A dynamical systems interpretation of epigenetic landscapes for infant motor development

This paper presents a unified dynamical systems theory of motor learning and development and addresses the normative order and timing of activities in the infant motor development sequence. The emphasis is on the role of intention in modulating the epigenetic landscapes to the emerging forms of infant motor development and how the evolution of attractor landscape dynamics in infancy arises from the multiple time scales of constraints to action. The development of prone progression in infancy is exemplified as a case study and experimental hypotheses of the theory of attractor landscape dynamics and infant motor development are provided.     

The dynamics of perception and action

How might one account for the organization in behavior without attributing it to an internal control structure? The present article develops a theoretical framework called behavioral dynamics that integrates an information-based approach to perception with a dynamical systems approach to action. For a given task, the agent and its environment are treated as a pair of dynamical systems that are coupled mechanically and informationally. Their interactions give rise to the behavioral dynamics, a vector field with attractors that correspond to stable task solutions, repellers that correspond to avoided states, and bifurcations that correspond to behavioral transitions. The framework is used to develop theories of several tasks in which a human agent interacts with the physical environment, including bouncing a ball on a racquet, balancing an object, braking a vehicle, and guiding locomotion. Stable, adaptive behavior emerges from the dynamics of the interaction between a structured environment and an agent with simple control laws, under physical and informational constraints.     

THE SPECIAL COMPOSITION QUESTION IN ACTION

Abstract:  Just as we may ask whether, and under what conditions, a collection of objects composes a single object, we may ask whether, and under what conditions, a collection of actions composes a single action. In the material objects literature, this question is known as the "special composition question," and I take it that there is a similar question to be asked of collections of actions. I will call that question the "special composition question in action," and argue that the correct answer to this question depends on a particular kind of consequence produced by the individual constituent actions.     

Kinematic adaptation to sudden changes in visual task constraints during reciprocal aiming

In a series of three experiments the visual modulation of movement during a reciprocal aiming task was examined when participants were confronted with sudden changes in visually specified task constraints. Amplitude and precision constraints were manipulated independently in Experiments 1 and 2, respectively, while their simultaneous effects were analyzed in Experiment 3. Analysis of the evolution of kinematic characteristics following a sudden change in task constraints revealed two different times scales of adaptation: a rapid adjustment occurring during the deceleration phase of the first movement following change and a more gradual adaptation, affecting the kinematic pattern as a whole, occurring over the next few movements. Overall, the results indicate that visual information with respect to the adequacy of the unfolding movement is continuously monitored, even under the least constraining conditions, and serves to modulate the pattern of movement to (a) comply with the (new) task constraints and (b) optimally tailor the pattern of movement to the situation at hand. We interpret these findings in the framework of a dynamical perspective on movement organization, with information modulating the parameters of an otherwise invariant underlying dynamical structure.     

Effect of visual-verbal load and spatial compatibility on stimulus response

This study examined the effects of visual-verbalload (as measured by a visually presented reading-memory task with three levels) on a visual/auditory stimulus-response task. The three levels of load were defined as follows: "No Load" meant no other stimuli were presented concurrently; "Free Load" meant that a letter (A, B, C, or D) appeared at the same time as the visual or auditory stimulus; and "Force Load" was the same as "Free Load," but the participants were also instructed to count how many times the letter A appeared. The stimulus-response task also had three levels: "irrelevant," "compatible," and "incompatible" spatial conditions. These required different key-pressing responses. The visual stimulus was a red ball presented either to the left or to the right of the display screen, and the auditory stimulus was a tone delivered from a position similar to that of the visual stimulus. Participants also processed an irrelevant stimulus. The results indicated that participants perceived auditory stimuli earlier than visual stimuli and reacted faster under stimulus-response compatible conditions. These results held even under a high visual-verbal load. These findings suggest the following guidelines for systems used in driving: an auditory source, appropriately compatible signal and manual-response positions, and a visually simplified background.     

The You-I event: on the genesis of self-awareness

I present empirical evidence suggesting that an infant first becomes aware of herself as the focal center of a caregiver's attending. Yet that does not account for her awareness of herself as agent. To address this question, I bring in research on neonatal imitation, as well as studies demonstrating the existence of a neural system in which parts of the same brain areas are activated when observing another's action and when executing a similar one. Applying these findings, I consider gestural exchanges between infant and caregiver, such as reciprocal smiles and imitative vocalizations. Lacking self-awareness at first, the infant is unaware of her own agency. By returning her unwitting gesture, the caregiver singles out for her—thanks to neural matching—the gesture's kinesthesis. Moreover, the caregiver's smile, imitative vocalization, or other gesture is the form that focusing takes. The kinesthesis of the infant's gesture, in being singled out, is experienced by the infant as what the caregiver is focusing on. It is experienced as being within the focal center. In this way, the infant becomes aware of herself as a bodily entity acting toward the caregiver. Exchanges that involve matching are at first essential, I argue, in making the infant present to herself in action. Matching will cease to be necessary, but self-awareness continues to depend fundamentally on others until the acquisition of language, when the child becomes capable of talking to herself as if she were the caregiver.     

