Marco Vasconcelos is an experimental psychologist specialized in learning theory and comparative cognition. He received his undergraduate education from the University of Minho and his Ph.D. from Purdue University (USA). After receiving his doctorate, he joined the Department of Zoology of the University of Oxford (UK) where he stayed for four years. After a brief return to the University of Minho, he moved to his current position at the University of Aveiro. His main stream of research deals with decision making and rationality. He integrates concepts and techniques from operant conditioning and comparative cognition research with normative theoretical models from optimal foraging theory and microeconomics. To understand the thread of his research it is necessary to define decision making. Decisions are not a subclass of behavior but a way to investigate it; all behavior can be described as 'choice'. In practice, however, researchers deal with preferences between alternatives modeling how they are valued and how valuation drives choices. He uses optimality and learning theory to deal with valuation, and empirically supported algorithms to translate valuation into choice. Most of his experimental work involves individual starlings in computer-controlled environments, where reward and stimulus conditions are manipulated to understand the rules animals follow as they adapt to these changes. Currently, he is associate editor of the journal Behavioural Processes.