1,818 research outputs found
The influence of task complexity and information value on feedback processing in younger and older adults : No evidence for a positivity bias during feedback-induced learning in older adults
Humans flexibly adapt their behavior using feedback from their environment. This ability is impaired in old age, but recent research suggests this mainly concerns processing of negative feedback and that positive feedback might be spared. The aim of this study was to test this idea of an age-related positivity bias against the possibility of a strategic focus on relevant feedback due to limited processing resources in old age. For this purpose, 17 younger (aged 19 to 28âŻyears) and 18 older (aged 69 to 79âŻyears) adults performed a learning task in which they learned the correct response to a stimulus via feedback. Learning relevance was manipulated by varying the informational value of positive and negative feedback. To manipulate available processing resources, the task was conducted under two difficulty levels. Our results showed no hint of a positivity bias in older adults. On the contrary, we found that they learned worse when the information value of the negative feedback was reduced. This is in line with the idea that the positivity effect in older adults reflects a strategic change in motivation, i.e., older adults preferably process positive information if they have a choice, but they can process negative information as effectively when it is relevant for the task at hand. For younger adults, negative feedback seemed to be more important, too, because it modulated later higher-order feedback processing as indexed by the P3b. They showed reduced working memory updating and a more frontal P3b distribution indicating a higher processing effort in conditions in which the information value of negative feedback was reduced
CONJOINT ANALYSIS OF THE MID-ATLANTIC FOOD-FISH MARKET FOR FARM-RAISED HYBRID STRIPED BASS
Conjoint analysis was used to examine buyer preferences toward farm-raised hybrid striped bass at the wholesale, retail, and restaurant levels. Low price and round form were found to be important attributes in the product preference rating for the wholesale and retail markets. The filleted form contributed the most to restaurants' preference rating. Following these, larger fish size was preferred by all markets.Agribusiness,
PREFERENCES OF MID-ATLANTIC SEAFOOD BUYERS TOWARD FARM-RAISED HYBRID STRIPED BASS
A market survey of three mid-Atlantic food-fish market levels was conducted to provide information on finfish buyers' market characteristics, finfish attribute preferences, and buyers' attitudes toward farm-raised hybrid striped bass. Results showed that most firms are located in the suburban areas, and they purchased their fish from producers and wholesalers. Quality was rated as the most important finfish attribute; and, aside from restaurants, buyers are generally familiar with hybrid striped bass and indicated that it could easily be substituted for wild striped bass. Most buyers were either not sure or feel hybrid striped bass could not substitute for other fish species although they all expressed a willingness to offer farm-raised hybrid striped bass. Finally, the possibility of fish farmers selling directly to all market levels has great potential if the fish size is around two to three pounds and the form is whole for the wholesaler and retailer and fillet for the restaurants.Consumer/Household Economics,
Training and Transfer of Cue Updating in Older Adults Is Limited: Evidence From Behavioral and Neuronal Data
Cognitive control processes, such as updating task-relevant information while switching between multiple tasks, are substantially impaired in older adults. However, it has also been shown that these cognitive control processes can be improved by training interventions, e.g., by training in task switching. Here, we applied an event-related potential (ERP) approach to identify whether a cognitive training improves task-preparatory processes such as updating of relevant task goals. To do so, we applied a pretest-training-posttest design with eight training sessions. Two groups of older adults were either trained in task switching (treatment group) or in performing single tasks (control group) and we compared their performance to a group of untrained younger adults. To foster cue updating in the treatment group, we applied a cue-based switching task in which the two task cues were randomly selected prior to target presentation so that participants had time to prepare for the upcoming task. In contrast, the control group also received task cues but those were redundant as only one task had to be performed. We also examined whether training in cue updating during task switching can be transferred to a similar cognitive control task measuring updating of context information, namely a modified version of the AX-Continuous Performance Task (AX-CPT). The results revealed training-specific improvements in task switching, that is, a larger improvement in blocks requiring switching in comparison to single tasks at the behavioral level. In addition, training specific-effects were also found at the neuronal level. Older adults trained in cue updating while switching showed a reduction in mixing costs in the cue-related P3, indicating an improvement in preparatory updating processes. Additionally, P3 topography changed with training from a very broad to a parietally focused scalp distribution similar to the one found in younger adults. However, we did not obtain training-specific improvements in context updating in the AX-CPT neither at the behavioral level nor at the neuronal level. Results are discussed in the context of the ongoing debate on whether transfer of cognitive training improvements is possible
Interpreting silent gesture:Cognitive biases and rational inference in emerging language systems
Natural languages make prolific use of conventional constituentâordering patterns to indicate âwho did what to whom,â yet the mechanisms through which these regularities arise are not well understood. A series of recent experiments demonstrates that, when prompted to express meanings through silent gesture, people bypass native language conventions, revealing apparent biases underpinning word order usage, based on the semantic properties of the information to be conveyed. We extend the scope of these studies by focusing, experimentally and computationally, on the interpretation of silent gesture. We show crossâlinguistic experimental evidence that people use variability in constituent order as a cue to obtain different interpretations. To illuminate the computational principles that govern interpretation of nonâconventional communication, we derive a Bayesian model of interpretation via biased inductive inference and estimate these biases from the experimental data. Our analyses suggest people's interpretations balance the ambiguity that is characteristic of emerging language systems, with ordering preferences that are skewed and asymmetric, but defeasible
Symmetric Operation of the Resonant Exchange Qubit
We operate a resonant exchange qubit in a highly symmetric triple-dot
configuration using IQ-modulated RF pulses. At the resulting three-dimensional
sweet spot the qubit splitting is an order of magnitude less sensitive to all
relevant control voltages, compared to the conventional operating point, but we
observe no significant improvement in the quality of Rabi oscillations. For
weak driving this is consistent with Overhauser field fluctuations modulating
the qubit splitting. For strong driving we infer that effective voltage noise
modulates the coupling strength between RF drive and the qubit, thereby
quickening Rabi decay. Application of CPMG dynamical decoupling sequences
consisting of up to n = 32 {\pi} pulses significantly prolongs qubit coherence,
leading to marginally longer dephasing times in the symmetric configuration.
