Effects of delayed conditioned reinforcement in chain schedules.

The contingency between responding and stimulus change on a chain variable-interval 33-s, variable-interval 33-s, variable-interval 33-s schedule was weakened by interposing 3-s delays between either the first and second or the second and third links. No stimulus change signaled the delay interval and responses could occur during it, so the obtained delays were often shorter than the scheduled delay. When the delay occurred after the initial link, initial-link response rates decreased by an average of 77% with no systematic change in response rates in the second or third links. Response rates in the second link decreased an average of 59% when the delay followed that link, again with little effect on response rates in the first or third links. Because the effect of delaying stimulus change was comparable to the effect of delaying primary reinforcement in a simple variable-interval schedule, and the effect of the unsignaled delay was specific to the link in which the delay occurred, the results provide strong evidence for the concept of conditioned reinforcement.     

Fostering young children's representation, planning, and reflection: A focus in three current early childhood models

Many educators and developmental psychologists have pointed to the development of symbolic thought and representational abilities as a set of fundamental capacities that underlie the development of self-regulation, problem solving, planning, and higher level thought processes. While many early childhood programs value children's development of symbolic capacities, three approaches, High/Scope, Tools of the Mind, and Reggio Emilia, were analyzed in terms of one context from the array of strategies and experiences that characterizes the approach in order to examine the distinctive way that three different preschool programs apply the theoretical construct of representational development to pedagogical strategies.     

Das Ontologische Dilemma der Normativen Ethik

The Ontological Dilemma of Normative Ethics. This paper pursues two goals. The first is to show that normative ethics is confronted with the following dilemma: to be coherent, this discipline is ontologically committed to acknowledge the existence of objective values, but, to be scientifically respectable, it is committed to repudiate such values. The second goal is to assess the possible solutions to this dilemma. To this end, the following strategies are discussed: Kant’s constructive objectivism, Jürgen Habermas’ “epistemic ersatzism”, Franz von Kutschera’s “confirmation pragmatism”, and David Brink’s “objectivist tour de force”. The paper’s conclusion is that the dilemma cannot be solved because it rests on a clash of intuitions none of which can be given up. This revised version was published online in August 2006 with corrections to the Cover Date.     

Sex differences in the levels of generality of values/preferences related to work

The current literature on sex differences in values/preferences related to work appears polarized around two apparently contradictory sets of findings and conclusions. One set of studies fails to detect sex differences. The other set of studies indicates that males are more concerned about money, independence, security, and career goals, while females appear more concerned about people and environmental issues at work. Following W. D. Siegfried, I. MacFarlane, D. B. Graham, N. A. Moore, and P. L. Young (Journal of Vocational Behavior, 1981, 18, 30–42) it is suggested that level of analysis may be a crucial factor accounting for much of the prevailing confusion in the literature. This study investigated sex differences in values/preferences related to work at various levels of generality. A sample of 1081 senior high school students was administered the Work Aspect Preference Scale (WAPS). Complete-link cluster analyses were performed for males and females separately. Comparison of the two dendrograms reveals the substantial similarity of the preference patterns of males and females. However, the basic difference in the patterns focused on the Altruism and Physical Activity subscales. Females appeared more likely to associate helping others with personal achievement whereas males tended to see helping people in terms of controlling and organizing them. Females also linked physical activity with helping others and self-development whereas males tended to associate physical activity with extrinsic rewards of work. It is concluded that the use of cluster analysis techniques may provide the best procedure to effect an adequate reconciliation of the conflicting results to be found in the current literature.     

The role of attentional resources in automatic detection

The question of whether an automatic detection task requires the use of limited-capacity resources was investigated in a series of dual-task experiments. The automatic task required subjects to detect a consistently mapped target digit in a display of letters. This task was paired with a variety of concurrent visual discriminations that could either occur in close proximity to the automatic target or in a disparate display area. The main finding was that accuracy in each task was higher in conditions allowing attention to be shared than when it had to be divided between separate areas. These results indicate that detection of automatic targets depends on the allocation of spatial attention to the target's area.     

