A longitudinal study of lateral biases in parents' cradling and holding of infants

Lateral preferences in parents' cradling and holding of their infants were assessed in a longitudinal study commencing 1–3 days after birth and ending at 18 months. Right-handed parents showed a consistent left-side preference, which declined slightly as the infants grew older. Left-handed mothers showed an initial left-side preference and then more variable holding behavior, including right-side preferences, in some conditions. No relationship between the parents' holding behavior and two measures of infant head posture was found. It is suggested that parental side-holding preferences and infant head orientation biases are components of a biobehavioral system designed to enhance the organization of the caregiver-infant relationship.     

Contextual control of negative transfer produced by prior CS-US pairings

When a conditioned stimulus (CS) is repeatedly paired with a weak unconditioned stimulus (US) prior to being paired with a stronger US in a second conditioning phase, interference, or negative transfer, is often observed during Phase 2. Two conditioned suppression experiments with rat subjects examined the effect of a context switch between phases in this “Hall-Pearce negative transfer paradigm.” In Experiment 1, negative transfer was obtained when the context remained the same for both phases, but there was no evidence of negative transfer when the context was switched between phases. Experiment 2 was designed to control for familiarity with the Phase 2 context, and showed that a context switch between phases again attenuated negative transfer. The effect of context on negative transfer was also similar to its effect on latent inhibition produced under comparable conditions. The results are not consistent with a model proposed by J. M. Pearce and G. Hall (Psychological Review, 87, 532–555, 1980), which ascribes no major role to the context in this situation, but are consistent with A. R. Wagner's (In S. H. Hulse, H. Fowler, & W. K. Honig, Eds., Cognitive Processes in Animal Behavior, pp. 177–209. Hillsdale NJ: Erlbaum, 1978) short-term memory model of conditioning, or with the view that contexts may signal specific CS-US relations. The results extend previous research on other interference paradigms, like latent inhibition and extinction, where context may play a similar role.     

The diamond ratio: A visual indicator of the extent of heterogeneity in meta-analysis

The result of a meta-analysis is conventionally pictured in the forest plot as a diamond, whose length is the 95% confidence interval (CI) for the summary measure of interest. The Diamond Ratio (DR) is the ratio of the length of the diamond given by a random effects meta-analysis to that given by a fixed effect meta-analysis. The DR is a simple visual indicator of the amount of change caused by moving from a fixed-effect to a random-effects meta-analysis. Increasing values of DR greater than 1.0 indicate increasing heterogeneity relative to the effect variances. We investigate the properties of the DR, and its relationship to four conventional but more complex measures of heterogeneity. We propose for the first time a CI on the DR, and show that it performs well in terms of coverage. We provide example code to calculate the DR and its CI, and to show these in a forest plot. We conclude that the DR is a useful indicator that can assist students and researchers to understand heterogeneity, and to appreciate its extent in particular cases.     

From Modal Discourse to Possible Worlds

The possible-worlds semantics for modality says that a sentence is possibly true if it is true in some possible world. Given classical prepositional logic, one can easily prove that every consistent set of propositions can be embedded in a ‘maximal consistent set’, which in a sense represents a possible world. However the construction depends on the fact that standard modal logics are finitary, and it seems false that an infinite collection of sets of sentences each finite subset of which is intuitively ‘possible’ in natural language has the property that the whole set is possible. The argument of the paper is that the principles needed to shew that natural language possibility sentences involve quantification over worlds are analogous to those used in infinitary modal logic.