Your caption for a photograph of immigrants at Ellis Island (A. Saini Nature 571, 474–475; 2019) perpetuates the myth that immigrants routinely underwent IQ tests as part of the process for entering the United States in the 1920s. The Immigration Act of 1924 did not mandate intelligence testing of immigrants.

The myth came about in part because of ill-founded claims by psychologist and eugenicist Henry Goddard, who conducted research on the island in 1913. Goddard subsequently gained notoriety for having manipulated photographs to highlight the supposed deleterious effects of illegitimate parentage.

The photograph depicts immigrant screening for suspected cases of severe cognitive impairment, as devised by assistant surgeon Howard Knox. Candidates were tasked with solving puzzles such as jigsaws with a few rectangular pieces. The aim was to refer to medical staff any applicants who might need institutional care and so be a burden on public funds. Contrary to your implication, the inspection station was entirely unsuited to formal intelligence testing.