Mutual interactions between cognition and welfare: The horse as an animal model

•Individual characteristics such as temperament or stereotypies influence learning.•Vertebral problems, depression and anemia lower attentional and sensory engagement.•Type of training/reinforcement influences cognition, welfare and motivation to work.•Brain lateralization and EEG are promising tools for measuring cognition and welfare.•Evolution of brain functions and life conditions are influential in shaping cognition. Research in cognitive psychology has repeatedly shown how much cognition and emotions are mutually related to one another. Psychological disorders are associated with cognitive (attention, memory and judgment) biases and chronic pain may affect attention, learning or memory. Laboratory studies have provided useful insights about the processes involved but observations about spontaneous animal models, living in different stress/welfare conditions may help understand further how cognition and welfare are interrelated in the « real world ». Domestic horses constitute such a model as they live in a variety of conditions that impact differently their welfare state. In the present review, we try and provide an overview of the scientific literature on cognition and welfare of domestic horses and their interrelationship. We address how emotions and welfare may affect cognitive processes in horses and impact the way they perceive their environment (including work). We propose new methods for assessing the relationship between welfare and cognition and open up the discussion on the evolution of the brain and the part domestication may have played.