Recall and recognition processes in motor memory: effects of feedback and knowledge of results delay

In linear movement tasks of 200 msec (Experiment 1 -ballistic movement) and 500 msec (Experiment 2 - nonballistic movement), motor recall strength was assessed by absolute, constant, and variable error; recognition strength was assessed by Z'-transformed actual-estimate correlations and absolute actual-estimate difference scores. Contrary to predictions, neither increased KR delay (45 vs. 5 sec) nor limited visual-auditory-tactile feedback caused decrements in recognition processes over KR-training or KR-withdrawal trial blocks for the 200-msec task. In the 500-msec task, the independent variables impaired recognition through training and transfer trials but impaired recall only in the training trials. Results generally did not support the hypothesized independence between recall and recognition processes. Several methodological issues related to recall, and recognition research were discussed.     

The Effects of Charismatic Leadership on Followers' Self-Concept Accessibility

Shamir, House, and Arthur (1993) suggested that the effects of charismatic leadership on followers' motivation are mediated by the increased salience of collective identities in followers' self-concepts. This study empirically examines the effects of leadership messages on followers' self-concept accessibilities. Charismatic and integrative (combined charismatic and individualized consideration) leadership increased the accessibility of followers' collective self-concepts. Individualized consideration increased the accessibility of followers' private self-concepts. These results support the propositions of the self-concept-based theory of charismatic leadership. Charismatic and integrative leadership messages from a leader resulted in higher follower collective self-concept accessibilities than did routinized messages. This finding underscores the importance of a charismatic leader, even when charismatic messages have become routinized.     

Social spatial cognition: social distance dynamics as an identifier of social interactions

We suggest that socio-spatial behavior, which is an interaction between social and spatial cognition, can be viewed as a set of excursions that originate and end in close proximity to another individual(s). We present an extension of earlier studies that perceived spatial behavior in individual animals as a series of excursions originating from a particular location. We measured here the momentary distance between two individuals (social distance) to differentiate among eight possible types of social excursion originating in a state of proximity between excursion-participants. The defined excursion types are based on whether or not the excursion initiator also concludes the excursion, whether or not the excursion starts and ends at the same location, and the dynamics of the distance between excursion participants. We validated this approach to socio-spatial behavior as a set of excursions using it to analyze the behavior of the two sexes in rodents, of normal vs. stereotyped rats, as well as of different rodent species. Each of these groups displays a prevalent excursion type that reflects a distinct social dynamics. Our approach offers a useful and comprehensive tool for studying socio-spatial cognition, and can also be applied to distinguish among different social situations in rodents and other animals.

     

Learning models for a continuum of sensory states reexamined

Dorfman and Biderman evaluated an additive-operator learning model and some special cases of this model on data from a signal-detection experiment. They found that Kac's pure error-correction model gave the poorest fit of the special models when the predictions were generated from the maximum likelihood estimates and the initial cutoffs were set at an a priori value rather than estimated. First, this paper presents tests of an asymptotic theorem by Norman, which provide strong support for Kac's model. On the final 100 trials, every subject but one gave probability matching, and the response propcrtions appropriately normed were approximately normally distributed with variance π(1 ? π). Further analyses of the Dorfman-Biderman data based upon maximum likelihood and likelihood-ratio tests suggest that Kac's model gives a relatively good, but imperfect fit to the data. Some possible explanations for the apparent contradiction between the results of these new analyses and the original findings of Dorfman and Biderman were explored. The investigations led to the proposal that there may be nonsystematic, random drifts in the decision criterion after correct responses as well as after errors. The hypothesis gives a minor modification of the conclusions from Norman's theorem for Kac's model. It gives asymptotic probability matching for every subject, but a larger asymptotic variance than π(1 ? π), which agrees with the data. The paper also presents good Monte Carlo justification for the use of maximum likelihood and likelihood-ratio tests with these additive learning models. Results from Thomas' nonparametric test of error correction are presented, which are inconclusive. Computation of Thomas' p statistic on the Monte Carlo simulations showed that it is quite variable and insensitive to small deviations from error correction.     

Testing the significance of interobserver agreement measures in the presence of autocorrelation: The jackknife procedure

Users of interobserver agreement statistics have heretofore ignored the problem of autocorrelation in behavior sequences when testing the statistical significance of agreement measures. Due to autocorrelation traditional reliability tests based on the 2 × 2 contingency-table model (e.g., kappa, phi) are incorrect. Correct tests can be developed by using the bivariate time series as a statistical model. Seen from this perspective, testing the significance of interobserver agreement becomes formally equivalent to testing the significance of the lag-zero cross-correlation between two time series. The robust procedure known as the jackknife is suggested for this purpose.     

Waveform moment analysis: An ASYST program for topographical analyses of nonnegative bounded waveforms

The moments of a nonnegative bounded waveform (e.g., bounded probability density functions or responses that can be expressed as bounded probability density functions) provide the basis for characterizing the waveform. Traditionally, only the lower-order moments (k ≤ 4) have been utilized in deriving topographical indices of these waveforms. Recent advances in waveform moment analysis, however, have made it possible to derive comprehensive and interpretable indices of complex nonnegative bounded waveforms by utilizing both lower-order and higher-order moments. Waveform moment analysis is reviewed briefly, and a flexible and efficient computer program is presented for conducting waveform moment analyses.     

A small step for rats alters spatial behavior: rats on a bi-level arena explore each level separately

Animal Cognition - We tested rats on a ‘bi-level open-field’ whose two halves were separated vertically by an 8-cm step that the rats could easily ascend/descend. We sought to determine...