A Similarity-Based Process for Human Judgment in the Parietal Cortex

One important distinction in psychology is between inferences based on associative memory and inferences based on analysis and rules. Much previous empirical work conceive of associative and analytical processes as two exclusive ways of addressing a judgment task, where only one process is selected and engaged at a time, in an either-or fashion. However, related work indicate that the processes are better understood as being in interplay and simultaneously engaged. Based on computational modeling and brain imaging of spontaneously adopted judgment strategies together with analyses of brain activity elicited in tasks where participants were explicitly instructed to perform similarity-based associative judgments or rule-based judgments (n = 74), we identified brain regions related to the two types of processes. We observed considerable overlap in activity patterns. The precuneus was activated for both types of judgments, and its activity predicted how well a similarity-based model fit the judgments. Activity in the superior frontal gyrus predicted the fit of a rule-based judgment model. The results suggest the precuneus as a key node for similarity-based judgments, engaged both when overt responses are guided by similarity-based and rule-based processes. These results are interpreted such that similarity-based processes are engaged in parallel to rule-based-processes, a finding with direct implications for cognitive theories of judgment

Similarity-based processes in human multiple-cue judgment : evidence from brain imaging and cognitive modelling

Background: We often make judgments that require the consideration of several sources of information. For example, a teacher that grades a student´s exam question often integrates multiple sources of information (cues: details provided in the answer) into a single criterion dimension (the grade). This is an example of a multiple-cue judgment: a continuous estimate based on multiple cues. One common idea in the literature is that people often utilize different memory representations during this kind of judgment process. People sometimes rely on rules, where they weigh the impact of different cues together in an additive linear way. At other times, people focus on the similarity between a probe and their experience of previous similar cases.  It has been proposed that similarity is an important organizing principle by which people make judgments, and that similarity always influence the judgment process to some degree. Behavioral methods with cognitive modelling (fitting cognitive models of rule-based and similarity-based processes to behavioral judgment data) have been used to test when people engage in either process, based on the classification of the better model fit. The brain networks that support human multiple-cue judgment could provide some answers to the role of similarity-based processes, but the existing knowledge on this topic is limited.  Here, I combined functional magnetic resonance imaging (fMRI), cognitive modelling and experimental methods to extend previous behavioral research, and I focused on the nature of similarity in human multiple-cue judgment. I explored how the two types of memory representations are represented in the brain, if rule-based and similarity-based processes are exclusively engaged or operate as an interplay during the judgment process, and tested if similarity-based processes are the default process in rule-based judgment.  Results: Study I investigated how the relationship between rule-based and similarity-based processes should be understood. The results revealed that a similarity-based process in the precuneus is shared between the two conditions: a key brain region for similarity-based processes is thus critical for human judgment. Study II further explored the precuneus role in similarity-based judgment learning, and demonstrated that the precuneus contribute to a mnemonic process related to storing and retrieving memory representations that are used for similarity comparison. Study III tested the influence of similarity-based processes in rule-based judgment when a learned rule could not be applied, and results suggested that similarity-based processes influenced rule-based behavior.  Conclusion: These findings converge to the idea that similarity-based processes are critical for human multiple-cue judgment. Specifically, a similarity-based process in the precuneus, presumably involved in storage and retrieval of memory representations that are used for similarity comparison, stands out as a novel contribution to the neuroscience of human multiple-cue judgment

Similarity-based processes in human multiple-cue judgment : evidence from brain imaging and cognitive modelling

