Last summer in a taped interview in the Vancouver provincial cabinet office, B.C. Finance Minister Colin Hansen nearly told me that he was examining the harmonized sales tax in March 2009.

This would have been more than a month before the May 12, 2009 provincial election.

Here is Hansen's exact quote: "When we started looking seriously at this at the end of March—sorry, at the end of May—I spent a fair amount of time on-line.”

If you don't believe me, it's on this audiotape:

Colin Hansen on the HST.

Yesterday (September 1), documents obtained by CBC through a freedom-of-information request indicated that Hansen had been briefed in March 2009 on the HST, which combines the five percent GST with the seven percent provincial sales tax.

The six-page briefing document was requested on March 2, 2009.

It was prepared on March 12, 2009 by Glen Armstrong, then the acting assistant deputy minister of the strategic and corporate policy division.

The document was addressed to Hansen and described such things as the fiscal impact and distributional impact of harmonizing provincial and federal sales taxes.

So how could Hansen continue to insist that the HST was not on his "radar screen" before the May 12, 2009 provincial election?

This is an intriguing question in light of his apparent Freudian slip to the Georgia Straight last summer, in which he said "we started looking seriously at this at the end of March" before correcting himself.

There are three possibilities.

Number 1: The first is that Hansen is lying. That's the view of many British Columbians. After all, the premier's advisory group, the B.C. Progress Board, publicly recommended the implementation of a harmonized sales tax in December 2008.

Number 2: The second possibility is that Hansen didn't consciously remember discussing the HST in March 2009, but it remained stored in his nonconscious memory. Hence, the Freudian slip. Three UBC researchers recently studied the phenomenon of nonconscious memory, which was the subject of a Straight cover story last month.

Number 3: There is another explanation: Hansen has a faulty memory.

I can hear the guffaws from the Fight HST people as they read this, but bear with me.

During the 2008 campaign for the Democratic presidential nomination, Hillary Clinton gave a speech, in which she recalled being under sniper fire in Tuzla, Bosnia in 1996.

"There was supposed to be some kind of a greeting ceremony at the airport, but instead we just ran with our heads down to get into the vehicles to get to our base," Clinton told an audience at George Washington University.

In fact, there was no such sniper fire. The media later proved it by showing video footage of Clinton strolling off the plane in Bosnia, where she was warmly greeted.

Psychology professors Christopher Chabris and Daniel Simons analyzed this case in their recent book, The Invisible Gorilla: And Other Ways Our Intuitions Deceive Us.

They wrote that a "plausible explanation" for Clinton's recollection of fictitious snipers was that her memory was "systematically distorted to become consistent with her internalized, personal narrative".

Chabris and Simons added that Clinton's distorted memory could have revived a popular impression that she would "say anything to get elected (an impression that was compounded by her initial refusal to acknowledge the error after the videos surfaced)."

"Unfortunately, people regularly use vividness and emotionality as an indicator of accuracy; they use these cues to assess how confident they are in a memory," the psychology professors stated.

Hansen might, in fact, believe he is telling the truth about the HST not being on the radar screen before the May 12, 2009 election because he has a distorted memory of what happened in March.

If you don't think this is plausible, I highly recommend you read The Invisible Gorilla.

So what do you think? Number 1, Number 2 or Number 3?

Follow Charlie Smith on Twitter at twitter.com/csmithstraight.