A targeted cross-species retro-analysis was conducted using three independent published datasets to test whether the DNA demethylase recruiter gadd45b occupies a functionally distinct category from canonical immediate early genes (IEGs). Whereas canonical IEGs generally respond to sufficiently intense neural or behavioral stimulation, gadd45b appears to be preferentially induced by genuine social engagement and social outcome resolution. In Betta splendens, gadd45bb (BSP_05575) was not different