Measures of metacognition on signal-detection theoretic models

Analysing metacognition, specifically knowledge of accuracy of internal perceptual, memorial or other knowledge states, is vital for many strands of psychology, including determining the accuracy of feelings of knowing, and discriminating conscious from unconscious cognition. Quantifying metacognitive sensitivity is however more challenging than quantifying basic stimulus sensitivity. Under popular signal detection theory (SDT) models for stimulus classification tasks, approaches based on type II receiver-operator characteristic (ROC) curves or type II d-prime risk confounding metacognition with response biases in either the type I (classification) or type II (metacognitive) tasks. A new approach introduces meta-d′: the type I d-prime that would have led to the observed type II data had the subject used all the type I information. Here we (i) further establish the inconsistency of the type II d-prime and ROC approaches with new explicit analyses of the standard SDT model, and (ii) analyse, for the first time, the behaviour of meta-d′ under non-trivial scenarios, such as when metacognitive judgments utilize enhanced or degraded versions of the type I evidence. Analytically, meta-d′ values typically reflect the underlying model well, and are stable under changes in decision criteria; however, in relatively extreme cases meta-d′ can become unstable. We explore bias and variance of in-sample measurements of meta-d′ and supply MATLAB code for estimation in general cases. Our results support meta-d′ as a useful measure of metacognition, and provide rigorous methodology for its application. Our recommendations are useful for any researchers interested in assessing metacognitive accuracy

Advances in Old-Fashioned Heterotic String Model Building

I review findings of various research groups regarding perturbative heterotic string model building in the last 12 months. Attention is given to recent studies of extra U(1)'s and local discrete symmetries (LDS's) in generic string models. Issues covered include the role of U(1)'s and LDS's in limiting proton decay, developments in classification of models containing anomalous U(1), and possible complications resulting from kinetic mixing between observable and hidden sector U(1)'s. Additionally, recent string-derived and string-inspired models are briefly reviewed. Talk Presented at SUSY '97.Comment: Talk presented at SUSY'97. Latex w/ espcrc2.sty, 10 pages, reference corrections and update

Blind insight: metacognitive discrimination despite chance task performance

Blindsight and other examples of unconscious knowledge and perception demonstrate dissociations between judgment accuracy and metacognition: Studies reveal that participants’ judgment accuracy can be above chance while their confidence ratings fail to discriminate right from wrong answers. Here, we demonstrated the opposite dissociation: a reliable relationship between confidence and judgment accuracy (demonstrating metacognition) despite judgment accuracy being no better than chance. We evaluated the judgments of 450 participants who completed an AGL task. For each trial, participants decided whether a stimulus conformed to a given set of rules and rated their confidence in that judgment. We identified participants who performed at chance on the discrimination task, utilizing a subset of their responses, and then assessed the accuracy and the confidence-accuracy relationship of their remaining responses. Analyses revealed above-chance metacognition among participants who did not exhibit decision accuracy. This important new phenomenon, which we term blind insight, poses critical challenges to prevailing models of metacognition grounded in signal detection theory

Kaluza-Klein States versus Winding States: Can Both Be Above the String Scale?

When closed strings propagate in extra compactified dimensions, a rich spectrum of Kaluza-Klein states and winding states emerges. Since the masses of Kaluza-Klein states and winding states play a reciprocal role, it is often believed that either the lightest Kaluza-Klein states or the lightest winding states must be at or below the string scale. In this paper, we demonstrate that this conclusion is no longer true for compactifications with non-trivial shape moduli. Specifically, we demonstrate that toroidal compactifications exist for which all Kaluza-Klein states as well as all winding states are heavier than the string scale. This observation could have important phenomenological implications for theories with reduced string scales, suggesting that it is possible to cross the string scale without detecting any states associated with spacetime compactification.Comment: 8 pages, LaTeX, no figure

Towards a viable grand unified model with MG∼MstringM_G\sim M_{\rm string} and MI∼1012M_I\sim 10^{12} GeV

We present a model based on the gauge group SU(2)$_L\times$SU(2)$_R\times$SU(4)$_C$ with gauge couplings that are found to be unified at a scale $M_G$ near the string unification scale. The model breaks to the minimal supersymmetric standard model at a scale $M_I\sim 10^{12}$ GeV, which is instrumental in producing a neutrino in a mass range that can serve as hot dark matter and this scale can also solve the strong CP problem via Peccei-Quinn (PQ) mechanism with an invisible harmless invisible axion. We show how this model can accommodate low and high values of $\tan\beta$ and ``exotic" representations that often occur in string derived models. We show that this model has lepton flavor violation which can lead to processes which are one or two orders of magnitude below the current experimental limits.Comment: 16 pages(Latex), 1 PS Figures (uuencoded, epsf.tex), Typo in the archive title (not in the paper), no change in pape

