Ganzfeld perceptual field and gender effects on short-term memory as a function of rate of digit presentation

Efforts to enhance short term memory for digit span (in serial recall) included the Ganzfeld perceptual field and variation in the rate (interstimulus interval: 1 sec., 2 sec., 3 sec.) of 25 auditorily presented computer-generated random numbers (1 to 5). Undergraduate volunteers (52 men and 91 women) wore goggles consisting of halves of translucent ping-pong balls while viewing a red lamp and listening to 60 decibels of white noise. Control subjects wore goggles with clear plastic lenses. Participants were instructed to recall 25 random digits in the correct series (vocalized sequentially through headphones worn by the subjects) immediately after their presentations. A mixed 2 x 2 x 3 split plot analysis of variance yielded a significant effect for digit rates, and post hoc Scheffe tests of multiple comparisons showed differences in recall between interstimulus intervals of 1 and 2 sec., 1 and 3 sec., and 2 and 3 sec. Other Scheffe comparisons showed that men scored higher than women with the 3-sec. interstimulus interval and with the "clear" perceptual field. Ganzfeld may have reduced distractibility for women as compared with recall following the "clear" perceptual field. Serial-position effects favored "primacy," yet the "recency effect" was seen within the last 5 serial positions.