Effects of containment and closure policies on controlling the COVID‐19 pandemic in East Asia

Growing efforts have been made to pool coronavirus data and control measures from countries and regions to compare the effectiveness of government policies. We examine whether these strategies can explain East Asia’s effective control of the COVID‐19 pandemic based on time‐series data with cross‐correlations between the Stringency Index and number of confirmed cases during the early period of outbreaks. We suggest that multidisciplinary empirical research in healthcare and social sciences, personality, and social psychology is needed for a clear understanding of how cultural values, social norms, and individual predispositions interact with policy to affect life‐saving behavioural changes in different societies.     

Affect and emotions in placebo and nocebo effects: What do we know so far?

Once considered nuisance variance in clinical trials, placebo effects and nocebo effects are now widely recognized as important and mutable psychobiological contributors to mental and physical health. Psychological theory explaining these effects emphasizes associative learning and conscious expectations. It has long been suggested, however, that affective states such as moods, emotions, and distress could play a significant role. In this paper, we draw together and review the empirical data linking affective states to placebo and nocebo effects. To organize this disparate literature, three questions are addressed: (1) Does pre‐existing state and trait affect modulate placebo and nocebo effects? (2) Does administering placebo and nocebo treatments change affective states, and if so, does the resulting affect causally influence placebo and nocebo effects? Finally, (3) Can placebo treatments be successfully employed as a regulation strategy to modulate different affective states? In reviewing the evidence in relation to these three questions, it is clear that affect does play a key role in placebo and nocebo effects in many circumstances, and further, there may be a reciprocal dynamic at play between a treatment event, affect, and placebo/nocebo effects. The paper concludes by discussing implications for theory and intervention and recommends future research priorities.     

Defensive reactions of “wild-type” and “Domesticated” wild rats to approach and contact by a threat stimulus

Selective breeding of wild rats over many generations on the basis of low or high defensive threat and attack to human approach and contact has produced highly polarized “domesticated” and “wild-type” animals. Because the selection procedure selectively involves these two defense patterns, and these clearly differ in the two groups, it is of interest to determine if other, nonselected, defensive behaviors to threat stimuli also change. “Domesticated” and “wild-type” rats of the thirty-fifth generation were run in a fear defense test battery (F/DTB) to systematically evaluate defensive behaviors to a variety of present threat stimuli. “Domesticated” rats showed reduced avoidance and slower flight speed to an approaching experimenter, reduced jump/startle response to handelap and dorsal contact, less vocalization and boxing to vibrissae stimulation or to an anesthetized conspecific, and reduced defensiveness to an attempted pickup by the experimenter. These results indicate that selective bi-directional breeding for defensive threat and attack to human approach and contact produces group differences in a variety of defensive behaviors, and in defensiveness to stimuli other than those on which the selection was based. © 1994 Wiley-Liss, Inc.     

Predatory aggression in the mink (Mustela vison): Roles of serotonin and food satiation

5-Hydroxytrypotophan at a dose of 50 mg/kg intraperitoneally (i.p.) sharply increased neural serotonin (5-HT) levels in mink and considerably inhibited that animal's predatory attack on rats. Intraperitoneal injection of 5-HT (10 and 20 mg/kg) did not influence such rat-killing. Neural levels of 5-HT or 5-hydroxyindoleacetic acid (5-HIAA) and subsequent aggression by the predator did not change to any great degree after ingestion of a single meal. Abundance of natural mink food for 3 days was associated with an increased level of 5-HIAA in the lateral hypothalamus and the amygdala as well as with an increased latency to attack and to kill rats. 5-HT seems to represent an endogenous factor that inhibits predatory attack by the mink; this effect appears to function through increased metabolism of 5-HT in some brain regions, which is evident after abundant intake of tryptophan with the natural diet.     

Preference and resistance to change in concurrent variable-interval schedules

Pigeons were trained on a multiple schedule in which separate concurrent schedules were presented in the two components of the schedule. During one component, concurrent variable-interval 40-sec variable-interval 80-sec schedules operated. In the second component, concurrent variable-interval 40-sec variable-interval 20-sec schedules operated. After stable baseline performance was obtained in both components, extinction probe choice tests were presented to assess preference between the variable-interval 40-sec schedules from the two components. The variable-interval 40-sec schedule paired with the variable-interval 80-sec schedule was preferred over the variable-interval 40-sec schedule paired with the variable-interval 20-sec schedule. The subjects were also exposed to several resistance-to-change manipulations: (1) prefeeding prior to the experimental session, (2) a free-food schedule added to timeout periods separating components, and (3) extinction. The results indicated that preference and resistance to change do not necessarily covary.     

Action-based and vision-based selection of input: Two sources of control

In the first part of this paper we review evidence suggesting that there exists a mechanism that selects input on the basis of its similarity to the required action. This response-based input selection differs from the more established space- and object-based input selection in that it is not constrained by the structure of the input. Our evidence suggests that the two-choice Stroop effect is caused by this response-based selection mechanism. By contrast, it is known that the flanker effect is determined by the space- and object- based selection mechanisms. We explore whether the conflict resolution of the Stroop and flanker tasks is different as well by embedding these two tasks in a PRP (Psychological Refractory Period) paradigm. We show that the Stroop and the PRP effects are additive whereas the flanker and the PRP effects are underadditive, suggesting that the processes in charge of the conflict resolution in the Stroop and the flanker tasks are indeed different. We discuss possible reasons for this difference, and discuss possible ways in which the response-based mechanism can be implemented in information processing models.     

Inhibition and superconditioning

Superconditioning is said to occur when learning an association between a conditioned stimulus (CS) and unconditioned stimulus (US) is facilitated by pairing the CS with the US in the presence of a previously established conditioned inhibitor. Previous demonstrations of superconditioning have been criticized because their control conditions have allowed alternative interpretations. Using a within–subjects autoshaping procedure, the present study unambiguously demonstrated superconditioning. The results support the view that superconditioning is the symmetric opposite of blocking.     

Win-shift and win-stay learning in the short-beaked echidna (<Emphasis Type="Italic">Tachyglossus aculeatus</Emphasis>)

Numerous previous investigators have explained species differences in spatial memory performance in terms of differences in foraging ecology. In three experiments we attempted to extend these findings by examining the extent to which the spatial memory performance of echidnas (or "spiny anteaters") can be understood in terms of the spatio-temporal distribution of their prey (ants and termites). This is a species and a foraging situation that have not been examined in this way before. Echidnas were better able to learn to avoid a previously rewarding location (to "win-shift") than to learn to return to a previously rewarding location (to "win-stay"), at short retention intervals, but were unable to learn either of these strategies at retention intervals of 90 min. The short retention interval results support the ecological hypothesis, but the long retention interval results do not. Electronic Publication