A maximum likelihood method for fitting the wandering vector model

After introducing some extensions of a recently proposed probabilistic vector model for representing paired comparisons choice data, an iterative procedure for obtaining maximum likelihood estimates of the model parameters is developed. The possibility of testing various hypotheses by means of likelihood ratio tests is discussed. Finally, the algorithm is applied to some existing data sets for illustrative purposes.     

The effects of spatial,temporal, and control variables on the free-recall serial position curve of retardates and equal-MA normals

Memory & Cognition - In Experiment I seven pictures were sequentially illuminated at a 3-see rate through seven translucent windows. A different window provided the starting point for each of...     

Word frequency and age of acquisition as determiners of picture-naming latency

In multiple-regression analysis of picture-naming latencies from an experiment modelled on Oldfield and Wingfield's (1965), with 94 stimuli and 37 adult subjects, two word frequency measures had insignificant beta weights, while two measures estimating age at which the word was learned had highly significant weights. Objects whose names were learned early were named faster. This result may have important implications for the interpretation of studies using word frequency as a critical variable. It is suggested that word retrieval may be a one-stage process that depends upon the age at which a word was learned.     

Mothers' responses to infants' facial expressions of sadness,anger, and physical distress

It was hypothesized the mothers' predictions of their caregiving interventions would be differentially influenced by infants' facial expressions of sadness, anger, and physical distress. Mothers viewed slides of infants whose facial displays had first been objectively classified with the Maximally Discriminative Facial Movement Coding System (Izard, 1979). Mothers imagined their infants showing similar expressions while scaling their own tendencies to respond with a number of specific caregiving and socializing interventions and affective reactions. Multivariate ANOVAs showed that the mothers' predictions differed for the three types of negative display. In an emotion decoding task, mothers' responses did not differ as a function of the infants' sex. The patterns of decoded emotions were most similar between physical distress and anger expressions, and least similar between physical distress and sadness expressions. Generally, the findings supported the hypothesis that the negative facial displayes signaled different affective states and had differential motivational effects on the mothers.     

Translating cognition into action: the role of visual guidance in observational learning

This experiment examined the role of two forms of visual guidance in facilitating the translation of cognitive representations into action. Subjects matched a modeled action pattern either concurrently with the model or after the modeled display. They then either did or did not visually monitor their actions during tests of production accuracy in the model's absence. Acquisition of the cognitive representation was assessed periodically. Concurrent matching of modeled actions or visual monitoring of productions both increased the level of observational learning. The more accurate the cognitive representation, the more skilled were subsequent reproductions of the modeled actions. After acquiring proficiency in converting cognition to action, subjects maintained their level of performance accuracy even though modeled and visual-monitoring guidance were withdrawn. These results are in accordance with the theory that cognitive representation mediates response production and that corrective adjustments through visual guidance aid in the translation of conception into action.