Damian G Kelty-Stephen

State University of New York at New Paltz | SUNY New Paltz · Department of Psychology

Ergodicity breaking is a challenge for biological and psychological sciences. Ergodicity is a necessary condition for linear causal modeling. Long-range correlations and non-Gaussianity characterizing various biological and psychological measurements break ergodicity routinely, threatening our capacity for causal modeling. Long-range correlations (...

Turing inspired a computer metaphor of the mind and brain that has been handy and has spawned decades of empirical investigation, but he did much more and offered behavioral and cognitive sciences another metaphor—that of the cascade. The time has come to confront Turing’s cascading instability, which suggests a geometrical framework driven by powe...

Ergodicity breaking is a challenge for biological and psychological sciences. Ergodicity is a necessary condition for linear causal modeling. Long-range correlations and non-Gaussianity characterizing various biological and psychological measurements break ergodicity routinely, threatening our capacity for causal modeling. Long-range correlations (...

The brain-as-computer metaphor has anchored the professed computational nature of mind, wresting it down from the intangible logic of Platonic philosophy to a material basis for empirical science. However, as with many long-lasting metaphors in science, the computer metaphor has been explored and stretched long enough to reveal its boundaries. Thes...

The creativity and emergence of biological and psychological behavior tend to be nonlinear—biological and psychological measures contain degrees of irregularity. The linear model might fail to reduce these measurements to a sum of independent random factors (yielding a stable mean for the measurement), implying nonlinear changes over time. The pres...

Turing inspired a computer metaphor of the mind and brain that has been handy and has spawned decades of empirical investigation, but he did much more and offered behavioral and cognitive sciences another metaphor—that of the cascade. The time has come to confront Turing’s cascading instability, which suggests a geometrical framework driven by powe...

The stochastic processes underlying the growth and stability of biological and psychological systems reveal themselves when far from equilibrium. Far from equilibrium, nonergodicity reigns. Nonergodicity implies that the average outcome for a group/ensemble (i.e., of representative organisms/minds) is not necessarily a reliable estimate of the aver...

The stochastic processes underlying the growth and stability of biological and psychological systems reveal themselves when far from equilibrium. Far from equilibrium, nonergodicity reigns. Nonergodicity implies that the average outcome for a group/ensemble (i.e., of representative organisms/minds) is not necessarily a reliable estimate of the aver...

The ubiquity of tool use in human life has generated multiple lines of scientific and philosophical investigation to understand the development and expression of humans’ engagement with tools and its relation to other dimensions of human experience. However, existing literature on tool use faces several epistemological challenges in which the same...

We see the computer metaphor of the brain as a holdover from premodern scientific traditions hoping to anchor the mind’s computational ability in a material anatomical part. Despite having prompted decades of valuable empirical insights, the computer metaphor has likely outgrown its usefulness. Brains are context-sensitive and capable of adapting t...

The ubiquity of tool use in human life has generated multiple lines of scientific and philosophical investigation to understand the development and expression of humans’ engagement with tools and its relation to other dimensions of human experience. However, existing literature on tool use faces several epistemological challenges in which the same...

Speech perception and memory for speech require active engagement. Gestural theories have emphasized mainly the effect of speaker's movements on speech perception. They fail to address the effects of listener movement, focusing on communication as a boundary condition constraining movement among interlocutors. The present work attempts to break new...

The creativity and emergence of biological and psychological behavior tend to be nonlinear—biological and psychological measures contain degrees of irregularity. The linear model might fail to reduce these measurements to a sum of independent random factors (yielding a stable mean for the measurement), implying nonlinear changes over time. The pres...

When humans handle a tool, such as a tennis racket or hammer, for the first time, they often wield it to determine its inertial properties. The mechanisms that contribute to perception of inertial properties are not fully understood. The present study’s goal was to investigate how proprioceptive afferents contribute to effortful perception of heavi...

Speech perception and memory for speech require active engagement. Gestural theories have emphasized mainly the effect of the movements of the speaker on speech perception. They fail to address the effects of listener movement, focusing on communication as a boundary condition constraining movement among interlocutors. The present work attempts to...

Quiet standing exhibits strongly intermittent variability that has inspired at least two interpretations. First, variability can be intermittent through the alternating engagement and disengagement of complementary control processes at distinct scales. A second and perhaps deeper way to interpret this intermittency is through the possibility that p...

Modern biomedical, behavioral and psychological inference about cause-effect relationships respects an ergodic assumption, that is, that mean response of representative samples allow predictions about individual members of those samples. Recent empirical evidence in all of the same fields indicates systematic violations of the ergodic assumption. I...

Visually guided postural control emerges in response to task constraints. Task constraints generate physiological fluctuations that foster the exploration of available sensory information at many scales. Temporally correlated fluctuations quantified using fractal and multifractal metrics have been shown to carry perceptual information across the bo...

The ‘quiet eye’ (QE) approach to visually-guided aiming behavior invests fully in perceptual information’s potential to organize coordinated action. Sports psychologists refer to QE as the stillness of the eyes during aiming tasks and increasingly into self- and externally-paced tasks. Amidst the ‘noisy’ fluctuations of the athlete’s body, quiet ey...

