Effects of negative air ions, noise, sex and age on maze learning in rats

An equal number of male and female rats of the King-Holtzman hybrid breed, divided into two age groups (group A1 : 21–30 days old and group A2 : 90–100 days old), were exposed to two levels of noise: N0 = 30 db and N1 = 90 db, (Ref. 0.0002µ bar), and three levels of negative air ions: IO = no measurable ion concentration, I1 = 7 × 106 ions/cm3 and I2 = 7 × 107 ions/cm3. Time and error scores of 240 rats running a modified Lashley left-right maze with an escape-from-water motive served as criteria. A randomized complete blocks design with replications (2×3×2×2×10) was selected for treatment by analysis of variance. The results indicate that (a) the males show significantly lower error score in negatively ionized air; and (b) the females swim significantly faster than males under all investigated conditions with no apparent effect of noise or ions on their performance.