The Evolution of Games: Originality & Chreodes

Seeking the Original

Why are we not inundated with new and original games? Developers, publishers and reviewers alike are crying out for originality, and yet rather than being washed away in a flood of creativity, the games we see appear to be predominately clones of one another. In an industry that generally seems to be dominated by sequels, it is easy to see why such accusations could be leveled, but the question of the alleged absence of creativity warrants a closer examination.

Games are frequently accused of being derivative, but is this conservative approach to games development actually a problem? When a developer has a hit new game, sequels are an inevitable next step. In a competitive market, companies whose existence depends on regular income cannot be expected to abandon the brands that have achieved proven market success, and there are definite issues surrounding the question of whether or not sequels have any obligation to tread new ground.

To explore the possible factors behind the apparent contradiction of a market apparently craving originality but delivering largely similar product, we need a mechanism to consider the market as a whole. To enable us to build a mental image of the shape of the market, we need a metaphor. Starting with an idea proposed in the 1950s, we will use the concept of chreodes to travel back almost 600 million years to begin our search for fresh perspectives on the question of originality in games.

Chreodes

The notion of a chreode, or a pathway of probability, was created by the biologist C.H. Waddington in the 1950s as part of his attempt to find descriptive language to describe the way organisms develop [1]. He was largely concerned with the process of embryonic development, but the idea applies to any field of probability. The term is not in wide use in the modern scientific community, but this does not reduce its value as a metaphorical concept.

An easy way to picture chreodes is to consider a commonly encountered example, for example the flow of water over a surface that can be eroded. Initially this surface is flat, but as water flows across the plane of the material, it gradually begins to erode a canal. If there were no random factors involved, this canal would be an even trench in the surface, but since the flow of water is a chaotic process, the canals that result spread out unevenly. The deepest parts of the pathways occur where most erosion takes place, with shallower channels spreading out around it.

If you imagine a ball placed at the top of the canals, it will roll down and end up at the lowest point of one of the pathways. It is most likely to end up at the bottom of the deepest and widest channel, but has a chance of ending up at the end of any of the pathways. The waterways that result are a physical representation of the fields of probability that could be used to mathematically express the shape of the canals.

With respect to the development of organisms, the whole sphere of organic life can be pictured as a probability field, with chreodes representing the different kingdoms of life, and within those pathways, smaller chreodes representing orders, genus and species. These chreodes channel the possible developmental options for evolving life; a shallow channel represents an instance of life that can easily evolve into new forms. A deeper chasm is representative of a species or set of species that have painted themselves into an evolutionary corner (generally implying that they are both highly specialised, and highly successful).

Polychete worms, for instance, are an abundant, simplistic life-form which has evolved into and taken over a particular niche. So engrained is their position in this niche, that they are effectively doomed to remain in their current form, barring an improbable series of events and have remained effectively unchanged for millions of years. This does not blunt their success at exploiting this niche, however. Mammals, by comparison, which are complex entities with considerable room to maneuvre in an evolutionary sense, have taken over many different niches - herbivores, carnivores and omnivores of all manner of sizes on the land, bats in the air and cetaceans in the sea - and remain one of the orders of life with the greatest mobility of form (when looked at in geological time, at least).

Similarly, the entirety of games can be looked at as a series of chreodes, with the channels corresponding to the genres of games. This landscape would include all types of games, with a ubiquitous and simple game like 'I Spy' (with little room for innovation or mutation) being much like the polychete worms, and computer and video games more like our friends the mammals in their potential for diversity. For our purposes, we will focus on just the landscape represented by the different forms of computer games.

The Creative Explosion

By mentally rendering the sphere of organic life and the games market in terms of a landscape of chreodes, we create a metaphorical model allowing us to make comparisons between the evolution of life, and the evolution of computer games. From a certain perspective, the evolution of life has been about an ever-changing, diverse set of creatures discovering, adapting to and exploiting a number of evolutionary niches. Games, similarly, have been varied set of genres exploring a set of market niches. Food to an animal is much like money to a game as if the game does not prove profitable, fewer and fewer people will be willing to make more games in that genre.

