Choice between delayed reinforcers and fixed-ratio schedules requiring forceful responding.

This experiment measured pigeons' choices between delayed reinforcers and fixed-ratio schedules in which a force of approximately 0.48 N was needed to operate the response key. In ratio-delay conditions, subjects chose between a fixed-ratio schedule and an adjusting delay. The delay was increased or decreased several times a session in order to estimate an indifference point--a delay duration at which the two alternatives were chosen about equally often. Each ratio-delay condition was followed by a delay-delay condition in which subjects chose between the adjusting delay and a variable-time schedule, with the components of this schedule selected to match the ratio completion times of the preceding ratio-delay condition. The adjusting delays at the indifference point were longer when the alternative was a fixed-ratio schedule than when it was a matched variable-time schedule, which indicated a preference for the matched variable-time schedules over the fixed-ratio schedules. This preference increased in a nonlinear manner with increasing ratio size. This nonlinearity was inconsistent with a theory that states that indifference points for both time and ratio schedules can be predicted by multiplying the choice response-reinforcer intervals of the two types of schedules by different multiplicative constants. Two other theories, which predict nonlinear increases in preference for the matched variable-time schedules, are discussed.     

The utility of verbal and behavioral assessments of value.

Subjects lived in a laboratory apartment for up to 30 days, engaging in ordinary activities such as reading, sewing, and artwork. The amount of time devoted to each activity was recorded and compared with periodic verbal ratings of the amount of time devoted to the activities. The verbal and observational assessments of the time distribution were very similar, but there were some discrepancies. Based on self-reports and on observation of time actually devoted to the activities, contingencies were arranged in which time devoted to one activity produced time available for a second activity. When the contingency relation was based on behavioral assessment, predictions of time redistribution were more accurate than when the relations were based on verbal assessment. The close correspondence between observed distributions of time and verbally assessed distributions was probably due to the well-specified situation and rigorous assessment methods. Contrary to some cognitive-behavioral accounts, the contingency results suggest that verbal assessment is not necessarily preferable to observation when the two make discrepant predictions. It is suggested that verbal reports might be used more often in behavior analysis in place of lengthy or difficult observations, and attention is drawn to a personality model that parallels important components of behavior analysis.     

Unification of models for choice between delayed reinforcers.

Two models for choice between delayed reinforcers, Fantino's delay-reduction theory and Killeen's incentive theory, are reviewed. Incentive theory is amended to incorporate the effects of arousal on alternate types of behavior that might block the reinforcement of the target behavior. This amended version is shown to differ from the delay-reduction theory in a term that is an exponential in incentive theory and a difference in delay-reduction theory. A power series approximation to the exponential generates a model that is formally identical with delay-reduction theory. Correlations between delay-reduction theory and the amended incentive theory show excellent congruence over a range of experimental conditions. Although the assumptions that gave rise to delay-reduction theory and incentive theory remain different and testable, the models deriving from the theories are unlikely to be discriminable by parametric experimental tests. This congruence of the models is recognized by naming the common model the delayed reinforcement model, which is then compared with other models of choice such as Killeen and Fetterman's (1988) behavioral theory of timing, Mazur's (1984) equivalence rule, and Vaughan's (1985) melioration theory.     

Metaphysics of causation

Conclusion The world contains not only causes and effects, but also causal relations holding between causes and effects. Because causal relations enter into the structure of the world, their presence has various modal and probabilistic consequences. Causation and necessary and sufficient conditions do often go hand in hand. Causation, however, is a robust ingredient within the world itself, whereas modalities and probabilities supervene on the nature of the world as a whole, and on the resulting relations between one possible world and others. Some modalities, therefore, are essentially causal; but causation is not essentially modal.¹⁹     

Overt responding in computer-based training

This experiment compared the extent to which students learned facts included in computer-based-training frames that required an overt response to those that did not. Frames included two types of facts: Some facts had one word missing which had to be supplied by the student (active facts). Other facts had no missing words and required no overt response (passive facts). Each student completed four 14-fact modules in random order. Two of the modules contained frames with all active facts. Each frame in the other two modules contained one active and six passive facts. Paper pretests and posttests showed that students learned twice as many facts when all facts in the module were active than when only one in seven were active. The modules that included passive facts required one-fifth the time to complete than those with only active facts. Students learned more facts per minute of training in one of the two modules that included passive facts than in the two modules with only active facts.     

MEMORY PROCESSES IN DELAYED SPATIAL DISCRIMINATIONS: RESPONSE INTENTIONS OR RESPONSE MEDIATION?

Pigeons were trained on a pair-comparison task in which left versus right choices were reinforced following different sequences of two center-key stimuli. Choice accuracy was higher when retention intervals occurred after the entire sequence than when they separated the two stimuli comprising it, and this effect occurred independently of whether the initial and terminal stimuli came from the same or different dimensions. The initial stimulus from the prior trial was a source of proactive interference only in groups for which the retention interval separated the two sequence stimuli. By contrast, differential delay-interval behavior was observed only in groups for which the retention interval followed presentation of the entire sequence. These results indicate that coding processes in delayed discriminations are influenced by the location of the retention interval, and that response mediation affects retention performances if the reinforced choice can be determined prior to the interval.     

追踪作业中几种心理负荷评估指标敏感性的研究

本研究在模拟追踪作业情境下 ,对主任务绩效测定、主观评定和若干生理测量在心理负荷评估中的敏感性进行了实验。实验采用重复测量的被试者内设计 ,2 0名被试 (男女各半 )在六档负荷下分别从事五分钟追踪作业。所选用的指标有追踪作业平均误差距离、追踪警告次数、主观负荷评定、心率、心率变异和血压。结果发现 :1主任务绩效在评估追踪作业心理负荷中具有最高的敏感性 ,主观评定次之 ,心率变化率和心率变异变化率也随负荷变化 ,血压指标随负荷变化的趋势不明显 ;2除血压指标外 ,其余各指标之间均存在明显的相关 ,这提示它们在评估追踪作业心理负荷中具有较大的可靠性。     

Some correlates of health locus of control among multicultural individuals

The relationship of locus of control to depression, anxiety, hostility, and physical health was assessed in a sample of multicultural college students (N = 162). Powerful Others Health Locus of Control was correlated with depression, anxiety, hostility, and recent physical symptoms while Chance Health Locus of Control (CHLC) was correlated with all of the above as well as chronic physical symptoms and major health problems. When controlling for a variety of health risk factors (viz., age, sex, body mass, exercise, smoking, salt, alcohol, and caffeine), only CHLC remained significant in the physical health models. Results support the cognitive model of mental health which emphasize the importance of adaptive beliefs. Specifically, they suggest that issues about control are related to negative affect and indicate that the often-cited relationship of an external locus of control to depression and anxiety also holds for hostility. The findings do not, however, support the view that anxiety and depression are associated with different types of external locus of control but rather suggest a unified set of locus of control beliefs underlying the three types of negative affect. In addition, evidence is provided for the external validity of the Multidimensional Health Locus of Control (MHLC) Scales with respect to mental health. Further, the results indicate that belief about one’s health may play a significant role in one’s physical health and that the health behavior model of the relationship between locus of control and physical health is insufficient to explain the relationship. As the Chance and Powerful Others MHLC scales were not related to health habits in this sample but were related to mental health (viz., depression, anxiety, and hostility), locus of control beliefs may be related to physical health via their relationship with mental health.