Cognitive-affective model of the interruptive function of pain

The cognitive-affective model focuses on the interaction between painful stimuli and pain perception and how it is affected by a variety of cognitive and affective factors (Eccleston et al., 1999a). This model proposes that pain, which is a threatening signal, interrupts ongoing behavior in order to protect ourselves by prompting us to manage the pain (Bar-Haim et al., 2007; Eccleston et al., 1999a; Van Damme et al., 2010b). Similar to Allport’s model of attention, ongoing behavior can be disturbed when critical demands such as threats appear unpredictably (as discussed in Section 2.1) (Allport, 1989; Eccleston et al., 1999a; Van Damme et al., 2010b).

According to a cognitive-affective model of the interruptive function of pain, various cognitive and affective factors including saliency and novelty of stimuli, as well as individual characteristics such as pain catastrophizing and hypervigilance, modulate attention to pain

(Eccleston et al., 1999a; Legrain et al., 2009; Torta et al., 2017a; Van Ryckeghem et al., 2018).

The following is a brief description of these influential cognitive and affective factors.

Due to their distinctive physical features compared to other sensory stimuli, salient sensory stimuli, can involuntarily capture attention (Egeth et al., 1997; Knudsen, 2007; Legrain et al., 2013; Yantis et al., 1990). We can detect salient stimuli in our environment due to specific neurons that are sensitive to contrasts and changes between stimuli (Desimone et al., 1995; Itti et al., 2001; Legrain, 2011b). Salience detectors react more strongly to those contrasts and changes, resulting in greater cortical resources allocated to salient sensory input (Downar et al., 2002; Eccleston et al., 1999b; Kucyi et al., 2012; Legrain et al., 2013; Legrain, 2011b; Seeley et al., 2007). One feature that can make stimuli salient is novelty, which describes stimuli presented for the first time or presented infrequently (Eccleston et al., 1999a; Legrain et al., 2013; Legrain, 2012; Norman et al., 1986). Novel stimuli can capture attention and interrupt ongoing cognitive activities (Crombez et al., 1997; Eccleston et al., 1999a; Escera et al., 2007;

Näätänen, 2011). This capture of attention occurs by involuntary selection (a bottom-up process) (Legrain, 2012; Torta et al., 2017a). In regards to nociceptive processing, one study found that participant performance was decreased in an auditory discrimination task in which random painful stimuli were presented. The results indicated that attention was directed from the auditory target to the painful distractor irrelevant to the task goal, indicating involuntary capture of attention by salient and novel painful stimuli (Crombez et al., 1994; Eccleston et al., 1999b).

Studies have shown that the cortical response to nociceptive stimuli is more sensitive to their novelty rather than their intensity. For example, in one study, the authors applied two kinds of nociceptive stimuli with the same intensity. Some of the stimuli were novel and unexpected, as

they were presented irregularly, while the others were presented regularly. The findings indicated that the novel stimuli provoked larger amplitude event-related brain potentials (ERPs) compared to the regularly presented stimuli (Legrain et al., 2003). In another study, participants had to perform a visual task in which some of the stimuli were followed by novel nociceptive stimuli that were task-irrelevant, compared to a condition in which the nociceptive stimuli were not novel. The results showed that the novel nociceptive stimuli could disturb performance on the visual task. In summary, saliency and novelty of painful stimuli are factors that increase the threat value of pain and contribute to attentional engagement (Eccleston et al., 1999a; Gisèle, 2015; Legrain, 2012; Van Ryckeghem et al., 2018).

Another important factor that can modify pain perception is pain catastrophizing, which is the tendency to predict catastrophic outcomes from pain, ruminate about pain, and feel helpless about pain (Eccleston et al., 1999b; Sullivan et al., 1995). Catastrophizing increases attention to painful stimuli and leads to perceiving pain more intensely (Crombez et al., 1998;

Dillmann et al., 2000; Eccleston et al., 1999a; Keogh et al., 2001; Sullivan et al., 1995). For example, one study used a tone-discrimination task with several short durations and low-intensity electrocutaneous stimuli, while participants were informed that they would experience high-intensity pain. At the beginning of the experiment, participants were categorized as either high or low pain catastrophizers by applying the Pain Catastrophizing Scale (Crombez et al., 1998; Sullivan et al., 1995). The findings revealed that the attentional disruption by electrocutaneous stimuli and pain perception was increased for the high pain catastrophizers (Crombez et al., 1998; Eccleston et al., 1999a; Torta et al., 2017a).

Vigilance – amplified awareness of threat – is related to high levels of fear, which can worsen pain perception (Eccleston et al., 1999a; Eysenck, 1992). For example, chronic pain patients are typically hypervigilant to pain and their bodily sensations. In parallel, the fear-avoidance model also supports the idea that fearful patients show hypervigilance and pay more attention to threat signals, leading to avoidance behavior, increased disability, and the development of chronic conditions (Vlaeyen et al., 2000). Some patients with fibromyalgia or chronic low back pain maintain and amplify bodily sensations and avoid exercise (Crombez et al., 1998; Eccleston et al., 1999a; Torta et al., 2017a; Van Ryckeghem et al., 2018; Vlaeyen et al., 1995; Vlaeyen et al., 2000).

In summary, the cognitive-affective model focuses on explaining how cognitive and affective factors contribute to the selection of painful stimuli over other stimuli (Eccleston et al., 1999a). This theoretical framework identifies several cognitive and affective aspects of painful stimuli that moderate the interruptive strength of pain, including saliency and novelty.

Cognitive factors such as saliency and novelty can disturb attention more than pain intensity, and facilitate attentional capture. In addition, affective factors including pain catastrophizing and hypervigilance can also increase the interruptive effects of pain on attention (Eccleston et al., 1999a).