Do emotion-induced blindness and the attentional blink share underlying mechanisms? An event-related potential study of emotionally-arousing words

Cogn Affect Behav Neurosci (2017) 17:592–611 DOI 10.3758/s13415-017-0499-7 Do emotion-induced blindness and the attentional blink share underlying mechanisms? An event-related potential study of emotionally-arousing words Jeffrey MacLeod 1 & Brandie M. Stewart 1 & Aaron J. Newman 1 & Karen M. Arnell 2 Published online: 6 March 2017 # Psychonomic Society, Inc. 2017 Abstract When two targets are presented within approximately 500 ms of each other in the context of rapid serial visual presentation (RSVP), participants’ ability to report the second target is reduced compared to when the targets are presented further apart in time. This phenomenon is known as the attentional blink (AB). The AB is increased in magnitude when the first target is emotionally arousing. Emotionally arousing stimuli can also capture attention and create an AB-like effect even when these stimuli are presented as to-be-ignored distractor items in a single-target RSVP task. This phenomenon is known as emotion-induced blindness (EIB). The phenomenological similarity in the behavioral results associated with the AB with an emotional T1 and EIB suggest that these effects may result from similar underlying mechanisms – a hypothesis that we tested using event-related electrical brain potentials (ERPs). Behavioral results replicated those reported previously, demonstrating an enhanced AB following an emotionally arousing target and a clear EIB effect. In both paradigms highly arousing taboo/sexual words resulted in an increased early posterior negativity (EPN) component that has been suggested to represent early semantic activation and selection for further processing in working memory. In both paradigms taboo/sexual words also produced an increased late positive potential (LPP) component that has been suggested to represent consolidation of a stimulus in working memory. Therefore, ERP results provide evidence that the EIB and emotionenhanced AB effects share a common underlying mechanism. * Aaron J. Newman 1 Department of Psychology and Neuroscience, Life Sciences Centre, Dalhousie University, Box 15000, Halifax, NS B3H 4R2, Canada 2 Department of Psychology, Brock University, 500 Glenridge Avenue, St. Catharines, ON L2S 3A1, Canada Keywords Language . Attention . Reading . Emotion . Event-related potentials . Attentional blink . Emotion-induced blindness . Rapid serial visual presentation Introduction Humans receive a variety of sensory inputs at any one time, and typically do not have the resources to process all inputs with equally. Attention is used to select the most important inputs for further processing and awareness. If attentional selection exists to prioritize the processing of important sensory inputs, stimuli that are relevant to the welfare of an individual, such as threat or sexual stimuli, should be efficiently selected for further processing by the attentional system. Indeed, human behavioral research using a variety of cognitive paradigms and participant groups has shown that emotionally charged stimuli are processed preferentially by the attentional system (e.g., Aquino & Arnell, 2007; Frischen, Eastwood, & Smilek, 2008; MacKay, Shafto, Taylor, Marian, Abrams, & Dyer, 2004; Vogt, De Houwer, Koster, Van Damme, & Crombez, 2008). An examination of attention to emotional words in rapid serial visual presentation (RSVP) is the focus of the current work. In RSVP, stimuli are presented one-at-a-time at a central location with approximately 100 msec separating each item. This method of presentation causes each item to mask the previously presented item. Participants are typically able to identify a single target within an RSVP stream with a high level of accuracy. However, if participants are asked to identify two targets within a single RSVP stream, performance on the second target (T2) is detected with reduced accuracy when it appears less than 500 ms after the first target (T1; Raymond, Shapiro, & Arnell, 1992). This phenomenon is called the attentional blink (AB; Raymond et al., 1992). Cogn Affect Behav Neurosci (2017) 17:592–611 Emotionally arousing stimuli have consistently been found to modulate the AB. When emotionally arousing words are presented in the T1 position, they result in a larger and more prolonged AB compared to non-arousing T1 words (Mathewson, Arnell, & Mansfield, 2008). Emotionally arousing words presented as T2 are less susceptible to the AB than non-arousing T2 words (Anderson, 2005; Keil & Ihssen, 2004; Milders et al., 2006). However, emotional T2 words are more susceptible to the AB when preceded by an emotional T1 word (Schwabe & Wolf, 2010; Schwabe et al., 2011). Together these results suggest that emotional stimuli receive additional attentional resources at the expense of neutral stimuli in the AB paradigm. Emotionally arousing stimuli have also been presented as to-be-ignored distractor items in RSVP tasks (e.g., Most, Chun, Widders, & Zald, 2005; Arnell, Killman, & Fijavz, 2007). In these tasks, the emotional distractor appears prior to the target item, just as T1 would precede T2 in a typical AB task – but unlike in the AB task, these distractor items are not relevant to any task the participant is instructed to perform (see Fig. 1b for a depiction). In this emotional-distractor paradigm, emotionally arousing distractors have been shown to capture attention at the expense of accuracy for closely trailing target items; similar to T1 capturing attention at the expense of T2 in the AB paradigm (Arnell et al., 2007; Mathewson et al., 2008; Most et al., 2005; Most, Smith, Cooter, Levy, & Zald, 2007). This effect has been termed emotion-induced blindness (EIB; Most et al., 2005) or the emotional attentional blink (McHugo, Olatunji, & Zald, 2013). For example, Arnell and colleagues (2007) showed that relative to emotionally-neutral words, a sexual/taboo distractor word (e.g., orgasm, bitch) captured attention and resulted in an EIB for neutral word targets presented soon after the emotional word. Higher arousal ratings and greater surprise recognition memory for the emotional distractor word were found to predict the accuracy for subsequent targets presented at short lags, and memory fully mediated the relationship between arousal rating and target accuracy. Arnell et al. (2007) concluded that arousing distractor words were encoded into memory at the expense of targets presented at short lags following the distractor. The AB and EIB: Similar mechanisms? Mathewson et al. (2008) showed that similar patterns of behavioral data result from AB tasks with emotionally arousing T1 words, and EIB tasks with emotionally arousing distractors. Both with the AB and EIB, higher arousal ratings and greater surprise recognition memory for the emotional words were found to predict reduced accuracy for subsequent targets presented at short lags, and memory fully mediated the relationship between arousal rating and target accuracy. Mathewson et al. (2008) used the same w (...truncated)