From the bad science department...
This doesn't show that intelligence (as measured by IQ) has declined. It shows that reaction times have slowed. If reaction times are an accurate measure of intelligence, then intelligence has declined -- but we know that, contrary to the core trope of Idiocracy, intelligence (IQ) has actually increased (the "Flynn Effect"). The proper conclusion is that reaction times do not correlate well with intelligence (IQ). Anyone watching a dumb kid do well on an twitch video game ought to recognize that.
Whether the quality measured by IQ tests, or the quality measured by reaction time tests, is better labelled "intelligence" is left as an exercise for the reader. It may well be that like "consciousness", "intelligence" is simply an ill-defined term.
REVEALED: Disturbing Trend In Human Intelligence (The Huffington Post)
Our technology may be getting smarter, but a provocative new study suggests human intelligence is on the decline. In fact, it indicates that Westerners have lost 14 I.Q. points on average since the Victorian Era.
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As for Dr. te Nijenhuis and colleagues, they analyzed the results of 14 intelligence studies conducted between 1884 to 2004, including one by Sir Francis Galton, an English anthropologist and a cousin of Charles Darwin. Each study gauged participants' so-called visual reaction times -- how long it took them to press a button in response to seeing a stimulus. Reaction time reflects a person's mental processing speed, and so is considered an indication of general intelligence.
In the late 19th Century, visual reaction times averaged around 194 milliseconds, the analysis showed. In 2004 that time had grown to 275 milliseconds. Even though the machine gauging reaction time in the late 19th Century was less sophisticated than that used in recent years, Dr. te Nijenhuis told The Huffington Post that the old data is directly comparable to modern data.