Animacy is a basic category, yet one that is difficult to define precisely. The category of animate things is not the same as living things (since plants and sessile animals for the most part should not be included, while robots and other artificial beings perhaps should be). Animacy is more than simply a category, but constitutes what Minsky calls a "realm of thought" with its own distinctive style of mental representation and reasoning. The dichotomy between animate and inanimate seems to manifest itself in different ways at different cognitive levels. In this section I attempt to sketch out some different approaches to understanding how we think about the animate realm. The roots of animacy are found in basic perceptual processes, but its ramifications go beyond perception and affect the way we think about action and social behavior.
The division between animate and inanimate appears to be both a universal and innate part of how we see the world. An obscure but fascinating thread of research in perceptual psychology indicates that the ability to distinguish between animate and inanimate objects may be in some sense perceptual primitives, hard-wired into our brains at the lowest level (see (Gelman and Spelke 1981) for a survey). At this level, animacy is manifest in the perception of motion, specifically motion that appears to arise autonomously, without visible external causation. The ability to distinguish between caused and autonomous motion appears to be innate and can be detected experimentally.
Research on the perception of causality began with the work of Michotte (Michotte 1950). His experiments involved showing subjects a set of moving abstract shapes on a screen, and asking them to make judgments about what they had seen. In a typical experiment, a moving shape A would approach a second stationary shape B. When A contacted B, depending upon the experimental situation B might start to move either immediately, or after a span of time, and A might stop or continue to move. The subjects were then asked to interpret what had happened.
All subjects tended to interpret these scenes in terms of causal relationships between the two shapes: that is, the experimental situation would strongly suggest either a direct causal relationship between the two movements, or an autonomous (non-caused) origin for the movement of the second object. For example, in the case where A stopped and B immediately began moving, the scene was interpreted as a collision or "launching". In the case where A continued to move along with B, the scene was interpreted as a case of A dragging B along with it. In another case, similar to the first but with the difference of including a delay before B began to move, the subjects would attribute autonomy or self-causation to B's movement. The striking thing about these experiments was the immediacy and power of their ability to induce particular kinds of causal perceptions in the subjects, given the highly abstract character of the objects and motions involved.
Michotte's experiments have been replicated with six-month old infants (Leslie 1979)(Leslie and Keeble 1987). It was found that these young subjects could distinguish between causal and non-causal scenarios. These experiments involved showing the subjects a sequence of presentations similar to those of Michotte, which would consist of all causal presentations with one interposed non-causal presentation, or the inverse. In either case the infants would show a startle response when the interposed presentation was shown.
Stewart (1982)(Stewart 1982) performed similar moving image experiments on adults. In this case, both the motions and the judgments observers were asked to make were somewhat more complex than in the earlier experiments. Stewart's shapes would follow one another or avoid one another, or start, stop, or change directions arbitrarily. Observers were asked to judge whether the shapes in motion were "objects or creatures". All of these motions induced judgments of animacy or aliveness in observers, whereas shapes that followed less complex paths were judged as inanimate or mechanical.
To generalize from the results of these experiments, it appears that humans strongly distinguish between externally caused and autonomous motions, and that the ability to do so is to some extent innate, or at least appears early in development. These perceptual abilities seem to form the perceptual basis for the later development of concepts about living vs. non-living things and purposefulness. To a first degree of approximation, any object moving in ways that appear to violate basic Newtonian laws of motion--that is, an object that changes its motion without apparent external cause, other than friction--tends to induce a judgment that the object is alive, purposeful, and autonomous. On the other hand, objects in unchanging motion, or objects that change their motion only in response to visible external causes, are judged to be inanimate.
The implications of these experiments are that the perceptual system is attuned to changes in motion and relations in changes in motion, and that there is a need to interpret or explain such changes by assigning their cause to either internal or external factors (Premack 1990). The apparent innateness and universality of these effects argues that causality is in some sense a perceptual primitive. Related concepts of aliveness, purpose, intent, self-awareness build upon and refine these primitives.
That there should be such an innate mechanism makes a good deal of sense from an evolutionary standpoint, since it is important for animals to be able to judge which objects in their environment are alive and which are not. From the physiological point of view, it is well-known that the visual system includes many sorts of motion detection mechanisms. The ability to sense changes in motion and relations between different motions is a step up in complexity, but not a very large one. There is even some evidence from studies on brain-damaged and autistic subjects that indicates the presence of a physiological localized mechanism to detect agency and causality (Baron-Cohen 1995).
