What Is an Affordance?

What should and should not be considered an affordance is still an open issue. At the 2002 North American meeting of the International Society for Ecological Psychology, a symposium was held concerning this topic. The articles in this special issue are expanded versions of the papers presented at that symposium. To set the stage for those discussions, this article presents an analysis of the evolution of J. J. Gibson's thinking on this issue, from some of his earliest writings (i.e., J. J. Gibson & Crooks, 1938) through his most recent writings (i.e., J. J. Gibson, 1979/1986). It is hoped that this forum will stimulate thinking concerning this important ecological concept.     

Gibson's Affordances and Turing's Theory of Computation

The concept of affordance is a central component of the ecological psychology of J. J. Gibson (1966, 1977, 1979/1986). Affordances are properties of the environment taken relative to an observer. Ecological theorists have developed formal models for the analysis of affordances. Models proposed by Shaw and Turvey (1981), Turvey (1992), and Greeno (1994) are described and evaluated, and another approach, using Turing's (1936-1937/1965) theory of computation, is outlined. Affordances are characterized as the configurations of Turing machines. It is shown that Turing's work provides a natural vehicle for exploring Gibson's ideas.     

Affordance Types and Affordance Tokens: Are Gibson’s Affordances Trustworthy?†

Late in their paper on hypersets, Chemero and Turvey characterize affordances as “quicksilvery,” prone to rapid appearance and disappearance. We contrast this view with Gibson’s emphasis on the stability of affordances. We argue that this apparent discrepancy can be resolved by appeal to the distinction between affordances as indefinite abstract types and definite affordance tokens (instances of the type that share the resemblance relation). These issues will be discussed in the context of their consistency with ecological realism, where Platonic idealism is eschewed in favor of a more Aristotelian process theory. These ideas will be examined in the broader context of the domain ontology to ensure that Gibson's seminal affordance concept has its greatest theoretical utility. Finally, we develop a process theory of ontological descent by which indefinite affordance possibilities become more definite affordance potentialities and these eventuate in the most definite affordance actualizing actions.     

Theoretical Hubris and the Willingness To Be Radical: An Open Letter to James J. Gibson

J.J. Gibson's direct perception thesis is the cornerstone of ecological psychology. Not to understand this is not to understand ecological psychology. Beginning in the summer of 1968, when I first met Gibson, and after working with him for the next year at Cornell, I underwent a conversion crisis. I came to appreciate his thesis through a few philosophical insights that I here share with the reader through an open letter to Gibson, where I seek to illuminate the reasons for my conversion from being a Miller-Chomsky psycholinguist and a Piaget devotee to a radical Gibsonian. This conversion has influenced my work even until the present. Indeed, I am still working through its implications in all that I attempt. I share this intimate portrait of my relationship to Gibson and his profound ideas in hope that others who have struggled with his thesis might be helped along their way as I was.     

The Ecological Revolution: The Senses Considered as Perceptual Systems, 50 Years Later - Part 2

ABSTRACT

This editorial presents the second of a 2-part special issue honoring the publication of James J. Gibson's 1966 book, The Senses Considered as Perceptual Systems. As was pointed out by several reviews of this book written just after its publication (i.e., between 1967 and 1969), Gibson's 1966 book represents a revolution not only for the psychological science but also for domains beyond that of psychology. This second part of the special issue is composed of 5 theoretical contributions that represent, in addition to the 4 pieces previously published in the first part, the far-reaching influence of Gibson's ecological revolution.     

1966 and All That: James Gibson and Bottom-Down Theory

ABSTRACT

The “later” James Gibson is widely misrepresented as an extreme stimulus–response theorist. In fact, Gibson's 1966 book presents a radical alternative to stimulus–response theory. “Perceptual systems” are not passive and receptive but “organs of active attention” (1966/1968, p. 58). Perceivers “reach out” into the world. This commentary examines some of the implications of Gibson's systems-cum-functionalist-cum-ecological approach, including the relations between the senses; the concept of “sensationless” perception; and most fundamentally, the nature of perceptual systems as extending beyond the body. I conclude that an adequate understanding of perception cannot be limited to the already severely limited domain of psychology. If Gibson is right, “ecological psychology” is a contradiction in terms.     

