. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. VARIATION IN LEARNING 229 ^ O I— O o or °~ I 234567 DAYS SR< FIGURE 3. Frequency distribution of runs of spontaneously suppressed phototaxis in the test-only group. All animals scored < at least once in 20 tests over 31 days. indicating that larger animals in the sample were not consistently slower or faster than the smaller ones. Factors influencing latencies in naive animals across time were not identified in this study. We conclude that positive phototaxis in Hermiss
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. VARIATION IN LEARNING 229 ^ O I— O o or °~ I 234567 DAYS SR< FIGURE 3. Frequency distribution of runs of spontaneously suppressed phototaxis in the test-only group. All animals scored < at least once in 20 tests over 31 days. indicating that larger animals in the sample were not consistently slower or faster than the smaller ones. Factors influencing latencies in naive animals across time were not identified in this study. We conclude that positive phototaxis in Hermissenda does not significantly habituate or sensitize over one month of testing and that, within the limits reported, latencies are not a significant function of body size. Prolonged periods of reduced responsiveness to light in animals treated with paired stimulation may, when compared statistically to spontaneously occurring runs of suppressed phototaxis in control treatment animals, be assigned to long-term retention of associatively suppressed phototaxis. Acquisition Ninety percent of all experimental animals responded to light within ten minutes in the baseline test. When baseline latencies were compared between all groups no significant difference was found (Kruskal-Wallis one-way ANOVA, H' , df = 9, P ~ ). Although results from the test-only group showed that latencies fluctuate on a daily basis, exposure of animals to paired stimulation should, if acquisition increases with experience, result in a trend towards increasing latencies with number of sessions in the paired but not the unpaired and random groups (Table II, Fig 4). Arrays of within-group latencies, measured daily from baseline scores across treatment days to the first post-treatment test, were analyzed with Page's L-test for ordered alternatives. All groups (two, three, four, six days) exposed to paired light and rotation showed significant ordered increases in latency across treatment sessions (P &
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
