Research in non-human animal (hereafter, animal) cognition has found strong evidence that some animal species are capable of meta-cognitively monitoring their mental states. They know when they know and when they do not know. In contrast, animals have generally not shown robust theory of mind (ToM) capabilities. Comparative research uses methods that are non-verbal, and thus might easily be labelled ‘implicit’ using the terminology of traditional human cognition. However, comparative psychology has developed several non-verbal methods that are designed to test for aspects of meta-cognition that – while perhaps not fully explicit – go beyond the merely implicit or associative. We believe similar methods might be useful to developmental researchers who work with young children, and may provide a sound empirical alternative to verbal reports. Comparative psychology has moved away from all-or-none categorical labels (e.g., ‘implicit’ vs. ‘explicit’) towards a theoretical framework that contains a spectrum of mental abilities ranging from implicit to explicit, and from associative to cognitive to fully conscious. We discuss how this same framework might be applied to developmental psychology when it comes to implicit versus explicit processing and ToM.