Feeling one's way in the world: Making a life

This paper argues for the psychoanalytic relevance of the works of James Gibson and Susanne Langer in explicating the early development of the human child and makes use of this combined formulation of development to think about psychoanalytic theory and practice. From the insights of James Gibson's ecological psychology we can appreciate the embodiment and embeddedness of the child's growing mind within both her physical and social environments. Making use of Susanne Langer's concept of feeling to redefine ecological psychology's perceptual counterpart to action allows us to understand the child's seamless transition into active participation in her culture, as she learns to project her animalian capacity to feel into intersubjectively defined forms of behavior and experience with others. The paper presents a lengthy exposition of Gibson's ecological psychology, before explaining Langer's thinking and launching into the combined insights of these scholars to explicate the nature of the child's mind as she feels her way in the world and makes a life for herself within it. This is the life she will be able to remake in the embeddedness of a psychoanalytic therapeutic relationship where she can learn to feel her way in the world in a new light.     

Visual illusions and direct perception: Elaborating on Gibson's insights

Gibson argued that illusory pictorial displays contain “inadequate” information (1966, p. 288) but also that a “very special kind of selective attention” (p. 313) can dispel the illusion–suggesting that adequate perceptual information could in fact be potentially available to observers. The present paper describes Gibson's treatment of geometrical illusions and reviews pertinent empirical evidence. Interestingly, Gibson's insights have been corroborated by recent findings of inter- and intra-observer variability in susceptibility to visual illusions as a function of culture, learning and task. It is argued that these findings require a modification of the general Gibsonian principle of perception as the detection of specifying information. Withagen and Chemero's (2009) evolutionary motivated reconceptualization of perception predicts observers' use of both specifying and non-specifying information and inter- and intra-observer variability therein. Based on this reconceptualization we develop an ecological approach to visual illusions that explains differential illusion effects in terms of the optical variable(s) detected.     

The Senses Considered as One Perceptual System

ABSTRACT

J. J. Gibson (1966) rejected many classical assumptions about perception but retained 1 that dates back to classical antiquity: the assumption of separate senses. We suggest that Gibson's retention of this assumption compromised his novel concept of perceptual systems. We argue that lawful, 1:1 specification of the animal–environment interaction, which is necessary for perception to be direct, cannot exist in individual forms of ambient energy, such as light, or sound. We argue that specification exists exclusively in emergent, higher order patterns that extend across different forms of ambient energy. These emergent, higher order patterns constitute the global array. If specification exists exclusively in the global array, then direct perception cannot be based upon detection of patterns that are confined to individual forms of ambient energy and, therefore, Gibson's argument for the existence of several distinct perceptual systems cannot be correct. We argue that the senses function as a single, irreducible perceptual system that is sensitive exclusively to patterns in the global array. That is, rather than distinct perceptual systems there exists only 1 perceptual system.     

进化心理学与生态心理学的整合：理解适宜可用性

进化心理学源自达尔文进化论,以分析心理机能及起源为主要研究目的。同样,生态心理学在Brunswik(1956)和Gibson(1979)开创引领下,探讨了有机体的知觉、判断、行为等因素在环境适应中的作用。尽管进化心理学和生态心理学都具有生物机能主义倾向,但过去研究较少探讨二者联系。该文引入适宜可用性观点来整合进化心理学和生态心理学的理论与实证研究。适宜可用性的观点认为,生存与繁衍问题中的代价与利益分析有助于特定种群的动物采取趋近或回避行为来保证潜在适宜性。适宜可用性的观点源自进化生物学中的知觉理论,它解决了认识论中许多传统问题,也整合了进化心理学和生态心理学的实验研究成果。适宜可用性的观点为新世纪的感觉、知觉、认知、情绪和决策的研究提供了新的理论基础     

Potentiation of action by undetected affordant objects

The physical attributes of objects that are relevant to motor behaviour, or action, are referred to as affordances (Gibson, 1979). Recent evidence has shown that an object's affordance can potentiate an unrelated motor response even when there is no intention to respond to it (e.g., Tucker & Ellis, 1998). In the five experiments, we examined whether conscious perception of an affordance is necessary to produce motor priming by presenting images of affordant objects (e.g., hammer) under conditions which cause them to be undetectable: Brief masked exposure (BME) and attentional blink (AB). We successfully demonstrated that conscious perception is not necessary for an object's affordance to produce motor priming. Since these findings are consistent with the abilities/disabilities of patients with blindsight and visual form agnosia, it is possible that processing accomplished by the dorsal stream produced this effect, though more research is needed to confirm this assertion.     

