Learning to ignore irrelevant stimuli: Variations within and between displays

Pigeons were exposed to stimuli differing in orientation. Some birds received both horizontal and vertical on every trial; others received two horizontals on some trials and two verticals on other trials. These stimuli were irrelevant, i.e., did not predict reliably the availability of reinforcement. When required to learn a discrimination between horizontal and vertical, the birds that had experienced the stimulus variation within each display learned more slowly. This was true whether the test problem was a simultaneous or a successive discrimination. It is argued that this result implies that animals will actively learn to ignore stimuli that are irrelevant.     

Sex differences in student—teacher interactions in the college classroom

An observational analysis of student—teacher interactions in 60 college classes revealed sex differences in student behaviors. Male students were the majority sex more often than females in classes taught by male lecturers; there was no sex difference for classes taught by female lecturers. Male students engaged in proportionately more student—teacher interactions than female students in male-taught classes; there was no sex difference in female-taught classes. Neither male nor female professors appeared to respond differentially to male and female students. Possible causes and implications of these findings are discussed.Portions of this paper were presented at the biennial meeting of the Society for Research in Child Development, Denver, April 1975.     

A controlled evaluation of token economy procedures with chronic schizophrenic patients

Eighteen chronic schizophrenic patients were allocated to 3 matched groups, one group acting as an own-ward no-treatment control group. The two other groups moved to a token-economy ward, where the token group received contingent tokens, social reinforcement, and informational feedback as a consequence of appropriate behaviour, and where the control group received contingent social reinforcement and feedback with a matched amount of non-contingent tokens. After a 3 month baseline phase, this procedure was followed for a total of 15 months. A continuous assessment system was used with some weekly and monthly assessments, incorporating nursing checklists and ratings, psychiatric ratings, psychological tests, and time-sampling procedures, as well as continuous monitoring of the ward programme. The introduction of contingent tokens had an immediate positive effect in 3 areas of behaviour, but this advantage disappeared over the 15 months owing to the slower but sustained improvement in the control group. Significant improvement was limited to the areas of Social Withdrawal. Appearance and Routine. The patients who improved the most on any measure were those who were initially the most deteriorated. There were paradoxical changes in non-target behaviour, and in symptomatic behaviour. Suggestions and instructions to nurses may play a major part in influencing patient behaviour within and between experimental phases.     

Altering student responses through changes in teacher verbal behavior

Two experiments were conducted in a junior-high special-education class of eight pupils in an inner-city school. In the first experiment, the teacher doubled the number of words used by the pupils in answering questions by altering the type of questions asked. In the second experiment, the number of words used by students and the percentage of answers given in complete sentences, increased from less than 5% to approximately 90% when the teacher instructed the pupils to answer in complete sentences and asked another pupil to answer using a sentence if the first one did not do so. In both experiments, a brief return to baseline conditions brought a return to low levels of verbal responding. An analysis of which pupils were called on by the teacher, teacher praise, and in the second experiment the types of questions asked, indicated that these variables were not responsible for the increases in verbal responding.     

Converse Ackermann Croperty and semiclassical negation

A prepositional logic S has the Converse Ackermann Property (CAP) if (AB)C is unprovable in S when C does not contain . In A Routley-Meyer semantics for Converse Ackermann Property (Journal of Philosophical Logic, 16 (1987), pp. 65–76) I showed how to derive positive logical systems with the CAP. There I conjectured that each of these positive systems were compatible with a so-called semiclassical negation. In the present paper I prove that this conjecture was right. Relational Routley-Meyer type semantics are provided for each one of the resulting systems (the positive systems plus the semiclassical negation).     

Influence of rearing conditions on voluntary ethanol intake and response to stress in rats

The effects of exposure to four environmental rearing conditions on subsequent voluntary ethanol intake and response to immobilization stress were examined. Male weanling rats were reared in an enriched environment, with a female partner, with a male partner, or individually, for 90 days. At 111 days of age, voluntary consumption of ethanol in increasing concentrations (3 to 9%, v/v) was assessed. Following the ethanol-exposure period, rats were randomly divided into stressed and nonstressed groups and exposed to 3 h of immobilization. Results indicated that the enriched animals consumed greater amounts of ethanol as compared to all other groups, suggesting that the enriched environment and not handling, housing conditions, or the presence of another male or female is responsible for the observed increase in ethanol drinking behavior. Ulcer data indicated that among environmentally enriched rats, ethanol attenuated stress ulcer development relative to their non-ethanol-exposed but stressed controls. In nonstressed enriched rats, ethanol alone exacerbated stomach damage. We suggest that environmental rearing conditions markedly influence the complex interaction between ethanol intake and the response to stress.     

Test-retest reliability of the Profile of Mood States using visually impaired athletes

The test-retest reliabilities of the Profile of Mood States when items were read aloud on consecutive days to 15 nationally ranked visually impaired athletes ranged from .78 to .95, so the scale can be used with visually impaired athletes who cannot complete the profile in the traditional written manner.     

Phonetic awareness and reading acquisition

Summary Three issues are dealt with: the relationship between phonetic awareness and reading acquisition, the nature of the cognitive capacities that make phonetic awareness possible, and the potential influence of phonetic awareness on language perception and comprehension. Data on the relationships between phonetic awareness and reading acquisition support an interactive view. For most people, learning to read in the alphabetic system stimulates phonetic awareness. On the other hand, phonetic awareness is a critical factor for success in reading acquisition. Indications about the nature of the cognitive capacities that underlie phonetic awareness may be obtained by inspecting its development. Two capacities at least seem to be required: the capacity to ignore meaning and focus on the sound properties of speech and the capacity of segmentation.Lack of phonetic awareness does not imply that phonetic processing does not take place during speech perception. Recent data suggest that speech perception includes a stage of extraction of phonetic features regardless of whether or not the subject is able to segment speech into phones explicitly. However, phonetic awareness may influence perceptual strategies and the relative weight of meaning expectancies in identification.Our work received support from the Belgian Fonds de la Recherche fondamentale collective (F.R.F.C.) under contracts No. 2.4505.76 and 2.4505.80 as well as from the Belgian Ministère de la Politique et de la Programmation scientifiques (Action de Recherche concertée Processus cognitifs dans la lecture)