Some words hurt more than others: Semantic activation of pain concepts in memory and subsequent experiences of pain

Theory suggests that as activation of pain concepts in memory increases, so too does subsequent pain perception. Previously, researchers have found that activating pain concepts in memory increases pain perception of subsequent painful stimuli, relative to neutral information. However, they have not attempted to quantify the nature of the association between information studied and ensuing pain perception. We subliminally presented words that had either a low or high degree of association to the word ‘pain’, although this was only partially successful and some words were consciously perceived. Participants then received randomized laser heat stimuli, delivered at one of three intensity levels (low, moderate, high), and we measured the effect of this on behavioural and electrophysiological measures of pain. Participants (N = 27) rated moderate and high intensity laser stimuli as more painful after viewing high relative to low associates of pain; these effects remained present when measures of mood, anxiety and physical symptom reporting were controlled for. Similar effects were observed physiologically, with higher stimulus preceding negativity after high relative to low associates and greater amplitudes for the N2 component of the laser-evoked potential (LEP) after presentation of high associates in the moderate and high laser intensity conditions. These data support activation-based models of the effects of memory on pain perception.