| 1. |
- Josefsson, Maria, 1979-, et al.
(författare)
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Genetic and Lifestyle Predictors of 15-Year Longitudinal Change in Episodic Memory
- 2012
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Ingår i: Journal of The American Geriatrics Society. - : Wiley. - 0002-8614 .- 1532-5415. ; 60:12, s. 2308-2312
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To reveal distinct longitudinal trajectories in episodic memory over 15 years and to identify demographic, lifestyle, health-related, and genetic predictors of stability or decline. Design: Prospective cohort study. Setting: The Betula Project, Umeå, Sweden. Participants: One thousand nine hundred fifty-four healthy participants aged 35 to 85 at baseline. Measurements: Memory was assessed according to validated episodic memory tasks in participants from a large population-based sample. Data were analyzed using a random-effects pattern-mixture model that considered the effect of attrition over two to four longitudinal sessions. Logistic regression was used to determine significant predictors of stability or decline relative to average change in episodic memory. Results: Of 1,558 participants with two or more test sessions, 18% were classified as maintainers and 13% as decliners, and 68% showed age-typical average change. More educated and more physically active participants, women, and those living with someone were more likely to be classified as maintainers, as were carriers of the met allele of the catechol-O-methyltransferase gene. Less educated participants, those not active in the labor force, and men were more likely to be classified as decliners, and the apolipoprotein E ɛ4 allele was more frequent in decliners. Conclusion: Quantitative, attrition-corrected assessment of longitudinal changes in memory can reveal substantial heterogeneity in aging trajectories, and genetic and lifestyle factors predict such heterogeneity.
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| 2. |
- Angelov, Angel G., et al.
(författare)
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Four-decision tests for stochastic dominance, with an application to environmental psychophysics
- 2019
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Ingår i: Journal of mathematical psychology (Print). - : Elsevier. - 0022-2496 .- 1096-0880. ; 93
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Tidskriftsartikel (refereegranskat)abstract
- If the survival function of a random variable X lies to the right of the survival function of a random variable Y, then X is said to stochastically dominate Y. Inferring stochastic dominance is particularly complicated because comparing survival functions raises four possible hypotheses: identical survival functions, dominance of X over Y, dominance of Y over X, or crossing survival functions. In this paper, we suggest four-decision tests for stochastic dominance suitable for paired samples. The tests are permutation-based and do not rely on distributional assumptions. One-sided Cramér–von Mises and Kolmogorov–Smirnov statistics are employed but the general idea may be utilized with other test statistics. The power to detect dominance and the different types of wrong decisions are investigated in an extensive simulation study. The proposed tests are applied to data from an experiment concerning the individual’s willingness to pay for a given environmental improvement.
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| 3. |
- Ljung Aust, Mikael, 1973
(författare)
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Developing Theoretical and Empirical Definitions of Safety Problems in Driving Suitable for Active Safety Function Evaluation
- 2009
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In passive safety, the requirement specifications used for evaluation of protective functions are both standardised and specified at a high level of detail regarding evaluation scenario definition, performance metrics and pass/fail criteria. For active safety, while several propositions for evaluation scenarios have been made, neither these, nor performance metrics and pass/fail criteria have yet reached a similar level of detail and standardisation. The objective of this thesis is to address two underlying reasons for this difference. One is theoretical in nature. On a general level, a set of principles and concepts which capture the fundamental ideas of a field of science can be called a conceptual framework. For active safety function evaluation, such a framework is currently lacking. To address this issue, a conceptual framework called Situational control was developed. The framework integrates fundamental ideas relevant for active safety function evaluation into a holistic and practically applicable picture. Its applicability was demonstrated by applying it in the context of writing and implementing requirement specifications for active safety function evaluation.The second reason is of empirical character. To evaluate the extent to which active safety functions prevent and/or mitigate crashes, it is essential to characterize the sequence of events which leads to collisions in a way which includes information on causal factors. To do this, data from official databases (macroscopic data), and in-depth case studies is often used. Macroscopic data is usually statistically representative but has limited information on why crashes happen, while the opposite is true of case studies. Using the two in combination would therefore seem ideal. However, the principles for connecting them are far from clear and current approaches suffer inherent weaknesses. To address this issue, a generalization methodology which links information in case studies to macroscopic crash types, in a way which covers not only context but also causation similarity, was developed. The feasibility of the methodology was tested through application on three sets of intersection crash data. Results indicate that the methodology was sufficiently successful to warrant further exploration with larger data sets.
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| 4. |
- Edvardsson, Bo, 1944-, et al.
(författare)
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Measures of attitudinal polarization
- 1975
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Ingår i: Scandinavian Journal of Psychology. - Oxford : Blackwell. - 0036-5564 .- 1467-9450. ; 16:1, s. 247-254
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Tidskriftsartikel (refereegranskat)abstract
- Criteria for measures of attitudinal polarization, i.e. degree of opposition among people on a specific issue, are proposed and some formulas, including the standard deviation, are evaluated in relation to the criteria. The formulas were also tested on empirical data with respect to level, dispersion and agreement of received values. The measures on the whole showed a high degree of agreement. There clearly exist instances where the standard deviation is not an adequate measure of attitudinal polarization. Some guidelines are given for the choice of constant values in one of the proposed formulas.
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| 5. |
- Neiberg, Daniel, et al.
