Object Recognition: Insights From Advances in fMRI Methods

ABSTRACT— Recent advancements in imaging methods and analysis approaches have provided important insights about the neural bases of object recognition. We address the potential limitations of standard functional magnetic resonance imaging (fMRI) and discuss methodological advancements, including fMRI-adaptation, pattern analyses, and high-resolution fMRI, that may be more appropriate for studying object and face representations. fMRI-adaptation and high-resolution fMRI measure responses of neural subpopulations within standard fMRI voxels, and pattern analyses examine the information in the distributed activations across voxels, which may differ from the mean response across these voxels. These methods have provided evidence for a multitude of representations across the human ventral stream that provide empirical constraints for cognitive theories of recognition.     

An Experimental Analysis of Mathematics Instructional Components: Examining the Effects of Student-Selected Versus Empirically-Selected Interventions

Within the context of an experimental analysis, the current study examined the effects of student- and empirically-selected interventions on the mathematics computational fluency of three elementary-aged students. For all of the participants, the empirically-selected intervention resulted in higher levels of computational fluency then the student-selected intervention. These results suggest that empirically-selected interventions may enhance the mathematics computational fluency of students experiencing mathematics problems. However, individual responsiveness to empirically-selected interventions suggests the importance of conducting brief experimental analyses to determine the most efficacious intervention. The implication of these results for intervention selection and incorporating choice-making opportunities into academic interventions are discussed.     

Psychosocial mediators of a lifestyle physical activity intervention in women

ObjectivesA lifestyle physical activity intervention in women based on the transtheoretical model and social–cognitive theory effectively increased physical activity. The aim of the present study was to examine possible mediators (perceived benefits and barriers of physical activity, self-efficacy, processes of change, and social support) of these physical activity changes.MethodsMembers of four units of a women's organization followed a six-month minimal-contact physical activity program. The intervention program included one group meeting, a self-help booklet and five monthly reminder letters. Members of two other units served as control group. Physical activity (accelerometer counts), and psychosocial constructs (self-report questionnaires) were assessed at baseline (pretest) and directly after the intervention (posttest). Women who completed all measurements (n = 101) were included in the mediation analyses.ResultsParticipants in the intervention group reported significantly greater increases in the use of behavioral processes from pretest to posttest than participants in the control group. None of the proposed psychosocial constructs showed a mediating effect on changes in physical activity.ConclusionsThe mechanisms proposed by the transtheoretical model and social–cognitive theory could not explain the positive effect of the intervention on physical activity. Identifying the working components of an intervention remains a challenging and necessary step in the development of effective low-cost and high-reach physical activity interventions.     

情绪信息的多通道整合

自然环境中人类情绪信息的交流是依靠多个感觉通道实现的,多通道整合是情绪加工的基础。近年来的行为学、电生理学与神经成像的研究表明,情绪信息的加工具有跨通道自动整合的特点,它发生在认知加工的早期阶段,与颞上回、颞中回、海马旁回和丘脑等脑区密切相关。不同情绪的整合既有共同的神经基础,又有各自独特的加工区域。情绪信息的整合机制还可能与加工类型及注意资源有关。在未来研究中,实验的标准化、动态化、自然化有助于提高研究的准确性和研究间的可比性,而对特殊群体的研究,以及综合研究情绪加工与注意等其他认知过程则有助于我们进一步探索多通道整合的神经机制。     

Conditional Reinforcers and Informative Stimuli in A Constant Environment

Five pigeons responded on steady-state concurrent variable-interval variable-interval schedules of food presentation in which half of the foods were removed and replaced with nonfood stimuli. Across conditions, the stimuli were either paired or unpaired with food, and the correlation between the ratio of food deliveries on the two alternatives and the ratio of nonfood stimuli was either −1, 0, or +1. Neither the pairing of stimuli with food, nor the correlation between stimuli and food, affected generalized-matching performance, but paired stimuli had a demonstrable effect at a local level of analysis. This effect was independent of the food–stimulus correlation. These results differ from results previously obtained in a frequently changing environment. We attribute this difference in results to differences in the information value of response-contingent stimuli in frequently changing versus relatively constant environments, as well as to differences between forward pairing and simultaneous pairing of the stimuli with food.     

TAKING PRAGMATISM SERIOUSLY: A REVIEW OF WILLIAM BAUM'S UNDERSTANDING BEHAVIORISM: BEHAVIOR,CULTURE, AND EVOLUTION (SECOND EDITION)

This important book has two main purposes. The first is to present, in a non‐technical way, accessible to intelligent laypeople, a scientific, behavioral approach to all aspects of human activity including choice, rule‐governed behavior, self control, religious belief, linguistic interaction, ethics, and culture. Its scope equals that of Skinner's nontechnical writings, but Baum's approach is more molar and more pragmatic than Skinner's. The book's second purpose is to embed behavioral science firmly in the context of Darwinian evolution. Baum is generally successful, we believe, in both of these ambitious purposes.     