Experimental design: Problems in understanding the dynamical behavior-environment system

In this paper, I attempt to describe the implications of dynamical approaches to science for research in the experimental study of behavior. I discuss the differences between classical and dynamical science, and focus on how dynamical science might see replication differently from classical science. Focusing on replication specifically, I present some problems that the classical approach has in dealing with dynamics and multiple causation. I ask about the status and meaning of "error" variance, and whether it may be a potent source of information. I show how a dynamical approach can handle the sort of control by past events that is hard for classical science to understand. These concerns require, I believe, an approach to variability that is quite different from the one most researchers currently employ. I suggest that some of these problems can be overcome by a notion of "behavioral state," which is a distillation of an organism's history.     

Uncovering the problem-solving process: cued retrospective reporting versus concurrent and retrospective reporting

This study investigated the amounts of problem-solving process information ("action," "why," "how," and "metacognitive") elicited by means of concurrent, retrospective, and cued retrospective reporting. In a within-participants design, 26 participants completed electrical circuit troubleshooting tasks under different reporting conditions. The method of cued retrospective reporting used the original computer-based task and a superimposed record of the participant's eye fixations and mouse-keyboard operations as a cue for retrospection. Cued retrospective reporting (with the exception of why information) and concurrent reporting (with the exception of metacognitive information) resulted in a higher number of codes on the different types of information than did retrospective reporting.     

Representations in dynamical embodied agents: re-analyzing a minimally cognitive model agent

Understanding the role of 'representations' in cognitive science is a fundamental problem facing the emerging framework of embodied, situated, dynamical cognition. To make progress, I follow the approach proposed by an influential representational skeptic, Randall Beer: building artificial agents capable of minimally cognitive behaviors and assessing whether their internal states can be considered to involve representations. Hence, I operationalize the concept of representing as 'standing in,' and I look for representations in embodied agents involved in simple categorization tasks. In a first experiment, no representation can be found, but the relevance of the task is undermined by the fact that agents with no internal states can reach high performance. A simple modification makes the task more "representationally hungry," and in this case, agents' internal states are found to qualify as representations. I conclude by discussing the benefits of reconciling the embodied-dynamical approach with the notion of representation.     

Chiasm and hyperdialectic: re-conceptualizing sensory deprivation in infancy

The literature on sensory processing disorders in institutionalized infants highlights the impact of early deprivation on infant perception. Through a Merleau-Pontian, hyperdialectic analysis of the extraordinary development of infant perception under circumstances of severe deprivation the intimate link between environmental affordances and perceptual systems becomes apparent. This paper offers an updated reading of Merleau-Ponty’s late work as a philosophy of systems (“structures”, “forms”, “gestalts”, as he called them) and outlines some fertile philosophical concepts and methods developed by Merleau-Ponty in The visible and the Invisible. Merleau-Ponty’s concept of the chiasm, understood from a systems perspective, and his method of the hyperdialectic are applied in a child case study of an infant who suffered severe neglect in a Romanian orphanage.     

A functional role for the motor system in language understanding: evidence from theta-burst transcranial magnetic stimulation

Does language comprehension depend, in part, on neural systems for action? In previous studies, motor areas of the brain were activated when people read or listened to action verbs, but it remains unclear whether such activation is functionally relevant for comprehension. In the experiments reported here, we used off-line theta-burst transcranial magnetic stimulation to investigate whether a causal relationship exists between activity in premotor cortex and action-language understanding. Right-handed participants completed a lexical decision task, in which they read verbs describing manual actions typically performed with the dominant hand (e.g., "to throw," "to write") and verbs describing nonmanual actions (e.g., "to earn," "to wander"). Responses to manual-action verbs (but not to nonmanual-action verbs) were faster after stimulation of the hand area in left premotor cortex than after stimulation of the hand area in right premotor cortex. These results suggest that premotor cortex has a functional role in action-language understanding.     

Manipulating informational constraints shapes movement reorganization in interceptive actions

Movement organization of cricket batters' actions was analyzed under three distinct experimental task constraints: a representative condition of a practice context in which the batters batted against a "live" bowler, a ball projection machine, and a near life-size video simulation of a bowler. Results showed that each distinct set of task constraints led to significant variations in the patterns of movement control. Removal of advanced information sources from a bowler's actions when the batters faced the ball projection machine caused significant delays in movement initiation, resulting in reduced peak bat swing velocities and a reduction in the quality of bat-ball contact, when compared with batting against a "live" bowler. When responding to a two-dimensional video simulation, batters were able to use information from the bowlers' action, enabling fidelity of initial behavioral responses consistent with the task of batting against a "live" bowler. However, without interceptive task requirements or actual ball flight information, significant variations in downswing initiation timing and peak bat velocities were demonstrated. Findings stress the need for representative experimental and learning designs in fast ball sports for developing performers.     

