(This blog drafted back in November 2012, but held back to avoid spoilers)
I won't post this blog until after the show has been broadcast.
Lots of thought provoking aspects to consider.
The emotional conjunctions that create a seemingly mystical religious experience (which isn't - despite Derren's rhetoric - the same as a religious conversion!)
The failure to give due weight to poetic and symbolic realities - as if we are all irrational and stupid to want to avoid stabbing a photograph of a loved one with a knife in a satanic rite (when we don't actually believe in satan as an objective reality)
The potential hurt in our own sense of our love for the person - the blunting that is inevitable to allow such a mimicking of deadly attack (a photo REPRESENTS a person - so there is inevitable power in violence against such an image. We can easily imagine the meaning of tearing up a photo of someone, or dispoiling it with marks/scratches.)
What else? The imagining of phantom presences in an empty room, after planting the idea of a ghost.
The subconscious influence of a non-existent witness (a haunted chair that cuts down on cheating: the 'God-as-Policeman' usefulness in upholding morality - - - and the humorous cartoon of the Darwinian explanation of inventing the God-figure to watch us and keep us from disruptive actions to the tribe (such as infidelity)
The looking for patterns - faces - when they aren't really there (again linked to the survival advantage of glimpsing a tiger (or a shape that looks like a tiny bit of a tiger that 'might' be a tiger) - and reacting versus seeing the same and not reacting)
The perfume that wasn't there - and the low-frequency sound that supposedly makes you smell the scent of mint. - Used to demonstrate the power of suggestion in creating a sensory experience that the person believes they are actually experiencing.
The assumption of purpose and meaning in events - the projection of agency when it's not really there, because we start looking for it. THIS PART WAS THE MOST INTERESTING TO ME.
Like placebos, the mechanics of religious faith (such as intercessory prayer) no longer work when you can see behind the curtain. And it's sad in a way. There are some secular equivalents - the psychologically helpful non-religious version of the 'examen', where you reflect on your day (or longer period) and discern what has been life-enhancing and what has been depleting, using this to construct your own lessons to inform your onward path.