The Pacific Standard Time exhibitions in Los Angeles show that arts and culture from south of the border have shaped an architectural identity for the region that is much more interesting than what's found in the Northeast US, says Aaron Betsky.

As a longtime denizen of the Southwest (if California, in addition to Arizona, counts), I feel myself part of another culture than that of the more eastern parts of the United States. The landscape here is fundamentally different, but so is the quality of the place humans have built on that land.

To put it simply, everything here is as much Mexican, and thus Spanish, as it is English. The spaces we inhabit look south as much as they are the result of the westward movement of Northern Europeans. They are not white in colour or inhabitants, and their shapes are quite simply different. The architecture of the Americas is not white. It is a mix that gives force and diversity to our lives.

Despite what some demagogues would tell you, borders are, after all, political constructs. We know this in architecture. Design works from and in a particular area, defined by geology, climate, and local traditions, but is also part of a global flow of culture. So it is with the border between the United States and the states to the south.

The artificiality of how politicians apportion place has been in evidence for several years now in the exhibitions that have been part of the biannual Pacific Standard Time (PST) event. This is a group of presentations the Getty has sponsored all around Southern California to promote the notion that the West Coast of America has been shaped by the continual flow of ideas and images moving up and down the Pacific Coast, as well as those that have spread across the North American Continent.

Several of the exhibitions in the latest edition of PST, which opened this fall, are magnificent in their celebration of the complex relation between the various countries and cultures. They also feed the current debate about appropriation, by showing just how beautiful and important the results of adopting and adapting forms and images developed by other people can be.

At the Getty Research Institute, in two rooms off to the side of the museum's grand sequence of galleries, The Metropolis in Latin America 1830-1930, mines the institute's archives to show that metropolitan life shared characteristics from New York to Havana to Buenos Aires.

The message there, at least to me, is that when you get to cities over a certain size, it matters little where they are. They conform to the same grid, even if its proportions might be different depending on whether they were French, Spanish, or Hapsburg in their origins. That organising field pushed up into first hotels, office buildings, department stores, and apartment buildings, then, once the intensity of activity downtown became great enough, into skyscrapers.

The West Coast of America has been shaped by the continual flow of ideas and images moving up and down the Pacific Coast

The forms the major civic and private buildings took reflected whatever was the universal style at the time, whether beaux-arts classicism or high modernism, while the underlying structure became ever thinner and more flexible.

Put Francisco Mujica's The City of the Future: Hundred Story City in Neo-American Style of 1929 – the exhibition's show-stopping image – next to Hugh Ferris' Metropolis of Tomorrow of the same year, and you see the same creation of human-made mountain ranges, even if Mujica's sports vague memories of Mayan or Aztec detailing.

At the Riverside Art Museum, Myth & Mirage: Inland Southern California, Birthplace of the Spanish Colonial Revival (I contributed an essay to the catalog) shows how the various attempts to create an authentic style for California melded into the Spanish Colonial Revival in the Inland Empire, and how that style then became the tide of red-tile roofs that engulfed the landscape.

The flexible use of historical sources proved capable of giving image and shape to hotels such as the Mission Inn in Riverside, fast food restaurants such as Taco Bell, and hotel chains such as La Quinta, as well as homes that you can now find as far afield as China and, yes, Guadalajara.

The core of this PST edition is the Los Angeles County Museum of Art (LACMA), which has done the most credible job of being reflective of the population it serves of any major museum in this country.

Two exhibitions in particular, Home – So Different, So Appealing (which unfortunately opened and closed at the edge of the PST framework), and Design in California and Mexico 1915-1985, manage to show how ingrained a common sense of place and culture have become both north and south of the United States border.

The motifs and attributes developed in the jungles of Yucatan and the plains of Mexico worked as well for houses in the Hollywood Hills

The latter exhibition traces the ways in which California (both Baja and El Norte) has looked to the heritage of the Spanish occupation of its land for more than two centuries before it became part of the United States in 1848.

It uncovers an interesting, though not quite acknowledged aspect of that appropriation: just as the English created an empire that sucked up Indian, Chinese, African, and Middle Eastern artefacts and used them to inspire art and design, so the Spanish controlled an empire in the Americas whose heritage became fair game for use by former members of that realm once it broke up.

Thus Mexican artists rediscovered their Mayan, Aztec, and Olmec roots, sensing how its forms worked with the land they occupied, but the forms also inspired architects and designers in California. It turned out that the motifs and attributes developed in the jungles of Yucatan and the plains of Mexico worked as well for houses in the Hollywood Hills (Frank Lloyd Wright's Ennis House) and movie palaces, as they did for housing the pavilion of Mexico City at various World's Fairs, starting with Paris in 1899.

The core of the exhibition shows the forms developed for haciendas and missions by the Spanish, using native materials and traditions mixed with the memories and techniques they brought with them from Europe, that is, in turn, at the heart of the shared legacy.

It is particularly wonderful to see these forms not only develop into lavish houses on both sides of the border, but also become progressively more modernist in the designs of Irving Gill, George Washington Smith, and Luis Barragán.

Design in California and Mexico's real revelation lies in its collection of craft, from the socialist bench Xavier Guerrero and Amado de la Cueva created for the Casa Zuno in Guadalajara, to the spread of the sling chair from Mexican houses to the American suburbs.

A new kind of culture is rising into a terrible beauty in which we all eat tacos and live in Spanish Colonial Revival homes

Mexican silversmiths, having learned from the Spanish and from native craftspeople, influenced their American counterparts, who brought in motifs from Native American tribes, while graphic designers in Mexico City picked up on the vibrant colours of California's brand of modernism in that field, which itself had been influenced by designers such as Alvin Lustig's and Charles and Ray Eames' travels to the south.

Some of the images are whimsical: you cannot beat the clips of Raquel Welch dancing a vaguely Carribean, vaguely Martha Graham dance in front of both the pyramids of Teotihuacan and sculptures by Mattias Goerritz.

On a more serious note, the net sculpture Ruth Asawa created in 1961 for Buckminster Fuller based on techniques she learned while studying in Mexico, show the power of learning, assimilating, and taking further the traditions of several places at the same time.

Similarly, Diego Rivera's Pan American Unity fresco of 1940, now in the San Francisco Art Institute, depicting San Francisco as the kind of metropolis, born in Spanish colonialism and on a landscape long inhabited by Native Americans, that has emerged all over the two continents.

The spaces of the American Southwest and Latin and South America are not just multicultural places, but spaces in which a new kind of culture, born in violence and injustice, but rising into a terrible beauty in which we all eat tacos and live in Spanish Colonial Revival homes while surfing the World Wide Web, has created a reality that is, I would daresay, more exciting and more comfortable then what has emerged in the frozen plains in these two continents' northeast quarter.