Guiding Movement by Coupling Taus

Studies of sensory guidance of movement in animals show that large nervous systems are not necessary for accurate control, suggesting that guidance may be based on some simple principles. In search for those principles, a theory of guidance of movement is described, which has its roots in Gibson's pathfinding work on visual control of locomotion (J. J. Gibson, 1958/this issue). The theory is based on the use of the simple but powerful variable tau, the time-to-closure of a gap at the current gap closure rate (whatever the gap's dimension—distance, angle, force, etc.); and on the principle of tau-coupling (keeping two Ts in constant ratio). In this article, I show how tau-coupling could be used to synchronize movements and regulate their kinematics. Supportive experimental results are reported. I also show theoretically how sensory-taus, defined on sensory input arrays, can specify motion-taus through tau-coupling; how the braking procedure of keeping tau.dot stable is a particular case of tau.coupling; and how tools for steering (e.g., limbs, whole bodies, cars, or aircraft) could be built from tau-couplings, which would enable steering control in a variety of situations, including steering straight and curved courses to goals, steering and controlling speed at the same time, steering around obstacles, and asymptoting on surfaces as when landing. Some movements also involve intrinsic guidance from within, and a hypothesis on intrinsic guidance by tau is introduced, supported by experiments spanning different activities.     

Heideggerian Meditations on an Alternative Ontology for Ecological Psychology: A Response to Turvey's (1992) Proposal

In his last book, Gibson (1979/1986) clearly described crucial elements for an ontology for ecological psychology, but left his overarching ontology implicit and incomplete. As a partial remedy, Turvey (1992) presented a compact, well- packaged outline of an ontology for ecological psychology derived in part from the work of Bunge. In appreciation of Turvey's pioneering and thought-provoking attack on this difficult issue, we offer our own reflections on Turvey's propertied realism. In reviewing Turvey's work we use both the insights of Heidegger and recent experimental findings in ecological psychology to argue for the need for a different ontological foundation. We argue that a Heideggerian ontology can provide us with a broader and more complete ontological foundation with which to deal with complex issues, such as prospective control, than can Turvey's proposed ontology. Also, we suggest that a Heideggerian ontology can be used to supply what is missing or understated in Gibson. We argue against propertied realism as a basis for ecological psychology's ontology and contend that a proper conception of intentionality provides a way to transcend traditional object-subject ontologies. We propose that fields should be considered real ontological entities that differ from matter. Finally, we reflect on how the highly nonscientific language of Heidegger might possibly be formalized to make it more suitable for scientific use.     

Visually Controlled Locomotion: 40 years Later

Gibson's article, Visually Controlled Locomotion and Visual Orientation in Animals(1958/this issue), is the leading statement of a nonrepresentational, information-based approach to visual control. The core ideas he introduced 40 years ago resurface, explicitly or implicitly, in much contemporary work on perception and action in humans, insects, robots, and autonomous agents. The purpose of this special issue is to assess the continuing pertinence of these insights and illustrate current directions in research on visually controlled locomotion. In this article, I locate the 1958 article in the context of Gibson's emerging theory of perception, contrast information-based control with standard model-based and cybernetic control architectures, evaluate the current status of Gibson's visual control formulae, and situate visual control within an informational-dynamical approach to agent-environment systems. Locomotion is a biologically basic function, and if that can be accounted for then the problem of human space perception may appear in a new light. The question, then, is how an animal gets about by vision.     

The Essential Elements of an Evolutionary Theory of Perception

ABSTRACT

Traditional theories of perception developed for centuries before Darwin conceived his theory of evolution by means of natural selection. Although many areas of psychological theory and research now have mainstream approaches strongly influenced by evolutionary thinking, mainstream perceptual theory remains close to its pre-Darwinian roots. This paper draws on insights from ecological psychology, especially as represented in J. J. Gibson's The Senses Considered as Perceptual Systems (1966), to identify 4 elements that any future evolutionary approach to perception should be expected to include: (a) an ecological analysis of ambient energy, (b) a comparative understanding of the perceptual abilities of different species, (c) a dynamic understanding of organism–environment interaction as essential for perception, and (d) an understanding of perceptual attunement based on the concept of affordances. Each of these elements serves an essential theoretical role while also pointing toward lines of research where much work remains to be done. The presence of these elements explains, in part, the affinity between ecological psychology and other evolutionarily grounded approaches to psychology, including the emerging fields of enactivism and embodied cognition.     

