Infants' responses to mothers' imitative behaviors

Several investigators have suggested that young infants' smiles and vocalizations following their mothers' imitative behaviors might reflect infant recognition that the mother's behavior is imitative or at least contingent. This study investigated whether infants smile and vocalize more frequently subsequent to maternal imitative than non-imitative behavior during both spontaneous and imitative face-to-face interactions. Fourteen 3 1/2-month-old infants and their mothers were videotaped in these two face-to-face interaction situations. The infants vocalized more frequently during the imitative situation and infant vocalizations plus simultaneous smiling, and vocalizations occurred more often following maternal imitative than non-imitative behavior. Although these data suggest that infant vocalizations and simultaneous smiles and vocalizations may reflect the infants' recognition of maternal imitative behavior, they do not establish definitively that it is the imitation per se vs. the contingency aspect that is recognized by the infant.     

Some experiments on the organization of a class of imitative behaviors

A retarded child was taught to imitate diverse demonstrations made by an experimenter, until new demonstrations were imitated correctly upon first presentation without direct training. These imitations could be maintained without reinforcement, when they were distributed among other reinforced imitations. Factors responsible for the continued performance of these unreinforced imitations were examined. When subjected to massed extinction trials, unreinforced imitations eventually disappeared; they reappeared when again interspersed among reinforced imitations. In addition, the stimulus function of "similarity of response between subject and experimenter" was examined. The subject was taught a set of non-imitative responses, through discriminative stimuli controlled by the experimenter, and a comparable imitative set. Unreinforced non-imitations, like reinforced imitations, were maintained only when interspersed among reinforced imitations. When all reinforcement was discontinued, all responses extinguished similarly, indicating that reinforcement was necessary to maintain the response-class organization, but not confirming an essential role for "similarity" as such.     

Promoting imitative play through generalized observational learning in autisticlike children

Three autisticlike boys with deficits in imitative and appropriate play behaviors were taught to play with an unfamiliar toy by observing a peer model demonstrate appropriate play with the toy. Generalization was assessed across toys and models, and temporal maintenance was assessed at 1 and 3 weeks following generalization. Following training each child demonstrated increases in imitative play concomitant with decreases in the frequency of nonmanipulated selfstimulatory behavior. Results are discussed in terms of their implications for the amelioration of social isolation and self-stimulatory behavior.The authors wish to acknowledge the help and cooperation of the Henry Wiseman Kendall Center and the Highpoint Preschool Enrichment Program.     

The generalized control of excessive behaviors

Two theoretical approaches to generalization in behavioral interventions designed to reduce behavioral excesses are discussed; approaches based on stimulus generalization and those based on response generalization. The potential advantages and disadvantages of each model are outlined, and implications evolving from the application of each model for practitioners are discussed. The article concludes with an overview of guidelines for practitioners and researchers.     

A variable neighborhood search method for generalized blockmodeling of two-mode binary matrices

The clustering of two-mode proximity matrices is a challenging combinatorial optimization problem that has important applications in the quantitative social sciences. We focus on one particular type of problem related to the clustering of a two-mode binary matrix, which is relevant to the establishment of generalized blockmodels for social networks. In this context, clusters for the rows of the two-mode matrix intersect with clusters of the columns to form blocks, which should ideally be either complete (all 1s) or null (all 0s). A new procedure based on variable neighborhood search is presented and compared to an existing two-mode K-means clustering algorithm. The new procedure generally provided slightly greater explained variation; however, both methods yielded exceptional recovery of cluster structure.     

A generalized strategy for measuring performance in the velocity-position phase plane

ABSTRACT Recent work has proposed the reformulation of smoothness measures derived from standard integrated squared jerk, as a function of position, not time. However, its promulgation was in the context of monotonic excursion data extracted from single degree-of-freedom (DOF) movements; the result was a formulation of a phase smoothness measure with limited generalizability. Here, we present a complete methodology for implementing the phase smoothness measure in arbitrary datasets, i.e. for multi-DOF movements with no assumptions of monotonicity in the kinematic profile. Additional suggestions are made for best practices.     

Human variable ratio performance

The generality of the mathematical principles of reinforcement (MPR) was tested with humans. In Experiment 1A, participants’ mouse clicks were reinforced according to a series of variable-ratio (VR) values. In one condition, a situated task was used (searching for treasure on a map presented via a PC monitor); in the other, abstract version of the task, participants clicked on a white screen. Under the “map” condition, response rates increased with increasing ratio value before decreasing with further ratio increases; under the “no-map” condition, response rates decreased linearly from a peak at the smallest ratio. In Experiment 1B, the pattern of responding was confirmed under the “map” conditions using a different set of ratio values. In Experiment 2, reinforcer magnitude was manipulated using the “map” context. Response rates did not differ significantly when large rather than small cash reinforcers were delivered according to a VR 30 but were significantly higher when large rather than small cash reinforcers were delivered according to a VR 120. Together these experiments offer qualified support for extending MPR to the behavior of human participants.     

A qualitative study of leader behaviors perceived to enable salesperson performance

Abstract

This study builds on and extends previous sales leadership research by exploring sales professionals’ perceptions of effective leadership behaviors. Semistructured interviews with both sales leaders and salespeople working in a global enterprise software company were examined through a qualitative analysis. Results indicated that participants believed sales leadership played an important role in influencing sales performance. When asked to describe specific sales leader behaviors that best enable salesperson performance, sales professionals – both sales leaders and salespeople – overwhelmingly referenced coaching, followed by collaborating, championing, and customer engaging. We define and describe these four key sales leader behaviors and identify four potential mediating variables (trust, confidence, optimism, and resilience), from which emerges a conceptual framework of sales leader behaviors perceived to enable salesperson performance. We examine these four key sales leader behaviors and mediators in the broader context of leadership theory, particularly transformational, servant, authentic, and adaptive leadership theories. The key contribution of this study is the identification of a set of leader behaviors that are likely to be especially effective in modern sales organizations given that they originated from the perceptions of sales professionals themselves.     