In both cases, early examples were simple and without any existing chreodes to limit and channel the next stages, an explosion of originality resulted. Games were unconstrained by preconceptions, and so explored all manner of directions, only learning the hard way what would prove profitable, and what wouldn't. Life too started with no competition for resources, allowing an unprecedented era of biological creativity with all manner of strangeness resulting.

This early period of developmental simplicity for organisms was the Cambrian (570-505 million years ago). The huge diversity of multicellular life that came into existence in the early Paleozoic has been termed "The Cambrian Explosion". With only very basic life to compete with, and essentially no competition for organisms that could move and search for food, diversity was unparalleled. Fossils show creatures like opabina which appears to have five eyes at the base of a head stalk, and hallucigenia which apparently supports a trunk and globular head on seven pairs of rigid spines. These species have no known descendents - rather, they are experimental oddities, forced out of the evolutionary game by luckier and more successful species [2].

For computer games it was the 1970s and 1980s. This period contains a number of game oddities with few or no modern descendents. In the arcade, we find games such as Exidy's Circus (1977) which featured clowns bouncing off a seesaw to pop baloons, or Cinematronic's Sundance (1979) in which players score points by opening hatches to catch suns that are bouncing between two grids [3]. Like opabina and hallucigenia, these games are early experiments that just didn't pan out (although not necessarily because they were deficient for some reason).

What happened next also parallels between the two metaphorical realms. The Cambrian was followed by the Ordovician which brought along the first fishes, and by the time of the Devonian (sometimes called "The Age of Fish") just a hundred million years later, fish had essentially completely exploited their niche. Compare the success of the genre exemplified by Taito's 1978 Space Invaders (albiet not the first shooter) which by the 1990's had evolved into the first person shooter and had codified the genre into a streamlined, simplistic game structure making it the fish of the games world.

Returning to the concept of chreodes, the pathway of probability defined by fish constrains certain aspects of what a fish can be. In general, any fish is going to be a vertebrate that lives in water and acquires oxygen for respiration through gills. There can be many differences between any two fish species (saltwater or freshwater, large or small, tropical or arctic) but almost all fit the basic general description.

The mudskipper - which spends part of its life out of the water - represents a tiny side chreode in the canal of fish, showing a little biological creativity. It's quite possible that similar species that shared that chreode in the past were the ancestors of all land vertebrates, including the versatile mammals, but first they had to overcome the substantial energy barrier of living outside of water, a barrier represented by the steep sides of the fish chreode. That putative evolutionary breakthrough would have been made considerably easier by the lack of any significant competition for land at the time.

In our comparison of metaphors, we have made first person shooters the equivalent of fish (admittedly a largely arbitrary conflation). In principle, at least, the mudskipper of first person shooters could appear at any moment, opening up a new chreode and new possibilities. The question is, what is the equivalent energy barrier to the fishes' life in water problem in respect of first person shooters?

That the chreode metaphor holds any water for game genres at all suggests that something is constraining their evolution. Barring the existence of other inheritance mechanisms, the nature of genetics (and specifically DNA-based genetics) serves to provide the framework limiting the rate of mutation and change in organisms. However, the reason evolution takes place primarily on the scale of millions of years is that biological evolution appears to be largely driven by essentially random processes, which are very slow indeed. Games are designed - why should they show the same slow rate of change (albeit on the faster scale of decades)?

We have already observed that market competition for revenue can be seen to parallel competition for energy (food) in organic life. Nebulous 'market forces' might also be seen to be the constraining force that prevents originality, or at least restrains it. The companies that underwrite games development (an increasingly expensive business) are unwilling to invest millions of dollars on games projects without knowing that they will get a correspondingly large return on their investment. That the right project might create new genre territory (found a new genre chreode) and be worth a fortune is offset by the general difficulty of assessing the market prospects of anything that deviates from previous product. The market only knows what has sold in the past - it has no way of accurately assessing what will sell in the future.

