scholarly journals Heading Perception Depends on Time-Varying Evolution of Optic Flow

2018 ◽  
Author(s):  
Charlie S. Burlingham ◽  
David J. Heeger
Keyword(s):  
Flow Field ◽  
Optic Flow ◽  
Discrimination Task ◽  
Extended Period ◽  
Time Varying ◽  
Temporal Derivative ◽  
Novel Method ◽  
Considerable Support ◽  
Over Time ◽  
Phase Motion

There is considerable support for the hypothesis that perception of heading in the presence of rotation is mediated by instantaneous optic flow. This hypothesis, however, has never been tested. We introduce a novel method, termed “non-varying phase motion,” for generating a stimulus that conveys a single instantaneous optic flow field, even though the stimulus is presented for an extended period of time. In this experiment, observers viewed stimulus videos and performed a forced choice heading discrimination task. For non-varying phase motion, observers made large errors in heading judgments. This suggests that instantaneous optic flow is insufficient for heading perception in the presence of rotation. These errors were mostly eliminated when the velocity of phase motion was varied over time to convey the evolving sequence of optic flow fields corresponding to a particular heading. This demonstrates that heading perception in the presence of rotation relies on the time-varying evolution of optic flow. We hypothesize that the visual system accurately computes heading, despite rotation, based on optic acceleration, the temporal derivative of optic flow.

scholarly journals Heading perception depends on time-varying evolution of optic flow

2020 ◽  
Vol 117 (52) ◽  
pp. 33161-33169
Author(s):  
Charlie S. Burlingham ◽  
David J. Heeger
Keyword(s):  
Flow Field ◽  
Visual System ◽  
Optic Flow ◽  
Discrimination Task ◽  
Extended Period ◽  
Time Varying ◽  
Temporal Derivative ◽  
Considerable Support ◽  
Over Time ◽  
Phase Motion

There is considerable support for the hypothesis that perception of heading in the presence of rotation is mediated by instantaneous optic flow. This hypothesis, however, has never been tested. We introduce a method, termed “nonvarying phase motion,” for generating a stimulus that conveys a single instantaneous optic flow field, even though the stimulus is presented for an extended period of time. In this experiment, observers viewed stimulus videos and performed a forced-choice heading discrimination task. For nonvarying phase motion, observers made large errors in heading judgments. This suggests that instantaneous optic flow is insufficient for heading perception in the presence of rotation. These errors were mostly eliminated when the velocity of phase motion was varied over time to convey the evolving sequence of optic flow fields corresponding to a particular heading. This demonstrates that heading perception in the presence of rotation relies on the time-varying evolution of optic flow. We hypothesize that the visual system accurately computes heading, despite rotation, based on optic acceleration, the temporal derivative of optic flow.

Continuous Decisions

2020 ◽  
Author(s):  
Seng Bum Michael Yoo ◽  
Benjamin Hayden ◽  
John Pearson
Keyword(s):  
Decision Making ◽  
Control Theory ◽  
Hierarchical Structure ◽  
Action Planning ◽  
Extended Period ◽  
Microeconomic Theory ◽  
Engineering Control ◽  
Over Time ◽  
Academic Study

Humans and other animals evolved to make decisions that extend over time with continuous and ever-changing options. Nonetheless, the academic study of decision-making is mostly limited to the simple case of choice between two options. Here we advocate that the study of choice should expand to include continuous decisions. Continuous decisions, by our definition, involve a continuum of possible responses and take place over an extended period of time during which the response is continuously subject to modification. In most continuous decisions, the range of options can fluctuate and is affected by recent responses, making consideration of reciprocal feedback between choices and the environment essential. The study of continuous decisions raises new questions, such as how abstract processes of valuation and comparison are co-implemented with action planning and execution, how we simulate the large number of possible futures our choices lead to, and how our brains employ hierarchical structure to make choices more efficiently. While microeconomic theory has proven invaluable for discrete decisions, we propose that engineering control theory may serve as a better foundation for continuous ones. And while the concept of value has proven foundational for discrete decisions, goal states and policies may prove more useful for continuous ones.

