Robust conditioned flavor preferences with a sensory preconditioning procedure

During sensory preconditioning, rats were given two distinct flavors (saccharin and coffee) in sequence with 0, 9, or 27 sec between the two flavors. A control group received the flavors unpaired. In subsequent training, the second flavor preceded sucrose by 5 min. Later, the subjects that had had 0- or 9-sec delays between the two flavors showed a significant preference for the flavor not directly reinforced, whereas those that had had a 27-sec delay showed only a marginally significant preference. Although taste aversions have been produced using these methods, this is the first demonstration of conditioned preferences for flavors not directly associated with the reinforcers. These results offer an alternative way to study flavor-flavor learning.     

Control of instrumental behavior by deprivation stimuli

In Experiment 1, rats were given one trial per day in a straight alley under food deprivation on half of the trials and under water deprivation on the other half. Wet mash was available in the goal box under food deprivation for Group H and under water deprivation for Group T, the other deprivation being nonrewarded for each group. After 15--18 trials both groups ran significantly faster on their rewarded than on their nonrewarded deprivation days. A third group showed that random variation of alley color retarded formation of the discrimination. A fourth group was run in a conditional discrimination in which under food deprivation wet mash was available in a black alley, nonreward in a white alley, and vice versa under water deprivation. This group took 114 trials to begin running significantly faster in their rewarded than in their nonrewarded alley under each deprivation. In Experiment 2, it was shown that prior learning about deprivation cues "blocks" learning about alley color when alley color is subsequently presented in compound with the deprivation cue but that when both alley color and deprivation cues are relevant from the start of training, the rat learns about both cues. It is suggested that previous studies have underestimated the importance of deprivation cues by using conditional discrimination designs, choice measures rather than speeds, and parameters that are not optimal for discrimination learning.     

Effects of expectancies of different reward magnitudes in transfer from noncontingent pairings to instrumental performance

In two experiments, rats received noncontingent pairings of two stimuli with food reward, one paired with small reward and the other with large reward, and received bar press training with large reward or with small reward. When the noncontingent stimuli (NS) were presented for test during subsequent rewarded bar pressing and during early extinction of bar pressing, responding for each group was faster in the presence of the NS which was paired with the same reward magnitude that group received in bar press training than to the NS which had been paired with a different reward magnitude. As extinction progressed, all groups responded more slowly in the presence of the NS which had been paired with the large reward than in the presence of the NS which had been paired with small reward. These results were interpreted as indicating that responding in the presence of an NS depends on: (i) whether the reward expectancy elicited by the NS has been conditioned to the instrumental response, and (ii) the relationship between the reward expected in the presence of the NS and that received in test.     

Is the worldview of qualitative inquiry a proper guide for psychological research?

Qualitative methods are becoming increasingly popular in psychology. Although the distinction between qualitative and quantitative often is stated in terms of methods, the real distinction is between worldviews: that favored by most qualitative methodologists, which emphasizes subjective experience and multiple realities, and that commonly accepted in science. The worldview accepted by most adherents of qualitative inquiry suggests the exclusive use of methods that include verbal reports of lived experience. Qualitative methods serve an important function in psychology, but their use as recommended by their adherents is limited in 2 respects: The adherents use a narrow and unconventional approach to qualitative methods that differs from that normally understood, and they favor use of a restricted range of qualitative methods over other qualitative methods and quantitative methods. If qualitative inquiry is to make a greater contribution to psychology, researchers in that tradition must acquire a better understanding of contemporary science, correct their misunderstandings of the rationale for quantitative methods, and address the apparent limitations of their methods emphasizing reported experience.     

The course of depressive symptoms in men from early adolescence to young adulthood: identifying latent trajectories and early predictors

Heterogeneity in the longitudinal course of depressive symptoms was studied through the use of general growth mixture modeling for young men in the Oregon Youth Study (N=206), who ranged in age from 15 to 24 years. Four trajectory classes were identified: the very-low, the moderate-decreasing, the high-decreasing, and the high-persistent classes. The 3 lowest classes differed primarily quantitatively with the initial level or mean level across time being the major determinant of class differences, whereas the high-persistent class appeared qualitatively different in terms of long-term developmental trends and variation. Findings from univariate and multivariate analyses revealed specific effects of childhood, parental, contextual, and individual risk factors on the class membership as well as on the growth within each trajectory class.     

What is bioethics without Christianity?

The author uses the essays in this issue as a springboard for making three points. First, he argues that most, if not all, current institutional versions of Christianity have failed to provide a meaningful framework for the spiritual life. Second, he argues that there is no ethics other than Judeo-Christian ethics and that there can be no bioethics other than Judeo-Christian bioethics. Finally, he argues that the overriding issue we face is not whether to address bioethical issues from a Christian perspective or from a non-Christian perspective, but rather whether we shall address biological and medical issues from an ethical or a scientific-technological perspective.