This situation may be the reason that many games designers choose to blame the publishers for the state of the industry. Nonetheless, when one is aware of a problem, the first barrier to progress has already been removed. Additionally, it is not that the publishers are not interested in originality, just that changes are constrained to a gradual process. By working within the existing chreodes, we have a mechanism for introducing elements of originality with some confidence that they will still appeal to a significant proportion of the market.

The Underground

We have seen the codification of form in other media where the cost of production or the size of the audience have risen significantly; witness the chreodes of mass market literature, or the canals of Hollywood. Creative and original films and books come from a vibrant underground (where the cost of creation is fractional compared to the mass market end of the spectrum). Gradually, changes in the underground filter through the whole of the media landscape. The same is broadly true of games.

Id Software's Wolfenstein 3D (1992) was not a major release for any publisher, but rather a small shareware title that caught the imagination of a large audience. In doing so, it expanded and deepened the chreode of first person shooters and as such caused it to 'break away' from the shoot 'em up chreode which went before it. Until this point, the major commercial titles were 2D scrolling shooters - and whilst Wolfenstein 3D did not create the first person shooter, it was the game that began the process of 2D shooters being forced out of the games ecosystem and largely replaced with the first person shooter (and other 3D shooter games).

In this case, the breakthrough was technological in nature. Improvements in hardware allowed for fast rendering of simple full 3D environments with the illusion of solidity (earlier 3D games being largely vector graphics and basic polygonal structures). The creation of other games chreodes have been founded by other factors.

Maxis' The Sims (2000), whilst making use of improved technology to power its AI, could have easily occurred several years earlier since the breakthrough here was primarily design-level. Graphically simplistic, the game hooked into the same fly-on-the-wall instincts which had made reality TV popular. It expanded the chreode begun earlier by simple 'virtual pets' and The Activision Little Computer People Discovery Kit (1985) which was also a big hit in its day, relative to the size of the market at the time. The Sims has yet to manifest its possible influence on games within its genre (and hence its chreode) but it is clear that the sim game genre has never experienced such commercial domination by a single game before.

These examples show two different ways in which new game chreodes (or new paths within existing chreodes, depending on your perspective) can come into existence: one through the small but significant computer game underground, the other in a high profile, abundantly funded project. In both cases, however, the changes have come from within existing chreodes. Except for the earliest years of the games industry (and with the possible exception of the Japanese games industry), the freedom to be relentlessly innovative must be constrained by the financial needs of the companies that create games.

Extinction

As well as acquiring new chreodes, a landscape of probability can lose canals and pathways. This does not happen with our original example of water eroding a plain (not without some contrivance) but it happens to biology in the form of mass extinctions. Accepting the plausible but still debatable Alvarez Hypothesis, the dinosaurs were wiped out at the end of the Cretaceous by the impact of a giant meteor. Whole chreodes representing dinosaur and other species were wiped out from probability landscape of organic life [4]. These mass extinctions extend to games, too.

The arrival of the Sony PlayStation (and to a lesser extent, the Sega Saturn) with architecture specifically geared to rendering in 3D marked a mass extinction of 2D games, with no 2D genre being unaffected. The 2D games, like the dinosaurs, were driven to occupy new niches in order to survive. For the dinosaurs, they appear to have taken to the skies and survived in the form of birds [5]. For 2D games, the handheld market kept them alive.

A theory that is gaining ground in the paleontological field is based upon the observation that the fossil record is not a continuous record of change. Rather, mass extinctions mark boundaries between geological ages, and the fossils that may be found in one era vary significantly from the fossils found in another. Rather than seeing continuous change between species in the fossil record, it seems as if species reach a state of relative stasis - with very similar fossils being found across tens or hundreds of millions of years of rocks - with change occurring largely in the wake of a mass extinction. This is the theory of punctuated equilibrium [6].