Do even six-month old infants construct causal models of their world and distinguish between external and internal causes? It seems more likely that there are at least two levels of processing at work here: one, the level of basic perceptual processing, and another process of interpretation and explanation that involves more conceptual thought. The perceptual mechanisms may be able to provide the basic ability to distinguish between caused and uncaused motions, while the conceptual mechanisms, which develop later, have the task of fitting these perceptions into categories and constructing explanations for them.
Piaget's studies of children's thinking revealed a phenomenon he called childhood animism (Piaget 1929). This is the tendency of children to attribute properties normally associated with living things to the non-living. The qualities that are projected onto the inanimate world by childhood animism include both aliveness and consciousness. These are obviously two separate concepts, but they apparently follow similar stages through development, suggesting that they are based on a common underlying concept. Other qualities that are brought into play by childhood animism include freedom and the ability to have intentions or will. While some of Piaget's results have been challenged as being oversimplified (see (Carey 1985)), his central results are still of interest.
Piaget found that children will attribute the quality of being alive to different object types at different stages of development. In general, each stage exhibits a refinement, or narrowing, of the class of things that are considered alive. The stages are outlined in Table 3.1.
| Stage |
Name |
Description |
| Stage 0 |
No concept |
random judgments |
| Stage 1 |
Activity |
anything active is alive |
| Stage 2 |
Movement |
only things that move are alive |
| Stage 3 |
Autonomous movement |
only things that move by themselves are alive |
| Stage 4 |
Adult concept (animals) |
only animals (and plants) are alive. |
As a result of this developmental process, children can exhibit notions of aliveness that depart quite dramatically from the adult version of the concept. For instance, a child of 8 (in stage 1), when asked if a bicycle was alive, replied "No, when it doesn't go it is not alive. When it goes it is alive". Objects might be endowed with consciousness of some things but not others:
If you pricked this stone, would it feel it?--No.--Why not?--Because it is hard.--If you put it in the fire, would it feel it?--Yes.--Why?--Because it would get burned (p176).
Children in the earlier stages (0, 1, and 2) tend to produce mixed and unsystematic judgments. Piaget characterizes stage 2 as primarily a transition period in which the child develops the distinction between things that move on their own (such as a person) and things that only move under outside impetus (such as a bicycle). When this distinction is made the child reaches the third stage, which Piaget considered to be the most "systematic and interesting" of the four. Here is an example of a child struggling to express the Stage 3 idea that autonomous motion is the salient quality that determines the ability to feel:
Tell me what you think, what makes you think that perhaps the wind doesn't feel when it is blowing?--Because it is not a person.-- And why do you think perhaps it does feel?--Because it is it that blows (p183).
Piaget gives special attention to this last answer as a striking illustration of the nature of third-stage childhood animism. "It is it that blows" beautifully illustrates the child's mind arriving at the idea that it is initiators of action that are thought to be feeling and thus animate.
Piaget's view is that only at the third stage (usually reached at ages 7 or 8) do children make the distinction between motion in general and autonomous motion. This would appear to be in conflict with the results of Michotte, Leslie, et al, who believed that this distinction was present much earlier. This conflict might be resolved by realizing that the Piagetian studies operate purely in the conceptual realm, whereas the other researchers are studying the perceptual ability to detect distinctions. Children may have an innate ability to distinguish types of observed motion, but lack the ability to construct coherent explanations for such motion. The latter ability must be learned, and in some sense the Piagetian developmental sequence is a case of the conceptual mind lagging behind and eventually catching up to the distinctions generated innately by the perceptual system.
Piaget's theory of animism has been critiqued on a number of grounds. For instance, the questions asked by the experimenter can induce particular forms of thought and styles of judgment (Piaget himself was aware of this). Also, children at all ages seem to use a large variety of techniques for judging whether or not something is alive, and never use exclusively the fact of autonomous movement (Carey 1985). Carey's critique seems valid--the development of children's representation of the concept of living things is no doubt a more complex story than the simple stage theory has it. However, as Carey admits, her study is not aimed at the heart of the Piagetian theory of animism, which is concerned more with the developing notions of causality rather than the definition of the word "alive" in any narrow sense. Despite her disagreements with Piaget, she agrees that "the separation of intentional causality from other types is central to what is changing." This is really the only aspect of the theory that concerns us here.
A more sophisticated way to handle the distinction between animate and inanimate is to treat them, not as categories into which objects must be slotted, but as two alternative approaches with which to analyze everyday phenomena. Even children are able to flexibly apply these approaches to some extent (recall the child who thought the bike was alive when it moved and not otherwise). Philosophers and psychologists, who perhaps have a greater need to think in fixed categories than children, often try to fix these approaches into categories, but even they eventually have abandoned vitalism and dualism, recognizing the need to treat animacy and aliveness as epistemological stances rather than fixed facts of the world. Dennett has articulated this about as well as anybody with his distinction between intentional and physical stances (Dennett 1987), but see also (Boden 1978) on the checkered history of purposive explanation in psychology, and (Schaefer 1980) on how Freud blended both mechanistic and animate stances in his metapsychology.
