No. Researchers use tricks to get people to answer honestly. For example: they ask people to toss a coin before answering. If the coin comes up 'heads' the person must answer 'yes' even if their real answer would be 'no'. If the coin comes up 'tails' they must answer truthfully.
The introductory text explains that there is no way to know if the person is answering truthfully or following the coin 'heads' rule.
When you get the results you adjust for probability of the coin toss.
