Alexander Luria, the developmental psychologist, knew that ‘perception depends on historically established human practices that can alter the system of codes used to process incoming information’ (Cognitive Development: Its Cultural and Sociological Foundations). Luria conducted a series of experiments in the collective farms of 1930s Soviet Central Asia to examine the psychological changes (in perception, problem solving, and memory) that take place as a result of cultural development of poorly educated minorities. His research suggested that as cultural levels change, observed geometrical figures are interpreted less and less as representing real world objects (that’s a road, that’s a bird-cage, that’s a saucepan) and more as categories (that’s a line, a rectangle, a square). As culture develops, norms and rules are established which enable and underpin our ability to think in generalisations and abstractions.

In the development of artistic representations of reality too, we develop rules and norms that help us create and interpret works of art. The Rules of Pieter de Grebber (1600-1652/3), for example, were influential in shaping the theories of Salomon de Bray (1597-1664) and his three sons in 17th century Haarlem. A number of paintings in the summer exhibition of all four de Brays at the Dulwich Picture Gallery elucidate these theories. Salomon’s ‘Joseph receives his father and brothers in Egypt’ (Catalogue 9), displays the foreshortened and squat figures which coincided with his theories of the ideal human proportion. We see the further development of this pictorial language in Jan de Bray’s ‘Leda shows her daughter Helen to Tyndareus’ (Catalogue 22). And we see the culmination of Salomon and de Grebber’s theories in ‘The Queen of Sheba before the temple of King Solomon’ (Catalogue 11), where the interplay of light and perspective clearly demonstrate his thinking about perspective and his struggle to realise what he believed to be absolute mathematical laws governing ‘true art’.

Both Salomon and Jan were architects as well as painters and thought about both disciplines in the light of a unified theory. Just as there were iron laws of engineering to obey in building, so too there were explicit rules of perspective to be followed in painting. But both created their own language of art, as did their more famous contemporary Saenredam, in which to express these rules. Here the differences between the members of this artistic family are perhaps more illuminating than the accident of their shared genetics. While the existence of artistic families (Holbeins, Bruegels, Teniers, Cranachs, to name a few) may be striking, we can best understand it in the context of the production of art in this period in the setting of family owned commercial workshops. It was only the elder son Jan, for instance, who was chosen to follow his father into the high status field of history painting, whereas the younger sons Joseph and Dirck were relegated to still-life to make money: largely painting flowers and herrings.

As a history painter, Jan developed the form of portraiture known as the portrait historié, where the sitters – in many cases members of his own family – take on the roles of historic or mythological figures. In doing this he took on board the teaching of his father, himself taught by Rembrandt’s tutor Pieter Lastman, the influence of Frans Hals and the Utrecht Caravaggists (consider the striking ‘Jael, Deborah and Barak’, Catalogue 3). He came into his own in the 1660s as his competitors – notably Hals - died or moved away from Haarlem.

Jan de Bray was by this time equally a master of the well-known conventions of the Dutch portraiture of the Golden Age. The final room of the exhibition shows four portraits of contemporary notables, in the traditional – although very expensive - black and white attire of god-fearing and sober early Protestants. The striking inclusion, however, of ‘The Judgement of Zaleucus’ (Catalogue 39), shows off by contrast a riot of colour: something reserved in this artistic language for representing the mythological, for religious scenes, for the poor (who don’t count) and brute materiality. Humanity (insofar as it is here represented by the Dutch bourgeoisie of course) is shown in black and white, precisely because it has set itself apart from the imaginary and the natural world: it has created its own language for representing itself. Black no longer means black: black is the new way of representing an abstract category of thought. We have developed.

Dulwich is a fitting setting for this coming together of the de Bray family. Britain’s first public art gallery is housed in a building designed by the noted architect and connoisseur Sir John Soane and houses a hugely important collection including Albani, Carracci, Correggio, Hogarth, Poussin, Raphael, Reni, Rubens, Veronese, and Zuccarelli – a very lexicon of European old master paintings of the 1600s and 1700s. In it, and in this thought-provoking exhibition, we can trace the development of the language of art.

Leon Trotsky said in his Literature and Revolution that ‘at various periods, and by various methods, realism gave expression to the feelings and needs of different social groups. Each one of these realistic schools is subject to a separate and social literary definition’. For the de Brays as painters, being convincing was their only absolutely overriding rule: they demonstrate Trotsky’s exhortation to eschew romanticism and mysticism and evince a real ‘feeling for life as it is, in an artistic acceptance of reality… an active interest in the concrete stability and mobility of life’.

Till 5 October 2008