A model for residence time in concurrent variable interval performance

A component-functions model of choice behavior is proposed for performance on interdependent concurrent variable-interval (VI) variable-interval schedules based on the product of two component functions, one that enhances behavior and one that reduces behavior. The model is the solution to the symmetrical pair of differential equations describing behavioral changes with respect to two categories of reinforcers: enhancing and reducing, or excitatory and inhibitory. The model describes residence time in interdependent concurrent VI VI schedules constructed from arithmetic and exponential distributions. The model describes the data reported by Alsop and Elliffe (1988) and Elliffe and Alsop (1996) with a variance accounted for of 87% compared to 64% accounted for by the Davison and Hunter (1976) model and 42% by Herrnstein's (1970) hyperbola. The model can explain matching, undermatching, and overmatching in the same subject under different procedures and has the potential to be extended to performance on concurrent schedules with more than two alternatives, multiple schedules, and single schedules. Thus, it can be considered as an alternative to Herrnstein's quantitative law of effect.     

A moderated mediation model of the relationship between organizational citizenship behaviors and job performance

Addressing numerous calls for future research on understanding the theoretical mechanisms that explain the relationship between organizational citizenship behaviors (OCBs) and job performance, this study focused on how an employee's relationships with coworkers mediate the relationship between his or her OCBs and his or her job performance. It also looked at how task autonomy might moderate this mediated relationship. The results of an empirical study involving 364 jewelry designers, 310 coworkers, and 284 supervisors indicated that coworker relations mediated the relationship between OCBs and job performance. In addition, task autonomy positively moderated both paths of this mediated relationship. Finally, these results hold for OCBs that are targeted at individuals but not for OCBs that are targeted toward organizations.     

Factors in social comparison of performance influencing actual performance

Seven experiments were conducted which measured changes in the subjects' actual performance resulting from manipulated personal and categorical comparison of performance with another subject. In line with Festinger's (1954) theory of social comparison of ability, it was found that subjects who were visually isolated from sources of evaluation (setting 2, experiment 2 and 3) showed relatively low performance after a VI (very inferior) or VS (very superior) outcome and relatively high performance after an EQ (equal) outcome, whereas subjects who were visually exposed to sources of evaluation (setting 1, experiment 1 and 4) showed relatively low performance only after a VS outcome and relatively high performance after both a VI and EQ outcome. When (also in setting 1) the manipulation of outcome was combined with a manipulation of expectation (experiment 5), it was found that an EQ expectation did not alter the original pattern of outcome effects, but that a VI or VS expectation markedly influenced the effect of outcome: A complete confirmation of VI expectation and an almost complete disconfirmation of VS expectation resulted in relatively high performance, whereas all other combinations of VI or VS expectation with a given outcome resulted in relatively low performance. Finally, it was found that changing the manipulation of personal comparison of performance of the previous experiments into a manipulation of categorical comparison of performance of the previous experiments into a manipulation of categorical comparison of performance (experiment 6a and 6b) resulted in a pattern of data wich was about the opposite of the typical previous pattern. In setting 1 (experiment 6a), the subjects' performance was relatively low after being categorized into a VI or EQ category and relatively high after being categorized into a VS category, whereas in setting 2 (experiment 6b) both the VI and VS categorization resulted in the same performance and the EQ categorzation resulted in a slightly lower performance.     

Observer states and traits and the imitative process: A test of a new formulation

In three studies the formulation was tested that characteristics of the observer have an effect on imitation only in situations which provide little information concerning appropriate or expected behaviors. In Experiment I, female college students of high, medium, and low need for social approval underwent either a high or low arousal manipulation. Subjects observed a videotaped model who engaged in a size judgment task. For half the subjects the model received verbal reward (high information); for the other half the model received no feedback (low information). Subsequently, the model and subject responded alternately in the task during which no feedback was given. Neither need for social approval nor manipulated arousal was found to be systematically related to imitation in either information condition. However, the hypothesized relationships were found when subjects' arousal or anxiety levels were determined by self ratings. These results were replicated in a second, similar experiment. In a third experiment, which involved an improved arousal manipulation, the hypothesized relationships were confirmed.     

Contribution of imitative suicide to the suicide rate in prisons

Suicide rates in prisons are high. Our aim was to investigate the contribution of imitative suicide to the prison suicide rate. We used Knox tests for space-time clustering in a case register of natural and self-inflicted deaths in prisons in England and Wales and model simulations to estimate the effect size. We found significant space-time clustering among 657 self-inflicted deaths in 90 prisons over 10 years but no space-time clustering among 430 deaths from natural causes in 87 prisons over this period. Model simulations with an imitation rate of 5.8% (CI 1%-11%) reproduced the observed space-time clustering.     

Temporal factors influencing performance in the missing scan paradigm

Sixty Ss were each presented 120 random sequences of 9 of the 10 digits (0–9); their task on each trial was to supply the missing digit. Two stimulus input rates and two response time limits were combined factorially to yield four experimental conditions. Contrary to expectation, evidence seeming to support the use of a strategy based on the ordinal properties of the stimuli was found only when rapid (1-sec) responses were required, regardless of input rate. It is suggested that this result is most reasonably attributed to the operation of a guessing bias for numbers in the middle of the ordinal sequence. Differences in the constitution of the stimulus series may account for the failure to confirm previous findings of an ordinal strategy.