Background: We often make judgments that require the consideration of several sources of information. For example, a teacher that grades a student´s exam question often integrates multiple sources of information (cues: details provided in the answer) into a single criterion dimension (the grade). This is an example of a multiple-cue judgment: a continuous estimate based on multiple cues. One common idea in the literature is that people often utilize different memory representations during this kind of judgment process. People sometimes rely on rules, where they weigh the impact of different cues together in an additive linear way. At other times, people focus on the similarity between a probe and their experience of previous similar cases.  It has been proposed that similarity is an important organizing principle by which people make judgments, and that similarity always influence the judgment process to some degree. Behavioral methods with cognitive modelling (fitting cognitive models of rule-based and similarity-based processes to behavioral judgment data) have been used to test when people engage in either process, based on the classification of the better model fit. The brain networks that support human multiple-cue judgment could provide some answers to the role of similarity-based processes, but the existing knowledge on this topic is limited.  Here, I combined functional magnetic resonance imaging (fMRI), cognitive modelling and experimental methods to extend previous behavioral research, and I focused on the nature of similarity in human multiple-cue judgment. I explored how the two types of memory representations are represented in the brain, if rule-based and similarity-based processes are exclusively engaged or operate as an interplay during the judgment process, and tested if similarity-based processes are the default process in rule-based judgment.  Results: Study I investigated how the relationship between rule-based and similarity-based processes should be understood. The results revealed that a similarity-based process in the precuneus is shared between the two conditions: a key brain region for similarity-based processes is thus critical for human judgment. Study II further explored the precuneus role in similarity-based judgment learning, and demonstrated that the precuneus contribute to a mnemonic process related to storing and retrieving memory representations that are used for similarity comparison. Study III tested the influence of similarity-based processes in rule-based judgment when a learned rule could not be applied, and results suggested that similarity-based processes influenced rule-based behavior.  Conclusion: These findings converge to the idea that similarity-based processes are critical for human multiple-cue judgment. Specifically, a similarity-based process in the precuneus, presumably involved in storage and retrieval of memory representations that are used for similarity comparison, stands out as a novel contribution to the neuroscience of human multiple-cue judgment

Hyresjämförelse mellan privata och allmännyttigt ägda lägenheter i nio kommuner

Syftet med denna studie är för det första att kartlägga om lägenheter med samma bruksvärde har olika hyror beroende på om de är privat eller allmännyttigt ägda. Studien syftar vidare till att undersöka om utfallen skiljer sig mellan kommuner där allmännyttans hyror är systematiskt satta och kommuner där så inte är fallet. Hypotesen är att hyresskillnaderna är mindre mellan bestånden i kommuner där allmännyttans hyror är systematiskt satta. De kommuner som ingår i studien är Borås, Göteborg, Helsingborg, Lund, Malmö, Stockholm, Södertälje, Umeå och Västerås. Av dessa är Lund, Södertälje, Umeå och Västerås systematiskt hyressatta. För att undersöka huruvida det finns någon generell skillnad i hyra mellan privat och allmännyttigt bestånd görs en regression där samtliga kommuner ingår. Denna tyder på att hyrorna generellt är högre i det privata beståndet än i det allmännyttiga beståndet. För att undersöka hur eventuella hyresskillnader mellan privat och allmännyttigt bestånd ser ut för varje kommun och huruvida hyresskillnaden skiljer sig mellan kommuner där allmännyttans hyror är systematiskt hyressatta och kommuner där så inte är fallet görs en till regression. Enligt resultaten från denna är hyrorna högre i privat bestånd i Borås, Göteborg, Helsingborg, Malmö, Stockholm och Södertälje. I Lund, Umeå och Västerås är hyrorna högre i allmännyttigt bestånd. Vidare tyder resultaten på att hyresskillnaderna är lägst i Lund, följt av Umeå och Västerås. Detta skulle kunna vara ett tecken på att hypotesen om att skillnaden i hyra mellan privat och allmännyttigt bestånd skulle kunna tänkas bli lägre i kommuner med systematisk hyressättning stämmer. I Södertälje är dock hyresskillnaden relativt hög och därför är det svårt att dra några säkrare slutsatser kring hypotesen ifråga