Robustness Over Time-Varying Channels in DNN-HMM ASR Based Human-Robot Interaction

2017 ◽  
Author(s):  
José Novoa ◽  
Jorge Wuth ◽  
Juan Pablo Escudero ◽  
Josué Fredes ◽  
Rodrigo Mahu ◽  
...  
Keyword(s):  
Human Robot Interaction ◽  
Time Varying ◽  
Robot Interaction ◽  
Time Varying Channels ◽  
Over Time

scholarly journals Epidemic Processes Over Time-Varying Networks

2018 ◽  
Vol 5 (3) ◽  
pp. 1322-1334 ◽  
Author(s):  
Philip E. Pare ◽  
Carolyn L. Beck ◽  
Angelia Nedic
Keyword(s):  
Time Varying ◽  
Time Varying Networks ◽  
Over Time

scholarly journals Longitudinal Patterns of Ethical Organisational Culture as a Context for Leaders’ Well-Being: Cumulative Effects Over 6 Years

2021 ◽  
Author(s):  
Mari Huhtala ◽  
Muel Kaptein ◽  
Joona Muotka ◽  
Taru Feldt
Keyword(s):  
Latent Profile Analysis ◽  
Temporal Dynamics ◽  
Ethical Dilemmas ◽  
Extended Period ◽  
Well Being ◽  
Organisational Culture ◽  
Cumulative Effects ◽  
Ethical Culture ◽  
Continuous Increase ◽  
Over Time

AbstractThe aim of this longitudinal study was to investigate the temporal dynamics of ethical organisational culture and how it associates with well-being at work when potential changes in ethical culture are measured over an extended period of 6 years. We used a person-centred study design, which allowed us to detect both typical and atypical patterns of ethical culture stability as well as change among a sample of leaders. Based on latent profile analysis and hierarchical linear modelling we found longitudinal, concurrent relations and cumulative gain and loss cycles between different ethical culture patterns and leaders’ well-being. Leaders in the strongest ethical culture pattern experienced the highest level of work engagement and a decreasing level of ethical dilemmas and stress. Leaders who gave the lowest ratings on ethical culture which also decreased over time reported the highest level of ethical dilemmas, stress, and burnout. They also showed a continuous increase in these negative outcomes over time. Thus, ethical culture has significant cumulative effects on well-being, and these longitudinal effects can be both negative and positive, depending on the experienced strength of the culture’s ethicality.

scholarly journals Effects of Time-Varying Parent Input on Children’s Language Outcomes Differ for Vocabulary and Syntax

2021 ◽  
pp. 095679762097055
Author(s):  
Catriona Silvey ◽  
Özlem Ece Demir-Lira ◽  
Susan Goldin-Meadow ◽  
Stephen W. Raudenbush
Keyword(s):  
Standardized Tests ◽  
Child Outcomes ◽  
Time Varying ◽  
Syntactic Complexity ◽  
Language Outcomes ◽  
Optimal Sequence ◽  
Linguistic Input ◽  
Language Input ◽  
The Impact ◽  
Over Time

Early linguistic input is a powerful predictor of children’s language outcomes. We investigated two novel questions about this relationship: Does the impact of language input vary over time, and does the impact of time-varying language input on child outcomes differ for vocabulary and for syntax? Using methods from epidemiology to account for baseline and time-varying confounding, we predicted 64 children’s outcomes on standardized tests of vocabulary and syntax in kindergarten from their parents’ vocabulary and syntax input when the children were 14 and 30 months old. For vocabulary, children whose parents provided diverse input earlier as well as later in development were predicted to have the highest outcomes. For syntax, children whose parents’ input substantially increased in syntactic complexity over time were predicted to have the highest outcomes. The optimal sequence of parents’ linguistic input for supporting children’s language acquisition thus varies for vocabulary and for syntax.

scholarly journals Detecting moving objects in an optic flow field using direction- and speed-tuned operators

2014 ◽  
Vol 98 ◽  
pp. 14-25 ◽  
Author(s):  
Constance S. Royden ◽  
Michael A. Holloway
Keyword(s):  
Flow Field ◽  
Optic Flow ◽  
Moving Objects
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