Suppression of visual observing by rhesus monkeys produced by conditioned aversive visual stimuli.

Nine rhesus monkeys were tested in a visual observing situation to determine the influence of conditioned aversive visual stimulation. A set of meaningless visual stimuli was selected on the basis of cumulative frequency and cumulative duration of observing during a pretest phase of the experiment. Three subsets of stimuli (low, medium, high) were formed indicating level of observing during pretesting. A portion of the "medium" category of slides then served as conditioned stimuli in a classical conditioning procedure by being paired with electric shock. Following conditioning the entire set of stimuli was again presented in a visual observing situation. The results showed a significant decrease in both frequency and duration of observing of the slides with conditioned aversive qualities, relative to non-shock control slides. These findings support an aversion-produced suppression of observing relatively unconfounded by methodological, procedural, and other differences existing among previous reports on the role of fear or anxiety in this context.     

The Rescorla-Wagner model: losses in associative strength in compound conditioned stimuli

This series of experiments demonstrated that compound conditioned stimuli (CSs) highly conditioned in isolation lose conditioned response strength when compound-CS-unconditioned stimulus (US) pairings are given. This loss in conditioned responding was a positive function of the number of compound-CS-US pairings and was greater for the more salient stimulus. Finally, if a previously neutral stimulus was compounded with two previously conditioned cues, the neutral stimulus could acquire conditioned inhibitory properties with only compound-CS-US pairings. These results provide support for some aspects of the Rescorla-Wagner model.     

Effect of posttrial episodes on conditioning in compound conditioned stimuli

The effect of signaled and nonsignaled posttrial episodes (PTEs) on conditioning to the target CS of a preceding compound CS-US trial was examined in two conditioned emotional response (CER) experiments with rats. Experiment 1 revealed that a nonsignaled PTE, a second shock US, interfered with conditioning to the preceding target CS and that the interference effect of the PTE was greater when it occurred 5 sec as opposed to 1,800 sec after the preceding compound CS-US trial. Experiment 2 revealed that if the shock PTE was signaled by a CS, its ability to interfere with conditioning was reduced. This second study also revealed that omission of an "expected" US interfered with conditioning to the target CS. The implications of these data for information processing models of Pavlovian conditioning are discussed.     

Taking stress response out of the box: stability, discontinuity, and temperament effects on HPA and SNS across social stressors in mother-infant dyads

This study investigated continuity and stability of hypothalamic-pituitary-adrenal (HPA) and sympathetic nervous system (SNS) response measures in mother-infant dyads across 2 different types of social stress sessions. Synchrony of response trajectories across systems (SNS-HPA coordination) and partners (mother-infant attunement) was addressed, as were associations with infant temperament. Primiparous mothers and their 18-month-old infants (n = 86 dyads) completed an attachment stressor--Strange Situation (Ainsworth, Blehar, Waters, & Wall, 1978)--at Session 1 and challenge stressors--cleanup task and emotion task battery--at Session 2. Mother and infant saliva samples collected to index pre-stress, stress, and post-stress response during each session were assayed for cortisol (HPA marker) and salivary alpha-amylase (sAA; SNS marker). Multilevel modeling of cortisol/sAA trajectories across sessions revealed rank-order stability in mother/infant stress measures but discontinuity in absolute levels; cortisol trajectories were higher during attachment stress, and sAA trajectories were higher during challenge stress. Varying degrees of mother-infant attunement were found across sessions/systems. Infant surgency predicted higher stress measures, and negative affect and effortful control predicted lower stress measures, though associations depended on session/system. Findings are discussed in terms of advancing a multisystemic, contextual definition of developing stress responsiveness.     

Adverse Events in Emerging Adulthood Are Associated with Increases in Neuroticism

Previous studies have produced mixed results when examining whether experiencing an adverse event can lead to changes in Neuroticism. We sought to examine this effect when (a) the event was relatively recent, (b) the event occurred during a relatively early development stage (i.e., emerging adulthood), and (c) the event was severely adverse. A sample of 1,108 undergraduates completed three measures of Neuroticism twice, separated by approximately 3 months, and indicated the most traumatic or adverse event they experienced during the intervening 3 months. We examined two operationalizations of adverse events: one that is more objectively defined (indicated experiencing a trauma listed on a trauma history measure) and another more subjectively defined (participant ratings of event centrality). The results revealed that high Neuroticism at Time 1 predicted future exposure to both types of adverse events. Critically, participants who experienced either type of adverse event during the semester reported significant increases in Neuroticism. Experiencing a high event centrality event was also associated with small increases in the personality traits Openness to Experience and Conscientiousness. The results are discussed in terms of the conditions necessary for adverse events to affect personality traits.     

A comparison of intra- and inter-limb relative motion information in modelling a novel motor skill

The importance of intra- and inter-limb relative motion in modelling a whole body coordination skill was examined. Participants were assigned to one of four groups: Full-Body point light model of a cricket bowler, INTRA-LIMB relative motion of the bowling arm, INTER-LIMB relative motions of the right and left wrists or NO-Relative motion, showing only the motions of the right wrist. During 60 acquisition trials, participants viewed the model five times before each 10-trial block. Retention was examined the following day. Although all groups improved on intra-limb coordination of the bowling arm, the INTRA-LIMB and FULL-BODY groups were more accurate than the INTER-LIMB group in acquisition, although these groups did not differ in retention. For inter-limb coordination, the three groups who received relative motion information performed more like the model than the NO-Relative motion group (even though the INTRA-LIMB group did not see the other limb). The amount of information within a display plays a constraining role on acquisition, perhaps more so than the type of information, such that the acquisition of coordination is more an emergent feature of observational learning, rather than a direct approximation of the model.     

A test of the relations between avoidance of panic-related situations and substance use, substance dependence, and depression among subclinical panickers

The hypotheses that among subclinical panickers, avoidance of panic-related situations would be associated with elevated substance use levels and increased likelihood of lifetime diagnoses of substance dependence and major depressive disorder (MDD) were tested. Findings confirmed that panic-related avoidance was associated with an elevated likelihood of lifetime diagnoses of nicotine and alcohol dependence as well as MDD, but not drug dependence. Panic avoidance was also related to relatively greater daily levels of cigarette and alcohol use.     

How Truth Behaves When There’s No Vicious Reference

In The Revision Theory of Truth (MIT Press), Gupta and Belnap (1993) claim as an advantage of their approach to truth “its consequence that truth behaves like an ordinary classical concept under certain conditions—conditions that can roughly be characterized as those in which there is no vicious reference in the language.” To clarify this remark, they define Thomason models, nonpathological models in which truth behaves like a classical concept, and investigate conditions under which a model is Thomason: they argue that a model is Thomason when there is no vicious reference in it. We extend their investigation, considering notions of nonpathologicality and senses of “no vicious reference” generated both by revision theories of truth and by fixed-point theories of truth. We show that some of the fixed-point theories have an advantage analogous to that which Gupta and Belnap claim for their approach, and that at least one revision theory does not. This calls into question the claim that the revision theories have a distinctive advantage in this regard.