The generation effect in primed word-fragment completion reexamined

Summary Two experiments were designed to test a claim made by Gardiner (1988) that there are generation effects in implicit memory as measured by word-fragment completion. Subjects either read words at study or generated the words from fragments. As in previous research, fragments were completed to a greater extent if they were identical at study and test than if they differed. In Experiment 1 it was found that subjects could recognize explicitly the exact form of fragments that had been used for self-generation and distinguish these from other forms of fragments. An analysis of the contingency relations between recognition of fragments and fragment completion showed a high degree of dependence between the two tests. In Experiment 2 it was found that the match of surface features between study and test was a necessary, but not sufficient, condition to produce enhancement of priming. The results are interpreted as supporting the claim that generation does involve a data-driven component in addition to semantic elaboration.This research was supported by a grant from the Swedish Council for Research in the Humanities and Social Sciences to Lars-Göran Nilsson.     

The effect of enactment on memory for order

The effect of enactment on memory for serial order was investigated in two experiments. In both experiments a reconstruction task was used to separate order from item information. In Experiment 1 enactment and test information was manipulated between groups. For subjects who had not been informed about the reconstruction test, performance of verbal and motor groups was similar with regard to both serial-position curves and overall performance. For subjects who knew beforehand that they would be tested for memory of the order of the action events, performance in the verbal condition was significantly better than in the motor condition. In Experiment 2, the reversed enactment effect for test-informed subjects was replicated with a within-subjects design. The results agree with Engelkamp and Zimmer's (1984, 1994) position that enactment serves exclusively to enhance item information, and indicate that subjects have less control over the encoding processes when they are enacting than during verbal encoding (cf. Cohen, 1981).     

Response force is sensitive to the temporal uncertainty of response stimuli

Three experiments examined whether temporal uncertainty about the delivery of a response stimulus affects response force in a simple reaction time (RT) situation. All experiments manipulated the foreperiod; that is, the interval between a warning signal and the response stimulus. In the constant condition, foreperiod length was kept constant over a block of trials but changed from block to block. In the variable condition, foreperiod length varied randomly from trial to trial. A visual warning and response stimulus were used in Experiment 1; response force decreased with foreperiod length in the variable condition, but increased in the constant condition. This result is consistent with the hypothesis that responses are less forceful when the temporal occurrence of the response stimulus is predictable. In a second experiment with an auditory warning signal and a response stimulus, response force was less sensitive to foreperiod manipulations. The third experiment manipulated both the modality and the intensity of the response signal and employed a tactile warning signal. This experiment indicated that neither the modality nor the intensity of the response signal affects the relation between response force and foreperiod length. An extension of Näätänen’s (1971) motor-readiness model accounts for the main results.     

Geometry, intuition and experience: From kant to husserl

I take this opportunity to thank my colleagues at ZiF for their very helpful comments and criticisms during the academic year. For the preparation of this paper, I am especially indepted to Michael Hallett, who not only improved my English but also saved me from a number of errors.     

An elementary student as a behavioral engineer

Four first-grade public school students exhibited non-study behaviors during a period when all children were to study individually. A fifth-grade student modified the maladaptive behaviors of the four first-grade students. Lights on the four students' desks, which were associated with opportunity for reinforcement, rapidly brought study behavior under stimulus control. Differential reinforcement of other behaviors dramatically decreased studying. Reinforcement was reinstituted and studying returned to a high and stable rate. Surreptitious post-experimental observation using closed-circuit TV indicated that the behavioral changes effected during the experimental phases were partially maintained by the regular classroom environment. A replication of the baseline phase with the observer in the classroom produced an increase in the rate of study behavior, indicating that the observer's presence acted as a discriminative stimulus for studying. An additional contingency requiring improved academic behavior was imposed before the fifth grader was given the opportunity to engage in the behavior modification experiment.