75 research outputs found
States of curiosity modulate hippocampus-dependent learning via the dopaminergic circuit
People find it easier to learn about topics that interest them, but little is known about the mechanisms by which intrinsic motivational states affect learning. We used functional magnetic resonance imaging to investigate how curiosity (intrinsic motivation to learn) influences memory. In both immediate and one-day-delayed memory tests, participants showed improved memory for information that they were curious about and for incidental material learned during states of high curiosity. Functional magnetic resonance imaging results revealed that activity in the midbrain and the nucleus accumbens was enhanced during states of high curiosity. Importantly, individual variability in curiosity-driven memory benefits for incidental material was supported by anticipatory activity in the midbrain and hippocampus and by functional connectivity between these regions. These findings suggest a link between the mechanisms supporting extrinsic reward motivation and intrinsic curiosity and highlight the importance of stimulating curiosity to create more effective learning experiences
Densities of Bornean orangâutans ( Pongo pygmaeus morio ) in heavily degraded forest and oil palm plantations in Sabah, Borneo
The conversion of forest to agriculture continues to contribute to the loss and fragmentation of remaining orangâutan habitat. There are still few published estimates of orangâutan densities in these heavily modified agricultural areas to inform rangeâwide population assessments and conservation strategies. In addition, little is known about what landscape features promote orangâutan habitat use. Using indirect nest count methods, we implemented surveys and estimated population densities of the Northeast Bornean orangâutan (Pongo pygmaeus morio) across the continuous logged forest and forest remnants in a recently salvageâlogged area and oil palm plantations in Sabah, Malaysian Borneo. We then assessed the influence of landscape features and forest structural metrics obtained from LiDAR data on estimates of orangâutan density. Recent salvage logging appeared to have a little shortâterm effect on orangâutan density (2.35âind/km 2), which remained similar to recovering logged forest nearby (2.32âind/km 2). Orangâutans were also present in remnant forest patches in oil palm plantations, but at significantly lower numbers (0.82âind/km 2) than nearby logged forest and salvageâlogged areas. Densities were strongly influenced by variation in canopy height but were not associated with other potential covariates. Our findings suggest that orangâutans currently exist, at least in the shortâterm, within humanâmodified landscapes, providing that remnant forest patches remain. We urge greater recognition of the role that these degraded habitats can have in supporting orangâutan populations, and that future rangeâwide analyses and conservation strategies better incorporate data from humanâmodified landscapes
Children Base Their Investment on Calculated Pay-Off
To investigate the rise of economic abilities during development we studied children aged between 3 and 10 in an exchange situation requiring them to calculate their investment based on different offers. One experimenter gave back a reward twice the amount given by the children, and a second always gave back the same quantity regardless of the amount received. To maximize pay-offs children had to invest a maximal amount with the first, and a minimal amount with the second. About one third of the 5-year-olds and most 7- and 10-year-olds were able to adjust their investment according to the partner, while all 3-year-olds failed. Such performances should be related to the rise of cognitive and social skills after 4 years
Inferring cellular networks â a review
In this review we give an overview of computational and statistical methods to reconstruct cellular networks. Although this area of research is vast and fast developing, we show that most currently used methods can be organized by a few key concepts. The first part of the review deals with conditional independence models including Gaussian graphical models and Bayesian networks. The second part discusses probabilistic and graph-based methods for data from experimental interventions and perturbations
Planck 2015 results. XIX. Constraints on primordial magnetic fields
We compute and investigate four types of imprint of a stochastic background of primordial magnetic fields (PMFs) on the cosmic microwave background (CMB) anisotropies: the impact of PMFs on the CMB temperature and polarization spectra, which is related to their contribution to cosmological perturbations; the effect on CMB polarization induced by Faraday rotation; the impact of PMFs on the ionization history; magnetically-induced non-Gaussianities and related non-zero bispectra; and the magnetically-induced breaking of statistical isotropy. We present constraints on the amplitude of PMFs that are derived from different Planck data products, depending on the specific effect that is being analysed. Overall, Planck data constrain the amplitude of PMFs to less than a few nanoGauss, with different bounds that depend on the considered model. In particular, individual limits coming from the analysis of the CMB angular power spectra, using the Planck likelihood, are B1 Mpc < 4.4 nG (where B1 Mpc is the comoving field amplitude at a scale of 