Reproducibility and a unifying explanation: Lessons from the shape bias

The goal of science is to advance our understanding of particular phenomena. However, in the field of development, the phenomena of interest are complex, multifaceted, and change over time. Here, we use three decades of research on the shape bias to argue that while replication is clearly an important part of the scientific process, integration across the findings of many studies that include variations in procedure is also critical to create a coherent understanding of the thoughts and behaviors of young children. The “shape bias,” or the tendency to generalize a novel label to novel objects of the same shape, is a reliable and robust behavioral finding and has been shown to predict future vocabulary growth and possible language disorders. Despite the robustness of the phenomenon, the way in which the shape bias is defined and tested has varied across studies and laboratories. The current review argues that differences in performance that come from even seemingly minor changes to the participants or task can offer critical insight to underlying mechanisms, and that working to incorporate data from multiple labs is an important way to reveal how task variation and a child’s individual pathway creates behavior—a key issue for understanding developmental phenomena.     

Human coffee drinking: manipulation of concentration and caffeine dose.

In a residential research ward coffee drinking was studied in 9 volunteer human subjects with histories of heavy coffee drinking. A series of five experiments was undertaken to characterize adlibitum coffee consumption and to investigate the effects of manipulating coffee concentration, caffeine dose per cup, and caffeine preloads prior to coffee drinking. Manipulations were double-blind and scheduled in randomized sequences across days. When cups of coffee were freely available, coffee drinking tended to be rather regularly spaced during the day with intercup intervals becoming progressively longer throughout the day; experimental manipulations showed that this lengthening of intercup intervals was not due to accumulating caffeine levels. Number of cups of coffee consumed was an inverted U-shaped function of both coffee concentration and caffeine dose per cup; however, coffee-concentration and dose-per-cup manipulations did not produce similar effects on other measures of coffee drinking (intercup interval, time to drink a cup, within-day distribution of cups). Caffeine preload produced dose-related decreases in number of cups consumed. As a whole, these experiments provide some limited evidence for both the suppressive and the reinforcing effects of caffeine on coffee consumption. Examination of total daily coffee and caffeine intake across experiments, however, provides no evidence for precise regulation (i.e., titration) of coffee or caffeine intake.     

Low-dose caffeine discrimination and self-reported mood effects in normal volunteers.

A caffeine versus placebo discrimination procedure was used to determine the lowest caffeine dose that could produce discrimination and self-reported mood effects in normal volunteers. During daily sessions under double-blind conditions, caffeine-abstinent subjects orally ingested a capsule containing 178 mg caffeine or placebo. Before beginning discrimination training, the compounds were identified to subjects by letter codes. Fifteen, 30, and 45 min after capsule ingestion, subjects guessed the capsule's letter code. Correct guesses at 45 min earned money. After each session, subjects received a supplementary capsule containing caffeine or placebo to ensure that, within each phase of the study, subjects received the same daily dose of caffeine equal to the training dose. Five of the 15 subjects acquired the caffeine versus placebo discrimination within the first 20 sessions (greater than or equal to 75% correct); 6 other subjects acquired the discrimination with additional training. Nine subjects who acquired the discrimination were subsequently trained at progressively lower caffeine doses. In general, the lowest dose to produce discrimination (greater than or equal to 75% correct) was also the lowest dose to produce self-reported mood effects: 4 subjects showed discrimination and self-reported mood effects at 100 mg caffeine, 2 at 56 mg, 1 at 32 mg, and 1 at 18 mg. One of these subjects also showed self-reported mood effects at 10 mg. The present study documents discriminative stimulus and self-reported mood effects of caffeine at doses below those previously shown to affect any behavior in normal volunteers.     

Evaluating treatment effects in single-subject behavioral experiments using quality-control charts

Quality-control charts can be particularly useful in identifying treatment effects and patterns of behaviors in single-subject behavior-analytic experiments that cannot be determined by visual inspection of their graphs. Using an example from the behavior analysis literature the quality-control charts identified the presence of treatment effects across phases as well as the presence of trends within and between phases. The ease of their calculations suggest use of them by behavior analysts whenever the effects of particular interventions are questionable.     

