Models for the analysis of alternative sources of growth in correlated stochastic variables

An approach to the analysis of multivariate time series is presented in which linear structural relationships among multiple stochastic variables are investigated. A number of alternative structural models are considered for the case of two stochastic variables. Each model represents a possible hypothesis concerning the relationship of growth in one variable to growth in the second. Both symmetric and asymmetric models are considered. Extensions of two of the models to three variables are illustrated by means of a numerical example. Implications of the models for the problem of detecting change in multivariate time series are discussed.This paper is based in part on a paper read at the Psychometric Society Meetings, Princeton, N. J., Mar. 30–31, 1972. The research was supported by the Committe on Basic Research in Education, National Academy of Sciences, Grant No. OEG-0-9-140396-4497(010), Project No. 9-0396.     

Evidence for all-or-none preperceptual processing in perceptual set

“Set” is known to improve the accuracy of report of the stimulus attributes for which Ss are set to respond. The set may produce this effect by acting on either preperceptual or postperceptual processes, or both. To elucidate the manner by which set produces its effect, this paper explores the consequences of two assumptions concerning set (1) On any given trial, a S is either “set” or “not set”: (2) if “set” by the stimulus information. S’s perception of the stimulus actually improves, whereas, if “not set” by the stimulus reformation, the S’s report correctness is improved by an independent interaction of stimulus and set information on a response process. Evidence is provided for both these assumptions. In addition. It is argued that only set given before stimulation can affect a perceptual process.     

Reduction of intraspecies aggression in rats by positive reinforcement of incompatible behaviors

Fighting responses were elicited by response-independent shocks delivered to pairs of rats. Food pellets were presented following different non-fighting responses to shock: some pairs of rats received pellets dependent upon a specific non-fighting response to shock; others received pellets dependent upon any non-fighting response to shock; and control pairs never received pellets. The mean probability of an elicited aggressive response to shock was reduced to 0.2 by food reinforcement for a specific non-fighting response, and to 0.5 by food reinforcement for any kind of non-fighting response. These values contrasted with the 0.8 probability of elicited aggression when pairs of rats received no food reinforcement. Consistent findings were obtained when treatment conditions were changed for individual pairs of rats.     

The calibration of neutral density wedges

A method for calibrating neutral-density filters is described.     

Instructions,strategies, and pattern uncertainty in a visual discrimination task

A card-sorting task involved discrimination of patterns from the same equivalence set, patterns from different sets of the same size, and patterns from different sets of different sizes. Instructions, experimental conditions, and the number of different patterns to be sorted into two trays were varied in an attempt to change Ss’ strategies from whole-pattern processing to single-element processing. Instructions alone were ineffectual in preventing whole-pattern processing, and physical masks over most of the criterion stimuli (patterns used as guides in sorting) were only somewhat effective. Differences among tasks that were attributable to size of equivalence set were eliminated only by arranging the stimuli so that a whole-pattern strategy required a great deal more information processing, or so that such a strategy could not lead to the required discrimination. The results were interpreted as confirming the influence of the properties of sets of stimuli, as well as the strength of the tendency of human Ss to process and categorize patterns in their entirety. nt]mis|This research was supported in part by a University Research Council grant.     

Rate of response as a visual social stimulus

In Exp. 1, a high rate of responding (chain pulling) of a stimulus monkey was established as a visual positive discriminative stimulus for the operant behavior (bar pressing) of an observer monkey. The terminal performance of the observer under conditions in which a high rate of response of the stimulus monkey alternated in a variable temporal arrangement with a zero rate of response of the stimulus monkey (negative discriminative stimulus) was essentially the same as when nonbehavioral stimuli are correlated with the availability of reinforcement. By manipulating the schedule of reinforcement to change the rate of responding of the stimulus subject without changing its rate of reinforcement, Exp. 2 showed that the effective behavioral stimulus for the observer was the rate of chain pulling by the stimulus subject. A novel intermediate rate of responding by the stimulus monkey resulted in an intermediate rate (generalization) on the part of the observer during an extinction test. These experiments demonstrated that the rate of responding of one organism can function as a discriminative stimulus to control the rate of responding of another organism; and that the rate of responding is similar to other physical stimuli in terms of discrimination and generalization.