Hyresjämförelse mellan privata och allmännyttigt ägda lägenheter i nio kommuner

Syftet med denna studie är för det första att kartlägga om lägenheter med samma bruksvärde har olika hyror beroende på om de är privat eller allmännyttigt ägda. Studien syftar vidare till att undersöka om utfallen skiljer sig mellan kommuner där allmännyttans hyror är systematiskt satta och kommuner där så inte är fallet. Hypotesen är att hyresskillnaderna är mindre mellan bestånden i kommuner där allmännyttans hyror är systematiskt satta. De kommuner som ingår i studien är Borås, Göteborg, Helsingborg, Lund, Malmö, Stockholm, Södertälje, Umeå och Västerås. Av dessa är Lund, Södertälje, Umeå och Västerås systematiskt hyressatta. För att undersöka huruvida det finns någon generell skillnad i hyra mellan privat och allmännyttigt bestånd görs en regression där samtliga kommuner ingår. Denna tyder på att hyrorna generellt är högre i det privata beståndet än i det allmännyttiga beståndet. För att undersöka hur eventuella hyresskillnader mellan privat och allmännyttigt bestånd ser ut för varje kommun och huruvida hyresskillnaden skiljer sig mellan kommuner där allmännyttans hyror är systematiskt hyressatta och kommuner där så inte är fallet görs en till regression. Enligt resultaten från denna är hyrorna högre i privat bestånd i Borås, Göteborg, Helsingborg, Malmö, Stockholm och Södertälje. I Lund, Umeå och Västerås är hyrorna högre i allmännyttigt bestånd. Vidare tyder resultaten på att hyresskillnaderna är lägst i Lund, följt av Umeå och Västerås. Detta skulle kunna vara ett tecken på att hypotesen om att skillnaden i hyra mellan privat och allmännyttigt bestånd skulle kunna tänkas bli lägre i kommuner med systematisk hyressättning stämmer. I Södertälje är dock hyresskillnaden relativt hög och därför är det svårt att dra några säkrare slutsatser kring hypotesen ifråga

Similarity-based processes in human multiple-cue judgment : evidence from brain imaging and cognitive modelling

Background: We often make judgments that require the consideration of several sources of information. For example, a teacher that grades a student´s exam question often integrates multiple sources of information (cues: details provided in the answer) into a single criterion dimension (the grade). This is an example of a multiple-cue judgment: a continuous estimate based on multiple cues. One common idea in the literature is that people often utilize different memory representations during this kind of judgment process. People sometimes rely on rules, where they weigh the impact of different cues together in an additive linear way. At other times, people focus on the similarity between a probe and their experience of previous similar cases.  It has been proposed that similarity is an important organizing principle by which people make judgments, and that similarity always influence the judgment process to some degree. Behavioral methods with cognitive modelling (fitting cognitive models of rule-based and similarity-based processes to behavioral judgment data) have been used to test when people engage in either process, based on the classification of the better model fit. The brain networks that support human multiple-cue judgment could provide some answers to the role of similarity-based processes, but the existing knowledge on this topic is limited.  Here, I combined functional magnetic resonance imaging (fMRI), cognitive modelling and experimental methods to extend previous behavioral research, and I focused on the nature of similarity in human multiple-cue judgment. I explored how the two types of memory representations are represented in the brain, if rule-based and similarity-based processes are exclusively engaged or operate as an interplay during the judgment process, and tested if similarity-based processes are the default process in rule-based judgment.  Results: Study I investigated how the relationship between rule-based and similarity-based processes should be understood. The results revealed that a similarity-based process in the precuneus is shared between the two conditions: a key brain region for similarity-based processes is thus critical for human judgment. Study II further explored the precuneus role in similarity-based judgment learning, and demonstrated that the precuneus contribute to a mnemonic process related to storing and retrieving memory representations that are used for similarity comparison. Study III tested the influence of similarity-based processes in rule-based judgment when a learned rule could not be applied, and results suggested that similarity-based processes influenced rule-based behavior.  Conclusion: These findings converge to the idea that similarity-based processes are critical for human multiple-cue judgment. Specifically, a similarity-based process in the precuneus, presumably involved in storage and retrieval of memory representations that are used for similarity comparison, stands out as a novel contribution to the neuroscience of human multiple-cue judgment

Performance studies of a magnetostrictive actuator with varying mechanical and magnetic bias levels by dynamic simulations

The performance of a magnetostrictive actuator with varying mechanical and magnetic bias levels has been studied by dynamic simulations. The actuator efficiency was deduced from the simulations for a medium high level of excitation and for resonant and subresonant conditions. The actuator efficiency showed pronounced maxima at a certain magnetic bias level when the mechanical prestress was varied. The correlation between the mechanical prestress and magnetic bias level at maximum actuator efficiency showed a linear relationship for both resonant and subresonant conditions. This implies that a region in the strain-field plane can be found where the actuator shows optimal performance