Averaging Effects In The Study Of Fixed-ratio Response Patterns

Three rats were exposed to multiple fixed-ratio schedules in which large and small ratios alternated in an irregular order. Over a series of training phases, one ratio was held constant as the second ratio was increased to higher values. On average, postreinforcement pauses increased in duration as the ratio size was increased. Pausing was controlled by the size of the upcoming ratio; the previous ratio had smaller and less consistent effects. However, more detailed consideration of the aggregated data indicated that the pause distributions were positively skewed and that changes in average performances were more a consequence of increased skew rather than shifts of the entire distributions. Moreover, the distributions of pauses from condition to condition overlapped, and brief pauses were common even at the highest ratios. These results demonstrated that depictions of pausing based on aggregated data can be misleading without corresponding information about variations in the distribution on which the averages are based.     

Short-term memory in the pigeon: the previously reinforced response

Eighteen pigeons served in a discrete-trials short-term memory experiment in which the reinforcement probability for a peck on one of two keys depended on the response reinforced on the previous trial: either the probability of reinforcement on a trial was 0.8 for the same response reinforced on the previous trial and was 0.2 for the other response (Group A), or, it was 0 or 0.2 for the same response and 1.0 or 0.8 for the other response (Group B). A correction procedure ensured that over all trials reinforcement was distributed equally across the left and right keys. The optimal strategy was either a winstay, lose-shift strategy (Group A) or a win-shift, lose-stay strategy (Group B). The retention interval, that is the intertrial interval, was varied. The average probability of choosing the optimal alternative reinforced 80% of the time was 0.96, 0.84, and 0.74 after delays of 2.5, 4.0, and 6.0 sec, respectively for Group A, and was 0.87, 0.81, and 0.55 after delays of 2.5, 4.0, and 6.0 sec, respectively, for Group B. This outcome is consistent with the view that behavior approximated the optimal response strategy but only to an extent permitted by a subject's short-term memory for the cue correlated with reinforcement, that is, its own most-recently reinforced response. More generally, this result is consistent with “molecular” analyses of operant behavior, but is inconsistent with traditional “molar” analyses holding that fundamental controlling relations may be discovered by routinely averaging over different local reinforcement contingencies. In the present experiment, the molar results were byproducts of local reinforcement contingencies involving an organism's own recent behavior.     

Improper solutions in the analysis of covariance structures: Their interpretability and a comparison of alternate respecifications

A Monte Carlo approach was employed to investigate the interpretability of improper solutions caused by sampling error in maximum likelihood confirmatory factor analysis. Four models were studied with two sample sizes. Of the overall goodness-of-fit indices provided by the LISREL VI program significant differences between improper and proper solutions were found only for the root mean square residual. As expected, indicators of the factor on which the negative uniqueness estimate occurred had biased loadings, and the correlations of its factor with other factors were also biased. In contrast, the loadings of indicators on other factors and those factor intercorrelations did not have any bias of practical significance. For initial solutions with one negative uniqueness estimate, three respecifications were studied: Fix the uniqueness at .00, fix it at .20, or constrain the domain of the solution to be proper. For alternate, respecified solutions that were converged and proper, the constrained solutions and uniqueness fixed at .00 solutions were equivalent. The mean goodness-of-fit and pattern coefficient values for the original improper solutions were not meaningfully different from those obtained under the constrained and uniqueness fixed at .00 respecifications.This investigation was supported in part by a grant from the Baylor University Research Committee (#018-F83-URC). The authors gratefully acknowledge the comments and suggestions of Claes Fornell and Roger E. Kirk, and the assistance of Timothy J. Vance with the analysis.     

What is anger provoking?—Provokers and provoked in anger situations: Developmental trends and sex differences

Some structural properties of situations, described as anger-provoking by teenagers, were investigated. The study was directed toward exploring developmental trends and sex differences with respect to who was the provoker and who was provoked in the described situations. A simple classification, identical for both situational properties (provoker and provoked) was formed. The results showed that at age 18 years there was no sex difference in any of the aspects investigated. At age 12 years boys seemed to be more general than girls in their views on provokers. With increasing age the provoked in the described situations was more often someone else than the describing subject. This is interpreted as corroborating the often proposed relatedness between anger and morality.