The distinction between perceiving and memorizing in the presence of category cues.

The study proposed and tested 2 hypotheses to account for the claim by Appel, Cooper, Knight, McCarrell, Yussen, and Flavell (1972) that "memorizing and perceiving are functionally undifferentiated for the young child" by presenting preschool, second-, and fifth-grade children a "memory" and a "look" problem under several treatments in which semantic category cues were present. Surprisingly, preschoolers showed functional differentiation even in the absence of semantic cues--a finding interpreted as evidence for a functional differentiation in the young child's deployment of attention. Second and fifth graders also exhibited functional differentiation in the absence of semantic cues, and there were age changes in the facilitating effects of input and retrieval cues on children's memory.     

A Cross-Age Study of the Understanding of Three Genetic Concepts: How Do They Image the Gene, DNA and Chromosome?

The study was carried out with 175 Turkish students by using drawings at different ages understanding of gene, DNA and chromosome concepts. Students from 8th, 9th, 11th grades and, science and biology student teachers were simply asked to draw the structure of gene, DNA and chromosome in a cell and also to give explanations about these three concepts. Differences in understanding between the age groups were found to be significant for the concepts of gene and DNA. None of the groups exhibit sound understanding and regardless of the age levels, students in all groups had alternative ideas about the three concepts investigated.     

The necessity of each phase of the learning cycle in teaching high school physics

The learning cycle is a method of teaching—it is also a curriculum organization principle and is derived directly from the mental functioning model invented by Piaget. Although Jean Piaget contributed to the formation of the learning cycle (Piaget, 1973), its present structure has to be attributed to Dr. Robert Karplus and the persons who developed the materials of the Science Curriculum Improvement Study (SCIS). It was through the SCIS activities that many of us learned how to develop curricula and teach with the learning cycle. The learning cycle is built upon the premise that three distinct phases are necessary in developing understanding of a concept, that those phases have a definite sequence, and each phase has a definite structure or form. The research done in testing the form variable has already been reported in this journal (Renner, Abraham, & Birnie, 1985). This report explores whether or not each learning-cycle phase is necessary in learning a concept.     

A content analysis of the presentation of the mole concept in chemistry textbooks

The goal of this study was to examine the means used by textbook authors to introduce, define, and explain the mole concept in high school and introductory college chemistry textbooks. The analysis was framed by four questions:

• 1 How is the mole defined?
• 2 What concepts about the atom are introduced prior to the mole?
• 3 Is Avogadro's constant presented as an experimentally determined value?
• 4 What is the context for introducing the mole?

Twenty-nine high school and introductory college level chemistry texts were examined. After independent reading of appropriate sections of each text, discussion of differences, second or third readings of texts, and subsequent discussions, both authors reach 100% agreement concerning the results. Major conclusions were

• 1 Two ways of defining the mole dominate the texts. One way defines the mole as Avogadro's number (6.02 × 10²³) particles; the other method defines the mole in terms of carbon-12.
• 2 All texts that present a definition in terms of C-12 introduce and define concepts about the atom prior to introducing the mole.
• 3 Most texts at all levels point out that the value 6.02 × 10²³ is an experimentally determined quantity.
• 4 Nearly all texts discuss the mole in relation to die problem of finding a way to count particles that are too small to be directly weighed. Most texts also use a familiar counting unit, such as the dozen, to introduce the mole by analogy.

Four issues were discussed: (a) the defining attributes of the mole concept itself and the cognitive requirements for comprehending the two most frequently used definitions; (b) the connection between the definition of the mole presented in the text and the concepts about atoms that are introduced before the mole concept is developed; (c) the experimental nature of Avogadro's number; and (d) the context or setting for developing the mole concept.     

Deaf teacher candidates in hearing classrooms: a unique teacher preparation program

An undergraduate teacher education program at Gallaudet University prepares deaf students in "regular" education. This includes a required full-time internship with hearing students (assisted by sign language interpreters). Graduates then continue in a master's degree program in deaf education, thus acquiring dual certification. Several studies indicate that these deaf candidates progress through the same developmental stages as hearing candidates and that they develop high expectations for deaf learners. Issues related to implementing such a program are discussed.     

Characteristics of child sexual abuse treatment programs

Within the professional community, a vast number of sexual abuse treatment programs have emerged to meet the needs of victims and their families. Significant variations among these programs can be observed due to differences in philosophy, system context, client focus, problem definition, and the treatment strategy adopted. Unfortunately, little comparative information is available regarding the operation of different programs and, more importantly, their relative treatment effectiveness. This article presents the findings from a nationwide survey of 553 sexual abuse treatment programs. The survey focused on program context, client, and service characteristics. Overall it was found that most programs are affiliated with a larger public or private agency, focus on treating victims, and rely on a combination of individual, family, dyad, and group therapy approaches.     

Adjunctive drinking during variable and random-interval food reinforcement schedules

Rats were trained to leverpress for food and subsequently exposed to either arithmetic series or random variable-interval reinforcement schedules. Adjunctive drinking developed in all subjects exposed to arithmetic variable-interval reinforcement, but did not develop in six of the eight animals trained on the random schedule. The results suggest that adjunctive drinking is the result of an interaction between the tendency of rats to drink after eating and the ability of locally low probabilities of reinforcement within schedules to induce conditioned behavioral states.     

Response-cost punishment with pigeons: Further evidence of response suppression via token loss

Four pigeons responded on a two-component multiple token-reinforcement schedule, in which tokens were produced according to a random-interval 30-sec schedule and exchanged according to a variable-ratio 4 schedule in both components. To assess the effects of contingent token loss, tokens were removed after every second response (i.e., fixed-ratio 2 loss) in one of the components. Response rates were selectively lower in the loss components relative to baseline (no-loss) conditions, as well as to the within-condition no-loss components. Response rates were decreased to a greater degree in the presence of tokens than in their absence. To control for the effects of changes in the density of token and food reinforcement, two parts consisted of additional conditions where food density and token loss were yoked to those in a previous loss condition. In the yoked-food condition, tokens were produced as usual in both components, but the overall density of food reinforcement in one of the components was yoked to that obtained during a previous token-loss condition. In the yoked token-loss condition, tokens were removed during one component of the multiple schedule at a rate that approximately matched the obtained rate of loss from a previous token-loss condition. Response rates in these yoked components were less affected than those in comparable loss components, despite similar densities of token, exchange, and food reinforcement. On the whole, the results support the conclusion that contingent token loss serves as an effective punisher with pigeons.