The judges talked to Alice in text
The program triumphed in the annual competition to find the computer with the best conversational skills - held this year at the Science Museum in London, UK.
The organisers of the Loebner Prize hand medals and cash prizes to the inventors of computer programs that can maintain the most life-like dialogue.
One judge in the contest thought that the Alice chat software was more lifelike than one of the humans taking part.
The prize was established in 1990 by American philanthropist Hugh Loebner, who donated money to the US Cambridge Center for Behavioral Studies, which now administers the competition.
This year Hugh Loebner, himself, was one of the judges who scored the competing computer programs on a scale of 1 to 25.
The job of the judges was to chat via text to both the programs and human confederates and work out who was man and who was machine. This year, there were only two confederates instead of the usual four.
Alice convincingly beat the other programs entered and won by a greater margin than in 2000.
Unawarded prizes
One judge even ranked the Alice program as the second-most human talker in the event - more lifelike than one of the confederates.
Despite its success, Alice still only won the bronze medal and a cash prize of $2,000 (£1,400) for most convincing entry.
The gold medal, and a cash prize of $100,000 (£69,000), is reserved for the program which convinces half the judges it is human by spoken responses.
The silver medal, plus a cash prize of $25,000 (£17,000), goes to the text-based program which convinces half the judges. No gold or silver medals have ever been awarded.
Alice creator Richard Wallace started work on the software in 1995. Since its success last year, he has been refining the conversational skills of the software through the Alice Foundation.
Visitors to the Alice webpage can get a chance to converse with the software.
Some webpages are adopting chatbot software to make their sites more interactive and friendly.