Why should it be that change occurs most rapidly in the wake of extinction? One way to picture this is to consider the situation in light of our chreode models. When a system is left to its own devices long enough, the set of chreodes becomes a series of deep, distinct channels. New options are constrained because most entities (games or organisms) are canalized into the most successful forms. When a mass extinction occurs, large areas of the landscape of probability are wiped out (or at least, temporarily ignored). It is exactly equivalent to new niches opening up to exploitation, and sudden and significant changes are free to occur. The explosion of variety in the Cambrian Explosion can be seen as a result of unfettered freedom to explore new niches, and the wake of a mass extinction can be seen the same way.

We have likened the arrival of an easy-to-program 3D architecture to the extinction of the dinosaurs, but not all games extinctions originate from advances in hardware. Prior to 1985, the arcade game market was characterised by games that you paid for a single game and then played for as long as you could on one credit. Namco/Bally Midway's Pac-Man (1980) typified the arrangement, with a series of ever-more challenging mazes facing the player, and the reward coming for getting as deep into the game as possible, and from getting high scores. Games typically used lives as a mechanic to determine game length, so that a good player could last more or less indefinitely, whilst a poor player had a short play experience.

The arrival of Atari's Gauntlet (1985) heralded a mass extinction in the arcades and the start of the "pump and play" era. The notion of a “continue” had been around before, but games were not designed with this method of playing in mind. The design principle was generally that player's would put more money into the game in order to get better at it. With sufficient practice, players could make one credit last an hour or more in some games such as, for example, Capcom's classic vertically scrolling shooter 1942 (1984).

Gauntlet threw the old design principle and replaced it with a life-resource that ticked down as the players' progressed through the game. Now, players with a lack of skill could remain in the game by adding more money for more credits. Progress through the game was dominated not by the player's skill (although it remained a factor) but by the amount of money the player was willing to commit to the game. The fact that Gauntlet combined this financial masterstroke with an ambiguous multiplayer mechanic which offered both co-operation and competition in the same environment only served to heighten its appeal.

The mass extinction that resulted lead to an era in which any player could see the end of a game - if they were prepared to pay to see it. This also lead to more games being designed with an end point in mind since no-one would be compelled to pay more money if there was not more new things to see deeper into the game. Whereas before the expert players were the people returning to the games repeatedly, but were spending less and less money to play as their skills improved, now the arcade was opened up to the masses. All you needed was cash and you could see as much of a game as you wanted.

The chreodes representing the simple repetitive structure that had driven games design prior to 1985 were wiped out almost completely, and although this structure is still used in many simple games (e.g. those on mobile phones), its commercial significance has fallen away to almost nothing. This extinction was not driven by hardware, but by design issues. It is similar to a situation in biology where the arrival of new species with certain competitive advantages results in the sudden extinction of previously successful species.

Applying the concept of punctuated equilibrium to games suggests that metaphorical mass extinctions are a potential mechanism for originality to flourish - albeit briefly - but predicting how and when such an extinction will take place is an inexact science. For example, it is easy to predict that breakthroughs in interactive storytelling will create a mass extinction at some point, but much harder to anticipate exactly which breakthroughs will cause this, and which genres of games will be hit hardest by the transition. Similarly, cheap availability of virtual reality equipment will doubtless have characteristics of a mass extinction, but how and when this will occur is impossible to elucidate.

The failure of one game does not cause extinction, only the market collapse of an entire genre can be reasonably considered a 'game extinction'. Whereas in usual circumstances the chreodes of the games industry act like an eroding river, carving out the shape of the landscape of possible games and reinforcing the pathways of the successful products, extinction marks a period of upheaval. The old chreodes collapse and become filled in, and the flow of the canals of probability take a new course - or in some cases they collapse completely and cease to exist. This hints at the extent to which originality can impact on the landscape of the games market.

