On microprocessor-based computers

Economical microprocessor-based computers have been recently developed by Motorola and Control Logic, Inc. Apparently, in response to the price competition, DEC has introduced the PDP-8/A, incorporating the memory characteristics of the microprocessor-based computers. Relative to older minicomputers, the microprocessor-based systems and the PDP-8/A “miniprocessor” require more time to execute an experimentally useful task. However, their real-time operating characteristics would appear to be sufficient for on-line use in behavioral control and data acquisition. The PDP-8/A’s compatibility with older models of the PDP-8 series enables it to use previously developed software, but, for purposes of software development, the microprocessor systems offer a more powerful architecture and instruction set.     

An investigation of relative preference for consistency motivation

The present experiment was designed to determine relative preference for fulfillment of consistency motivation. Ninety-two students rated their attraction to, identification with, and idealization of a hypothetical stimulus person who was represented as having fulfilled particular social motives such as approval, power, achievement and consistency. Results confirmed that subjects prefer persons who have satisfied traditional needs more so than others whose consistency desires have been fulfilled. Implications for the role of consistency motivation in social behavior are considered.     

The law of effect and CR contingent modification of the UCS

A persistent theoretical contention in the American conditioning literature is that Conditional Reflexes (CR) are reinforced through some hidden Thorndikian law of effect. In its most general form, law of effect theories hold that Conditional Reflex-Unconditional Stimulus (UCS) overlap modifies the sensory consequences of the UCS to provide the source of differential reinforcement of CRs. However, consideration of the historical development of law of effect theories reveals they have lacked testability due to the fact that the sources of reinforcement have been alleged to beintrinsically related to the occurrence and topography of CRs. Such a postulated intrinsic relationship has made it difficult to experimentally manipulate the amount of CR-correlated reinforcement, since the source of reinforcement is presumed to be under The Subject’s (S’s) control. Some experiments will be reported in which the relation between CRs and properties of the UCS are madeextrinsic and, accordingly, permit an experimental assessment of law of effect formulations.     

A note on Lawley's formulas for standard errors in maximum likelihood factor analysis

Evidence is given to indicate that Lawley's formulas for the standard errors of maximum likelihood loading estimates do not produce exact asymptotic results. A small modification is derived which appears to eliminate this difficulty.The authors are indebted to Walter Kristof and Thomas Stroud for their helpful reviews of an earlier version of this paper and particularly to D. N. Lawley for his review, comments, and encouragement.     

Time-shared feeding and drinking

Barbary doves were tested in an operant situation in which they characteristically alternate between feeding and drinking. The experimental findings may be summarized as follows: (1) the cumulative distribution of the intervals between feeding bouts is little affected by reward rates; (2) a lock-on index is correlated with reward rate, but is not affected by altering reward rate per se, as long as the overall rate of ingestion remains the same; (3) when a primarily hungry animal is interrupted while feeding, or a primarily thirsty animal while drinking, the behaviour is resumed after the interruption; (4) when a primarily hungry animal is interrupted while drinking, or a primarily thirsty animal while feeding, the behaviour is resumed after a short interruption, but changes to the alternative behaviour following a long interruption; (5) titration of interruption period in the dominant region of the motivational state space is always stable, but becomes unstable if the dominance changes, or if the titrating criteria are reversed. From this evidence it is concluded that feeding and drinking can be time-shared in a manner analogous to that found in computers.