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.     

A two year follow-up study of public vocational school graduates

A 2-year follow-up study of public vocational school graduates revealed that the graduates successfully obtained jobs. Among the factors deemed important by both graduates and employer, communication skills were mentioned as vital. Counseling and preparation in getting along with others were perceived by graduates as inferior. Except for cooperative work program graduates, adjustment to an 8 hr workday caused some problems.     

Task differences on conservation and transitivity problems

Task differences were assessed with 120 first graders in a 2 × 3 × 3 factorial design combining Socioeconomic level (middle vs lower), Concepts (conservation of length, transitivity of length, and conservation of continuous quantity), and Tasks (three tasks for each concept selected on the basis of frequency of usage). As predicted, task by concept interactions were found on all four task response measures. This finding is consistent with Piaget's concept of horizontal decalage and with Flavell and Wohlwill's competence-performance model, which proposes that intermediate phases of stage transition are characterized by considerable intertask differences and initial and final phases by intertask consistency in performance. The importance of investigating the effects of task variables on multiple dependent measures at various age levels and points in time was emphasized. Concept, task, and socioeconomic class differences were also found on some of the measures.