Intensive meditation training improves perceptual discrimination and sustained attention

Abstract

The ability to focus one's attention underlies success in many everyday tasks, but voluntary attention cannot be sustained for extended periods of time. In the laboratory, sustained-attention failure is manifest as a decline in perceptual sensitivity with increasing time on task, known as the vigilance decrement. We investigated improvements in sustained attention with training (approximately 5 hr/day for 3 months), which consisted of meditation practice that involved sustained selective attention on a chosen stimulus (e.g., the participant's breath). Participants were randomly assigned either to receive training first (n = 30) or to serve as waiting-list controls and receive training second (n = 30). Training produced improvements in visual discrimination that were linked to increases in perceptual sensitivity and improved vigilance during sustained visual attention. Consistent with the resource model of vigilance, these results suggest that perceptual improvements can reduce the resource demand imposed by target discrimination and thus make it easier to sustain voluntary attention.

Fig 1

Stimuli and timing for the threshold procedure and sustained-attention task. Single lines (light gray, 40.29 cd/m²) were presented at the center of the screen against a black background (0.35 cd/m²) while participants fixated on a small yellow dot (shown in white) from a viewing distance of 57 cm. In the threshold procedure, long nontarget lines (4.82°) were presented 70% of the time, and short target lines (range = 2.76°-4.78°) were presented 30% of the time. In the sustained-attention task, target frequency was reduced to 10% of stimuli. Each stimulus was presented for 150 ms, and a mask was presented during the variable interstimulus interval of 1,550 to 2,150 ms. The instructions emphasized the importance of speed and accuracy in responding to the short target lines.

Fig 2

Improvements in discrimination in (a) Retreat 1 and (b) Retreat 2. Discrimination threshold is plotted as a function of the time of assessment (pretraining, midtraining, posttraining, and follow-up). Error bars correspond to ±1 SEM; brackets indicate statistical comparisons (*p < .05, **p < .01).

Fig 3

Improvements in vigilance and average sensitivity in Retreat 2 participants. In (a), A’ for the sustained-attention task is plotted as a function of the time of assessment. Results for each assessment are averaged across eight blocks (total duration of 32 min per assessment). In (b), A’ for the same task is plotted as a function of block (four contiguous 4-min blocks, 120 trials/block), separately for the same five assessment points shown in (a). Retreat 2 participants were assessed during Retreat 1 but did not begin training until Retreat 2. Error bars correspond to ±1 SEM; brackets indicate statistical comparisons (*p < .05, **p < .01).

Fig 4

Discrimination threshold as a function of the average amount of time spent in daily meditation at follow-up (n = 54). The graph shows the experimental data and a regression line fit to those data.