Two hands, one brain: cognitive neuroscience of bimanual skill

Bimanual coordination, a prototype of a complex motor skill, has recently become the subject of intensive investigation. Whereas past research focused mainly on the identification of the elementary coordination constraints that limit performance, the focus is now shifting towards overcoming these coordination constraints by means of task symbolization or perceptual transformation rules that promote the integration of the task components into a meaningful "gestalt". The study of these cognitive penetrations into action will narrow the brain-mind gap and will facilitate the development of a cognitive neuroscience perspective on bimanual movement control.     

Perspective-taking in dialogue as self-organization under social constraints

We present a dynamical systems account of how simple social information influences perspective-taking. Our account is motivated by the notion that perspective-taking may obey common dynamic principles with perceptuomotor coupling. We turn to the prominent HKB dynamical model of motor coordination, drawing from basic principles of self-organization to describe how conversational perspective-taking unfolds in a low-dimensional attractor landscape. We begin by simulating experimental data taken from a simple instruction-following task, in which participants have different expectations about their interaction partner. By treating belief states as different values of a control parameter, we show that data generated by a basic dynamical process fits overall egocentric and other-centric response distributions, the time required for participants to enact a response on a trial-by-trial basis, and the action dynamics exhibited in individual trials. We end by discussing the theoretical significance of dynamics in dialog, arguing that high-level coordination such as perspective-taking may obey similar dynamics as perceptuomotor coordination, pointing to common principles of adaptivity and flexibility during dialog.     

Development of using experimenter-given cues in infant chimpanzees: longitudinal changes in behavior and cognitive development

The use of gaze shifts as social cues has various evolutionary advantages. To investigate the developmental processes of this ability, we conducted an object-choice task by using longitudinal methods with infant chimpanzees tested from 8 months old until 3 years old. The experimenter used one of six gestures towards a cup concealing food; tapping, touching, whole-hand pointing, gazing plus close-pointing, distant-pointing, close-gazing, and distant-gazing. Unlike any other previous study, we analyzed the behavioral changes that occurred before and after choosing the cup. We assumed that pre-choice behavior indicates the development of an attentional and spatial connection between a pointing cue and an object (e.g. Woodward, 2005); and post-choice behavior indicates the emergence of object permanence (e.g. Piaget, 1954). Our study demonstrated that infant chimpanzees begin to use experimenter-given cues with age (after 11 months of age). Moreover, the results from the behavioral analysis showed that the infants gradually developed the spatial link between the pointing as an object-directed action and the object. Moreover, when they were 11 months old, the infants began to inspect the inside of the cup, suggesting the onset of object permanence. Overall, our results imply that the ability to use the cues is developing and mutually related with other cognitive developments. The present study also suggests what the standard object-choice task actually measures by breaking the task down into the developmental trajectories of its component parts, and describes for the first time the social-physical cognitive development during the task with a longitudinal method.     

Development of the coordination between posture and manual control

Studies have suggested that proper postural control is essential for the development of reaching. However, little research has examined the development of the coordination between posture and manual control throughout childhood. We investigated the coordination between posture and manual control in children (7- and 10-year-olds) and adults during a precision fitting task as task constraints became more difficult. Participants fit a block through an opening as arm kinematics, trunk kinematics, and center of pressure data were collected. During the fitting task, the precision, postural, and visual constraints of the task were manipulated. Young children adopted a strategy where they first move their trunk toward the opening and then stabilize their trunk (freeze degrees of freedom) as the precision manual task is being performed. In contrast, adults and older children make compensatory trunk movements as the task is being performed. The 10-year-olds were similar to adults under the less constrained task conditions, but they resembled the 7-year-olds under the more challenging tasks. The ability to either suppress or allow postural fluctuations based on the constraints of a suprapostural task begins to develop at around 10 years of age. This ability, once developed, allows children to learn specific segmental movements required to complete a task within an environmental context.     

ON TWO ISSUES IN SCIENCE AND RELIGION: A RESPONSE TO DAVID GRIFFIN

Abstract. In responding to David Griffin's critique of my book, Issues in Science and Religion , I suggest that most of the points which he initially presents as differences between us concerning reduction and emergence are resolved in the second half of his article. I spoke of the emergence of higher-level "properties" and "activities," rather than "entities," but my analysis of whole and parts is similar to his, although it was perhaps not always clearly articulated. We agree also that Alfred North Whitehead's God is involved in every event in ways which avoid the problems of the supernatu-ralist "God of the gaps," but we differ as to whether God's action might be taken into account in a new "post-modern" science.     

Grasping objects by their handles: a necessary interaction between cognition and action

Research has illustrated dissociations between "cognitive" and "action" systems, suggesting that different representations may underlie phenomenal experience and visuomotor behavior. However, these systems also interact. The present studies show a necessary interaction when semantic processing of an object is required for an appropriate action. Experiment 1 demonstrated that a semantic task interfered with grasping objects appropriately by their handles, but a visuospatial task did not. Experiment 2 assessed performance on a visuomotor task that had no semantic component and showed a reversal of the effects of the concurrent tasks. In Experiment 3, variations on concurrent word tasks suggested that retrieval of semantic information was necessary for appropriate grasping. In all, without semantic processing, the visuomotor system can direct the effective grasp of an object, but not in a manner that is appropriate for its use.