Figure 1.
Experimental apparatus and stimuli.
Newborn guppies were housed in an experimental tank for the entire experiment (a). Stimuli (groups of dots differing in numerosity and/or continuous quantities) were presented at the bottom of the tank. In the figure (b) we depicted a schematic representation of the stimuli used in the three experiments: number+continuous quantities (b1), only number (b2), only continuous quantities (b3).
Figure 2.
Accuracy is plotted against the three experiments. Subjects proved themselves able to discriminate between 7 vs. 14 both when number and continuous quantities were available simultaneously and when only numerical information was used. The ability to discriminate between continuous quantities was not found. Asterisks denote a significant departure from chance level (p<0.05). Bars represent the standard error.