Cognitive Mechanisms and Computational Models: Explanation in Cognitive Neuroscience

Cognitive Neuroscience seeks to integrate cognitive psychology and neuroscience. I critique existing analyses of this integration project, and offer my own account of how it ought to be understood given the practices of researchers in these fields. A recent proposal suggests that integration between cognitive psychology and neuroscience can be achieved `seamlessly' via mechanistic explanation. Cognitive models are elliptical mechanism sketches, according to this proposal. This proposal glosses over several difficulties concerning the practice of cognitive psychology and the nature of cognitive models, however. Although psychology's information-processing models superficially resemble mechanism sketches, they in fact systematically include and exclude different kinds of information. I distinguish two kinds of information-processing model, neither of which specifies the entities and activities characteristic of mechanistic models, even sketchily. Furthermore, theory development in psychology does not involve the filling in of these missing details, but rather refinement of the sorts of models they start out as. I contrast the development of psychology's attention filter models with the development of neurobiology's models of sodium channel filtering. I argue that extending the account of mechanisms to include what I define as generic mechanisms provides a more promising route towards integration. Generic mechanisms are the in-the-world counterparts to abstract types. They thus have causal-explanatory powers which are shared by all the tokens that instantiate that type. This not only provides a way for generalizations to factor into mechanistic explanations, which allows for the `upward-looking' explanations needed for integrating cognitive models, but also solves some internal problems in the mechanism literature concerning schemas and explanatory relevance. I illustrate how generic mechanisms are discovered and used with examples from computational cognitive neuroscience. I argue that connectionist models can be understood as approximations to generic brain mechanisms, which resolves a longstanding philosophical puzzle as to their role. Furthermore, I argue that understanding scientific models in general in terms of generic mechanisms allows for a unified account of the types of inferences made in modeling and in experiment

The Effects Of A Smoking Prevention Program On The Post-Test Knowledge Levels And Attitudes Of Seventh And Eighth Grade Students

Chronic health problems associated with smoking in the adult population have been linked with the use of tobacco in the influential adolescent years. Education aimed toward the adolescent may decrease the incidence of cigarette smoking in the adult population. Little research has been done regarding the knowledge and developmental levels of adolescent smoking and the risks for health problems. The purpose of this quasi-experimental study was to determine the effectiveness of a smoking prevention program on the knowledge and attitudes of seventh and eighth grade students. Orem’s Self-Care Deficit Theory served as the theoretical framework. The sample consisted of students (N=293) in the seventh and eighth grade from two randomly selected schools in urban central Mississippi. Each subject and parent received a letter describing the study and signed a consent form prior to participation. The subjects were assured confidentiality as participants. The Cigarette Smoking Questionnaire tool was utilized prior to and following participation in a thirty minute smoking prevention program on the causes of smoking in adolescents and the health risks associated with smoking. i v Descriptive analysis and the t test were utilized to analyze the data. The hypothesis which guided the study was that there would be no significant difference in the posttest knowledge and attitude scores in seventh and eighth grade students who attend a teaching program about the peer pressure and health risks associated with cigarette smoking. Seventh and eighth grade students who did attend the smoking prevention program had significantly higher posttest score than seventh and eighth grade students who did not attend. The researcher concluded that, after an educational intervention, subjects\u27 knowledge levels were significantly improved and attitudes were more positive. Implications for nursing included the continued use of Orem’s supportive- educative nursing system which appertains to promoting decision making skills and acquiring knowledge in adolescents. Recommendations for future research include replication of the study with a broader ethnic and socioeconomic population. Also, further studies are needed for long-term evaluation of smoking trends in adolescents

Use of interior design practices by Tennessee home demonstration club members and general homemakers

The major purpose of this study was to compare general homemakers and home demonstration club members in Tennessee as to their personal characteristics, family characteristics, use of recommended interior design practices, mass media sources used to obtain interior design information, sources of instruction received on interior design and requests made for additional training on interior design. Data were obtained through personal interviews by County Extension Agents with 1,197 home demonstration club members and 376 general homemakers in 67 Tennessee counties. The Nth number technique was used in each county to select individuals to be included in the survey. Data were analyzed by The University of Tennessee Computing Center. Percentages were used to compare the two study groups. The Chi Square test was used to determine levels of significance achieved by observed differences, Differences which achieved the .05 level were accepted as being significantly different. Data analysis indicated that the home demonstration club members differed significantly from the general homemakers in that the former tended to be older, to own their own home, were not employed outside the home, had a lower estimated family income, were more likely to be using the recommended interior design practices, were more likely to be using mass media sources to obtain interior design information, were more likely to have received instruction on interior design from Extension Agents and from commercial concerns and they also were significantly more interested than the general homemakers in receiving additional information on interior design subjects

