Launching dozens of vaccine development projects made perfect sense early in the Covid-19 pandemic, because it increased the chances that at least one would succeed. But what was prudent then is problematic now. Scientists, to their credit, have outdone themselves. So many vaccines may be soon be available that people will have a hard time deciding which one to get—and could end up choosing none.
The paralysis of choice is a well-known phenomenon in behavioral economics. In a famous study published in 2000, shoppers at an upscale supermarket in Menlo Park, Calif., were offered samples of jam. Some were given six choices and some were given 24. Standard economic theory says a greater number of choices is always better than a smaller selection. Indeed, customers who encountered the extensive array were more likely to stop and browse. But they were less likely to buy. Only 3% of them bought a jar of jam, vs. 30% of shoppers who encountered the limited collection.