Behavioral thresholds for tones during infancy

An adaptive up-down tracking procedure was used in combination with a visually reinforced head turn response to examine auditory sensitivity for 500, 2000, and 8000-Hz tone bursts in infants 6 to 18 months of age. Six- and 10-month-old infants were tested with headphone presentation of stimuli, while 10-, 14, and 18-month-olds were tested in sound field. Infant threshold estimates for both headphone and sound field were within 15 dB of adult comparisons for all frequencies and age groups. Six-month-olds were significantly less sensitive to the 8000-Hz tone than to either of the lower frequency stimuli, but older infants demonstrated approximately equal sensitivity for all three frequencies tested.     

Phonological processing during silent reading in aphasic patients

In a task involving the detection of a predesignated letter during the silent reading of a series of passages, left-brain-damaged aphasic patients and right-brain-damaged patients showed patterns of performance consistent with those of normal individuals. Both of the brain-damaged groups were more likely to detect letters when they were pronounced in a typical way (e.g., g in "ago") than in an atypical way (e.g., g in "through"), suggesting the use of phonological recoding during silent reading. In addition, both of these groups were more likely to detect letters when they occurred in content than in function words, suggesting a differential processing of these word types. Possible differences in the strategies predominantly relied on for phonological recoding and for the differential processing of content and function words by different groups of patients are discussed.     

Perception of causal relations in humans: Factors affecting judgments of response-outcome contingencies under free-operant procedures

In three experiments, college studients responded to and rated a range of positive, random, and negative response-outcome contingencies presented in free-operant formats. These experiments sought a paradigm that would yield sensitive and unbiased judgments of response-outcome relations and explored the role of time in the judgment of response-outcome covariation. In Experiment 1, the effects of making continuous and discrete responses on subjects' contingency judgments were compared. In Experiment 2, the effects of changing the temporal definition of discrete responses were examined as were the effects of the amount of exposure to contingency problems. In Experiment 3, the effects of temporal regularity in defining response occurrence and nonoccurrence were investigated. In all three experiments, subjects' judgments were strong linear functions of the programmed contingencies between telegraph key operation and the illumination of a brief light. This result shows free-operant scheduling of response-outcome contingencies to be a highly sensitive and unbiased method of investigating causal perception. Additionally, judgment accuracy was found to be higher for males than for females and to improve as the probability of the subject's making a recorded response rose from .00 toward .50. Finally, a correlational analysis of several possible judgment rules supported the conclusion that subjects rated response-outcome relations on the basis of the difference in the probability of an outcome given their having recently made or not made a response.     

Stimulus control of responding by response-reinforcer temporal contiguity

The stimulus properties of brief disruptions in response-reinforcer temporal contiguity were investigated using a discrete trial conditional discrimination procedure. Key pecking (nondelay) or key pecking followed by a brief interval of nonpecking (delay) in the sample component produced a stimulus change (choice component). Pecks in the choice component to one of two alternatives resulted in food or blackout, conditional upon which response requirement was met in producing the choice component. A baseline condition, in which key pecking always produced the choice component and correct choices were arranged randomly, alternated with experimental conditions that included nondelay and delay values of either 0.2, 0.5, or 1.0 sec between the last key peck and the initiation of the choice component. All subjects accurately discriminated brief temporal delays between a response and stimulus change, with choice accuracy increasing for three of four subjects as the temporal disruption in contiguity increase. Implications of the research for the study of delayed reinforcement, response-independent reinforcement, and the discrimination of causality are discussed.     

On unpredictability as a causal factor in “learned helplessness”

In two replications, two groups of dogs were exposed to a series of uncontrollable, electric shocks. For one group the shocks were preceded by a tone (i.e., Paired). For the other group the shocks were randomly related to the tones and hence unpredictable (i.e., Random). Each replication also included a third group; in the first it was exposed only to the series of tones (CS-only), while in the second, it was exposed only to a series of shocks (Shocks-only). Then, all dogs were required to learn a discriminative choice escape/avoidance task in which the required response was to lift the correct paw in the presence of each of two visual S^Ds to escape or avoid the shocks [($\text{S}{}_1{}^{\mathrm{D}}\text{?R}{}_1\text{)}\text{(S}{}_2{}^{\mathrm{D}}\text{?R}{}_2$)]. Dogs preexposed to random tones and shocks were least successful in learning the task relative to those groups which experienced either predicted shocks, only the tones, or only the shocks, which in turn did not differ from each other. These results permitted the inference that the proactive interference with choice behavior following random tone CSs and shocks was attributable to a learned irrelevance generalized with respect to CSs.