TURING'S COUCH:

During their time with Ellie, all participants had their faces scanned for signs of sadness, and were given a score ranging from zero (indicating none) to one (indicating a great degree of sadness). Also, three real, human psychologists, who were ignorant of the purpose of the study, analysed transcripts of the sessions, to rate how willingly the participants disclosed personal information.

These observers were asked to look at responses to sensitive and intimate questions, such as, "How close are you to your family?" and, "Tell me about the last time you felt really happy." They rated the responses to these on a seven-point scale ranging from -3 (indicating a complete unwillingness to disclose information) to +3 (indicating a complete willingness). All participants were also asked to fill out questionnaires intended to probe how they felt about the interview.

Dr Gratch and his colleagues report in Computers in Human Behaviour that, though everyone interacted with the same avatar, their experiences differed markedly based on what they believed they were dealing with. Those who thought Ellie was under the control of a human operator reported greater fear of disclosing personal information, and said they managed more carefully what they expressed during the session, than did those who believed they were simply interacting with a computer.

Crucially, the psychologists observing the subjects found that those who thought they were dealing with a human were indeed less forthcoming, averaging 0.56 compared with the other group's average score of 1.11. The first group also betrayed fewer signs of sadness, averaging 0.08 compared with the other group's 0.12 sadness score.

This quality of encouraging openness and honesty, Dr Gratch believes, will be of particular value in assessing the psychological problems of soldiers--a view shared by America's Defence Advanced Research Projects Agency, which is helping to pay for the project.

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