Modulation of Mind Wandering Using Monaural Beat Stimulation in Subjects With High Trait-Level Mind Wandering

Abstract

Mind wandering (MW) refers to a state when attention shifts from the task at hand or current situation toward thoughts, feelings, and imaginations. This state is often accompanied by a decline in mood, and patients suffering from major depression exhibit more perseverative MW. Hence, although the directionality of the relationship between mood and MW is still under investigation, it may be useful to explore possible avenues to reduce MW. In an earlier pilot study, we investigated MW during auditory beat stimulation in healthy subjects using thought-probes during a sustained attention to response task (SART). We found evidence for reduced MW during monaural 5 Hz beats compared to silence, sine tones, and binaural 5 Hz beats. Moreover, the data tentatively suggested that this reduction was particularly pronounced in subjects with high levels of MW during silence. In the current study, we therefore asked whether MW can be reduced by monaural theta beats in subjects with high trait-levels of MW, as indicated by an online MW questionnaire. Preselected subjects performed a SART task with thought-probes assessing the propensity to mind wander, meta-awareness, and the temporal orientation of MW. Stimulation conditions comprised monaural theta beats, as well as silence (headphones on), and sine tones as control conditions. Our main hypothesis stating that the propensity to mind wander during monaural theta beats is reduced compared to both control conditions was only partly confirmed. Indeed, MW was significantly diminished during exposure to the theta beats compared to sine tones. However, reduced MW during theta beats versus silence was only observed in a subgroup using stricter inclusion criteria. Considering possible reasons for this outcome, our data suggest that the preselection procedure was suboptimal and that beat effects are modulated by the individual responses to auditory stimulation in general.

Keywords: auditory beat stimulation; meta-awareness; mind wandering; mind wandering questionnaire; monaural beat; sustained attention to response task; temporal orientation.

Figure 1

Schematic illustration of the sustained attention to response task (SART) with embedded experience sampling probes. Subjects are instructed to respond with a button press when a non-target digit appears on the screen, with the exception of the target digit (3) for which they were instructed to withhold the button press. Subjects were also asked to respond to the embedded intermittent experience sampling probes when they appeared onscreen [probe 1: “Where was your attention focused immediately before the probe appeared?” (possible responses: “on task” or “off task”). Whenever participants indicated being “off-task,” a second probe assessed meta-awareness: “Were you aware that your attention was off-task?” (possible responses: “yes” or “no”). A third probe inquired as to the temporal orientation of MW: “Have you been thinking of the past, present or future?” (possible responses: “past,” “present,” and “future”)]. Participants were asked to respond as quickly and as accurately as possible.

Figure 2

Propensity to mind wander. The average propensity to mind wander shown across subjects for the three stimulation conditions. Mean and SEM are depicted.

Figure 3

Temporal orientation of mind wandering. The average ratios of past-, present-, and future-oriented MW shown across subjects for the three stimulation conditions. Mean and SEM are depicted.

Figure 4

Dependence of differences in MW propensities during monaural beats versus silence on MW scores. Differences in MW propensities during monaural beats versus silence [i.e., MW(beat)—MW(silence)] in the overall group (n = 34). Differences in MW propensities were negatively correlated with questionnaire-based MW scores (Spearman’s correlation: ρ = −0.322; p = 0.063).

Figure 5

Propensity to mind wander in subgroup with high MW questionnaire scores. The average propensity to mind wander shown across subjects in a subgroup with high MW questionnaire scores (≥19) for the three stimulation conditions. Mean and SEM are depicted.