Studying metacognitive processes at the single-neuron level

Over the past few decades, strides have been made toward understanding how higher level cognitive processes are mediated by neuronal spiking activity. Neuronal correlates of functions such as attention, executive control, working memory, decision-making, and reward processing have all been elucidated, to an impressive level of detail, at the single cell and circuit levels. This explosion in neurosciencebased discovery has depended crucially on nonhuman animal (animal, hereafter) models of the behaviors and processes under question. Developing animal models becomes a greater challenge for cognitive functions that approach the complexity of those arguably unique to humans. A prime example is metacognition. As reviewed in the Foundations of metacognition section of this volume, we know that humans engage in complex metacognitive behaviors. A metacognitive process is by definition about one of our own cognitive process, and is often referred to as ‘‘thinking about thinking.’’ Hence it is not surprising that metacognition is often associated with our subjective or conscious sense of self (e.g., [38]). Beyond the human brain, evidence for metacognition is less clear. There is, as yet, no definitive evidence that animals experience a subjective awareness, or a continuity of mental experience, similar to our own. Consequently, many investigators conclude that animals must not possess metacognition as humans do. Recent behavioral evidence, however, makes a case for some degree of metacognitive capability in a variety of animal species.