In an Experiment on Imprinting, Four Groups of Ducklings Were

In an experiment on imprinting, four groups of ducklings were exposed for an hour to a moving light bulb. Three days later a "tendency to follow"score was obtained for each when the moving light bulb was again presented. Group means, an ANOVA summary table, and the results of some HSD tests are shown below. Write an interpretation of the results. $\begin{array}{cc}\begin{array}{c}\text { Age When } \\\text { First Exposed }\end{array} & \begin{array}{c}\text { Mean } \\\text { Following Score }\end{array} \\\hline 6 \mathrm{hrs} . & 6.35 \\15 \mathrm{hrs} . & 8.72 \\30 \mathrm{hrs} . & 5.21\end{array}$


$\begin{array}{lrrl}\text { Source } & d f &{M S} & F \\\hline \text { Ages } & 2 & 2.14 & 5.62 \\\text { Error } & 28 & 0.38 &\end{array}$

$\begin{array}{cccc} & 6 \text { vs. } 15 & 15 \text { vs. } 30 & 6 \text { vs. } 30 \\H S D & 3.75 & 4.50 & 2.21\end{array}$