We tested for transposition effects (TEs) in Hindi (a Modern Indo-Aryan language) using unprimed lexical decision. TEs are less accurate and slower responses to transposed-nonwords (e.g., ‹PSATE›, formed from base-word ‹PASTE›) than corresponding replaced-nonwords (e.g., ‹PLUTE›). In Hindi’s orthography, letters map transparently to phonemes (excep...

Intermittency is a flexible control process entailing context-sensitive engagement with task constraints. The present work aims to situate the intermittency of dexterous behavior explicitly in multifractal modeling for non-Gaussian cascade processes. Multiscale probability density function (PDF) analysis of the center of pressure (CoP) fluctuations...

Standing still and focusing on a visible target in front of us is a preamble to many coordinated behaviors (e.g., reaching an object). Hiding behind its apparent simplicity is a deep layering of texture at many scales. The task of standing still laces together activities at multiple scales: from ensuring that a few photoreceptors on the retina cove...

Healthy human postural sway exhibits strong intermittency, reflecting a richly interactive foundation of postural control. From a linear perspective, intermittent fluctuations might be interpreted as engagement and disengagement of complementary control processes at distinct timescales or from a nonlinear perspective, as cascade-like interactions a...

Intermittency is a flexible control process entailing context-sensitive engagement with task constraints. The present work aims to situate the intermittency of dexterous behavior explicitly in multifractal modeling for non-Gaussian cascade processes. Multiscale probability density function (PDF) analysis of the center of pressure (CoP) fluctuations...

As a hallmark of dexterity, intermittency warrants explicit acknowledgment in models of dexterous behavior. However, intermittency poses a major challenge to modeling itself. The present work aims to situate investigation of intermittency on a firmer multifractal footing. In a previous study (Furmanek et al., 2020), multiscale probability density f...

Modern biomedical, behavioral and psychological inference about cause-effect relationships respects an ergodic assumption, that is, that mean response of representative samples allow predictions about individual members of those samples. Recent empirical evidence in all of the same fields indicates systematic violations of the ergodic assumption. I...

The ‘quiet eye’ (QE) approach to visually-guided aiming behavior invests fully in perceptual information's potential to organize coordinated action. Sports psychologists refer to QE as the stillness of the eyes during aiming tasks and increasingly into self- and externally-paced tasks. Amidst the ‘noisy’ fluctuations of the athlete’s body, quiet ey...

Vector autoregression (VAR) modeling allows probing bidirectional relationships in gender/sex development and may support hypothesis testing following multi-modal data collection. We show VAR in three lights: supporting a hypothesis, rejecting a hypothesis, and opening up new questions. To illustrate these capacities of VAR, we reanalyzed longitudi...

Standing still and focusing on a visible target in front of us is a preamble to many coordinated behaviors (e.g., reaching an object). Hiding behind its apparent simplicity is a deep layering of texture at many scales. The task of standing still laces together activities at multiple scales: from ensuring that a few photoreceptors on the retina cove...

A growing consensus across otherwise disparate perspectives on perception and action is that visually guided postural control emerges from within task constraints. Task constraints generate physiological fluctuations across various parts of the body. These fluctuations foster exploration of the available sensory information. For instance, standard...

Research into haptic perception typically concentrates on mechanoreceptors and their supporting neuronal processes. This focus risks ignoring crucial aspects of active perception. For instance, bodily movements influence the information available to mechanoreceptors, entailing that movement facilitates haptic perception. Effortful manual wielding o...

Healthy human postural sway exhibits strong intermittency, reflecting a richly interactive foundation of postural control. From a linear perspective, intermittent fluctuations might be interpreted as engagement and disengagement of complementary control processes at distinct timescales or from a nonlinear perspective, as cascade-like interactions a...

Quiet standing exhibits strongly intermittent variability reflecting a richly interactive foundation. This intermittency can be understood in various ways. First, variability can be intermittent through the engagement and disengagement of complementary control processes at distinct scales. A second and perhaps a deeper way to understand this interm...

Research into haptic perception typically concentrates on mechanoreceptors and their supporting neuronal processes. This focus risks ignoring crucial aspects of active perception. For instance, bodily movements influence the information available to mechanoreceptors, entailing that movement facilitates haptic perception. Effortful manual wielding o...

Effortful touch by the hand is essential to engaging with and perceiving properties of objects. The temporal structure of whole-body coordination must reflect the prospective control that provides for both the engagement with and perception of properties of the hefted objects. In the present study, we found signatures of multifractality in the time...

Objective To define static, dynamic, and cognitive fit and their interactions as they pertain to exosystems and to document open research needs in using these fit characteristics to inform exosystem design. Background Initial exosystem sizing and fit evaluations are currently based on scalar anthropometric dimensions and subjective assessments. As...

Vector autoregression (VAR) modeling allows probing bidirectional relationships in gender development and may support hypothesis testing following multi-modal data collection. We show VAR in three lights: supporting a hypothesis, rejecting a hypothesis, and opening up new questions. To illustrate these capacities of VAR, we reanalyzed longitudinal...

