Problems with using mechanisms to solve the problem of extrapolation

Proponents of evidence-based medicine and some philosophers of science seem to agree that knowledge of mechanisms can help solve the problem of applying results of controlled studies to target populations (‘the problem of extrapolation’). We describe the problem of extrapolation, characterize mechanisms, and outline how mechanistic knowledge might be used to solve the problem. Our main thesis is that there are four often overlooked problems with using mechanistic knowledge to solve the problem of extrapolation. First, our understanding of mechanisms is often (and arguably, likely to remain) incomplete. Secondly, knowledge of mechanisms is not always applicable outside the tightly controlled laboratory conditions in which it is gained. Thirdly, mechanisms can behave paradoxically. Fourthly, as Daniel Steel points out, using mechanistic knowledge faces the problem of the ