Hi Clandestino,
Thanks for the link to Aviation Investigation Report A08Q0051.
The report mentions:
"2.6.4 Spatial Disorientation and Interpretation of Indications of an Airspeed Indicator Error
From the start of the descent until the reduction in power, the somatogravic illusion due to the aircraft’s acceleration could have suggested that the aircraft had a nose-up attitude when in fact it had a nose-down attitude. The false impression of a nose-up attitude combined with the increase in aircraft speed may have prompted the captain into diagnosing an airspeed indication error."
Yet you say
I do know that notion that night makes maintaining attitude in passenger jet more difficult through lack of outside horizon to be utter tosh. You can combine it with the best psychological expertize and still you won't get anything true out of it.
Suppose AF447 crew experienced a similar somatogravic illusion, and the deceleration of the aircraft caused PF to "feel" a nose down sensation. It may help explain why PF was reluctant to believe his PFD.