1âMpc) at 95% confidence level, assuming zero helicity. By considering the Planck likelihood, based only on parity-even angular power spectra, we obtain B1 Mpc < 5.6 nG for a maximally helical field. For nearly scale-invariant PMFs we obtain B1 Mpc < 2.0ânG and B1 Mpc < 0.9ânG if the impact of PMFs on the ionization history of the Universe is included in the analysis. From the analysis of magnetically-induced non-Gaussianity, we obtain three different values, corresponding to three applied methods, all below 5ânG. The constraint from the magnetically-induced passive-tensor bispectrum is B1 Mpc < 2.8ânG. A search for preferred directions in the magnetically-induced passive bispectrum yields B1 Mpc < 4.5ânG, whereas the compensated-scalar bispectrum gives B1 Mpc < 3ânG. The analysis of the Faraday rotation of CMB polarization by PMFs uses the Planck power spectra in EE and BB at 70âGHz and gives B1 Mpc < 1380ânG. In our final analysis, we consider the harmonic-space correlations produced by AlfvĂ©n waves, finding no significant evidence for the presence of these waves. Together, these results comprise a comprehensive set of constraints on possible PMFs with Planck data
Vampires in the village Ćœrnovo on the island of KorÄula: following an archival document from the 18th century
SrediĆĄnja tema rada usmjerena je na raĆĄÄlambu spisa pohranjenog u DrĆŸavnom arhivu u Mlecima (fond: Capi del Consiglio deâ Dieci: Lettere di Rettori e di altre cariche) koji se odnosi na dogaÄaj iz 1748. godine u korÄulanskom selu Ćœrnovo, kada su mjeĆĄtani â vjerujuÄi da su se pojavili vampiri â oskvrnuli nekoliko mjesnih grobova. U radu se podrobno iznose osnovni podaci iz spisa te reÄeni dogaÄaj analizira u ĆĄirem druĆĄtvenom kontekstu i prate se lokalna vjerovanja.The main interest of this essay is the analysis of the document from the State Archive in Venice (file: Capi del Consiglio deâ Dieci: Lettere di Rettori e di altre cariche) which is connected with the episode from 1748 when the inhabitants of the village Ćœrnove on the island of KorÄula in Croatia opened tombs on the local cemetery in the fear of the vampires treating.
This essay try to show some social circumstances connected with this event as well as a local vernacular tradition concerning superstitions
Knowledge of Social Affiliations Biases Economic Decisions.
An individual's reputation and group membership can produce automatic judgments and behaviors toward that individual. Whether an individual's social reputation impacts interactions with affiliates has yet to be demonstrated. We tested the hypothesis that during initial encounters with others, existing knowledge of their social network guides behavior toward them. Participants learned reputations (cooperate, defect, or equal mix) for virtual players through an iterated economic game (EG). Then, participants learned one novel friend for each player. The critical question was how participants treated the friends in a single-shot EG after the friend-learning phase. Participants tended to cooperate with friends of cooperators and defect on friends of defectors, indicative of a decision making bias based on memory for social affiliations. Interestingly, participants' explicit predictions of the friends' future behavior showed no such bias. Moreover, the bias to defect on friends of defectors was enhanced when affiliations were learned in a social context; participants who learned to associate novel faces with player faces during reinforcement learning did not show reputation-based bias for associates of defectors during single-shot EG. These data indicate that when faced with risky social decisions, memories of social connections influence behavior implicitly
Schematic of task phases.
<p>(<b>a)</b> Economic Game task. On each trial, participants were presented with a virtual playerâs image and had to choose to cooperate or defect. After a 1s fixation screen, the outcome of the trial was presented for 3s. This outcome consisted of the participant and playerâs choices as well as the points earned or lost according to the payoff matrix (gray inset). (<b>b)</b> Friend association task (social framing task). Half of the participants learned associations between players form the initial EG phase and new faces in a social framing friend association task. On each trial, participants were presented with a player or novel face and instructed to choose the friend from among two faces presented below. The trial continued only after a response was made, at which point, a fixation screen was presented for 1s followed by a 3s feedback consisting of the correct friendship association. Each friendship pair was repeated six times over the course of the friend association task. (<b>c)</b> Associative face learning task (nonsocial framing task). The other half of participants learned associations between players and new faces in a nonsocial framing association task. Participants were instructed to choose the face that led to a reward without reference to a social relationship among faces. The participantsâ feedback consisted of either 5 star coins for correct trials or a red X for incorrect trials. The participantsâ goal was to acquire as many points as they could; accordingly, they saw a running total of their points in the upper right hand corner of the display. As in the friend association task, each face-face pair was presented six times during this phase.</p
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