Unit price as a useful metric in analyzing effects of reinforcer magnitude.

In this paper, we applied the behavioral-economic concept of unit price to the study of reinforcer magnitude in an attempt to provide a consistent account of the effects of reinforcer magnitude on behavior. Recent research in the experimental analysis of behavior and in behavioral pharmacology suggests that reinforcer magnitude interacts with the schedule of reinforcement to determine response rate and total consumption. The utility of the unit-price concept thus stems from its ability to quantify this interaction as a cost-benefit ratio (i.e., unit price = characteristics of the schedule of reinforcement divided by magnitude of reinforcement). Research employing the unit-price concept has shown that as unit price increases, a positively decelerating function exists for consumption (i.e., a function with an increasingly negative slope, when plotted on log coordinates) and a bitonic function exists for response rate. Based on these findings, the present analysis applied the unit-price concept to those studies of reinforcer magnitude and drug self-administration that examined the effects of reinforcer magnitude on response rate using simple schedules of reinforcement (e.g., fixed-ratio schedule). This resulted in three findings: (a) Reinforcer-magnitude manipulations and schedule manipulations interact in a manner that can be quantified in terms of unit price as benefit and cost factors, respectively; (b) different reinforcer-magnitude manipulations are functionally interchangeable as benefit factors in the unit-price ratio; and (c) these conclusions appear warranted despite the differences in reinforcers (food or drug), species (dogs, monkeys, or rats), and schedules (interval or ratio), and despite the fact that these studies were not designed for a unit-price analysis. In methodological terms, these results provide further evidence that employing the unit-price concept is a parsimonious method for examining the effects of reinforcer magnitude. In theoretical terms, these results suggest that a single process may underlie the effect of combined reinforcer-magnitude and schedule manipulations.     

How much can people really change?

The basic purpose of pastoral counseling, and counseling in general, is to help people change. Therefore, it's critically important to understand the nature of change and to have realistic expectations with respect to how much people can change. To expect too little change can lead to underachievement and despair, whereas to expect too much change can cause needless frustration and an abiding sense of failure. This article discusses behavioral change, its potential and its limits, from the point of view of genetic potential and offers some specific pastoral implications.     

Some relationships between the information function of IRT and the signal/noise ratio and reliability coefficient of classical test theory

It is shown that IRTs information function for an item is functionally related to local versions of classical test theories' signal/noise ratio and reliability coefficient.     

Coming to terms with stress: Effects of stress location in sentence processing

The purpose of this research was to determine the role of syllabic stress in language processing during the early on-line processing of speech and later in the representation of a sentence in memory. Experiment 1 used a syllable monitoring task while Experiment 3 used a probe task in which subjects heard a sentence and then were asked to determine whether a probe syllable had occurred in the sentence. In the monitoring task, stressed syllables were detected more rapidly in word-initial position, but unstressed syllables were detected more rapidly in word-final position. Stress facilitation in initial syllables was strongly related to high relative F0, but not to changes in perceived vowel quality as assessed in Experiment 2. This pattern is interpreted as evidence that lexical stress is used on-line to guide lexical access and/or lexical segmentation. The probe task of Experiment 3 showed stress facilitation in both positions, indicating that stress is independently retained in the postperceptual representation of a sentence.The research reported in this paper was supported by grant 80-0416 to Harvard University (Peter C. Gordon, Principal Investigator) from the Air Force Office of Scientific Research Life Sciences Directorate. We thank Chris Thurber for his extensive and competent assistance in testing subjects and making acoustic measurements, and Jay Rueckl for comments on an earlier version of this paper     

The effect of maternal depression on maternal ratings of child behavior

There have been continuing concerns about the extent to which maternal depression may influence maternal reports of child behavior. To examine this issue, a series of structural equation models of the relationships between maternal depression and errors in maternal reports of child behavior was proposed and tested. These models assumed that (a) maternal depression was unrelated to maternal reporting behavior; (b) maternal depression causally influenced maternal reporting accuracy; (c) maternal depression was correlated with reporting accuracy. These models were fitted to data on maternal depression and multipleinformant (mother, teacher, child) reports of conduct disorder and attention deficit behaviors for a birth cohort of 12 and 13yearold New Zealand children. The results of model fitting suggested the presence of small to moderate correlations (@#@ r=+.13 to+.40) between maternal depression and maternal reporting errors, indicating the presence of a tendency for increasing maternal depression to be associated with a tendency for mothers to overreport child behavior problems. However, independently of any effects of maternal depression on maternal reporting errors there was evidence of small but significant associations (r=.10 to .17; p<.05)between maternal depression and child conduct disorder and attention deficit behaviors.This research was funded by grants from the Health Research Council of New Zealand.     

Attitude change following persuasive communication: Integrating Social Judgment Theory and the Elaboration Likelihood Model

An experiment was conducted to examine the influence of the perceived extremity of a message and motivation to elaborate upon the process of persuasion. The first goal was to test a model of attitude change relating Social Judgment Theory to the Elaboration Likelihood Model. The second objective was to develop an instrument to measure attitude structure (latitudes of acceptance, non-commitment, and rejection) that allowed for a more refined assessment of the discrepancy between the position advocated in a message and the recipient's initial attitude. The main dependent variable was the attitude towards the use of automobiles in relation to environmental issues. Subjects were confronted with a message located in their own latitude of acceptance, rejection or non-commitment. Shortly after, a second measurement of attitude took place. The results showed that messages within the latitudes of non-commitment gave rise to the greatest attitude change. The data support the susceptibility hypothesis that subjects elaborate messages mainly in the latitude of non-commitment.     

Parts and wholes in face recognition

Are faces recognized using more holistic representations than other types of stimuli? Taking holistic representation to mean representation without an internal part structure, we interpret the available evidence on this issue and then design new empirical tests. Based on previous research, we reasoned that if a portion of an object corresponds to an explicitly represented part in a hierarchical visual representation, then when that portion is presented in isolation it will be identified relatively more easily than if it did not have the status of an explicitly represented part. The hypothesis that face recognition is holistic therefore predicts that a part of a face will be disproportionately more easily recognized in the whole face than as an isolated part, relative to recognition of the parts and wholes of other kinds of stimuli. This prediction was borne out in three experiments: subjects were more accurate at identifying the parts of faces, presented in the whole object, than they were at identifying the same part presented in isolation, even though both parts and wholes were tested in a forced-choice format and the whole faces differed only by one part. In contrast, three other types of stimuli--scrambled faces, inverted faces, and houses--did not show this advantage for part identification in whole object recognition.