Characteristics of Successful mainstreamed Hearing-Impaired Students: A Review of Selected Research

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An Exploration of Crime by Policewomen

The current study explores criminal conduct by policewomen. This information is increasingly relevant as police departments hire more women, especially if the crimes committed by policewomen differ from those of policemen. News searches identified 105 cases depicting arrests of policewomen. A content analysis was performed. Findings indicate differences exist between crimes committed by policemen and policewomen, as well as by policewomen and women in general. Crime by policewomen is most often profit-motivated. Policewomen had fewer years of service and lower ranks, committed less violent crimes, and were more likely to receive suspensions for off-duty crimes compared to their male peers

The history of stellar metallicity in a simulated disc galaxy

We explore the chemical distribution of stars in a simulated galaxy. Using simulations of the same initial conditions but with two different feedback schemes (McMaster Unbiased Galaxy Simulations – MUGS – and Making Galaxies in a Cosmological Context – MaGICC), we examine the features of the age–metallicity relation (AMR), and the three-dimensional age– [Fe/H]–[O/Fe] distribution, both for the galaxy as a whole and decomposed into disc, bulge, halo and satellites. The MUGS simulation, which uses traditional supernova feedback, is replete with chemical substructure. This substructure is absent from the MaGICC simulation, which includes early feedback from stellar winds, a modified initial mass function and more efficient feedback. The reduced amount of substructure is due to the almost complete lack of satellites in MaGICC. We identify a significant separation between the bulge and disc AMRs, where the bulge is considerably more metal-rich with a smaller spread in metallicity at any given time than the disc. Our results suggest, however, that identifying the substructure in observations will require exquisite age resolution, of the order of 0.25 Gyr. Certain satellites show exotic features in the AMR, even forming a ‘sawtooth’ shape of increasing metallicity followed by sharp declines which correspond to pericentric passages. This fact, along with the large spread in stellar age at a given metallicity, compromises the use of metallicity as an age indicator, although alpha abundance provides a more robust clock at early times. This may also impact algorithms that are used to reconstruct star formation histories from resolved stellar populations, which frequently assume a monotonically increasing AMR

Consequences of cosmic microwave background-regulated star formation

It has been hypothesized that the cosmic microwave background (CMB) provides a temperature floor for collapsing protostars that can regulate the process of star formation and result in a top-heavy initial mass function at high metallicity and high redshift. We examine whether this hypothesis has any testable observational consequences. First we determine, using a set of hydrodynamic galaxy formation simulations, that the CMB temperature floor would have influenced the majority of stars formed at redshifts between z=3 and 6, and probably even to higher redshift. Five signatures of CMB-regulated star formation are: (1) a higher supernova rate than currently predicted at high redshift; (2) a systematic discrepancy between direct and indirect measurements of the high redshift star formation rate; (3) a lack of surviving globular clusters that formed at high metallicity and high redshift; (4) a more rapid rise in the metallicity of cosmic gas than is predicted by current simulations; and (5) an enhancement in the abundances of alpha elements such as O and Mg at metallicities -2 < [Fe/H] < -0.5. Observations are not presently able to either confirm or rule out the presence of these signatures. However, if correct, the top-heavy IMF of high-redshift high-metallicity globular clusters could provide an explanation for the observed bimodality of their metallicity distribution.Comment: ApJ in press, 10 pages, emulateap

On 1-factorizations of Bipartite Kneser Graphs

It is a challenging open problem to construct an explicit 1-factorization of the bipartite Kneser graph $H(v,t)$, which contains as vertices all $t$-element and $(v-t)$-element subsets of $[v]:=\{1,\ldots,v\}$ and an edge between any two vertices when one is a subset of the other. In this paper, we propose a new framework for designing such 1-factorizations, by which we solve a nontrivial case where $t=2$ and $v$ is an odd prime power. We also revisit two classic constructions for the case $v=2t+1$ --- the \emph{lexical factorization} and \emph{modular factorization}. We provide their simplified definitions and study their inner structures. As a result, an optimal algorithm is designed for computing the lexical factorizations. (An analogous algorithm for the modular factorization is trivial.)Comment: We design the first explicit 1-factorization of H(2,q), where q is a odd prime powe

Off-Duty and Under Arrest: An Exploratory Study of the Arrests of Off-Duty Police Officers, 2005-2017

Presentation at the Annual Meeting of the Academy of Criminal Justice Sciences in National Harbor, MD, on March 17, 2023