“Next-to-nothings” and nothingness: A study of attention, attenuation and the stimulus prefix effect

The stimulus prefix effect, in which a non-recallable item placed at the beginning of a to-be-remembered string of items creates interference, was studied using a 1-s simultaneous visual method of presentation. Two variants on the standard prefix condition were used; in one, the prefix, o, was presented in a different colour from the memory string of seven digits and, in the other, the prefix consisted of three identical zeroes. The three prefix conditions were compared with two control conditions in which either seven or eight digits were presented. No evidence of prefix effects was found in the recall data over serial positions 1-4, for which retrieval was highly efficient, and it was concluded that the action of response set may exclude the prefix from a response buffer (c.f. Morton, 1970). There was also no evidence that the specialized prefixes led to an attenuation of the interference found in the remaining positions. The latter finding is considered to be contrary to a unit-formation hypothesis (Kahneman, 1973) but is consistent with a mode of operation of the logogen model (Morton, 1970).     

Visual texture as a factor in the apparent velocity of objective motion and motion aftereffects

The apparent velocity of an objectively rotating visually textured disk is an increasing monotonic function of the coarseness (size) of visual texture. The apparent velocity of a negative motion aftereffect increases with coarseness of moving induction texture but decreases with coarseness of stationary test texture, and there is an interaction between induction and test textures. An explanation of these effects is based principally on the assumption of greater lateral inhibition between neighboring elements in finer textures.     

Use of normative peer data as a standard for evaluating classroom treatment effects

This study illustrated the use of normative behavioral observation data as a standard for evaluating the practicality of treatment effects produced in other settings. Three groups of eight subjects each, displaying relatively low proportions of appropriate classroom behavior when compared with regular classroom peers, were selected for treatment within an experimental classroom setting. The three groups were exposed to intervention procedures designed to reinforce either direct academic performance and/or facilitative nonacademic classroom responses. The treatment was effective in changing levels of appropriate behavior (1) above baseline levels in the experimental classroom, and (2) to within normal peer-defined limits when reintegrated into the regular classroom. Further, the data reflect successful maintenance of these effects for a seven- to 12-week follow-up period. Several applications of a normative model for evaluating treatment, generalization, and maintenance effects were presented and discussed.     

The use of positive reinforcement in conditioning attending behavior

Individual conditioning techniques were applied in a controlled setting to increase attending behavior of an underachieving 9-yr-old male subject. The procedure involved: (1) determining a stable response pattern, (2) introducing a treatment variable to establish a high rate of task-attending behavior, (3) measuring the effect of withdrawal of the treatment variable after attaining criterion performance, and (4) transferring control to the classroom. The interval of attending behavior required for reinforcement was systematically increased from 30 sec to 600 sec as the behavior came under experimental control. Manipulating the reinforcing contingencies measurably changed the proportion of attending behavior and the frequency and duration of non-attending events. Once the behaviors were under experimental control, procedures were established to program generalization and to maintain the behavior outside the experimental setting.     

Encoding processes and the recall of text

Two experiments investigated the proposition that the amount of cognitive effort expended to encode information will be directly related to recall of that information. While previous research has shown that amount of processing may affect recall, these studies have generally drawn on the notion of an elaborated memory representation to explain their results. In this study, the amount of processing required to correctly interpret anaphoric relations was varied while the elaboration of the memory trace was held constant. These experiments employed a self-paced reading paradigm in which subjects read a series of short paragraphs and later were cued to recall the final sentence of each paragraph. It was found that recall was significantly improved when more processing was required to correctly interpret the anaphoric relationship expressed in the final sentence. These findings suggest that encoding processes can affect recall performance without elaboration of the memory representation.