The sociologist Erving Goffman explored the question of how such stances (frameworks, in his terms) are used in everyday life and how they function in organizing cognition and society. His approach (Goffman 1974) identifies two primary frameworks: social and natural, which correspond roughly to Dennett's intentional and physical stances:
When the individual in our Western society recognizes a particular event, he [employs] one or more frameworks or schemata of interpretation of a kind that can be called primary. I say primary because application of such a framework or perspective is seen by those who apply it as not depending on or harking back to some prior or "original" interpretation; indeed a primary framework is one that is seen as rendering what would otherwise be a meaningless aspect of the scene into something that is meaningful... In daily life in our society a tolerably clear distinction is sensed, if not made, between two broad classes of primary frameworks: natural and social. Natural frameworks identify occurrences seen as undirected, unoriented, unanimated, unguided, "purely physical"...It is seen that no willful agency causally and intentionally interferes, that no actor continuously guides the outcome. Success or failure in regard to these events is not imaginable; no negative or positive sanctions are involved. Full determinism and determinateness prevail. Social frameworks, on the other hand, provide background understanding for events that incorporate the will, aim, and controlling effort of an intelligence, a live agency, the chief one being the human being. Such an agency is anything but implacable; it can be coaxed, flattered, affronted, and threatened. What it does can be described as "guided doings." These doings subject the doer to "standards," to social appraisal of his action based on its honesty, efficiency, economy, safety, elegance... A serial management of consequentiality is sustained, that is, continuous corrective control, becoming most apparent when action is unexpectedly blocked or deflected and special compensatory effort is required. Motive and intent are involved, and their imputation helps select which of the various social frameworks of understanding is to be applied (p.21-22)/
These "guided doings" are subject to constant evaluation both from the doer and from other participants on the scene as to their efficacy and quality, distinguishing them from purely natural happenings, which are not so judged. Social frameworks, but not natural frameworks, involve actors, that is, humans (or occasionally other entities such as animals or gods) that can initiate actions and are responsible for their success.
Framework-based interpretation is fluid; a scene that appears to be a guided doing may be transformed (through accidents or "muffings", or by the realization that an act that seemed intentional was actually an accident) into a scene in which physics takes over from intention (for example, an ice-skater who slips and falls).
The concepts of muffings and fortuitousness have a considerable cosmological significance. Given our belief that the world can be totally perceived in terms of either natural events or guided doings and that every event can be comfortably lodged in one or the other category, it becomes apparent that a means must be at hand to deal with slippage and looseness (p34-35).
The relevance of Goffman to this discussion is his specifically cultural perspective on the dichotomy between animate and inanimate. The ability to distinguish between caused and autonomous motions may be innate, but the types of situations in which this distinction is applied can be enormously varied and conditioned by culture. For instance, differences in religious views can often lead to differing use of frameworks: where some might see a natural disaster others might see the will of a god.
The animate realm now takes on aspects of morality and the necessity of judgment: our social lives require us to make these distinctions and to be subject to them. Trials in which insanity defenses arise are an excellent example of a situation in which the distinction between natural and social arises. A defendant who can be judged subject to the presumptively external causation of insanity can escape having his actions judged according to the standards of social frameworks. Social frameworks impose standards. Actions viewed within social frameworks can be successful or otherwise, because they are initiated and guided by social actors.
Animacy appears to be a basic category of the human mind, appearing in a variety of forms at different levels of cognition. But to think of animacy as simply a category, in isolation from its role in understanding, is to miss its significance, which stems from its key role in the understanding of action and causality.
To try and understand the place of animacy in cognition, we need a theory of representation that takes into account the importance of action. We will use Minsky's frame-based theory of understanding (Minsky 1987, p245), in particular the theory of trans-frames which has its roots in Schank's conceptual dependency scheme for representing semantic information (Schank 1975). Using these tools, I will attempt to sketch out such a cognitive theory of animacy.
In Minsky's theory, a frame is essentially a conceptual template or schema, representing a single concept such as "chair" or "throw", with labeled slots or terminals that serve to connect it to other frames that represent related parts. So for instance a "chair" frame would have terminals to represent legs and back, while a "throw" frame would have terminals representing the object thrown, the thrower, and so forth. Understanding a scene, sentence, or situation involves selecting a frame for it and finding appropriate entities to fill its terminals.
