Electrical Brain Stimulation During a Retrieval-Based Learning Task Can Impair Long-Term Memory

Anodal transcranial direct current stimulation (tDCS) to the left dorsolateral prefrontal cortex (DLPFC) has been shown to improve performance on a multitude of cognitive tasks. These are, however, often simple tasks, testing only one cognitive domain at a time. Therefore, the efficacy of brain stimulation for complex tasks has yet to be understood. Using a task designed to increase learning efficiency, this study investigates whether anodal tDCS over the left DLPFC can modulate both learning ability and subsequent long-term memory retention. Using a within-subject design, participants (N = 25) took part in 6 training sessions over consecutive days in which active or sham stimulation was administered randomly (3 of each). A computer-based task was used, containing flags from countries unknown to the participants. Each training session consisted of the repetition of 8 pairs of flag/country names. Subsequently, in three testing sessions, free, cued, and timed cued recall, participants were assessed on all 48 flags they had learnt. No difference in learning speed between active and sham tDCS was found. Furthermore, in the timed cued recall phase, flags learnt in the sham tDCS sessions were recalled significantly better than flags learnt in the active tDCS sessions. This effect was stronger in the second testing session. It was also found that for the flags answered incorrectly; thus, meaning they were presented more frequently, subsequent long-term retention was improved. These results suggest that for a complex task, anodal tDCS is ineffective at improving learning speed and potentially detrimental to long-term retention when employed during encoding. This serves to highlight the complex nature of brain stimulation, providing a greater understanding of its limitations and drawbacks.

Observational learning and workplace safety: the effects of viewing the collective behavior of multiple social models on the use of personal protective equipment

INTRODUCTION

The current project evaluated the effects of the collective behavior of multiple social models on the use of personal protective equipment (PPE).

METHOD

Prior to completing a simulated baggage-screening task, participants (N=64) watched a scripted training video that included three confederate trainees. Participants were randomly assigned to one of four manipulations, where different proportions of confederates were shown putting on over-ear sound mufflers before starting the task (0, 1, 2, or 3). White noise played at 70 decibels in the test room, and PPE use was observed unobtrusively through a lab window at five time intervals.

RESULTS

The mean intervals of PPE use generally increased as the number of positive social models increased (0=0.63, 1=0.50, 2=1.25, 3=3.06), and differences between groups were significant [chi(2) (3, N=64)=14.92, p<.01, eta(2)=0.24]. The results suggest that the aggregate prevalence of safety behavior within work groups may be an important determinant of initial PPE use by new employees.

IMPACT ON INDUSTRY

Results suggest that new hires are likely to use PPE at a rate that is proportional to the collective PPE use observed among their peers. Safety leaders should regularly measure the collective level of PPE use at job sites and encourage majority usage through appropriate interventions such as increasing the availability or quality of PPE, training, or positive reinforcement for compliance.

A diagnostic approach to increase reusable dinnerware selection in a cafeteria

The current project tested a diagnostic approach to selecting interventions to increase patron selection of reusable dinnerware in a cafeteria. An assessment survey, completed by a sample of 43 patrons, suggested that the primary causes of wasteful behavior were (a) environmental arrangement of dinnerware options and (b) competing motivational variables. A functional relation between environmental arrangement and reusable product selection was demonstrated in a reversal design. However, the largest effect occurred as function of a multicomponent intervention involving environmental arrangement, employee involvement, and personal spoken prompts with motivational signs. The results support the use of informant assessments when designing community interventions.

Motivating operations and terms to describe them: some further refinements

Over the past decade, behavior analysts have increasingly used the term establishing operation (EO) to refer to environmental events that influence the behavioral effects of operant consequences. Nonetheless, some elements of current terminology regarding EOs may interfere with applied behavior analysts' efforts to predict, control, describe, and understand behavior. The present paper (a) describes how the current conceptualization of the EO is in need of revision, (b) suggests alternative terms, including the generic term motivating operation (MO), and (c) provides examples of MOs and their behavioral effects using articles from the applied behavior analysis literature.

Toward an operant model of power in organizations

The purpose of this paper is to suggest that behavior analysis can help to explain social power. In this approach, an individual's potential for influence is thought to be partially a function of his or her access to stimuli that can be used as consequences. This access can occur either through direct authority or indirectly through social networks and exchanges. Social power is also thought to be a function of an individual's skill in delivering the stimuli in ways that will have the most impact on behavior. A number of predictions about power based on an operant approach are offered.