SEPARATE AND COMBINED EFFECTS OF METHYLPHENIDATE AND A BEHAVIORAL INTERVENTION ON DISRUPTIVE BEHAVIOR IN CHILDREN WITH MENTAL RETARDATION

We investigated the separate and combined effects of a behavioral intervention and methylphenidate (Ritalin®) on disruptive behavior and task engagement in 3 children with severe to profound mental retardation. The behavioral intervention involved differential reinforcement of appropriate behavior and guided compliance. All 3 children demonstrated decreased disruptive behavior and improved task engagement in response to the behavioral intervention. Two of the 3 children demonstrated similar improvement in response to methylphenidate. Although both interventions were highly effective for these 2 participants, the relative efficacy of the interventions varied between the 2 children. There was no evidence of an additive or synergistic effect of the two interventions, but the high efficacy of each intervention alone limited our ability to detect such effects.     

SLEEP DEPRIVATION,ALLERGY SYMPTOMS,AND NEGATIVELY REINFORCED PROBLEM BEHAVIOR

We studied the relation between the presence versus the absence of sleep deprivation or allergy symptoms and the rate and function of problem behavior. Three students whose problem behavior was negatively reinforced by escape from instruction were studied across several weeks using analogue functional analyses. Our results indicated that the extraexperimental events were associated with (a) termination of instruction functioning as a negative reinforcer, (b) increased rates of negatively reinforced problem behavior, or (c) increased rates of problem behavior across all conditions.     

Round-robin analysis of social interaction: Exact and estimated standard errors

Kenny has proposed a variance-components model for dyadic social interaction. His Social Relations model estimates variances and covariances from a round-robin of two-person interactions. The current paper presents a matrix formulation of the Social Relations model. It uses the formulation to derive exact and estimated standard errors for round-robin estimates of Social Relations parameters.We are grateful to George Gilbert for comments on an earlier draft.     

再认的两种机制及其与启动效应的关系

通过两个实验对两种再认所涉及的心理机制及其与启动效应的关系进行探讨。实验一用高频字和低频字作实验材料,分别测量集中注意和分散注意条件下,两种再认的成绩。结果表明：学习阶段的注意分散使以提取为基础的再认成绩下降,对以熟悉性为基础的再认成绩没有影响。低频字以熟悉性为基础的再认优于高频字,但字频对以提取为基础的再认没有影响。实验二分别测量两种再认项目的补笔正确率。结果表明：以熟悉性为基础的再认的补笔正确率显著高于以提取为基础的再认的补笔正确率。据此可以推论：两种再认可能有不同的心理机制。以提取为基础的再认属于有意识记忆的范畴,以熟悉性为基础的再认属于无意识记忆的范畴。后者和启动效应的心理基础可能是共同的。     

Perceived social context and risk preference: A re-examination of framing effects in a life-death decision problem

This study examines the effects of perceived group context on subjects risk attitudes and their sensitivity to the framing of choice outcomes in a ‘life-death’ decision problem. It seeks to uncover the psychological mechanisms underlying decision-making biases by systematically manipulating the decision context in which the ‘life-death’ problem was described. The study revealed that subjects risk preferences varied as a function of the experimental manipulations. Previously observed reversals in preferences (framing effects) appeared in large-group contexts and disappeared in small-group and family contexts. When considering the fate of small groups, subjects unambiguously favored the probabilistic outcome, no matter how the ‘life-death’ decision problem was framed. The empirical data obtained from the present study suggest that human choice patterns are behaviorally distinguishable across large-group, small-group, and family social contexts.     

Effects of lines of progress and semilogarithmic charts on ratings of charted data

The extent to which interrater agreement and ratings of significance on both changes in level and trend are affected by lines of progress and semilogarithmic charts was investigated. Thirteen graduate students rated four sets of charts, each set containing 19 phase changes. Set I data were plotted on equal interval charts. In Set II a line of progress was drawn through each phase on each chart. In Set III data points were replotted on semilogarithmic charts. In Set IV a line of progress was drawn through each phase of each Set III chart. A significant main effect on interrater agreement was found for lines of progress as well as a significant 2-way interaction between lines of progress and change type. Three main effects (chart type, lines of progress, and type of change) and a significant 3-way interaction were found for ratings of significance. Implications of these data for visual analysis of charted data are discussed.