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PubMed1983

Alcohol and proactive interference: a test of response eccentricity theory of alcohol's psychological effects.

A theory is offered which proposes that alcohol induces eccentricity in the neurophysiological mechanism by which responses are selected for emission by the nervous system. Hence, in a specific stimulus situation, normally high probability responses decrease in frequency, while lower probability responses increase in frequency. From this postulate, the prediction is derived that in a verbal paired-associate learning task administered over two days, alcohol will decrease proactive interference from first-day learning (high probability associate) and result in enhanced acquisition of second day items. This paper reports two experimental tests of the prediction, each of which employs four subject groups tested over two days. Experiment 1 (n = 24) provides tentative support while ruling out some potential confounds. With these confounds eliminated, Experiment 2 (n = 40) confirms the prediction in a more direct test. A variety of possible alternative explanations for the counter-intuitive finding of improved cognitive performance under alcohol are evaluated against the theory proposed, as are other recent theories which address the variable behavioral effects of alcohol. Finally, the new data gathered on the effects of imagery instructions on proactive interference are considered.

Adult↗
PubMed1990

The diagnostic value of cerebellar-vestibular tests in detecting learning disabilities, dyslexia, and attention deficit disorder.

Neurological and optokinetic measures of cerebellar-vestibular (CV) dysfunctioning were shown to be of significant diagnostic value in differentiating between learning disabled subjects and controls matched for chronological age, sex, handedness, IQ, and background (ns = 35). Although traditionally used electronystagmographic positional and caloric parameters were not similarly discriminating, quantitative measures of vertical nystagmus in various eyes-closed positions appeared to have diagnostic potential and were related significantly to such CV-determined neurological signs as positive monopedal Romberg. As a substantial majority of learning disabled (82.9%) evidenced ADD-like symptoms and since learning disabled subsamples with and without Attention Deficit Disorder (ADD) shared similar coexisting symptoms and CV signs, it appeared probable that learning disabilities and ADD were reflections of the same underlying CV determinants.

Adolescent↗
PubMed1990

Detectability as a function of spatial location: effects of selective attention.

In a series of previous reports we have described differences in detectability of a target in a background of nontarget patterns as a function of its spatial location. These differences, referred to as a "detectability gradient," have been attributed to target detection accomplished by a serial processing mechanism--a scan. The mathematical model of such a mechanism, developed in the previous report, is equally applicable to a series of attentional shifts or to a perceptual, i.e., a preattentive, mechanism. The present experiments were designed to test the hypothesis that this scan is attentional in nature. The results provide additional evidence for the scanning hypothesis but do not support the view that this scan represents a series of attentional shifts.

Adult↗
PubMed2006

The comparator theory fails to account for the selective role of within-compound associations in cue-selection effects.

In a human causal learning experiment, we investigated cue selection effects to test the comparator theory (Denniston, Savastano, & Miller, 2001; Miller & Matzel, 1988). The theory predicts that the occurrence of cue selection is independent of whether the relevant learning trials are presented in a standard forward manner or in a backward manner and that within-compound associations are of equal importance in both cases. We found that the strength of the cue-selection effect was positively correlated with knowledge of within-compound associations in the backward condition but not in the forward condition. Furthermore, cue-selection effects were less pronounced in the former than in the latter condition. These results are at variance with the comparator hypothesis but are in agreement with a modified associative theory and with the suggestion that retrospective revaluation might be due to rehearsal processes.

Adult↗
PubMed1999

Stability and change in longitudinal water-level task performance.

Three longitudinal samples of children (N = 481), 8 to 16 years old, were assessed 3 times at yearly intervals on 8 water-level items. The within-child change in task performance over age is viewed as a stochastic process of the child changing or remaining in 1 of 3 latent (strategy) states: (a) bottom-parallel responders, (b) random responders, or (c) accurate responders. A random-effects binomial mixture distribution is used to model performance at each age. Change over age is gauged by a stochastic transition model. Although there was improvement in task performance over age, the more general finding is that strategy stability, not change, is most typical.

Adolescent↗
PubMed1996

Testing models of decision making using confidence ratings in classification.