Adventures in Thermal Duality (II): Towards a Duality-Covariant String Thermodynamics

In a recent companion paper, we observed that the rules of ordinary thermodynamics generally fail to respect thermal duality, a symmetry of string theory under which the physics at temperature T is related to the physics at the inverse temperature 1/T. Even when the free energy and internal energy exhibit the thermal duality symmetry, the entropy and specific heat are defined in such a way that this symmetry is destroyed. In this paper, we propose a modification of the traditional definitions of these quantities, yielding a manifestly duality-covariant thermodynamics. At low temperatures, these modifications produce "corrections" to the standard definitions of entropy and specific heat which are suppressed by powers of the string scale. These corrections may nevertheless be important for the full development of a consistent string thermodynamics. We find, for example, that the string-corrected entropy can be smaller than the usual entropy at high temperatures, suggesting a possible connection with the holographic principle. We also discuss some outstanding theoretical issues prompted by our approach.Comment: 31 pages, 6 figures, 1 conversatio

String Cosmology: A Review

The second string revolution, which begin around 1995, has led to a drastic alteration in our perception of the universe, perhaps even more so then did the first string revolution of 1984. That is, extending 10-dimensional string theory to 11-dimensional M-theory has had more profound implications than did the original extension of 4-dimensional quantum mechanics and relativity to 10-dimensional string theory. After a brief review of M-theory, I discuss some implications of large extra dimensions. I then consider astronomical evidence for, and constraints on, large compactified dimensions. I conclude with a possible resolution to the apparent inconsistency between the MSSM scale and string scale in the weak coupling limit. Talk presented at COSPAR '02, Houston, Texas, October 2002.Comment: 10 pages. Standard Latex. Changes to match retitled published versio

The relationship between strategic control and conscious structural knowledge in artificial grammar learning

We address Jacoby’s (1991) proposal that strategic control over knowledge requires conscious awareness of that knowledge. In a two-grammar artificial grammar learning experiment all participants were trained on two grammars, consisting of a regularity in letter sequences, while two other dimensions (colours and fonts) varied randomly. Strategic control was measured as the ability to selectively apply the grammars during classification. For each classification, participants also made a combined judgement of (a) decision strategy and (b) relevant stimulus dimension. Strategic control was found for all types of decision strategy, including trials where participants claimed to lack conscious structural knowledge. However, strong evidence of strategic control only occurred when participants knew or guessed that the letter dimension was relevant, suggesting that strategic control might be associated with – or even causally requires – global awareness of the nature of the rules even though it does not require detailed knowledge of their content

Hypnotic suggestibility is unaffected by a challenging inhibitory task or mental exhaustion

Executive functioning is paramount to the successful exertion of inhibitory control over automatic impulses and desires. Despite disagreements in determining the exact mechanisms responsible for hypnosis, many theories involve the use of, or alterations in, frontal processing and top-down executive functioning. The present study sought to explore this relationship by examining whether a transient state of reduced inhibitory control influences susceptibility to hypnosis. Specifically, participants completed a color naming task designed to place differing demands on inhibitory control processes before experiencing a hypnotic induction and four suggestions. Bayesian analysis indicated substantial evidence that the prior exertion of inhibitory control processes does not influence subsequent susceptibility to hypnotic suggestion. The study provides evidence that inhibitory impairment, often experienced by those with a range of disorders (such as anxiety and depression), should not affect receptiveness to hypnotic procedures

Probing TeV-scale gauge unification by hadronic collisions

Grand unified theories (GUTs) and extra dimensions are potential ingredients of the new physics that may resolve various outstanding problems of the Standard Model. If the inverse size of (one of) the extra dimension(s) is smaller than the GUT scale and standard gauge bosons are allowed to propagate in the bulk then, among other consequences, the evolution of the gauge couplings deviates from the usual logarithmic running somewhat below and between these two scales. In this work, we show that if the compactification scale is the order of 10 TeV, then this modified running may be observable at the CERN Large Hadron Collider in the dijet invariant mass distribution. We also demonstrate that dijets are highly sensitive to the renormalization effects of the extra dimensions, and are potential tools for determining the number of dimensions and the value of the compactification scale.Comment: 10 pages, 2 figures, using JHEP styl