Wednesday, 2 August 2006

Psychopaths unmoved by words

Imagine I show you the word “love” and I ask you to classify it as positive or negative. You’ll classify it far quicker as positive, if just beforehand I had showed you another positive word such as “honesty” – a phenomenon that’s known as affective priming. Now James Blair and colleagues at the National Institute for Mental Health in America have shown that affective priming is greatly reduced in callous people who score high on psychopathy.

Blair’s team think psychopaths show reduced affective priming because positive and negative words don’t trigger activity in their brains’ fear and reward hub, the amygdala, in the same way as happens in healthy people. In healthy people, it’s this amygdala activity, triggered by the sight of one positive/negative word that is thought to speed the response to a subsequent positive/negative word.

The researchers made these observations by testing affective priming in thirty people resident in a high security institution in England, 15 of whom were psychopathic and 15 of whom weren’t, based on their scores on an established measure of psychopathy.

It’s not that psychopathic people have some kind of general language or priming problem because the researchers found psychopaths showed normal semantic priming. Similar to affective priming, semantic priming is when we’re quicker to categorise a word when it follows a preceding word that had a related meaning.

The researchers said their observations fit with the idea that “…individuals with psychopathy do represent the lexical meaning of emotions, but they do not experience their affective value; they ‘know the words but not the music’”.

Blair, K.S., Richell, R.A., Mitchell, D.G.V., Leonard, A., Morton, J. & Blair, R.J.R. (2006). They know the words, but not the music: Affective and semantic priming in individuals with psychopathy. Biological Psychology, 73, 114-123.

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

Link to complete PDF download of Hervey Cleckley's classic text on psychopathy - 'The Mask of Sanity'. Thanks to Vaughan at MindHacks for the heads up.

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