• An editing error had Rachel Nowak implying that birth rates in the US have fallen below the rate needed to maintain the population (7 April, p 13). In fact, the US is one of a handful of western countries to have bucked the trend of declining birth rates – for reasons that include high birth rates in some segments of the population offsetting low birth rates in others.
• We said that Stanley Milgram’s electric shock experiment was published in 1974 (14 April, p 42). That was his book Obedience to Authority; the experiment was published in 1963 in the Journal of Abnormal and Social Psychology, vol 67, p 371.
