Special Effectivities: On the Intersection of Spatial Knowledge and Bodily Skill


Ian here—

The following is the spoken presentation version of my talk from the 2013 Philosophy of Computer Games conference in Bergen, Norway. The full paper, as drafted up for the conference’s proceedings, is available here. You can follow along with the visual presentation for this spoken version here.

Over the past decade, the term “affordances” has nestled itself into a firm and comfortable position within the vocabulary of videogame theory, having found widespread adoption among both academic videogame theorists and practicing videogame designers. Exact definitions of the term vary, but within a fairly predictable range. So, for a few examples, we have:

  • “the opportunities for action made available by an object or interface” (Michael Matteas)[i]
  • “what an object offers an organism to do with it” (Ulf Wilhemsson)[ii]
  • “the functional input-output relationship of an object in the context of an environment” (Dan Pinchbeck)[iii]

We can see traces here of different theoretical backgrounds, with some borrowing the term directly from ecological psychology, and others being more inspired by its use in HCI and experience design theory by Donald Norman.

But, despite these different backgrounds, everyone agrees that the term “affordances” provides a convenient shorthand for discussing the differences between environmental objects that can and cannot be destroyed by the gun in Quake, for differentiating the objects we can and cannot pick up with the gun in Half-Life 2, and for designating the distinction between grey walls and black metal when wielding the gun in Portal. We could even apply it when discussing the varieties of cube manipulation allowed by the gun in Antichamber!


And, certainly, having a vocabulary for discussing these sorts of distinctions is useful. But it has the effect of shaving off some of the more interesting resonances the term affordances has within ecological psychology.

Within the ecological approach to perception, affordances are profoundly bound up in with issues of embodiment. Within the ecological approach, perception is defined not as an ability possessed by a given organism, but as a property of an organism-environment system. Affordances are dispositional properties of a synergetic organism-environment system—features of the physical environment “partitioned relevant to an animal’s, or more aptly a species of animal’s, capacity for activity.”[iv] In short, they are always in reference to specific bodily capabilities of the actant in question.

Often, there is this assumption in videogame theory that affordances simply jump from the screen, presenting themselves self-evidently to the player. But this split focus on player and screen essentially bypasses the mediating figure of the avatar—the very body that performs these in-game actions. (Fictionally, of course.)

And why should we concern ourselves with the avatar’s body? Videogames have long been inconsistent in their provision of players with avatars that genuinely seem to possess bodies. Two-dimensional, third-person games feature avatars that can instantly cancel momentum, or even elaborately change the direction of jumps in mid-air. These avatars are just moving centers-in-space, with no sense of weight or commitment to action, and no sense that they are capable of fatigue or strain.

Meanwhile, first-person shooters have so long fallen prey to “floating gun syndrome,” the feeling of controlling merely a mobile point-of-view, and not a body. It is little wonder that discussions of affordances in games gravitate towards the capabilities of guns rather than the bodies holding them: Unlike bodies, they are actually given a sense of heft, a differentiation of strengths and limitations.

Here, I am going to be focusing on the term that complements “affordances” within ecological psychology: effectivities. “Effectivities” describe “the causal propensities of an animal to affect or bring about a particular action.” As you can see, this definition forms a “fit” with the defintion of affordances. Objects in the environment afford activities. Organisms in the environment effect activities.


What are the benefits of borrowing this term? There are two opportunities offered here. As we have seen, not all (or even most) games sustain the impression of a truly embodied avatar. But exceptions to this trend do exist. And, when dealing with these exceptions, pairing the concept of affordances with that of effectivities allows us to better discuss ways in which videogame space is always shaped by the bodily abilities of the player’s in-game avatar.

Secondly, the issue of how players are able to quickly learn to recognize features of game environments in terms of the effectivities of the avatars they control is one that straddles two rich domains. On the one hand, it concerns practical issues of visual learning and conveyance in game design. On the other hand, it intersects with long-standing issues in the philosophy of game fictions, including the ways in which the avatar stands as a point of ontological fusion between actual and fictional actions, and the relationship between user interface and gameworld.

