Concentrative versus mindfulness meditation
There have been notable efforts to classify meditation practices based on techniques. Many attempts distinguish between concentrative and mindfulness meditation. Concentrative meditation refers to practices that involve focus on a particular stimulus, such as the breath, whereas mindfulness refers to unselective attention to the flow of thoughts, sensations, and experiences. In this classification, concentrative meditation involves the narrowing and mindfulness the expansion of attention (Ivanovski and Malhi 2007). In actual practice, it is difficult to distinguish these two broad types of meditation with regard to the use of a specific attentional focus. For example, Bishop and colleagues (2004, p. 238) defined concentrative meditation as “restricting the focus of attention to a single stimulus such as a word, sound, or sensation. When attention wanders, it is redirected back to that single stimulus.” This definition of concentrative meditation is very similar if not identical to their description of mindfulness meditation: “The client . . . attempts to maintain attention on a particular focus, most commonly the somatic sensations of his or her own breathing. Whenever attention wanders from the breath to inevitable thoughts and feelings that arise, the client will simply take notice of them and then let them go as attention is returned to the breath. This process is repeated each time that attention wanders away from the breath” (p. 232). Thus, breath-focused attention is variously referred to as a concentrative or mindfulness form.
To complicate matters, when a mantra is used, that is, the repetition of words, sounds, or phrases as an attentional focus, it is typically regarded as concentrative meditation (Cahn and Polich 2006; Ospina et al. 2007), despite the fact that definitions of mindfulness meditation do not specify the breath as the sole focus, mantra is often repeated in synchrony with the breath (Braboszcz et al. 2010), and conceptualizations of mantra describe it as a method to enhance present moment (Waelde 2015) and expanded states of awareness (Cahn and Polich 2006). Mantra repetition, like breath-awareness meditation used in mindfulness, tends to slow breathing and may alter autonomic tone (Braboszcz et al. 2010). Moreover, mantra meditations such as TM can produce increases in mindfulness (Tanner et al. 2009). These definitions of concentrative and mindfulness meditation leave open the question of whether mindfulness meditators practice concentrative meditation and whether those who use concentrative techniques such as breath awareness and mantra ever experience mindfulness as an outcome.
The dichotomy between concentrative and mindfulness techniques has led to distinctions between entire schools of meditation and their respective practitioners. For example, a review classified TM, yogic, and samatha meditation as concentrative and Zen and vipassana as mindfulness (Ivanovski and Malhi 2007), even though Zen and vipassana rely on concentrative techniques (Lutz et al. 2008). One unfortunate outcome of this classification practice is the difficulty in specifying what mindfulness is and is not. In neuroimaging studies of meditation, experimental tasks involving meditation on a specific sensory focus may be classified as mindfulness or concentrative apparently depending on the school of meditation of the research participants. In one study, participants who had received 8 weeks of MBSR training focused on scanner sounds during the “mindfulness” meditation scan (Kilpatrick et al. 2011); in another, Tibetan Buddhists performed a “concentration” meditation task involving focus on a dot on a screen (Brefczynski-Lewis et al. 2007). Studies of different meditation techniques have often confounded technique with school and thus it is difficult to evaluate the results of studies and meta-analyses of the comparative effectiveness of different meditation types.