Which of the following is NOT true according to this passage?
In the 1970s and 1980s a scientist did some research into the two main types of twins.
In the week of tests, he tested their speed of thinking, their speech, their memory and some other things.
There were twins who had been separated from each other as soon as they were born.
Very often, separated twins were found to choose things of the same kind, the same shape and the same color.