Confidence as a noisy decision reliability estimate

Decisions vary in difficulty. Humans know this and typically report more confidence in easy than in difficult decisions. However, confidence reports do not perfectly track decision accuracy, but also reflect response biases and difficulty misjudgments. To isolate the quality of confidence reports, we developed a model of the decision-making process underlying choice-confidence data. In this model, confidence reflects a subject's estimate of the reliability of their decision. The quality of this estimate is limited by the subject's uncertainty about the uncertainty of the variable that informs their decision ("meta-uncertainty"). This model provides an accurate account of choice-confidence data across a broad range of perceptual and cognitive tasks, revealing that meta-uncertainty varies across subjects, is stable over time, generalizes across some domains, and can be manipulated experimentally. The model offers a parsimonious explanation for the computational processes that underlie and constrain the sense of confidence.

What are the letters e and é in a language with vowel reduction? The case of Catalan

Although the Latin-based orthographies of most Western languages employ vowels with accent marks (e.g., é vs. e), extant models of letter and word recognition are agnostic as to whether these accented letters and their non-accented counterparts are represented by common or separate abstract units. Recent research in French with a masked priming alphabetic decision task was interpreted as favoring the idea that accented and non-accented vowels are represented by separate abstract orthographic units (orthographic account: é↛e and e↛é; Chetail & Boursain, 2019). However, a more parsimonious explanation is that salient (accented) vowels are less perceptually similar to non-salient (non-accented) vowels than vice versa (perceptual account: e→é, but é↛e; Perea et al., 2021a; Tversky, 1977). To adjudicate between the two accounts, we conducted a masked priming alphabetic decision experiment in Catalan, a language with a complex orthography-to-phonology mapping for non-accented vowels (e.g., e→/e/, /ə/, /ε/). Results showed faster responses in the identity than in the visually similar condition for accented targets (é–É < e–É), but not for non-accented targets (e–E = é–E). Neither of the above accounts can fully capture this pattern. We propose an explanation based on the rapid activation of both orthographic and phonological codes.

The cranial anatomy and relationships of Cardiocorax mukulu (Plesiosauria: Elasmosauridae) from Bentiaba, Angola

We report a new specimen of the plesiosaur Cardiocorax mukulu that includes the most complete plesiosaur skull from sub-Saharan Africa. The well-preserved three-dimensional nature of the skull offers rare insight into the cranial anatomy of elasmosaurid plesiosaurians. The new specimen of Cardiocorax mukulu was recovered from Bentiaba, Namibe Province in Angola, approximately three meters above the holotype. The new specimen also includes an atlas-axis complex, seventeen postaxial cervical vertebrae, partial ribs, a femur, and limb elements. It is identified as Cardiocorax mukulu based on an apomorphy shared with the holotype where the cervical neural spine is approximately as long anteroposteriorly as the centrum and exhibits a sinusoidal anterior margin. The new specimen is nearly identical to the holotype and previously referred material in all other aspects. Cardiocorax mukulu is returned in an early-branching or intermediate position in Elasmosauridae in four out of the six of our phylogenetic analyses. Cardiocorax mukulu lacks the elongated cervical vertebrae that is characteristic of the extremely long-necked elasmosaurines, and the broad skull with and a high number of maxillary teeth (28–40) which is characteristic of Aristonectinae. Currently, the most parsimonious explanation concerning elasmosaurid evolutionary relationships, is that Cardiocorax mukulu represents an older lineage of elasmosaurids in the Maastrichtian.

Implicit Bias and the Fragmented Mind

This chapter discusses the strengths and weaknesses of the belief fragmentation thesis vis-à-vis the attitudinal dissonance illustrated by implicit biases. It argues that, depending on the notion of belief at hand, the fragmentation strategy faces a dilemma: either it is a mere restatement of the phenomena it is intended to explain (when belief is understood in non-reductive, dispositional terms) or, when apparently successful, the explanatory grip on the dissonance comes from the notion of access, not fragmentation (when beliefs are understood as representations stored in the mind). More positively, it argues that a representational, contextualist, non-fragmentationalist, and affect-laden account of the dissonance between implicit and explicit biases provides a more plausible and parsimonious explanation of the target phenomenon than fragmentationalism.

Sensitivity of cohesin–chromatin association to high-salt treatment corroborates non-topological mode of loop extrusion

Cohesin is a key organizer of chromatin folding in eukaryotic cells. The two main activities of this ring-shaped protein complex are the maintenance of sister chromatid cohesion and the establishment of long-range DNA–DNA interactions through the process of loop extrusion. Although the basic principles of both cohesion and loop extrusion have been described, we still do not understand several crucial mechanistic details. One of such unresolved issues is the question of whether a cohesin ring topologically embraces DNA string(s) during loop extrusion. Here, we show that cohesin complexes residing on CTCF-occupied genomic sites in mammalian cells do not interact with DNA topologically. We assessed the stability of cohesin-dependent loops and cohesin association with chromatin in high-ionic-strength conditions in G1-synchronized HeLa cells. We found that increased salt concentration completely displaces cohesin from those genomic regions that correspond to CTCF-defined loop anchors. Unsurprisingly, CTCF-anchored cohesin loops also dissipate in these conditions. Because topologically engaged cohesin is considered to be salt resistant, our data corroborate a non-topological model of loop extrusion. We also propose a model of cohesin activity throughout the interphase, which essentially equates the termination of non-topological loop extrusion with topological loading of cohesin. This theoretical framework enables a parsimonious explanation of various seemingly contradictory experimental findings.