The Muddle of Anticipation

In J. J. Gibson's classic paper “The Problem of Temporal Order in Stimulation and Perception” (1966a Gibson, J. J. (1966a). The problem of temporal order in stimulation and perception. Journal of Psychology, 62, 141–149.[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]), he referred to the difficulties encountered when attempting a sharp distinction between memory and perception as “the muddle of memory.” Resolution of the muddle by J. J. Gibson proceeded by blurring the distinction itself. We develop the conjugate “muddle of anticipation” similarly by blurring the sharp distinction traditionally drawn between anticipation and perception. The subsequent redefinition of the problem is grounded in strong anticipation equated with anticipating synchronization—that which arises from a system itself via lawful regularities embedded in the system's ordinary mode of function. We identify the fit of strong anticipation's properties to J. J. Gibson's ecological approach and in so doing introduce the possibility of a potentially deep connection between them, namely, that the coordination of perception with surroundings (direct perception) is a special case of strong anticipation.     

BEHAVIOR ANALYSIS AND ECOLOGICAL PSYCHOLOGY: PAST,PRESENT, AND FUTURE. A REVIEW OF HARRY HEFT'S ECOLOGICAL PSYCHOLOGY IN CONTEXT

Relations between behavior analysis and ecological psychology have been strained for years, notwithstanding the occasional comment on their affinities. Harry Heft's (2001) Ecological Psychology in Context provides an occasion for reviewing anew those relations and affinities. It describes the genesis of ecological psychology in James's radical empiricism; addresses Holt's neorealism and Gestalt psychology; and synthesizes Gibson's ecological psychology and Barker's ecobehavioral science as a means for understanding everyday human behavior. Although behavior analysis is excluded from this account, Heft's book warrants a review nonetheless: It describes ecological psychology in ways that are congruent and complementary with behavior analysis (e.g., nonmediational theorizing; the provinces of natural history and natural science). After introducing modern ecological psychology, I comment on (a) Heft's admirable, albeit selective, historiography; (b) his ecological psychology—past and present—as it relates to Skinner's science and system (e.g., affordances, molar behavior); (c) his misunderstandings of Skinner's behaviorism (e.g., reductionistic, mechanistic, molecular); and (d) the theoretical status of Heft's cognitive terms and talk (i.e., in ontology, epistemology, syntax). I conclude by considering the alliance and integration of ecological psychology and behavior analysis, and their implications for unifying and transforming psychology as a life science, albeit more for the future than at present.     

动允直接知觉的共鸣原理

传统认知理论认为我们只能间接知觉动允,而生态认知心理学则认为对动允的知觉是个体与环境信息直接共鸣的过程。生态认知心理学首先判定动允并不是存在于我们头脑中的认识,而是实际存在于个体-环境系统中的事实,对动允的直接知觉就是对动允的检测而非推测,是对动允信息的拾取而非对记忆内容的提取。这种直接知觉表现为身体的相关动作机制（动作神经元、肌肉组织等）与环境中动允信息的共鸣。进化与学习在共鸣的形成与发展中具有重要作用。     

Invariants and Information Pickup in The Senses Considered as Perceptual Systems: Implications for the Experimental Analysis of Behavior

ABSTRACT

Although Gibson focused his agenda on the study of perception and Skinner on learning as contingencies of reinforcement, they shared a nonrepresentational approach. We propose that the ecological concept of invariants developed in Gibson's book The Senses Considered as Perceptual Systems (1966) could underlie Skinner's notion of contingencies of reinforcement as environmental opportunities for behaving. The proposal is divided in 3 parts: the concept of stimulus for perception, the role of the notion of invariants in the operant contingency, and the information for perception and behavior. We conclude that approximating contingencies of reinforcement as instances of environmental invariants can be fruitful for studying a number of phenomena within the context of operant conditioning.