Conservatism versus Originality

Evolution is frequently imagined as a constant and gradual progression of advancement, in life, from single celled creatures, to multi-cellular life, to comparatively 'advanced' organisms like mammals and birds. The metaphor of the 'ladder of progress' that has become synonymous with evolution is actually highly misleading. The most successful life forms in terms of the total biomass sustained are still the single celled organisms; the greatest variety of species and maximal adaptability lies with the insects. Mammals, with some 4,000 species, are a very small part of life as a whole [7]. Complex life has exploited certain niches, but left to their own devices the larger organisms hit periods of comparative stasis.

Dinosaurs were the prevailing multi-cellular form for almost two hundred million years; only their extinction at the end of the Cretaceous provided the opportunity for mammals to take their place. During the Mesozoic, when the dinosaurs 'ruled the Earth', they refined their biological 'designs' gradually, but these changes were very gradual. After an extinction, the rate of change accelerated as the landscape of life went through a period of dynamism, before settling down into a new, comparatively stable state. If it were not for the periods of conservatism in biological evolution, however, it would be difficult for any progress to be made. If mass extinctions occurred every million years, and not every fifty million years or so, no stable ecosystems could arise.

The same lesson appears to apply to games. Periodic outbreaks of originality, and the corresponding extinction of certain game genres, are useful to drive the form forward, but the conservative intervals between these events are what serve to sustain the market. Refinement of design is as valuable a process as raw originality. Sequels serve an important role in the development of games, and one quite separate from the occasional ground-breaking games that reconfigure the chreodes in a part of the landscape of games.

The value of sequels is well known by publishers and developers alike, although they sometimes feel the need to publicly play-down this conservatism and make claims to originality where no such claims are warranted or needed. Capcom completely recognised this pattern, and freely identify their market strategy as founding new chreodes with original products (or exploiting existing chreodes with new games) then refining and exploiting that chreode with a series of sequels which expand upon and polish the original game play. (Capcom do not use the term chreode, but the comparison is valid).

Even the gaming press recognises the value of sequels, albeit reluctantly. Edge magazine's review of Blizzard's Warcraft III: Reign of Chaos takes an almost apologetic tack. It is apparent that they enjoy and think highly of the game, and yet the author seems to feel the need to make excuses for the game's lack of originality [8]. There is no need to apologise for games that fulfill the role of sequels perfectly: Warcraft III Reign of Chaos refines the gameplay from earlier installments in the series, adding polish and clarifying the core gameplay. The market success of the game only serves to underline the point that the audience was looking for more of the same, and Blizzard's conservatism is in line with the needs of the market. They know which chreode they are exploiting, and have no need (with this particular product) to attempt to define new pathways.

By comparison, games such as Crystal Dynamics' Soulreaver 2 and Acclaim's Shadowman 2 have been criticised for not capitalising on the strengths of the first games in the sequence. By striking out in new directions, they have expended much of their development resources trying to break out of their current chreode, rather than refining the strengths of the originals. (In these particular cases, technical issues relating to the architecture of the PlayStation 2 are likely to have been key factors, showing once again the impact new hardware can have on the shape of the games landscape).

The value of sequels to the market is that their chreodes are clearly defined: original thinking may be required to fix apparent flaws in the initial outings, but refinement of the game design is a sufficient goal for any sequel. Originality should not be allowed to detract from the strengths of the previous game designs in the series. Considerable effort (and money) is sometimes spent fighting against the shape of the chreodes of the market, when it is rarely the sequels that are in a position to effect significant change.

Conclusion

Throughout this essay we have compared evolutionary biology to the games industry in a somewhat cavalier attitude, and before closing it is worth pointing out a few critical points. Firstly, this comparison is not rooted in science, but rather in an artistic viewpoint. We cannot claim to have proved anything by conflating organisms to games, merely to have explored the area of games more fully by virtue of a metaphorical construct (in this case chreodes).

The value of thinking in terms of chreodes is that it provides us a physical correlate for an otherwise ephemeral concept: we cannot see the shape of the games market, but imagining it mapped out by chreodes that represent the probability of a game following a particular design 'canal' allows us to think about that market in new and interesting ways.

