Time to rethink the neural mechanisms of learning and memory
Charles R. Gallistel a, Peter D. Balsam
Most studies in the neurobiology of learning assume that the underlying learning process is a pairing – 23 dependent change in synaptic strength that requires repeated experience of events presented in close 24 temporal contiguity. However, much learning is rapid and does not depend on temporal contiguity which has never been precisely defined. These points are well illustrated by studies showing that temporal relationships between events are rapidly learned- even over long delays- and this knowledge governs the form and timing of behavior. The speed with which anticipatory responses emerge in conditioning paradigms is determined by the information that cues provide about the timing of rewards. The challenge for understanding the neurobiology of learning is to understand the mechanisms in the nervous system that encode information from even a single experience, the nature of the memory mechanisms that can encode quantities such as time, and how the brain can flexibly perform computations based on this information.
h/t: Andrea Kuszewski
The Eye Pupil Adjusts to Imaginary Light
Bruno Laeng and Unni Sulutvedt
If a mental image is a rerepresentation of a perception, then properties such as luminance or brightness should also be conjured up in the image. We monitored pupil diameters with an infrared eye tracker while participants first saw and then generated mental images of shapes that varied in luminance or complexity, while looking at an empty gray background. Participants also imagined familiar scenarios (e.g., a “sunny sky” or a “dark room”) while looking at the same neutral screen. In all experiments, participants’ eye pupils dilated or constricted, respectively, in response to dark and bright imagined objects and scenarios. Shape complexity increased mental effort and pupillary sizes independently of shapes’ luminance. Because the participants were unable to voluntarily constrict their eyes’ pupils, the observed pupillary adjustments to imaginary light present a strong case for accounts of mental imagery as a process based on brain states similar to those that arise during perception.
h/t: Rebecca McMillan
Do programs designed to train working memory, other executive functions, and attention benefit children with ADHD? A meta-analytic review of cognitive, academic, and behavioral outcomes
Mark D. Rapport, Sarah A. Orban, Michael J. Kofler, and Lauren M. Friedman
Children with ADHD are characterized frequently as possessing underdeveloped executive functions and sustained attentional abilities, and recent commercial claims suggest that computer-based cognitive training can remediate these impairments and provide significant and lasting improvement in their attention, impulse control, social functioning, academic performance, and complex reasoning skills. The present review critically evaluates these claims through meta-analysis of 25 studies of facilitative intervention training (i.e., cognitive training) for children with ADHD. Random effects models corrected for publication bias and sampling error revealed that studies training short-term memory alone resulted in moderate magnitude improvements in short-term memory (d = 0.63), whereas training attention did not significantly improve attention and training mixed executive functions did not significantly improve the targeted executive functions (both nonsignificant: 95% confidence intervals include 0.0). Far transfer effects of cognitive training on academic functioning, blinded ratings of behavior (both nonsignificant), and cognitive tests (d = 0.14) were nonsignificant or negligible. Unblinded raters (d = 0.48) reported significantly larger benefits relative to blinded raters and objective tests (both p b .05), indicating the likelihood of Hawthorne effects. Critical examination of training targets revealed incongruence with empirical evidence regarding the specific executive functions that are (a) most impaired in ADHD, and (b) functionally related to the behavioral and academic outcomes these training programs are intended to ameliorate. Collectively, meta-analytic results indicate that claims regarding the academic, behavioral, and cognitive benefits associated with extant cognitive training programs are unsupported in ADHD. The methodological limitations of the current evidence base, however, leave open the possibility that cognitive training techniques designed to improve empirically documented executive function deficits may benefit children with ADHD.
STUDY ALERT: The rule-dependence model explains the commonalities between the Flynn effect and IQ gains via retesting
The rule-dependence model explains the commonalities between the Flynn effect and IQ gains via retesting
Elijah L. Armstrong and Michael A. Woodley
We present a new model of the Flynn effect. It is proposed that Flynn effect gains are partly a function of the degree to which a test is dependent on rules or heuristics. This means that testees can become better at solv- ing ‘rule-dependent’ problems over time in response to changing environments, which lead to the improve- ment of lower-order cognitive processes (such as implicit learning and aspects of working memory). These in turn lead to apparent IQ gains that are partially independent of general intelligence. We argue that the Flynn ef- fect is directly analogous to IQ gains via retesting, noting that Raven’s Progressive Matrices is particularly sensi- tive to both the effects of retesting and the Flynn effect. After an extensive review of the relevant supporting literature, we test our thesis by developing a rule-dependence typology and then correlate the vector of a test’s position in the typology with the vector of the Flynn effect that it yields. We find a significant vector correlation of r ~ .60 (N = 14). Finally, we make a number of novel and testable predictions based on our model.