A long history of research has pointed to the importance of fractal fluctuations in physiology, but so far, the physiological evidence of fractal fluctuations has been piecemeal and without clues to bodywide integration. What remains unknown is how fractal fluctuations might interact across the body and how those interactions might support the coor...

Movement coordination depends on directing our limbs to the right place and in the right time. Movement science can study this central requirement in the Fitts task that asks participants to touch each of two targets in alternation, as accurately and as fast as they can. The Fitts task is an experimental attempt to focus on how the movement system...

Children with Attention-Deficit Hyperactivity Disorder (ADHD) struggle to perform a host of daily activities. Many of these involve forceful interaction with objects and thus implicate dynamic touch. Therefore, deficits in dynamic touch could underlie functional difficulties presented by ADHD children. We investigated whether performance on a dynam...

The applied muscular effort to wield, hold, or balance an object shapes the medium by which action-relevant perceptual judgments (e.g., heaviness, length, width, and shape) are derived. Strikingly, the integrity of these judgments is retained over a range of exploratory conditions, a phenomenon known as perceptual invariance. For instance, judgment...

Complete list of embedded models from Hypotheses 1 and 2. (DOCX)

Description of data file. (DOCX)

AIC plots study 1. (DOCX)

AIC plots study 2. (DOCX)

By definition, perception is a multisensory process that unfolds in time as a complex sequence of exploratory activities of the organism. In such a system perception and action are integrated, and multiple energy arrays are available simultaneously. Perception of affordances interweaves sensory and motor activities into meaningful behavior given ta...

Collaboration with undergraduate students at a small liberal-arts college has accelerated our research programs. Liberal-arts students bring interdisciplinary flair—or sometimes just a fresh perspective not yet pigeonholed by post-graduate specialization. Liberal-arts students come from diverse backgrounds and reach beyond their comfort zones to tr...

Reading research uses different tasks to investigate different levels of the reading process, such as word recognition, syntactic parsing, or semantic integration. It seems to be tacitly assumed that the underlying cognitive process that constitute reading are stable across those tasks. However, nothing is known about what happens when readers swit...

Gender science epitomises the complexity of goal-directed experience: it exemplifies nonlinear interaction across many scales of space and time. Nonlinear dynamics provides a particularly good geometry-called "multifractal"-for quantifying, modelling, and predicting such interactions across scales of space and time. That sounds complex which I regr...

INTRODUCTION: Human-spacesuit fit is not well understood, especially the relation to operational performance and injury risk. Current fit decisions use subjective feedback. This work developed and evaluated new metrics for quantifying fit and assessed metric sensitivity to changes in padding between the human and hip brief assembly (HBA). METHODS:...

Movement science is a field that is quickly growing in its scope, leaning heavily on psychological expertise for research design with human participants but requiring computational and engineering ability. Undergraduate psychology curricula are in a unique position to train some of its future scholars. This report reviews an attempt to pilot a clas...

Model predictions representing the effects of multifractality WMF × tMF as well as its interactions with Precursor, with entropy measures ψ and ξ on the mouse-tracking measure of area under the curve (AUC). These ψ × ξ × WMF × tMF × Precursor interaction effects on AUC manifested differently across all context conditions: in real-speech context (le...

All coefficients from Poisson regression predicting cumulative “GA” responses without any block or trial effects.

Coefficients from Poisson regression of trial-by-trial x-position flips.

Model predictions representing the effects of multifractal-based nonlinear estimate tMF as well as its interactions with Precursor, with entropy measures ψ and ξ on the mouse-tracking measure of maximum displacement (MD). These ψ × ξ × tMF×Precursor interaction effects on MD manifested differently across all context conditions: in real-speech conte...

Model predictions representing the effects of multifractality WMF and its interactions with slow entropy ψ × WMF, with fast entropy ξ × WMF, and with precursor Precursor × WMF on x-position flips. Panels show predictions specific to real-speech contexts (top left and in solid black), simulated-speech contexts (top right and in dashed black), and to...

All coefficients from logistic regression predicting “GA” vs. “DA” without any block or trial effects.

All coefficients from Poisson regression predicting cumulative “GA” responses with block or trial effects.

Significant effects (p < 0.05) from linear regression of trial-by-trial area under the curve (AUC).

Model predictions representing the effects of multifractality WMF as well as its interactions with Precursor, with entropy measures ψ and ξ on the mouse-tracking measure of maximum displacement (MD). These ψ × ξ × WMF×Precursor interaction effects on MD manifested differently across all context conditions: in real-speech context (left panel), in si...

Significant effects (p < 0.05) from linear regression of trial-by-trial maximum displacement (MD).

Movement science is a field that is quickly growing in its scope, leaning heavily on psychological expertise for research design with human participants but requiring computational and engineering ability. Undergraduate psychology curricula are in a unique position to train some of its future scholars. This report reviews an attempt to pilot a clas...

The milkshake acting like a computer is an idea that appeared on my stupid professional website ten years ago when I was first struggling to begin a straight-faced professional, academic “web presence.” This text here has no new empirical evidence and is not an attempt to develop theory in any way. It is an attempt to thank the digital community of...