Classification implies decision making (or response selection) of some kind. Studying the decision process using a traditional signal detection theory analysis is difficult for two reasons: (a) The model makes a strong assumption about the encoding process (normal noise), and (b) the two most popular decision models, optimal and distance-from-criterion models, can mimic each other's predictions about performance level. In this article, the authors show that by analyzing certain distributional properties of confidence ratings, a researcher can determine whether the decision process is optimal, without knowing the form of the encoding distributions. Empirical results are reported for three types of experiments: recognition memory, perceptual discrimination, and perceptual categorization. In each case, the data strongly favored the distance-from-criterion model over the optimal model.

Adult↗
PubMed2005

Learned predictions of error likelihood in the anterior cingulate cortex.

The anterior cingulate cortex (ACC) and the related medial wall play a critical role in recruiting cognitive control. Although ACC exhibits selective error and conflict responses, it has been unclear how these develop and become context-specific. With use of a modified stop-signal task, we show from integrated computational neural modeling and neuroimaging studies that ACC learns to predict error likelihood in a given context, even for trials in which there is no error or response conflict. These results support a more general error-likelihood theory of ACC function based on reinforcement learning, of which conflict and error detection are special cases.

Brain Mapping↗
PubMed2007

Causal cognition in human and nonhuman animals: a comparative, critical review.

In this article, we review some of the most provocative experimental results to have emerged from comparative labs in the past few years, starting with research focusing on contingency learning and finishing with experiments exploring nonhuman animals' understanding of causal-logical relations. Although the theoretical explanation for these results is often inchoate, a clear pattern nevertheless emerges. The comparative evidence does not fit comfortably into either the traditional associationist or inferential alternatives that have dominated comparative debate for many decades now. Indeed, the similarities and differences between human and nonhuman causal cognition seem to be much more multifarious than these dichotomous alternatives allow.

Animals↗
PubMed2005

Dynamic response-by-response models of matching behavior in rhesus monkeys.

We studied the choice behavior of 2 monkeys in a discrete-trial task with reinforcement contingencies similar to those Herrnstein (1961) used when he described the matching law. In each session, the monkeys experienced blocks of discrete trials at different relative-reinforcer frequencies or magnitudes with unsignalled transitions between the blocks. Steady-state data following adjustment to each transition were well characterized by the generalized matching law; response ratios undermatched reinforcer frequency ratios but matched reinforcer magnitude ratios. We modelled response-by-response behavior with linear models that used past reinforcers as well as past choices to predict the monkeys' choices on each trial. We found that more recently obtained reinforcers more strongly influenced choice behavior. Perhaps surprisingly, we also found that the monkeys' actions were influenced by the pattern of their own past choices. It was necessary to incorporate both past reinforcers and past choices in order to accurately capture steady-state behavior as well as the fluctuations during block transitions and the response-by-response patterns of behavior. Our results suggest that simple reinforcement learning models must account for the effects of past choices to accurately characterize behavior in this task, and that models with these properties provide a conceptual tool for studying how both past reinforcers and past choices are integrated by the neural systems that generate behavior.

Animals↗
PubMed2002

Forward blocking depends on retrospective inferences about the presence of the blocked cue during the elemental phase.

When a compound cue AT is followed by an outcome (AT+), human participants will judge the relation between cue T and the outcome to be less strong if A alone was previously paired with the outcome (A+). According to the probabilistic contrast model, such a blocking effect is due to the fact that participants regard the A+ trials as trials on which A and the outcome are present but T is absent. The results of two studies showed that when the status of T was ambiguous during the A+ trials, judgments about T depended on subsequent information about the presence of T during the A+ trials. These findings support the probabilistic contrast model but are incompatible with the (revised) Rescorla-Wagner (Rescorla & Wagner, 1972) model.

Adult↗
PubMed1990

Response acquisition with delayed reinforcement.

