A new variable interval schedule with constant hazard rate and finite time range

We propose a new variable interval (VI) schedule that achieves constant probability of reinforcement in time while using a bounded range of intervals. By sampling each trial duration from a uniform distribution ranging from 0 to 2 T seconds, and then applying a reinforcement rule that depends linearly on trial duration, the schedule alternates reinforced and unreinforced trials, each less than 2 T seconds, while preserving a constant hazard function.     

Asymptotic confidence intervals for the Pearson correlation via skewness and kurtosis

When bivariate normality is violated, the default confidence interval of the Pearson correlation can be inaccurate. Two new methods were developed based on the asymptotic sampling distribution of Fisher's z′ under the general case where bivariate normality need not be assumed. In Monte Carlo simulations, the most successful of these methods relied on the (Vale & Maurelli, 1983, Psychometrika, 48, 465) family to approximate a distribution via the marginal skewness and kurtosis of the sample data. In Simulation 1, this method provided more accurate confidence intervals of the correlation in non-normal data, at least as compared to no adjustment of the Fisher z′ interval, or to adjustment via the sample joint moments. In Simulation 2, this approximate distribution method performed favourably relative to common non-parametric bootstrap methods, but its performance was mixed relative to an observed imposed bootstrap and two other robust methods (PM1 and HC4). No method was completely satisfactory. An advantage of the approximate distribution method, though, is that it can be implemented even without access to raw data if sample skewness and kurtosis are reported, making the method particularly useful for meta-analysis. Supporting information includes R code.     

Bias-corrected estimation of the Rudas–Clogg–Lindsay mixture index of fit

Rudas, Clogg, and Lindsay (1994, J. R Stat Soc. Ser. B, 56, 623) introduced the so-called mixture index of fit, also known as pi-star (π*), for quantifying the goodness of fit of a model. It is the lowest proportion of ‘contamination’ which, if removed from the population or from the sample, makes the fit of the model perfect. The mixture index of fit has been widely used in psychometric studies. We show that the asymptotic confidence limits proposed by Rudas et al. (1994, J. R Stat Soc. Ser. B, 56, 623) as well as the jackknife confidence interval by Dayton ( 2003 , Br. J. Math. Stat. Psychol., 56, 1) perform poorly, and propose a new bias-corrected point estimate, a bootstrap test and confidence limits for pi-star. The proposed confidence limits have coverage probability much closer to the nominal level than the other methods do. We illustrate the usefulness of the proposed method in practice by presenting some practical applications to log-linear models for contingency tables.     

准备间隔对口吃者言语反应速度的影响

为了考察准备间隔对口吃者言语反应速度的影响,作者采用固定准备间隔下的预备反应时范式,设置了6种准备间隔,通过三个系列实验,检测口吃者的最佳言语准备间隔。结果发现,无论时间压力（项目间隔）怎样变化,口吃被试的问题在于,当准备间隔增加到800ms时,他们无法有效保持或提高反应速度;而且,这一现象只在言语命名任务上表现明显。作者认为,口吃者在言语运动准备过程中的异常,很可能是引起口吃现象的重要原因。     

Interstimulus interval and delivery cues influence timed conditioned responding in rats

Appetitive contextual excitation supported by intertrial unconditioned stimuli was more easily overcome by timed conditioned responding in rats using quiet (Experiment 1) rather than noisy (Experiment 2) food pellet deliveries. Head-entry responding in acquisition peaked above the contextual baseline when pellet delivery occurred 10, 30, 60, or 90 s after the onset of the 120-s white-noise conditioned stimulus (CS). Special tests in extinction revealed CS onset and offset were conditioned by pellet delivery at 0 and 120 s, respectively. Responding was not undermined in Experiment 3 when noisy pellet deliveries replaced quiet pellet deliveries. Our results suggest that micro-stimuli occasioned at different times during the CS are vulnerable to overshadowing, but do not lose strength if they are already predictive.     

Confidence interval-based sample size determination formulas and some mathematical properties for hierarchical data

The use of hierarchical data (also called multilevel data or clustered data) is common in behavioural and psychological research when data of lower-level units (e.g., students, clients, repeated measures) are nested within clusters or higher-level units (e.g., classes, hospitals, individuals). Over the past 25 years we have seen great advances in methods for computing the sample sizes needed to obtain the desired statistical properties for such data in experimental evaluations. The present research provides closed-form and iterative formulas for sample size determination that can be used to ensure the desired width of confidence intervals for hierarchical data. Formulas are provided for a four-level hierarchical linear model that assumes slope variances and inclusion of covariates under both balanced and unbalanced designs. In addition, we address several mathematical properties relating to sample size determination for hierarchical data via the standard errors of experimental effect estimates. These include the relative impact of several indices (e.g., random intercept or slope variance at each level) on standard errors, asymptotic standard errors, minimum required values at the highest level, and generalized expressions of standard errors for designs with any-level randomization under any number of levels. In particular, information on the minimum required values will help researchers to minimize the risk of conducting experiments that are statistically unlikely to show the presence of an experimental effect.     