Intelligence indexes generalist genes for cognitive abilities
Maciej Trzaskowski, Nicholas G. Shakeshaft, Robert Plomin
Twin research has supported the concept of intelligence (general cognitive ability, g) by showing that genetic correlations between diverse tests of verbal and nonverbal cognitive abilities are greater than 0.50. That is, most of the genes that affect cognitive abilities are highly pleiotropic in the sense that genes that affect one cognitive ability affect all cognitive abilities. The impact of this finding may have been blunted because it depends on the validity of the twin method. Although the assumptions of the twin method have survived indirect tests, it is now possible to test findings from the twin method directly using DNA alone in samples of unrelated individuals, without the assumptions of the twin method. We applied this DNA method, implemented in a software package called Genome-wide Complex Trait Analysis (GCTA), to estimate genetic variance and covariance for two verbal tests and two nonverbal tests using 1.7 million DNA markers genotyped on 2500 unrelated children at age 12; 1900 children also had cognitive data and DNA at age 7. Because each of these individuals is one member of a twin pair, we were able to compare GCTA estimates directly to twin study estimates using the same measures in the same sample. At age 12, GCTA confirmed the results of twin research in showing substantial genetic covariance between verbal and nonverbal composites. The GCTA genetic correlation at age 12 was 1.0 (SE = 0.32), not significantly different from the twin study estimate of 0.60 (SE = 0.09). At age 7, the genetic correlations were 0.31 (SE = 0.32) from GCTA and 0.71 (SE = 0.15).from twin analysis. The results from the larger sample and stronger measures at age 12 confirm the twin study results that the genetic architecture of intelligence is driven by pleiotropic effects on diverse cognitive abilities. However, the results at age 7 and the large standard errors of GCTA bivariate genetic correlations suggest the need for further research with larger samples.
Experimental studies of ongoing conscious experience
Jerome L. Singer
A research programme designed to find ways of applying a variety of methods in psychological science to studying the seemingly ephemeral phenomena of the human stream of consciousness and its manifestations in daydreams, interior monologues, imagery and related private experiences is described. Approaches include psychometric studies to establish normative information on daydreaming and experimental studies using signal-detection paradigms to capture the ongoing stream of thought. Recent experiments involve thought-sampling methods for identifying the determinants of the content of the stream of thought in adolescents or the ways in which self-beliefs and emotions are manifested in a group of cocaine and heroin abusers. Children’s pretend play is studied as a possible forerunner of adult consciousness. It is proposed that the human condition involves a continuing tension between processing information generated from the physical and social milieu and the continuous operation of centrally generated material from long-term memory in the form of reminiscences, wishes, current concerns, expectancies and fantasies. This concept has implications for personality variation, affective arousal and adaptive behaviour.
K. Anders Ericsson and Tyler J. Towne
The study of expertise is based on the premise that experts in different domains follow a similar path of acquisition and development. This article distinguishes two research approaches to the study of expertise. The traditional approach assumes a steady progression from novice to expert as a function of training as well as years of experience often without measures of reproducible skill. A second and more recent one focuses on the identification of individuals with reproducibly superior performance for representative tasks that capture expertise in the domain. The focus of this review is on the latter, namely the expert-performance approach. The article describes how superior performance can be captured by standardized tasks, and how analyses of that superior performance can identify superior abilities, cognitive mechanisms, and physiological adaptations. The last part of the article reviews how deliberate practice and training can lead to the acquisition of complex mechanisms and physiological adaptations, which in turn can explain the experts’ attained superior performance. The review is concluded with a discussion of future directions of studies of expert performance and the challenges in understanding the development of general abilities and the motivation to engage in sustained daily deliberate practice.
h/t: Kevin McGrew
STUDY ALERT: The neuromodulator of exploration: A unifying theory of the role of dopamine in personality
The neuromodulator of exploration: A unifying theory of the role of dopamine in personality
Colin G. DeYoung
The neuromodulator dopamine is centrally involved in reward, approach behavior, exploration, and various aspects of cognition. Variations in dopaminergic function appear to be associated with variations in personality, but exactly which traits are influenced by dopamine remains an open question. This paper proposes a theory of the role of dopamine in personality that organizes and explains the diversity of findings, utilizing the division of the dopaminergic system into value coding and salience coding neurons (Bromberg-Martin et al., 2010). The value coding system is proposed to be related primarily to Extraversion and the salience coding system to Openness/Intellect. Global levels of dopamine influence the higher order personality factor, Plasticity, which comprises the shared variance of Extraversion and Openness/Intellect. All other traits related to dopamine are linked to Plasticity or its subtraits. The general function of dopamine is to promote exploration, by facilitating engagement with cues of specific reward (value) and cues of the reward value of information (salience). This theory constitutes an extension of the entropy model of uncertainty (EMU; Hirsh et al., 2012), enabling EMU to account for the fact that uncertainty is an innate incentive reward as well as an innate threat. The theory accounts for the association of dopamine with traits ranging from sensation and novelty seeking, to impulsivity and aggression, to achievement striving, creativity, and cognitive abilities, to the overinclusive thinking characteristic of schizotypy.