One particularly important kind of frame, used to represent action and change, is called a trans-frame. A trans-frame is a generalized representation of action, which can be specialized for particular circumstances by filling in terminals for various roles such as ACTION, ORIGIN, DESTINATION, ACTOR, MOTIVE, and METHOD. Trans-frames roughly correspond to sentences, in terms of the scale of the concept they encode, although the frame with its many terminals is capable of including more information than a typical sentence. Schank further categorizes trans events into PTRANS, MTRANS, and ATRANS types, corresponding to whether the action involves physical movement, the transmission of information, or the transfer of abstract relationships like ownership.
Trans-frames give us a way to think about the representation of action, and thus a way to think about animacy, leading to a simple theory of what it means for something to be animate: A thing will be seen as animate if its representation can plausibly fit into the ACTOR terminal of a trans-frame. Or in other words, something will seem animate if it can be seen as the initiator of an action. From the standpoint of language, this is equivalent to saying that it can be the subject of a sentence describing the action (assuming the sentence is in the active voice). This definition of animacy suggests the classical Aristotelian definition of an actor or agent as one who initiates action. Of course, this definition is slightly tautological, and it doesn't tell us what things will be able to take on this role or why. But it does give us a convenient way to think about how the animate category functions in relation to other mechanisms for understanding action.
Consider again the example from Piaget, where a child explains why he thinks that the wind can feel--"because it is it that blows". It appears that the child has a frame for BLOWING, which has an actor slot that needs to be filled. Unable to find anything else to put in that slot, the wind itself must be there: "it is it that blows". And, when the wind takes on this role, it is somehow endowed with the properties of the living, despite the fact that the child had concluded earlier that the wind could not feel, because "it is not a person". Another child denies animacy to the wind, "because it is the cloud that makes it blow" (that is, the wind here is an object rather than an actor), and yet another bestows feeling upon the clouds for the same reason. ACTORhood seems to play a powerful role in determining whether or not something is thought to be animate.
Why are actions and actors so important to cognition? Although the world may be in reality a unified flux of physical causation, we can't think about it that way on a practical level. Instead, we need to divide the changing world up into representable parts such as objects and actions. An action is a segment of activity with a beginning, generally in the form of an actor's intention, and an end, in which the world is in a new state as a result of the action. The idea of action, and the related ideas of autonomous, intentional actors (and the notion that they can have "free will") is an artifact of this need to represent the world in manageable chunks.
More complex reasoning requires understanding sequences of events, which in turn involves chaining trans-frames together. In such a chain, individual objects will change their roles: what was an OBJECT of action in one frame may become the ACTOR in the next. The ability to manipulate chains of changes is important to reasoning and suggests that the ability to switch between animate and inanimate may actually be a necessity born of the need to create such chains (see (Ackermann 1991) for a similar argument). The act of explanation chains trans-frames in the opposite direction: when we ask a question like "what made him do that?" we are seeking to build a frame that puts what was an ACTOR into an OBJECT-like role. When an ACTOR's initiation of action is explained by its internal properties, it appears purposeful; when explained by external factors, it appears reactive. If it can't be explained at all, which is often the case, the action might have to attributed to something like free will.
We have attempted to define the animate realm through multiple approaches. Based on the above analyses, I would like to posit three properties which together seem to characterize the animate domain:
These properties relate to each other in complex ways, and in some respects are in tension with each other. The concept of purposefulness is bound up with autonomy--an object's actions will be seen as more autonomous if they are directed toward a goal rather than being driven solely by outside forces. Reactivity is a crucial part of purposefulness--a creature acting to achieve a goal cannot do so blindly, but must be able to respond to changing conditions in the world.
However, reactivity can be in tension with autonomy, since if the creature is reacting to outside conditions, then it is in some sense being driven by outside forces, rather than initiating action. For instance, a frog catching a fly with its tongue can be considered to have both reacted to the fly and to have initiated the action. The frog is the central actor in this version of the story. But it would be just as valid, if odd, to tell a story with the fly as the main actor, acting causally on the frog to cause its own demise. The frog in this version is still reactive, but its autonomy has disappeared. The presence of autonomy is particularly dependent upon point of view and the choice of starting points when describing a sequence of causal events.
Animacy, then, is more properly understood as a framework or way of thinking, rather than as a category. Animate thinking stems from a basic need to explain happenings and tell simple stories about them, and a need to fit things into roles in the stories as actors and objects of action. Scientific and mechanistic ways of thinking are in some sense attempts to get beyond these basic animistic tendencies, in that they tend to eliminate autonomy by searching for a cause for every action. But the tendency to describe the world in terms of autonomous acters is strong. Even scientists who should know better tend to try to find simple explanations and single actors rather than grapple with the distributed causality of a complex system (Keller 1985) (Resnick 1992).