Information can be persistently represented on a multitude of devices beyond a single screen and session. This paper explores how technological display and device ecosystems (DDEs) may support human thinking, learning and sensemaking. We propose a theoretical foundation that extends Vygotsky’s sign mediation triangle to include digital information. Through a process we call objectification, perceivable objects, e.g. interface objects, tangible technologies, can be associated with signs to support thinking. We present a qualitative study of learning in a testbed DDE with 12 graduate students. We developed a method that traces digital objects within ‘thinking episodes’ to help us evaluate how technology configurations support objectification. Our findings relate two storylines of how DDE technologies may afford objectification. Our work advances a method informed by psychological theory to examine device ecologies for their potential for learning, and articulates affordances for the design of technology that can help to support higher thought.