O „dobrej” I „złej” indukcji

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On „good” and „bad” induction

     

The effect of social learning on avoidance of aposematic prey in juvenile great tits (<Emphasis Type="Italic">Parus major</Emphasis>)

Social learning plays an important role in acquiring new foraging skills and food preferences in many bird species but its potential role in learning to avoid aposematic prey has never been studied. We tested the effect of social learning on the acquisition of avoidance of aposematic insect prey (firebug Pyrrhocoris apterus; Heteroptera) in juvenile, hand-reared great tits (Parus major). Behaviour towards aposematic prey was compared between two groups of birds: (1) the observers that were, prior to encounter with firebugs, allowed to watch the experienced conspecific demonstrator repeatedly refuse to attack the prey, and (2) the control birds that lacked this opportunity. Observing an experienced demonstrator was not sufficient for learning complete avoidance, because birds from both groups attacked at least the first firebug they had encountered in avoidance training. However, the opportunity to observe the avoidance behaviour of another bird significantly increased the rate of subsequent individual learning of observers in comparison with control birds. Social learning also decreased mortality of firebugs killed by the birds during the avoidance learning. Socially enhanced learning to avoid aposematic prey might be a mechanism important especially for naive juvenile birds learning from their parents, but it could also enhance learning in adults from their more experienced flock mates. Because social learning of avoidance may also lead to decreased mortality of aposematic prey, its effect should be taken into account in scenarios considering evolution and maintenance of prey warning signals.     

A belief in trend reversal requires access to cognitive resources

There are two research traditions studying people's reactions to random binary events: one concerns serial choice reaction times, the other concerns predictions of events in a series. The present studies focused on comparing expectations between these two approaches. We formed and tested a general hypothesis that, regardless of the type of task, when an individual faces a sequence of events they initially expect trend continuation. Only when people assume that a sequence is random might they override the default and expect trend reversal instead. In a series of experiments we found that limitation of access to cognitive resources enhances expectations of trend continuation. Our interpretation of this finding is that an expectation of trend continuation is the default for the human cognitive system and that a belief in trend reversal requires access to cognitive resources to overcome the tendency to expect trend continuation.     

Emotional Distress Associated with Surgical Treatment and its Relationship with Coping Profiles Among Chronically ill Older Patients

The study determines the patterns of coping styles among older patients with hip osteoarthritis and assesses the derived profiles in terms of perceived stress and anxiety before and after arthroplasty. Sixty-one hospital patients (mean age 70.3 years) were analysed one day before arthroplasty and three months after. The participants were assessed with the Brief-COPE (coping style), PSS-10 (perceived stress) and STAI (anxiety) psychometric tests. Four coping patterns were yielded using data clustering: rational, enterprising (resourceful), potentially maladaptive and flexible. Repeated measures ANOVA indicated a main effect within subjects but did not indicate that decreases of stress and anxiety varied differently between groups. Cluster 1 (a coping profile characterised by high helplessness, low active coping, high avoidance) reported significantly greater stress and anxiety than all other groups before and after hip replacement, while clusters 2 (flexible), 3 (resourceful) and 4 (rational) were characterised by similar levels of anxiety and stress. Older patients with osteoarthritis might differ in terms of emotional response to surgical treatment. Screening for coping styles at admission to hospital may indicate more vulnerable individuals.