Laughing Rats Are Optimistic
Figure 1
Mean ± SEM optimism index (see text for details) of the “Laughing when tickled” (filled bars, N = 13) and “Non-laughing when tickled” (open bars, N = 13) groups of rats measured after handling and tickling. The optimism index above 0 indicates an overall positive judgement and optimistic interpretation of the ambiguous cue. * indicates significant (p≤0.05) differences between the “Laughing when tickled” and “Non-laughing when tickled” groups.
