Visualizing the gains from trade, mid-1870s to 1962

Visualization in economics was common, and in trade theory almost a primary mode of analysis and demonstration from the late 19th century until the 1960s. Why? This paper presents two versions of the gains from trade notion that have come to us in visual form, one due to Marshall, the other to Viner and Samuelson. The two are very different, a fact better understood against a backdrop of recent neurological research on visualization. A key finding of that work is that our ability to conceive and recognize forms depends on forms previously seen and stored in the brain. Early exposure and nurturing matter greatly. The research also stresses that there is no basis for distinguishing between seeing and understanding. A satisfactory answer to the ‘Why?’ question thus requires that we attend to audiences and their capabilities, some hints concerning which are offered here.