A new principle of pellet feeder design

Most current commercial devices dispense dry food pellets by moving the pellets horizontally toward a discharge point. Individual pellets, captured by perforations in a horizontal metal disk, are discharged one by one by stepwise rotation of the disk within the pellet reservoir. In our laboratory, where the average pellet discharge rate is some 20,000 pellets per week, feeders of this type produced occasional problems. Some were electronic; others involved failure always to capture a pellet in each perforation, particularly when the pellet supply was low. But the most common problem was an accumulation of pellet chips and dust under and around the perforated disk, which ultimately jammed the mechanism. Despite weekly cleaning and maintenance, troubles arose at least twice a month, prompting a search for a simpler pellet-feeder design which would be more reliable and require less maintenance. The present pellet feeder employs a vertical rather than horizontal design principle. It has been used extensively in operant conditioning applications for more than a year. More than 200,000 pellets have been reliably discharged from a single feeder without a breakdown. No maintenance, other than a weekly cleaning of the discharge tube, has been required.     

An Independent Education for all?

Studies in Philosophy and Education -     

Nurses' Anxieties about Biohazards as a Function of Context and Knowledge1

Final-year nursing students (N= 96) described their anxieties about biohazards, not only in relation to the occupational context of a hospital ward, but also in relation to their general life context. These contexts were reported to vary in the extent to which they permitted control over exposure to the two particular biohazards chosen for study: human immunodeficiency virus (HIV) and hepatitis B virus (HBV). The data showed that nurses' anxiety about contracting HIV infection varied significantly across the two contexts, while anxiety about contracting HBV infection did not. In the general life context, anxiety about HIV was greater than anxiety about HBV for all subjects. This difference was significantly greater for those with incorrect knowledge about objective HIV seroconversion rates than for those with correct knowledge.     

The role of theory in treating adolescent substance abuse

The adolescent substance abuser, like adult addicts, is most commonly considered from the perspective of the disease model. The usefulness of the disease model in conceptualizing adolescent substance abuse is questioned, and an alternative view of the topic is set forth. Substance abuse, is regarded as an adaptive aspect of the ongoing interactive processes within the family. The developmental process of the adolescent substance abuser is seen as a functional dynamic in the family's preservation. Three characteristic elements of parental interaction common to the development of adolescent substance abuse are highlighted.An earlier version of this paper was presented at the Texas Association for Marriage and Family Therapy annual conference on January 28, 1993 in Houston Texas.a research associate and director of the Don D. Jackson Archive at the Mental Research Institute, Palo Alto, CA. Authors are listed alphabetically.     

Modifying Beliefs and Attitudes to Exceeding the Speed Limit: An Intervention Study Based on the Theory of Planned Behavior1

This study builds on previous theory of planned behavior (TPB) studies in which we identified the beliefs and values which predict intention to commit driving violations. Four short experimental videos were developed in order to assess the effectiveness of an intervention grounded in the TPB. Three of the videos featured the major constructs of the TPB model. The fourth video featured anticipated regret, an addition to the TPB model which had previously been shown to add significantly to its predictive performance (Parker, Manstead, & Stradling, 1995). Results indicated that two of the videos brought about statistically significant belief changes with respect to scores on TPB items, and significant changes in general attitudes toward speeding. Discussion centers on the problems encountered in operationalizing the TPB constructs and on the potential of theory-based interventions to induce attitude change.     

Beauty Is Only "Name" Deep: The Effect of First-Name On Ratings of Physical Attraction

College students ( n = 197) voted to select a beauty queen from among six photographs equivalent in physical attractiveness, as determined by rankings of 35 students from a separate university. Half the photographs bore a desirable first-name and half were assigned an undesirable first-name. As predicted, firstname had a significant effect on physical attraction: Girls with desirable firstnames received 158 votes to 39 for those with undesirable names. These data were discussed in terms of an additive, rather than an interactive, effect, due to the nature of the task. The strength of these findings was related to the study's ecological validity.