MINDFULNESS AND INATTENTIONAL BLINDNESS 1 Brief Mindfulness Induction Reduces Inattentional Blindness

Prior research has linked mindfulness to improvements in attention, and suggested that the effects of mindfulness are particularly pronounced when individuals are cognitively depleted or stressed. Yet, no studies have tested whether mindfulness improves declarative awareness of unexpected stimuli in goal-directed tasks. Participants (N=794) were either depleted (or not) and subsequently underwent a brief mindfulness induction (or not). They then completed an inattentional blindness task during which an unexpected distractor appeared on the computer monitor. This task was used to assess declarative conscious awareness of the unexpected distractor’s presence and the extent to which its perceptual properties were encoded. Mindfulness increased awareness of the unexpected distractor (i.e., reduced rates of inattentional blindness). Contrary to predictions, no mindfulness × depletion interaction emerged. Depletion however, increased perceptual encoding of the distractor. These results suggest that mindfulness may foster awareness of unexpected stimuli (i.e., reduce inattentional blindness). MINDFULNESS AND INATTENTIONAL BLINDNESS 3 Brief Mindfulness Induction Reduces Inattentional Blindness People are often unaware of what is visible before them. For example, a classic study found that when participants were asked to count passes between basketball players, many participants failed to notice a person in a gorilla suit walking through the middle of the game (Simons & Chabris, 1999). Such failures of declarative awareness are termed inattentional blindness (IB) (Mack & Rock, 1998; Simons & Chabris, 1999). IB frequently occurs when unexpected stimuli appear during goal-directed tasks. These failures of visual awareness have important real-world consequences for effective self-regulation. For instance, many participants failed to notice a physical assault occurring nearby (Chabris, Weinberger, Fontaine, & Simons, 2011); oncoming motorcycles (Most & Astur, 2007); and airplanes parked across the runway during simulations (Haines, 1991). Despite these effects, very little research has considered what an individual may be able to do to reduce the risk of IB. One candidate protective factor may be presence of a mindful state. Mindfulness is the capacity to openly monitor sensory and perceptual stimuli and experiences, moment-bymoment in a non-judgmental manner (Bishop et al., 2004; Kabat‐Zinn, 2003). Mindfulness can be induced or trained using simple awareness exercises (e.g., mindfully eating raisins), mindfulness meditation practices, and intervention programs (e.g., the 8-week MindfulnessBased Stress Reduction [MBSR] program) (Brown, Ryan, & Creswell, 2007). One central feature of these mindfulness-enhancing practices is their focus on fostering greater attention to and awareness toward ongoing sensory and perceptual stimuli and experiences. The focus on developing capacity for non-judgmental monitoring of experience, helps to differentiate mindfulness from other forms of attention training (Lutz, et al., 2008). Indeed, recent studies suggest that a capacity to openly monitor internal and external experience during mindfulness meditation training improves behavioral measures of attention (Jha, Krompinger, & Baime, MINDFULNESS AND INATTENTIONAL BLINDNESS 4 2007; Moore, Gruber, Derose, & Malinowski, 2012; Tang et al., 2007). It is also possible that these mindfulness exercises, particularly the briefer inductions, may enhance attentional abilities relative to passive control conditions via instructions to attend to and engage with the tasks. Yet, no studies have tested whether a brief mindfulness induction, derived from the open monitoring framework, fosters greater awareness of unexpected stimuli in IB tasks. Here we test the novel prediction that a brief mindfulness exercise can reduce IB. This novel prediction is consistent with work in other paradigms; namely the change blindness and visual search paradigms. In change blindness paradigms, a characteristic of a stimulus changes (or the stimulus itself changes) and participants are tasked with detecting this change. Change detection is facilitated when participants adopt the passive search strategy of letting the distractor “pop out” (Smilek, Enns, Eastwood, & Merikle, 2006) and among those from cultural and employment backgrounds that promote bottom-up search (e.g., Asano, Kanaya, & Yokosawa, 2008; Masuda & Nisbett, 2006). Conceptually, such bottom-up search strategies are consistent with the open monitoring processes fostered by mindfulness inductions. Comparably, posthypnotic suggestion of similar bottom-up search strategies improves the speed with which participants can detect a target among an array of distractors (Lifshitz, Bonn, Fischer, Kashem, & Raz, 2013). What differentiates these detection effects from the postulated effect of mindfulness on IB is that IB is focused on the detection of unexpected distractors rather than expected targets. A growing body of research shows that mindfulness (and mindfulness-based training interventions) broadly