Web users voluntarily compromise their privacy by typing more personal information into online forms than is strictly needed, a study has found.
Researchers at the University of Cambridge and University College London invited a group of 1,500 US participants to enter information into an online form.
Although care was taken to ensure the subjects knew they did not have to provide most of the information, 82% of the participants included details about their health and 57% offered their full date of birth.
The researchers also found users provided more information than the questions asked for. For example, when participants were asked when they last spent more than $100, 14% added details about what they had spent the money on.
The study is thought to be the first experimental investigation into how web users behave when they are asked to provide personal information on an online form.
Findings of the study are to be presented on 25th June, at the Workshop on the Economics of Information Security (WEIS) in Berlin.
Study co-author Sören Preibusch, of the University of Cambridge Computer Lab, said that, although the received wisdom is that filling these forms in is a nuisance and that users complete as little of them as possible to protect themselves and save time, the study suggests that in fact people consistently and consciously disclose personal information, even when they know that doing so is optional.
"This raises the possibility that parts of an online form which are technically optional may actually be as invasive to people's privacy as those sections which are mandatory," Preibusch said.
Web forms are the primary mechanism by which companies and governments collect personal data about individuals on the internet today. Relatively little is known, however, about the attitudes towards privacy of the average user completing them, which was the reason for carrying out the study.
In a follow-up questionnaire, participants were asked to explain what personal information they had disclosed and why.
Many said force of habit was the reason for entering additional data about themselves. Researcher Kat Krol said some could not even remember entering the data.
"This shows that people often fill out online forms without thinking," Krol said.
Other participants said that they did not really know why they had filled in the extra questions, again suggesting that force of habit or a basic compulsion to complete all the questions on the form was their primary motivation.
