Generating Optimal Designs for Discrete Choice Experiments in R: The idefix Package

status: publishe

Symmetry and stimulus class formation in humans: Control by temporal location in a successive matching task

Symmetry refers to the observation that subjects will derive B-A (e.g., in the presence of B, select A) after being trained on A-B (e.g., in the presence of A, select B). Whereas symmetry is readily shown by most humans, it has been difficult to demonstrate in nonhuman animals. This difficulty, at least in pigeons, might result from responding to specific stimulus properties that change when sample and comparison stimuli switch roles between training and testing. In three experiments, we investigated to what extent human responding is influenced by the temporal location of stimuli using a successive MTS procedure. Our results indicate that temporal location does not spontaneously control responding in humans, while it does in pigeons. Therefore, the number of functional stimuli that humans respond to in this procedure might be half of the number of functional stimuli that the pigeons respond to. In a fourth experiment, we tested this assumption by doubling the number of functional stimuli controlling responding in human participants in an attempt to make the test more comparable to symmetry tests with pigeons. Here, we found that humans responded according to indirect class formation in the same manner as pigeons did. In sum, our results indicate that functional symmetry is readily observed in humans, even in cases where the temporal features of the stimuli prevent functional symmetry in pigeons. We argue that this difference in behavior between the two species does not necessarily reflect a difference in capacity to show functional symmetry between both species, but could also reflect a difference in the functional stimuli each species responds to.status: publishe

Data from: Estimating the reproducibility of psychological science

This record contains the underlying research data for the publication "Estimating the reproducibility of psychological science" and the full-text is available from: https://ink.library.smu.edu.sg/lkcsb_research/5257Reproducibility is a defining feature of science, but the extent to which it characterizes current research is unknown. We conducted replications of 100 experimental and correlational studies published in three psychology journals using high-powered designs and original materials when available. Replication effects were half the magnitude of original effects, representing a substantial decline. Ninety-seven percent of original studies had statistically significant results. Thirty-six percent of replications had statistically significant results; 47% of original effect sizes were in the 95% confidence interval of the replication effect size; 39% of effects were subjectively rated to have replicated the original result; and if no bias in original results is assumed, combining original and replication results left 68% with statistically significant effects. Correlational tests suggest that replication success was better predicted by the strength of original evidence than by characteristics of the original and replication teams