have larger effects in cognitively depleted or stressed populations (Creswell, 2014; Friese, Messner, & Schaffner, 2012). Cognitive (or “ego”) depletion refers to a meta-analytically supported (Hagger, Wood, Stiff, & Chatzisarantis, 2010) finding that having recently performed an act of self-regulation (typically acts requiring response 2 Tang et al. (2007) made use of integrative body-mind training which included a mindfulness meditation element. MINDFULNESS AND INATTENTIONAL BLINDNESS 5 inhibition) temporarily impairs subsequent self-regulation (Baumeister, Bratslavsky, Muraven, & Tice, 1998). In one illustration of a mindfulness × depletion interaction, Friese et al. (2012) found that the depleting effect of suppressing emotions on subsequent selfregulation was buffered by brief mindfulness meditation. Cognitive depletion also reduces working memory capacity (Hofmann, Schmeichel, & Baddeley, 2012), and mindfulness buffers working memory declines during cognitively demanding boot camp training periods in soldiers (Jha, Stanley, Kiyonaga, Wong, & Gelfand, 2010). Simiarly, mindfulness also reduces biological stress reactivity in high (but not low) stress conditions (Arch & Craske, 2010; Brown, Weinstein, & Creswell, 2012). One possibility raised by this depletion account is that mindfulness may not always reduce IB, but rather mindfulness will only reduce IB in participants whom are cognitively depleted or stressed (a depletion × mindfulness interaction). To evaluate this possible interaction account, we experimentally manipulated depletion prior to having participants complete the brief mindfulness induction in the present study. The present study thus manipulated self-regulatory depletion (depletion writing, neutral writing, no-writing) and mindfulness (mindfulness induction, control) in a 3×2 between-participants factorial design in a large sample of adults (N=794). Using previously validated procedures for self-regulatory depletion (Schmeichel, 2007), participants were instructed to complete a cognitively demanding writing task (depletion condition), an easy writing task (writing control condition), or no writing (no-writing control). Participants then completed either a short audio-guided mindfulness exercise (mindfully eating raisins) or an audio-listening task (hearing factual information about raisins). This exercise was selected as the brief mindfulness induction because this raisin eating exercise is commonly used as the first training exercise in mindfulness meditation training intervention studies (e.g., MBSR) MINDFULNESS AND INATTENTIONAL BLINDNESS 6 (Kabat-Zinn, 1982; Kabat-Zinn, 1990), and successfully induces a mindful state when used as a standalone induction in meditation novices (Heppner et al., 2008). After completing the mindfulness induction manipulation, participants completed a standard IB task (Most et al., 2001; Simons, 2003). This task consists of counting the number of times a subset of moving black or white letters touches the edge of the computer screen. During the task, a bright red plus symbol moves across the screen. Experiments have found 25-50% of individuals failed to notice the unexpected red plus symbol when tracking the white subset of letters and ignoring the black ones (Hannon & Richards, 2010; Most et al., 2001). IB was assessed using standard procedures: participants were probed on whether they detected something unusual or unexpected (or not), and to indicate what they observed. A person may identify the distractor because it was red or because it was a plus symbol, while being fully unaware of its other unique feature(s). As such, it is possible for a person who is aware of the distractor’s presence to have reported the distractor without having fully encoded its features. In fact, behavioral and neuroimaging work suggests that the distractor undergoes equivalent perceptual encoding independent of whether the participant experiences IB or not (Butler & Klein, 2009; Vandenbroucke, Fahrenfort, Sligte, & Lamme, 2013). In light of this, a secondary measure of depth-of-distractor processing was included to examine whether full encoding of the distractor had taken place (cf. Swettenham et al., 2014; Vandenbroucke et al., 2013), and whether mindfulness would influence full encoding of the unexpected distractor. We predicted: (1) a main effect of a mindfulness induction on reducing IB such that those in the mindfulness condition would be more likely to report the unexpected distractor during the task; and that (2) this main effect would be qualified by a mindfulness × depletion interaction, such that the induction of mindfulness would reduce IB among depleted individuals, but mindfulness would have no effect on IB among those in the non-depleted MINDFULNESS AND INATTENTIONAL BLINDNESS 7 conditions. We remained neutral as to whether the effects of mindfulness and depletion on distractor encoding would mirror declarative distractor awareness (i.e., be increased), be absent, or even diverge from declarative awareness, given that declarative awareness is dissociable from attention and encoding (Butler & Klein, 2009; Vandenbroucke et al., 2013).