“…Auditory stimuli, for example, can be verbal or nonverbal, depending on whether they are issued by a human subject or by a musical instrument, respectively. In relation to number, an ever increasing number of studies have emerged that include the presentation of two antecedent stimuli in a discrimination (e.g., Alonso‐Álvarez, 2010; Alonso‐Álvarez & Pérez‐González, 2006; Augustson, Dougher, & Markham, 2000; Carnerero & Pérez‐González, 2015; Carnerero, Pérez‐González, & Osuna, 2019; Groskreutz et al, 2010; Guerrero, Alós, & Moriana, 2015; Miguel, Carr, & Michael, 2001; Miguel, Petursdottir, & Carr, 2005; Pérez‐González & Alonso‐Álvarez, 2008). Some of these investigations could be linked to the concept of multiple control described by Michael (2003).…”