Photophobia in migraine: A symptom cluster?

Photophobia is one of the most common symptoms in migraine, and the underlying mechanism is uncertain. The discovery of the intrinsically-photosensitive retinal ganglion cells which signal the intensity of light on the retina has led to discussion of their role in the pathogenesis of photophobia. In the current review, we discuss the relationship between pain and discomfort leading to light aversion (traditional photophobia) and discomfort from flicker, patterns, and colour that are also common in migraine and cannot be explained solely by the activity of intrinsically-photosensitive retinal ganglion cells. We argue that, at least in migraine, a cortical mechanism provides a parsimonious explanation for discomfort from all forms of visual stimulation, and that the traditional definition of photophobia as pain in response to light may be too restrictive. Future investigation that directly compares the retinal and cortical contributions to photophobia in migraine with that in other conditions may offer better specificity in identifying biomarkers and possible mechanisms to target for treatment.

Homoplasy in the evolution of modern human-like joint proportions in Australopithecus afarensis

The evolution of bipedalism and reduced reliance on arboreality in hominins resulted in larger lower limb joints relative to the joints of the upper limb. The pattern and timing of this transition, however, remains unresolved. Here, we find the limb joint proportions of Australopithecus afarensis, Homo erectus, and Homo naledi to resemble those of modern humans, whereas those of A. africanus, Australopithecus sediba, Paranthropus robustus, Paranthropus boisei, Homo habilis, and Homo floresiensis are more ape-like. The homology of limb joint proportions in A. afarensis and modern humans can only be explained by a series of evolutionary reversals irrespective of differing phylogenetic hypotheses. Thus, the independent evolution of modern human-like limb joint proportions in A. afarensis is a more parsimonious explanation. Overall, these results support an emerging perspective in hominin paleobiology that A. afarensis was the most terrestrially adapted australopith despite the importance of arboreality throughout much of early hominin evolution.

Sensitivity of cohesin–chromatin association to high-salt treatment corroborates non-topological mode of loop extrusion

Cohesin is a key organizer of chromatin folding in eukaryotic cells. The two main activities of this ring-shaped protein complex are the maintenance of sister chromatid cohesion and the establishment of long-range DNA–DNA interactions through the process of loop extrusion. Although the basic principles of both cohesion and loop extrusion have been described, we still do not understand several crucial mechanistic details. One of such unresolved issues is the question of whether a cohesin ring topologically embraces DNA string(s) during loop extrusion. Here, we show that cohesin complexes residing on CTCF-occupied genomic sites in mammalian cells do not interact with DNA topologically. We assessed the stability of cohesin-dependent loops and cohesin association with chromatin in high ionic strength conditions in G1-synchronised HeLa cells. We found that increased salt concentration completely displaces cohesin from those genomic regions that correspond to CTCF-defined loop anchors. Unsurprisingly, CTCF-anchored cohesin loops also dissipate in these conditions. Because topologically engaged cohesin is considered to be salt resistant, our data corroborate a non-topological model of loop extrusion. We also propose a model of cohesin activity throughout the interphase, which essentially equates the termination of non-topological loop extrusion with topological loading of cohesin. This theoretical framework enables a parsimonious explanation of various seemingly contradictory experimental findings.

Poverty and economic decision making: a review of scarcity theory

Poverty is associated with a wide range of counterproductive economic behaviors. Scarcity theory proposes that poverty itself induces a scarcity mindset, which subsequently forces the poor into suboptimal decisions and behaviors. The purpose of our work is to provide an integrated, up-to-date, critical review of this theory. To this end, we reviewed the empirical evidence for three fundamental propositions: (1) Poverty leads to attentional focus and neglect causing overborrowing, (2) poverty induces trade-off thinking resulting in more consistent consumption decisions, and (3) poverty reduces mental bandwidth and subsequently increases time discounting and risk aversion. Our findings indicate that the current literature predominantly confirms the first and second proposition, although methodological issues prevent a firm conclusion. Evidence for the third proposition was not conclusive. Additionally, we evaluated the overall status of scarcity theory. Although the theory provides an original, coherent, and parsimonious explanation for the relationship between financial scarcity and economic decision making, the theory does not fully accord with the data and lacks some precision. We conclude that both theoretical and empirical work are needed to build a stronger theory.