Painting the town red in Mirror’s Edge


Released in 2008, firmly sandwiched between the 2007 release of the first entry in Ubisoft Montreal’s Assassin’s Creed series and the 2009 release of Sucker Punch’s inFAMOUS, DICE’s Mirror’s Edge seems to fit un-problematically into the subgenre of parkour-based 3D platforming. Some of the game’s most ardent admirers, however, have offered more far-flung descriptors, including “racing game” (not too unusual, perhaps, given the game’s focus on chase sequences and time trials) and even “driving game” (a bit odder, and perhaps more telling).[v]

Mirror’s Edge moves toward the direction of vehicle-based games precisely in the expectations is places on the player to take complete responsibility for a unique set of movement capabilities, grounded in the limitations of a consistent and decidedly non-cartoon physics. Unlike the distinctly “slack” controls of Assassin’s Creed, players of Mirror’s Edge really need to get a feel for how Faith, the game’s player character, “handles.”

The game’s first-person perspective is a complication here. In a third-person parkour game, one can always easily gauge the height of objects relative to one’s avatar at a glance, see relevant handholds, and the limbs that grab them. The first-person view presents different constraints. There are, in fact, several important things that one can ascertain a body simply by having access to their perspective on the environment: In terrains with a visible explicit horizon, for instance, the horizon optically bisects objects at the eye level of the perceiver, specifying the perceiver’s height in relation to their environment.


But this information is only useful if we also understand Faith’s jumping and vaulting effectivities, alongside her height and the height of objects. Recent studies of parkour traceurs in ecological psychology have shown that they perceive walls to be shorter than do non-traceurs. As the authors of one study succinctly put it, “[p]erceived height is scaled relative to anticipated ability.”[vi] But most players don’t have a background in parkour. So how can the game offer a first-person view onto the optic flow of Faith’s running while simultaneously “flavoring” that perceptual experience with Faith’s knowledge about her own body’s effectivities?

The solution Mirror’s Edge employs is “runner vision”: objects in the environment are re-colored if Faith is able to use them to move forward. Pipes Faith can successfully jump to, air vents that she can smash the grate out of and crawl into, piles of boxes she can scramble up to vault herself onto an otherwise unreachable ledge, walls she can run off of, ramps towards walls she can run off of, and jumping-off points on rooftops that will successfully land her onto the next rooftop (rather than splattered on the ground below) are colored bright red. This serves to quickly communicate to the player the affordances in the environment that match Faith’s effectivities.


Runner vision expertly skewers the “diegetic”/“non-diegetic” distinction. It penetrates the depicted space of the game, rather than hanging over it as an overlay. It clings to objects like a fresh coat of paint—and, in fact, details such as the red tag marks that dot the city, and a PSA that lists “a fondness for the color red” as a trait of runners create “fictional cover” for this interpretation: perhaps it is an indicator system painted on by Faith’s fellow rooftop couriers. But if that is the case, why can the inclusion of this paint be toggled on and off at will within the game’s menu? And why, even when activated, does the coloration fade in and out of existence based on proximity? Details such as these puckishly jam the spokes of attempts to pursue a tidy division between the gameworld and the game interface.

A more productive focus here, I think, is on the gap between player knowledge and skill and avatar knowledge and skill. Rune Klevjer has characterized the player-avatar relation as a “‘progressive mapping’ between an actual learning process and a fictional learning process”:

When the player has learned to time the jumps correctly, the avatar has learned to traverse the dangerous pits. When the player fails to perform, the avatar fails to perform; when the player improves, the avatar improves.[vii]

But the fictions of games can conflict with this logic of “progressive mapping.” In Half-Life 2, the gravity fun is introduced to the player and to Gordon Freeman simultaneously. The instruction to play around with the gravity gun as they master its range of functions is, in this way, fictionally motivated.