This is consistent with dynamical decoupling from low frequency noise, but
quantitatively cannot be explained by effective gate voltage noise and
Overhauser field fluctuations alone. Our results inform recent strategies for
the utilization of partial sweet spots in the operation and long-distance
coupling of triple-dot qubits.Comment: 6 pages, 5 figure
Negative spin exchange in a multielectron quantum dot
By operating a one-electron quantum dot (fabricated between a multielectron
dot and a one-electron reference dot) as a spectroscopic probe, we study the
spin properties of a gate-controlled multielectron GaAs quantum dot at the
transition between odd and even occupation number. We observe that the
multielectron groundstate transitions from spin-1/2-like to singlet-like to
triplet-like as we increase the detuning towards the next higher charge state.
The sign reversal in the inferred exchange energy persists at zero magnetic
field, and the exchange strength is tunable by gate voltages and in-plane
magnetic fields. Complementing spin leakage spectroscopy data, the inspection
of coherent multielectron spin exchange oscillations provides further evidence
for the sign reversal and, inferentially, for the importance of non-trivial
multielectron spin exchange correlations.Comment: 8 pages, including 4 main figures and 2 supplementary figurure
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Short-term impact of aged garlic extract on endothelial function in diabetes: A randomized, double-blind, placebo-controlled trial.
Impaired endothelial function portends an increased risk of cardiovascular disease. Vascular oxidative stress and systemic inflammation play a critical role in the pathogenesis and progression of vascular disease. Aged garlic extract (AGE) may improve impaired vascular endothelial function, while decreasing the progression of atherosclerotic plaque. We hypothesized that AGE may improve endothelial function, and in this study, we examined this hypothesis to determine whether this can be achieved over a period of 3 months, measured by the cardio-ankle vascular index (CAVI), by reducing intracellular oxidant stress and stimulating nitric oxide generation in endothelial cells. We conducted a double-blinded placebo controlled, randomized clinical trial to investigate the effects of AGE on CAVI in subjects with type 2 diabetes mellitus. A total of 65 individuals (38 men and 27 women) with a mean age of 58.8±11.1 years were enrolled and randomized to the AGE or placebo group in a double-blind placebo controlled trial. An ANOVA model with treatment as the main effect was used to compare changes in CAVI from baseline to follow-up between groups. The primary objective of this study was reduction in CAVI over a 3-month period. In the AGE group, CAVI was reduced on average by 0.71±1.27 vs. a mean reduction of 0.13±0.94 in the placebo group (P=0.04). On the whole, this study demonstrates that AGE has a positive impact on endothelial function in patients with T2DM and may play a role in the primary prevention of cardiovascular disease
Aggregate investor sentiment and stock return synchronicity
© 2019 Elsevier B.V. We show that the returns of individual stocks become more synchronous with the aggregate market during periods of high investor sentiment. We also document that the effect of sentiment on stock return synchronicity is especially pronounced for small, young, volatile, non-dividend-paying and low-priced stocks. This âdifference in differenceâ suggests that stocks with these characteristics are affected more by sentimentâconsistent with previous studies. Our results support the hypothesis that greater constraints on arbitrage and the prevalence of sentiment-driven demand during periods of high sentiment lead to increased comovement among stocks
Dominant factors hampering full participation of female contractors in the South African construction industry
Abstract: This paper analyses the experiences of female contractors in the South African construction industry in order to identify dominant factors hampering their meaningful participation in the industry
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