Quantifying false positives in simulated events using partial interval recording and momentary time sampling with dual‐criteria methods

The dual‐criteria (DC) and conservative dual‐criteria (CDC) methods allow clinicians and researchers to quantify the occurrence of false‐positive outcomes within single‐case experimental designs. The purpose of the current study was to use these DC and CDC methods to measure the incidence of false positives with simulated data collected via discontinuous interval methods (i.e., momentary time sampling, partial‐interval recording) as a function of data series length. We generated event data to create 316,800 unique simulated data series for analysis. In Experiment 1, we evaluated how changes in relevant parameters (i.e., interval sizes, event durations, IRT‐to‐event‐run ratios) produced false positives with momentary time sampling procedures. We also assessed the degree that the CDC method produced fewer false positives than the DC method with simulated interval data. In Experiment 2, we used similar procedures to quantify the occurrence of false positives with partial‐interval recording data. We successfully replicated outcomes from previous research in the current study, though such results only highlight the generality of the procedures relating to false positive (and not false negative) outcomes. That is, these results indicate MTS and PIR may adequately control for false positives, but our conclusions are limited by a lack of data on power.     

Mental Reinstatement of Context: Do individual differences in mental time travel and eyewitness occupation influence eyewitness performance over different delay intervals?

The Cognitive Interview is a memory‐enhancing interview protocol designed to optimise the access and retrieval of eyewitness memories. Its Mental Reinstatement of Context (MRC) component requires interviewees to mentally reconstruct the crime event they witnessed. Individual differences in mental time travel (MTT) relate to the extent to which a person mentally re‐experiences personal events from his or her past. Individual differences in MTT have been found to predict correct recall of a simulated crime event under immediate MRC recall conditions. To explore the relationship between MTT and performance under MRC conditions further, the present study presented a simulated crime video to 30 police officers and 26 members of the public. Eyewitness recall was tested under MRC conditions either immediately or 1 week later. Participants' general MTT and also MTT relating specifically to the crime video itself were measured via self‐report. Less correct information and more confabulations were produced after 1 week, but delay had no effect on the amount of incorrect information reported. No difference in recall was found between police officers and members of the public. Better quality MTT relating to the crime video was found to be a positive predictor of the amount of information correctly recalled under immediate conditions but not after 1 week. General MTT scores did not predict correct recall under either delay condition. Interviewers need to be aware that, due to individual differences, some witnesses may perform better under the MRC component than others.     

内源性空间线索有效性对视听觉整合的影响

采用内源性线索-靶子范式,操纵线索类型(有效线索、无效线索)和靶刺激通道类型(视觉刺激、听觉刺激、视听觉刺激)两个自变量,通过两个实验,分别设置50%和80%两种内源性空间线索有效性来考察不同空间线索有效性条件下内源性空间注意对视听觉整合的影响。结果发现,当线索有效性为50%时(实验1),有效线索位置和无效线索位置的视听觉整合效应没有显著差异;当线索有效性为80%时(实验2),有效线索位置的视听觉整合效应显著大于无效线索位置的视听觉整合效应。结果表明,线索有效性不同时,内源性空间注意对视听觉整合产生了不同的影响,高线索有效性条件下内源性空间注意能够促进视听觉整合效应。     

A precursor to the relational evaluation procedure: searching for the contextual cues that control equivalence responding.

The precursor to the relational evaluation procedure (pREP) is a go/no-go successive discrimination procedure for examining stimulus equivalence. Previous research has shown that it does not readily produce equivalence responding unless some matching-to-sample (MTS) procedures are incorporated into the experimental sequence. Two experiments attempted to identify contextual cues that would generate equivalence responding on the pREP. Experiment 1 examined the effects of using abstract symbols or various verbal labels as response options on the pREP. Only the words same and different, when used as response options, reliably produced equivalence responding across 4 subjects. Experiment 2 examined different pretraining preparations designed to attach the functions of the words same and different to abstract symbols that could then be used as response options on the pREP. The most effective pretraining procedure involved multiple-exemplar training during which subjects were trained to respond to abstract symbols in the presence of pairs of stimuli that were either formally the same or different. The abstract symbols were subsequently used as response options with the pREP, and all subjects reliably demonstrated equivalence responding. The findings suggest that the relations of same and different may be fundamental to equivalence responding. These findings are discussed in terms of what they suggest about the nature of the equivalence phenomenon specifically and derived relational responding more generally.