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.     

识别不同编码方式符号的仿真研究

本研究利用计算机技术 ,以执行过程交互控制 (EPIC)理论框架为基础 ,建立了一个人类信息加工过程的计算模型 ,并对人在简单任务下的作业绩效进行了仿真。结果说明 :(1 )本研究所建的模型克服了原有 EPIC理论无法控制模型中参数值变化的缺陷 ,促进了 EPIC理论的发展 ;(2 )仿真结果和实验结果拟合良好 ,模型具有良好的预测能力。本研究为以仿真方法研究简单任务的心理过程提供了一次有益的尝试。     

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.     

Some exact conditional tests of independence forR ×C cross-classification tables

Exact conditional tests of independence in cross-classification tables are formulated based on the ² statistic and statistics with stronger operational interpretations, such as some nominal and ordinal measures of association. Guidelines for the table dimensions and sample sizes for which the tests are economically implemented on a computer are given. Some selected sample sizes and marginal distributions are used in a numerical comparison between the significance levels of the approximate and exact conditional tests based on the ² statistic.The authors are grateful for the suggestions of the referees and for computer funding provided by the Northeast Regional Data Center at the University of Florida.     

A statistical analysis system (SAS) computer program for Markov chain analysis

A computer program for Markov chain analysis is presented and discussed. The program is written in the language of the Statistical Analysis System (SAS) but detailed knowledge of SAS is not required for its use. The program tests hypotheses about the goodness of fit of first- and second-order Markov models. It also tests if transition probabilities are homogeneous between the first and the second half of each sequence.Presented, in part, at the Association for the Advancement of Behavior Therapy Convention, November 1984.     

Exact conditional tests for cross-classifications: Approximation of attained significance levels

A procedure is proposed for approximating attained significance levels of exact conditional tests. The procedure utilizes a sampling from the null distribution of tables having the same marginal frequencies as the observed table. Application of the approximation through a computer subroutine yields precise approximations for practically any table dimensions and sample size.     

A feasible method for standard errors of estimate in maximum likelihood factor analysis

A jackknife-like procedure is developed for producing standard errors of estimate in maximum likelihood factor analysis. Unlike earlier methods based on information theory, the procedure developed is computationally feasible on larger problems. Unlike earlier methods based on the jackknife, the present procedure is not plagued by the factor alignment problem, the Heywood case problem, or the necessity to jackknife by groups. Standard errors may be produced for rotated and unrotated loading estimates using either orthogonal or oblique rotation as well as for estimates of unique factor variances and common factor correlations. The total cost for larger problems is a small multiple of the square of the number of variables times the number of observations used in the analysis. Examples are given to demonstrate the feasibility of the method.The research done by R. I. Jennrich was supported in part by NSF Grant MCS 77-02121. The research done by D. B. Clarkson was supported in part by NSERC Grant A3109.     

Learning a new human-computer alphabet: the role of similarity and practice

Two purposes motivated this study: (a) to quantify the difficulty in learning various symbols of the alphabet used to enter data into a personal digital assistant (PDA), and (b) to investigate the interaction of item difficulty with practice conditions that promote varying levels of cognitive effort. Levels of compatibility between members of the PDA alphabet and English were quantified through introspective ratings in Experiment 1 and objective performance measures in Experiment 2. Three levels of item compatibility were learned under conditions of proactive or retroactive augmented information in Experiment 3. Contrary to expectations, the item similarity effect did not interact with practice schedules—a retroactive augmented information condition resulted in degraded levels of acquisition performance, but superior retention levels, compared to the proactive condition. These findings are discussed in terms of the relative merits of cognitive effort in skill acquisition.     

The mind reduced to molecules?

According to Bickle, certain empirical results demonstrate that the bottom-up reduction of phychological concepts to the concepts of neuroscience has already been accomplished. I argue that this conclusion is hasty. Bickle claims that all high-level investigations depend on a mistake. I argue that this overstates the explanatory character of neuroscientific findings. Bickle's assessment is highly optimistic, but he is far from making a decisive argument. Those who wait for a full-blown reductionism will have to wait a little longer.     

Precis of <Emphasis Type="Italic">Philosophy and Neuroscience</Emphasis>: <Emphasis Type="Italic">A Ruthlessly Reductive Account</Emphasis>

This book precis describes the motives behind my recent attempt to bring to bear “ruthlessly reductive” results from cellular and molecular neuroscience onto issues in the philosophy of mind. Since readers of this journal will probably be most interested in results addressing features of conscious experience, I highlight these most prominently. My main challenge is that philosophers (even scientifically-inspired ones) are missing the nature and scope of reductionism in contemporary neuroscience by focusing exclusively on higher-level cognitive neuroscience, and ignoring the discipline's cell-physiological and molecular-biological core.