Discrete responses of experimentally naive, food-deprived White Carneaux pigeons (key pecks) or Sprague-Dawley rats (bar or omnidirectional lever presses) initiated unsignaled delay periods that terminated with food delivery. Each subject first was trained to eat from the food source, but no attempt was made to shape or to otherwise train the response. In both species, the response developed and was maintained. Control procedures excluded the simple passage of time, response elicitation or induction by food presentation, type of operandum, food delivery device location, and adventitious immediate reinforcement of responding as the basis for the effects. Results revealed that neither training nor immediate reinforcement is necessary to establish new behavior. The conditions that give rise to both the first and second response are discussed, and the results are related to other studies of the delay of reinforcement and to explanations of behavior based on contingency or correlation and contiguity.

Animals↗
PubMedDate not supplied

A comparative investigation on subspace dimension determination.

It is well-known that constrained Hebbian self-organization on multiple linear neural units leads to the same k-dimensional subspace spanned by the first k principal components. Not only the batch PCA algorithm has been widely applied in various fields since 1930s, but also a variety of adaptive algorithms have been proposed in the past two decades. However, most studies assume a known dimension k or determine it heuristically, though there exist a number of model selection criteria in the literature of statistics. Recently, criteria have also been obtained under the framework of Bayesian Ying-Yang (BYY) harmony learning. This paper further investigates the BYY criteria in comparison with existing typical criteria, including Akaike's information criterion (AIC), the consistent Akaike's information criterion (CAIC), the Bayesian inference criterion (BIC), and the cross-validation (CV) criterion. This comparative study is made via experiments not only on simulated data sets of different sample sizes, noise variances, data space dimensions, and subspace dimensions, but also on two real data sets from air pollution problem and sport track records, respectively. Experiments have shown that BIC outperforms AIC, CAIC, and CV while the BYY criteria are either comparable with or better than BIC. Therefore, BYY harmony learning is a more preferred tool for subspace dimension determination by further considering that the appropriate subspace dimension k can be automatically determined during implementing BYY harmony learning for the principal subspace while the selection of subspace dimension k by BIC, AIC, CAIC, and CV has to be made at the second stage based on a set of candidate subspaces with different dimensions which have to be obtained at the first stage of learning.

Air Pollution↗
PubMed2003

Phylogenetic signal in the song of crests and kinglets (Aves: Regulus).

Territorial song structures are often the most prominent characters for distinguishing closely related taxa among songbirds. Learning processes may cause convergent evolution of passerine songs, but phylogenetic information of acoustic traits can be investigated with the help of molecular phylogenies, which are not affected by cultural evolutionary processes. We used a phylogeny based on cytochrome b sequences to trace the evolution of territorial song within the genus Regulus. Five discrete song units are defined as basic components of regulid song via sonagraphic measurements. Traits of each unit are traced on a molecular tree and a mean acoustic character difference between taxon pairs is calculated. Acoustic divergence between regulid taxa correlates strongly with genetic distances. Syntax features of complete songs and of single units are most consistent with the molecular data, whereas the abundance of certain element types is not. Whether song characters are innate or learned was interpreted using hand-reared birds in aviary experiments. We found that convergent character evolution seems to be most probable for learned acoustic traits. We conclude that syntax traits of whole verses or subunits of territorial song, especially innate song structures, are the most reliable acoustic traits for phylogenetic reconstructions in Regulus.

Animals↗
PubMed2003

[Language acquisition and statistical learning].

Statistical learning is a basic mechanism of information processing in the human brain. The purpose lies in the extraction of probabilistic regularities from the multitude of sensory inputs. Principles of statistical learning contribute significantly to language acquisition and presumably also to language recovery following stroke. The empirical database presented in this manuscript demonstrates that the process of word segmentation, acquisition of a lexicon, and acquisition of simple grammatical rules can be entirely explained through statistical learning. Statistical learning is mediated by changes in synaptic weights in neuronal networks. The concept therefore stands at the transition to molecular biology and pharmacology of the neuronal synapse. It still remains to be shown if all aspects of language acquisition can be explained through statistical learning and which regions of the brain are involved in or capable of statistical learning. Principles of effective language training are obvious already. Most important is the massive, repeated interactive exposure. Conscious processing of the stimulus material may not be essential. The crucial principle is a high cooccurrence of language and corresponding sensory processes. This requires a more intense training frequency than traditional aphasia treatment programs provide.

Adult↗