Guided Wave Optics

Phenomena associated with the propagation and manipulation of light in thin-film dielectric waveguides are presently the object of considerable research effort, directed toward possible applications in communications and information processing. The theory of dielectric waveguide modes is reviewed, and the topics of directional coupling, input-output coupling, modulation, and distributed feedback laser sources are treated on the basis of coupled-mode theory. A summary of experimental results for each of the guided-wave optical phenomena covered by the theory is also presented

Linking Heuristic-Systematic Processing to Adoption of Behavior

This study sets out to draw connections among key components within three conceptual models: the Risk Information Seeking and Processing model, the Heuristic-Systematic Model, and the Theory of Planned Behavior. Specifically, it proposes and tests the theoretical linkages among heuristic and systematic information processing, depth of processing, attitude stability, and behavioral intention. Archival data drawn from a panel survey that concerns health risks from drinking municipal tap water are used for theory testing. Findings reveal that systematic processing is positively related to number of strongly held behavioral beliefs, strength of belief outcome evaluations, and strength of cognitive structure--all indicated depth of processing, and that heuristic processing is negatively related to all three measures. Cognitive structure and attitude toward the behavior appear to be consistent in direction and strength. Attitude toward the behavior, subjective norms, and alternative behavior are positively related to behavioral intention. An anticipated positive relationship between perceived behavioral control and behavioral intention was not found. Finally, theoretical and practical implications of the findings are discussed

Detecting and Estimating Signals in Noisy Cable Structures, I: Neuronal Noise Sources

In recent theoretical approaches addressing the problem of neural coding, tools from statistical estimation and information theory have been applied to quantify the ability of neurons to transmit information through their spike outputs. These techniques, though fairly general, ignore the specific nature of neuronal processing in terms of its known biophysical properties. However, a systematic study of processing at various stages in a biophysically faithful model of a single neuron can identify the role of each stage in information transfer. Toward this end, we carry out a theoretical analysis of the information loss of a synaptic signal propagating along a linear, one-dimensional, weakly active cable due to neuronal noise sources along the way, using both a signal reconstruction and a signal detection paradigm. Here we begin such an analysis by quantitatively characterizing three sources of membrane noise: (1) thermal noise due to the passive membrane resistance, (2) noise due to stochastic openings and closings of voltage-gated membrane channels (Na^+ and K^+), and (3) noise due to random, background synaptic activity. Using analytical expressions for the power spectral densities of these noise sources, we compare their magnitudes in the case of a patch of membrane from a cortical pyramidal cell and explore their dependence on different biophysical parameters

Enhancing Stimulus Integration in a Consumer Information Processing System: A Theoretical Foundation

Although much research has focused on how consumers process information, researchers and theorists in the field of marketing, more specifically consumer behavior, still have much to gain by expanding the existing assemblage of knowledge about information processing and the theories related to this topic. A deeper understanding of how consumers habitually process information may be extremely valuable to marketers when attempting to develop marketing plans, strategies, and messages that will effectively influence consumer attitudes and behavior. The most seemingly unified theory of information processing is the information integration theory. This theoretical approach concentrates on the ways individuals accumulate and organize information to form attitudes toward various concepts including individuals, objects, situations, or ideas. However, marketers must also consider the limitations of the human information processing system. Considering the research on information integration theory and information overload, a model for understanding consumer-oriented marketing messages is discussed. The model suggests that multiple, focused marketing messages should be more effective than relatively few, complex marketing messages. However, the complexity of messages should increase as the consumer becomes more involved with the product, moving from awareness to action

Using Mass Communication Theory; Cognitive Switching: A Behavioral Trace of Human Information Processing for Television Newscasts; Attitudes of Scientists and Journalists Toward Media Coverage of Science News

Reviews of Using Mass Communication Theory, by M.E. McCombs and L.B. Becker; Cognitive Switching: A Behavioral Trace of Human Information Processing for Television Newscasts, by Thomas A. McCain and Mark G. Ross; Attitudes of Scientists and Journalists Toward Media Coverage of Science News, by Michael Ryan