By contrast, Faith’s body is not an implement that has recently picked up: It is something she has lived in all her life, and we have every reason to assume that she knows how to use it.

In my paper, I turn here to James Paul Gee’s concept of “joint professional identities.” Here, I argue that although Gee has written insightfully about how expertise gets “parceled out, shared between, the virtual characters and the player,” his narrow focus on certain forms of “professional” expertise creates some blind spots.[viii] Knowing the scope and limits of one’s bodily effectivities is, in fact, a skill—a skill that is distributed in games with different realms of responsibility falling to both and to avatar. Faith recognizes the things she can climb on. It is the player’s responsibility to correctly time the inputs to perform these acrobatics. So the game literally colors the player’s perception, extending Faith’s embodied knowledge outward into the space of her world.

So runner vision is effective. It is admittedly also intrusive. But when the player is placed in control of such an unfamiliar range of movement effectivities, what other approaches work? To take a very different example … let’s turn to Namco’s Katamari Damacy (2004).

Dynamic diameters in Katamari Damacy

So, a quick note: Although the bodily abilities of the Prince of All Cosmos underly the movement of the katamari in Katamari Damacy, here I will be focusing on the katarami itself, rather than the Prince. The katamari’s constant changes in size, and the game’s forced constancy of its relative size onscreen, create a continuous re-scaling effect of the games’ environment, which is what I am most interested in here.

So, an example: Here is a set of bleachers that appears in an early level of the game. If, upon first arriving at these bleachers, the player’s katamari is under 14cm in diameter, the first bleacher can be rolled under. Upon returning to these bleachers with the katamari with a 25cm diameter, however, the bleachers now afford climbing, allowing the player to roll up the entire set, and access the area above.

Here, I need to introduce some new terminology. Ecological psychology tends to push away from extrinsic, “neutral” measurements, and towards intrinsic, body-scaled measurements when conducting research. So, rather than standard units, a popular alternative are what are called pi numbers. These are unitless values determined by ratios of animal properties (A) to environmental properties (E).[ix]


Because of the constant change in size of the katamari, the pi numbers of various obstacles within the game’s landscapes are also in a constant state of flux. Turning back to our bleacher example , we can observe that, a a diameter of less than 14cm, the bleacher height in pi number terms is 1.31, indicating a rolling-under affordance.  At a 25cm katamari diameter, alternately, bleacher height is 0.73, and affords climbing-over.


Much like Mirror’s EdgeKatamari Damacy frequently requires players to move in ways that they may not previously have been used to. Constant changes in size require players to track gradual shifts in the way the game’s spaces open up, close off, and provide a kaleidoscopic array of movement affordances. The game’s katamari-scaled visuals provide an elegant and deeply intuitive system for communicating these possibilities to players.

Nothing throws this elegance into relief as much as those moments in which it breaks down. For instance: during the construction of the game’s seventh star, players encounter a fence that cannot be surmounted until the katamari reaches 2m in diameter. At this point, the fence’s heigh in pi numbers is .53. This would seem to indicate a critical pi value of roughly .53 for a “fence-like obstacle vaulting affordance.” If they are still at 2m in diameter, however, players will soon encounter a fence-like row of road cones that, in pi number terms, has a height of .48. However, this fence remains impassable until the katamari is 3m in diameter—a violation of the critical pi value previously demonstrated.


In this case, the game’s previously fairly consistent perceptual rules become overridden by an arbitrary design choice, and this row of cones emanates a vague aura of unfairness.


Game spaces are never neutral warehouses of polygons; they are always, to borrow a phrase from an oft-quoted passage in Merleau-Ponty’s The Structure of Behavior, “pervaded with lines of force,” delineated by the possible actions of the avatar in question.[x] The effectivities of the avatar always open up and constrain the space of their respective games.

