Mental Arithmetic as a Function of Computerized Digit Rates, Gender, and Size of Audience

Mental-arithmetic tests were given to 117 undergraduate volunteers (40 men and 77 women) using three rates (between groups) of digit presentation (1 sec., 2 sec., and 3 sec.) under three (within-group) sizes of audience (2 observers, 1 observer, and alone condition). Subjects were instructed to sum mentally three sets of 25 numerals ranging from 1 to 5 in computer-generated random sequences, under each of the three audience conditions. A mixed 2×3×3 split-plot analysis of variance of correct scores showed a significant main effect for rate of digit presentation, and post hoc Scheffé tests of multiple comparisons showed significant differences between the 1-sec. rate and each of the other rates (2 sec. or 3 sec.), yet no significance between 2-sec. and 3-sec. rates indicating a “critical threshold” has been identified with implications for computer-scrolled numerical information. Also, there was a significant two-way interaction between gender and size of audience. Post hoc Newman-Keuls comparisons showed women scored higher than men in the one-observer condition while men scored higher than women in the two-observer condition. Interpretations regarding interpersonal relationships and social inhibition were offered.

Sex differences in memory estimates, revisited

207 undergraduate students (95 men and 112 women) representing all four years in college provided estimates of memory performance before and after a recall task involving 80 stimuli (41) pictures and 40 words). The study was intended as a replication of the work of Ionescu in 2000 wherein men underestimated their performance on the picture items and women underestimated their performance on the words. No sex differences were found for correct recall totals, recall for pictures, recall for words, and total prerecall performance estimates. Although both men and women underestimated their pre- and postrecall performance, women underestimated their postrecall performance more than men. More importantly, men underestimated their performance on recall of pictures, whereas women underestimated their performance on the word items, thereby validating prior results with a larger sample. The possible bases for this phenomenon are still not clear.

Time estimation: effects of cognitive task, presentation rate, and delay

The variables of which subjective time is a function extend throughout a myriad of "people, places, and things." This study measured subjective estimations of time as a function of complexity of cognitive task including arithmetic and recall (within subjects), the rate of stimulus (digit span) information (between subjects), and the delay between stimulus presentation and estimations of time (between subjects). A mixed analysis of variance 2 x 2 x 3 (repeated-measures) factorial design showed that retrospective time estimations were significantly different as a function of the main effects of rate of digit presentation and delay. Men and women showed no differences with no significant interactions so their data were pooled. Quotient values for ratios of delayed versus immediate estimates and slow versus fast rates showed overestimates of "real time." Explanations based on the "storage-size model," the "attention-allocation" model, and comparisons with Pedri and Hesketh's 1993 data are discussed.

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.