Wavelength generalization and discrimination in the pigeon

This three-part study describes wavelength generalization gradients around a series of training wavelengths ranging from 480 to 645 om. Luminance was controlled for the pigeon’s spectral sensitivity. The response measure was probability of keypecking during a 2-sec stimulus presentation. Both an extinction procedure, where stimulus wavelengths occurred in 15-nm steps, and a maintained discrimination procedure, where step size was 2 to 4 nm, were used to obtain gradients. During a portion of the maintained discrimination procedure, new luminances were introduced, so that the effect of luminance level on gradient slope could be examined. Comparison of the resulting functions across training wavelengths revealed: (1) consistent differences in gradient slope in different spectral regions and (2) an increase in slope with luminance increase. The findings are related to recent electroretinographic wavelength contrast data and to psychophysical measures of wavelength discriminability.     

The organization of motivated and conditional reflex processes

Recent observations on the plasticity of brain and behavior relationships indicate that the temporary connections between environmental and neuroanatomical substrates have tremendous specificity but at the same time are very plastic. Establishment of a conditional reflex by stimulation of the hippocampal pyramidal layer and/or the mesencephalic reticular formation did not interfere with the differential stimulation of very near points in the same structures. These correlations between brain and behavior confirmed the earlier belief that the development of temporary connections between environment and brain is an elementary process of the central nervous system. Complex behavioral functions are organized through both neuronal and humoral afferentation. Data accumulated recently indicate that the descending forebrain influence is inhibitory in the brain stem and diencephalon and controls the sensory input in a somatomotor-specific and situation-specific manner. Humoral factors affecting thresholds can change the dynamic equilibrium existing between ascending excitatory and descending inhibitory systems; these alterations always follow the rule of situation and somatomotor specificity.     

The effects of unavoidable shocks on a multiple schedule having an avoidance component

Two dogs were maintained on a multiple schedule having both a food reinforced and an avoidance component (Mult VI 1′ S^Δ Avoid_{SS20 RS20} S^Δ). The effects of superimposing an Estes-Skinner procedure for delivering unavoidable shocks on all components of the multiple schedule were observed. The buzzer-shock pairing of the Estes-Skinner procedure produced an increased rate of responding on the avoidance component of the schedule and also on the S^Δ components. No persistent change in rate was observed on the food component during the pre-shock stimulus. Control performances on all components could be regained by either extinguishing or eliminating the buzzer-shock pairing. Extinction of the avoidance responding had little effect on the increased rates of responding produced by the Estes-Skinner procedure on the S^Δ and avoidance extinction components and did not lead to a conditioned suppression of the food reinforced responding. Rate of responding during the pre-shock stimulus was observed to be relatively independent of changes in the maintaining schedules. Responding during the pre-shock stimulus could be conditioned and maintained after an extensive history of avoidance extinction.     

MEASUREMENT OF 'POLITICAL.' PREFERENCES: A further study of direct and indirect scaling methods

The direct methods of ratio estimation and magnitude estimation and the indirect method of pair comparison were used to construct scales of liberalism and conservatism. It was found ( a ) that the scales of conservatism are linearly related to each other and ( b ) those of liberalism are also linearly related to each other but with a discontinuity in the middle of the range; one linear function for the conservative statements and another for the liberal statements, with the discontinuity occurring in the middle of the subjective scale. Liberalism vs. conservatism was found to be reverse. The linear function between all kinds of scales as well as the reverse relation between liberalism vs. conservatism suggest that the continuum of political preferences is metathetic.     

Effects of active student response during error correction on the acquisition and maintenance of geography facts by elementary students with learning disabilities

An alternating treatments design was used to compare the effects of Active Student Response (ASR) error correction and No Response (NR) error correction during instruction of the capitals of states and countries. Three students with learning disabilities were provided one-to-one daily instruction on four sets of 14 unknown capitals (7 ASR capitals and 7 NR capitals). Student errors during instruction on ASR capitals were immediately followed by the teacher stating the capital and the student repeating it (an active student response). Errors on NR capitals were immediately followed by the teacher stating the capital while the student visually attended to a geography card with the correct capital handwritten on it (an on-task response). During instruction each of the three students correctly stated more capitals taught with ASR instruction than he or she stated with NR error correction. Results of same-day and next-day tests show that all three students learned more capitals with ASR error correction than with NR error correction The students also correctly stated more ASR error correction capitals on 1-week maintenance tests.     

Mental Arithmetic: A Componential Analysis of Speed-of-Processing Across Monolingual,Weak Bilingual,and Strong Bilingual Adults

Two experiments compared rates of solving simple and complex addition and multiplication problems in groups of speakers of French or English in Experiment 1 (n = 35) and Spanish or English in Experiment 2 (n = 84). Subjects were divided into groups of English unilinguals, weak bilinguals, and strong bilinguals according to their performance on a naming task. In both experiments, simple problems consisted of two single-digit numbers. At least three single-digit numbers were used for complex problems in Experiment 1 and double-digit numbers in Experiment 2. Mean solution times, particularly for complex problems, were lowest for the monolingual group, followed in turn by the weak bilingual and strong bilingual groups, but these differences were not statistically reliable in either experiment. In Experiment 2, however, componential analyses of solution times indicated that strong bilingual subjects were slower at executing the carry operation when solving complex problems, relative to the two remaining groups. Results were interpreted in terms of the relationship between bilingualism and the representation and processing of numerical information.