Abstract
The effects of shamatha meditation on attentional and imaginal variables were assessed in a group of 16 experienced meditators engaged in an intensive meditation retreat. Two control groups were tested on the same variables on a single occasion. One control group consisted of 16 similarly experienced meditators not engaged in intensive practice, and the other consisted of 18 undergraduates with no meditation experience.The experimental group showed significant or marginally significant gains on variables concerning the hallucinatory vividness and audio-visual imagery in daydreams, vividness of directed imagery, and controllability of visual imagery. There were no significant changes in the temporal perspective of daydreams.The experimental group did not perform significantly better at posttest on a random number generation task used as a measure of attention.One section of the Group Embedded Figures Test was administered at pretest and one at posttest for the experimental group. The control groups completed both sections during one session. There was no improvement in the experimental group's performance that was related to the meditation treatment.A word recognition memory test was administered to all groups (at posttest for the experimental group) to assess differences in attention related to semantic encoding and generalization. There were no significant differences in response patterns across groups.Comparisons of pre- and posttest scores for the experimental group with scores obtained by the control groups on a single occasion lend credence to the claim that postexperimental group differences were due to the meditation retreat.The study provides some corroboration of traditional descriptions of the effects of shamatha meditation. Implications for future research on attention variables in meditation are discussed.