their study “Appearances Can Be Deceiving,” a team of psychologists had students watch recorded lectures explaining why Calico cats are almost always female. (It’s essentially a genetics lesson, as the answer has to do with how the calico fur pattern is linked to X chromosomes.) One group saw a lecturer who presented with the skills of a TED speaker. The other watched the lecturer read haltingly from notes.