(författare)
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Classification of affect in speech using normalized time-frequency cepstra
- 2010
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Ingår i: Speech Prosody 2010. - Chicago, Illinois, U.S.A. - 9780557519316 ; , s. 100071-1-4
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Konferensbidrag (refereegranskat)abstract
- Subtle temporal and spectral differences between categorical realizations of para-linguistic phenomena (e.g., affective vocal expressions) are hard to capture and describe. In this paper we present a signal representation based on Time Varying Constant-Q Cepstral Coeffcients (TVCQCC) derived for this purpose. A method which utilizes the special properties of the constant Q-transform for mean F0 estimation and normalization is described. The coeffcients are invariant to segment length, and as a special case, a representation for prosody is considered. Speaker independent classifcation results using v-SVM with the Berlin EMO-DB and two closed sets of basic (anger, disgust, fear, happiness, sadness, neutral) and social/interpersonal (affection, pride, shame) emotions recorded by forty professional actors from two English dialect areas are reported. The accuracy for the Berlin EMO-DB is 71.2 %, and the accuracies for the first set including basic emotions was 44.6% and for the second set including basic and social emotions the accuracy was 31.7% . It was found that F0 normalization boosts the performance and a combined feature set shows the best performance.
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| 6. |
- Neiberg, Daniel, et al.
(författare)
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Intra-, inter-, and cross-cultural classification of vocal affect
- 2011
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Ingår i: Procedings of INTERSPEECH 2011. - Florence, Italy. : International Speech Communication Association. ; , s. 1581-1584, s. 1592-1595
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Konferensbidrag (refereegranskat)abstract
- We present intra-, inter- and cross-cultural classifications of vocal expressions. Stimuli were selected from the VENEC corpus and consisted of portrayals of 11 emotions, each expressed with 3 levels of intensity. Classification (nu-SVM) was based on acoustic measures related to pitch, intensity, formants, voice source and duration. Results showed that mean recall across emotions was around 2.4-3 times higher than chance level for both intra- and inter-cultural conditions. For cross-cultural conditions, the relative performance dropped 26%, 32%, and 34% for high, medium, and low emotion intensity, respectively. This suggests that intracultural models were more sensitive to mismatched conditions for low emotion intensity. Preliminary results further indicated that recall rate varied as a function of emotion, with lust and sadness showing the smallest performance drops in the crosscultural condition.
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| 7. |
- Enquist, Magnus, 1955-, et al.
(författare)
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Cultural traits operating in senders are driving forces of cultural evolution
- 2024
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : Royal society publishing. - 0962-8452 .- 1471-2954. ; 291:2018
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Tidskriftsartikel (refereegranskat)abstract
- We introduce a mathematical model of cultural evolution to study cultural traits that shape how individuals exchange information. Current theory focuses on traits that influence the reception of information (receiver traits), such as evaluating whether information represents the majority or stems from a trusted source. Our model shifts the focus from the receiver to the sender of cultural information and emphasizes the role of sender traits, such as communicability or persuasiveness. Here, we show that sender traits are probably a stronger driving force in cultural evolution than receiver traits. While receiver traits evolve to curb cultural transmission, sender traits can amplify it and fuel the self-organization of systems of mutually supporting cultural traits, including traits that cannot be maintained on their own. Such systems can reach arbitrary complexity, potentially explaining uniquely human practical and mental skills, goals, knowledge and creativity, independent of innate factors. Our model incorporates social and individual learning throughout the lifespan, thus connecting cultural evolutionary theory with developmental psychology. This approach provides fresh insights into the trait-individual duality, that is, how cultural transmission of single traits is influenced by individuals, who are each represented as an acquired system of cultural traits.
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| 8. |
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| 9. |
- Forssén, Jens, et al.
(författare)
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Auralization of traffic noise within the LISTEN project : Preliminary results for passenger car pass-by
- 2009
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Ingår i: Euronoise 2009. - Edinburgh : Institute of Acoustics.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Auralization of future traffic noise scenarios would be a valuable tool for city planners, noise consultants and decision makers, since it would make it possible to evaluate various noise mitigation solutions already at the planning stage. The main goal of the Swedish multidisciplinary research project LISTEN is to develop such a tool. In the present paper, auralizations of a single pass-by of a passenger car are investigated with respect to different simulation approaches, and the methodologies behind the approaches are described. Three listening experiments were conducted in order to perceptually evaluate the auralizations. The results showed a high degree of perceptual agreement between real and auralized sounds. However, slight differences between real and auralized sounds were found for perceived realism, annoyance and speed of vehicles, which calls for further improvements of the auralizations.
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| 10. |
- Kleberg, Johan L., et al.
(författare)
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Social feedback enhances learning in Williams syndrome
- 2023
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Williams syndrome (WS) is a rare genetic condition characterized by high social interest and approach motivation as well as intellectual disability and anxiety. Despite the fact that social stimuli are believed to have an increased intrinsic reward value in WS, it is not known whether this translates to learning and decision making. Genes homozygously deleted in WS are linked to sociability in the general population, making it a potential model condition for understanding the social brain. Probabilistic reinforcement learning was studied with either social or non-social rewards for correct choices. Social feedback improved learning in individuals with Williams syndrome but not in typically developing controls or individuals with other intellectual disabilities. Computational modeling indicated that these efects on social feedback were mediated by a shift towards higher weight given to rewards relative to punishments and increased choice consistency. We conclude that reward learning in WS is characterized by high volatility and a tendency to learn how to avoid punishment rather than how to gain rewards. Social feedback can partly normalize this pattern and promote adaptive reward learning.
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