Typical delay determines waiting time on periodic-food schedules: Static and dynamic tests

Pigeons and other animals soon learn to wait (pause) after food delivery on periodic-food schedules before resuming the food-rewarded response. Under most conditions the steady-state duration of the average waiting time, t, is a linear function of the typical interfood interval. We describe three experiments designed to explore the limits of this process. In all experiments, t was associated with one key color and the subsequent food delay, T, with another. In the first experiment, we compared the relation between t (waiting time) and T (food delay) under two conditions: when T was held constant, and when T was an inverse function of t. The pigeons could maximize the rate of food delivery under the first condition by setting t to a consistently short value; optimal behavior under the second condition required a linear relation with unit slope between t and T. Despite this difference in optimal policy, the pigeons in both cases showed the same linear relation, with slope less than one, between t and T. This result was confirmed in a second parametric experiment that added a third condition, in which T + t was held constant. Linear waiting appears to be an obligatory rule for pigeons. In a third experiment we arranged for a multiplicative relation between t and T (positive feedback), and produced either very short or very long waiting times as predicted by a quasi-dynamic model in which waiting time is strongly determined by the just-preceding food delay.     

Pigeons can discriminate locations presented in pictures

The present experiments were designed to teach pigeons to discriminate two locations represented by color photographs. Two sets of photographs were taken at two distinctive locations on a university campus. These sets represented several standpoints at each location. For the true-discrimination group, pictures from the two locations were differentially associated with reward; for the pseudodiscrimination group, half of the views from each location were arbitrarily but consistently associated with reward. The former group acquired the discrimination much more rapidly. These birds also showed good transfer to new views from the standpoints used in training and to a new standpoint at each location not used in training. In a second experiment, another group of pigeons could terminate any training trial by pecking an “advance” key. Three of 4 subjects used this option to reduce the duration of trials in which pictures from the negative location were presented. These data suggest that pigeons can integrate views shown in pictures into a “concept” of a location. The method used here may be the experimental analogue of a common, natural process by which animals learn to identify locations.     

Personality and relaxation therapy: changes among clinical and normal subjects

There are increasing numbers of self-referral stress-management programs, a few of which use group-relaxation techniques, but few data are available on the personalities of the symptomatic and asymptomatic clients who attend or on any changes in personality after the program. Scores on the Eysenck Personality Inventory, Multiple Health Locus of Control, and State-Trait Anxiety Inventory as well as demographic information were obtained from 255 adults who attended a 10-session, university-based, group-relaxation program. The symptomatic clients reported significantly less anxiety, less neuroticism, were more extraverted and ascribed less of their behavior to chance at a 1 month post-treatment follow-up than at intake. The small group of asymptomatic clients also reported less anxiety and neuroticism at the follow-up. There were no sex differences on the Eysenck inventory or the anxiety scales but there were for the Multiple Health internal and control scales. It was concluded that group relaxation appeared to improve mental health scores effectively for both stressed and nonstressed adults and that age was significantly related to some personality scores.     

Fixation accuracy and perceptual asymmetry for consonants

Fixation accuracy was related to perception of laterally presented consonants. Small left-eye fixation inaccuracy influenced perceptual performance of 8 men and 8 women.     

Relation between musical aptitude and intelligence among mentally retarded, advantaged, and disadvantaged subjects

The purpose of this study was to investigate differences in scores of 59 mentally retarded adults (mild, moderate, severe, or profound), 133 advantaged, and 130 disadvantaged (low income) children in Grades 1, 2, 3 on the Primary Measures of Music Audiation. Test-retest reliabilities for the Tonal and Rhythm subtests were .81 and .86, respectively, for the retarded group. Analysis of variance indicated that the mildly retarded children performed significantly better than other groups of retarded children on these two tests. 2 x 3 analyses of variance indicated that third graders from both advantaged and disadvantaged groups performed significantly better than the first or second graders on both subtests and that advantaged children performed significantly better than the disadvantaged. However, disadvantaged children made greater gains, especially for third graders, than the advantaged.     

The status of epileptic patients in a developing African country: northwest Ethiopia

Of 1240 first-time consultations in the neuropsychiatric clinic of the Gondar College of Medical Sciences in an eleven-month period during 1985 and 1986, 152 patients came seeking relief from seizures. This paper deals with the origins and background of diagnostic, differential diagnostic, and therapeutic problems, and with problems of social rehabilitation. While in such a tradition-bound society certain hypotheses continue to have an unfavorable effect, there are unmistakable signs of positive change against a background of rapid social change. Conclusions are drawn for the better management of epileptic patients in developing countries.