Thermodynamics of Chemical Waves

Chemical waves constitute a known class of dissipative structures emerging in reaction-diffusion systems. They play a crucial role in biology, spreading information rapidly to synchronize and coordinate biological events. We develop a rigorous thermodynamic theory of reaction-diffusion systems to characterize chemical waves. Our main result is the definition of the proper thermodynamic potential of the local dynamics as a nonequilibrium free energy density and establishing its balance equation. This enables us to identify the dynamics of the free energy, of the dissipation, and of the work spent to sustain the wave propagation. Two prototypical classes of chemical waves are examined. From a thermodynamic perspective, the first is sustained by relaxation towards equilibrium and the second by nonconservative forces generated by chemostats. We analytically study step-like waves, called wavefronts, using the Fisher-Kolmogorov equation as representative of the first class and oscillating waves in the Brusselator model as representative of the second. Given the fundamental role of chemical waves as message carriers in biosystems, our thermodynamic theory constitutes an important step toward an understanding of information transfers and processing in biology.Comment: 12 pages, 2 figure

Toward a Theory of Risk Information Processing: The Mediating Effects of Reaction Time, Clarity, Affect, and Vividness

This project examined the variables that mediate the relationship between the exogenous variables numerical presentation and numeracy and the endogenous variables risk perception and risk related decisions. Previous research suggested that numerical format and numeracy influence outcomes. The question that remained unanswered was why? The goal of this project was to peer into the proverbial black box to critically examine information processing at work. To examine possible mediating variables, two theoretical models that have emerged in the risk perception literature were tested. The first is an evolutionary theory proposing that over time, individuals have developed an augmented ability to process frequency information. Thus, frequency information should be clearer and people should be faster at forming risk perceptions with information in this format. According to this model, processing speed and evidence clarity mediate the relationship between evidence format and risk perception. A second framework, the affective processing theory, argues that frequency information is more vivid and people derive more affect from information in this format. Therefore, according to this model, affect and vividness mediate the relationship between presentation format and risk perception. In addition to these two perspectives, a third theory was proposed and tested. The integrated theory of risk information processing predicted that reaction time, clarity, affect, and vividness would all influence risk perception. Two experiments were conducted to test the predictions of these three theories. Overall, some support for an integrated model was found. Results indicated that the mediating variables reaction time, clarity, affect, and vividness had direct effects on risk perception. In addition, risk perception had a strong influence on risk related decisions. In Study 2, objective numeracy had a direct effect on reaction time, such that people with high numeracy spent more time forming risk evaluations. Furthermore, people with a preference for numerical information evaluated numerical evidence as clearer and more vivid than people who preferred to receive evidence in nonnumerical formats. Both theoretical and applied implications of these results are discussed and recommendations for future research are provided

Chained activation of the motor system during language understanding

Two experiments were carried out to investigate whether and how one important characteristic of the motor system, that is its goal-directed organization in motor chains, is reflected in language processing. This possibility stems from the embodied theory of language, according to which the linguistic system re-uses the structures of the motor system. The participants were presented with nouns of common tools preceded by a pair of verbs expressing grasping or observational motor chains (i.e., grasp-to-move, grasp-to-use, look-at-to-grasp, and look-at-to-stare). They decided whether the tool mentioned in the sentence was the same as that displayed in a picture presented shortly after. A primacy of the grasp-to-use motor chain over the other motor chains in priming the participants' performance was observed in both the experiments. More interestingly, we found that the motor information evoked by the noun was modulated by the specific motor-chain expressed by the preceding verbs. Specifically, with the grasping chain aimed at using the tool, the functional motor information prevailed over the volumetric information, and vice versa with the grasping chain aimed at moving the tool (Experiment 2). Instead, the functional and volumetric information were balanced for those motor chains that comprise at least an observational act (Experiment 1). Overall our results are in keeping with the embodied theory of language and suggest that understanding sentences expressing an action directed toward a tool drives a chained activation of the motor system