The concept of effectivities is more specialized than that of affordances, and I am under no illusion that it will gain as widespread adoption in game studies. However, it can be a useful addition to our toolbox in games featuring more robustly embodied avatars. Some examples in addition to the two examined in depth here would be games in which the player controls a character in different stages in their bodily growth, such as The Legend of Zelda: Ocarina of Time (Nintendo EAD, 1998), or the opening sections of Fallout 3 (Bethesda, 2008) …

… games in which players control a non-anthropomorphized animal or otherwise nonhuman avatar—both those in which players can transition between multiple bodies, such as Dishonored (Arcane Studios, 2012) …

… and those in which the player consistently controls an animal, such as the recent Shelter (Might and Delight, 2013) …

… or horror games that emphasize hiding, crawling, vaulting, and squeezing, such as the recent Outlast (Red Barrels, 2013).

In games such as these, the space of the game’s world is shaped and crafted by avatars’ bodies (and in terms of the knowledge, parceled out between player and player character, about these bodies’ skills) to such a degree that it would be incoherent to separate them. We could say, in effect, that these avatars are their gameworlds, existingly.[xi]

[i] Mateas, Michael. “A Preliminary Poetics for Interactive Drama and Games.” In First Person: New Media as Story, Performance, and Game. Edited by Noah Wardrip-Fruin and Pat Harrigan. Cambridge, MA: MIT Press, 2004. Pg 24.

[ii] Wilhelmson, Ulf. “Computer Games as Playground and Stage.” Paper presented at CGIE2006, the Joint International Conference on CyberGames and Interactive Entertainment, December 4-6, 2006, Perth, Australia.

[iii] Pinchbeck, Dan. “Story as a Function of Gameplay in First Person Shooters: An Analysis of FPS Diegetic Content, 1998-2007.” PhD Thesis, University of Portsmouth, 2009. Pg 13.

[iv] Turvey, Michael T. and Robert E. Shaw. “The Primacy of Perceiving: An Ecological Reformulation of Perception and Memory.” In Perspectives on Memory Research: Essays in Honor of Uppsala Universityʼs 500th Anniversary. Edited by Lars-Göran Nilsson. Hillsdale, NJ: Lawrence Erlbaum Associates, 1979. Pg 205.

[v] Boyd, Robert. “Why Games Like The Wonderful 101 Are a Poor Fit for the Gaming Press.” Zeboyd Games Pinchbeck, Dan. DOOM: SCARYDARKFAST. Ann Arbor: University of Michigan Press, 2013. Pg 171 n2.

[vi] Taylor, J. Eric T., Jessica K. Witt, and Mila Sugovic. “When Walls Are No Longer Barriers: Perception of Wall Height in Parkour.” Perception 40:6 (2011). Pg 758.

[vii] Klevjer, Rune. “What Is the Avatar? Fiction and Embodiment in Avatar-Based Singleplayer Computer Games.” PhD Thesis, University of Bergen, 2006. Pg 141.

[viii] Gee, James Paul. Why Video Games Are Good for Your Soul: Pleasure and Learning. Champaign, IL: Common Ground, 2005. Pg 47.

[ix] Warren, William H. Jr. “Perceiving Affordances: Visual Guidance of Stair Climbing.” Journal of Experimental Psychology: Human Perception and Performance 10:5 (1984). Pg 686. Mark, Leonard S. and David Vogele. “A Biodynamic Basis for Perceived Categories of Action: A Study of Sitting and Stair Climbing.” Journal of Motor Behavior 19:3 (1987). Pg 369.

[x] Merleau-Ponty, Maurice. The Structure of Behavior. Translated by Alden D. Fisher. Boston: Beacon Press, 1963. Pg 168.

[xi] Heidegger, Martin. Being and Time. Translated by John Macquarrie and Edward Robinson. New York: Harper Collins, 1962. Pg 416.


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