By using this perspective, we have been able to suggest that originality, if it is to flourish in a financially-driven art-form, should take advantage of new opportunities presented by breakthroughs in design and technology, but not stray too far from the commercially-viable probabilistic real estate at the centre of the market's chreodes. There is a place for rampant, uncontrolled originality (as the Japanese market demonstrates most clearly) but only on cheaper projects that can afford to gamble on their appeal.

We have also suggested that the shape of the market can be massively impacted by periodic 'mass extinctions', when previously viable genres lose their sales appeal, or old design methods become invalidated by new approaches to core issues. Each mass extinction in the games market represents an opportunity for new and original games to flourish, and as suggested by the theory of punctuated equilibrium, between these periods of rapid change the shape of the landscape of games remains relatively static.

By using this perspective we can suggest that originality can totally reconfigure large areas of the chreodes describing the games market - but that anticipating how and when these changes occur is largely a black art. It is easy to make predictions as to the nature of the changes, but not to the specifics of the games that will make the changes. The lesson here, perhaps, is that publishers looking to be at the forefront of change in the industry should occasionally step outside of their existing brand chreodes and gamble on new design or technology, because the potential rewards for founding a whole new chreode branch has the capacity to exceed the value of mining out existing chreodes.

The obvious candidates for such originality (from a publisher's perspective) are licensed games, ironically the traditional reserve of the most conservative of designs. Since these games already have a certain expectation of audience from the appeal of the license itself, they are great opportunities to pursue originality. However, this is only the case when the license materials suggest a new form of gameplay. Forcing innovation on a license that would be better served by a more conservative approach is more likely to result in developmental resources being wasted trying to break out of a chreode that would serve the licensed game more than adequately.

Despite the continual call for originality, it remains the case that the whole of the landscape of games remains valid territory (at least until an extinction radically alters the shape of the terrain). Conservative approaches to design - the decision to work within an existing chreode rather than attempt to create a new one - are populating viable niches in the market, and all such niches are viable for occupation. The refinement of an existing chreode is as valuable a contribution to the evolution of games as the foundation of new pathways.

Computer games have been driven by originality, but sustained by conservatism. Looking at this process through the metaphor of chreodes, and specifically through parallels with the journey of life, provides tools for thinking about how and why this might be, some advice for sustaining the market's viability, and perhaps some scant clues to the future evolution of the art form.

References

[1] The Strategy of Genes; C.H. Waddington; George Allen and Unwin Ltd, 1957

[2] Play it again, life; Stephen Jay Gould 1986; Natural History February 1986: 18-26.

[3] The Killer List of Videogames; originally by Mike Hughey with contributions by Jeff Hansen, revised 1993 by Jonathon Deitch, revised 1998-1999 by Brian L. Johnson, www.klov.com; 1993, 1998-1999, 2000.

[4] Extraterrestrial cause for the Cretaceous-Tertiary extinction; L.W. Alvarez, W. Alvarez, F. Asaro, H.V. Michel, 1980; Science 208:1095-1108

[5] Dinosaurs Take Wing: New fossil finds from China provide clues to the origin of birds; J. Ackerman, 1998; National Geographic 194: 74-99

[6] Punctuated equilibrium comes of age; Stephen Jay Gould and Niles Eldredge; Nature 366:223-227

[7] Ladders and Cones: Constraining evolution by canoncial icons; Stephen Jay Gould; taken from Hidden Histories of Science; Granta Publications Ltd, 1995.

[8] Warcraft III: Reign of Chaos (Review); author uncredited, 2002; Edge 114: 91

Author Bio

Chris Bateman

Chris Bateman is the founder and managing director of International Hobo Ltd, a company which provides game design and dialogue scripting services to the global games industry. Holding a Masters degree in Artificial Intelligence, he has worked as both a game designer and writer for over a decade, and his games include Discworld Noir and Ghost Master. He is also a published novelist, chapter co-ordinator for the IGDA North West UK, and sits on the executive panel of the IGDA Game Writers SIG.

The opinions expressed in this article do not necessarily represent the IGDA.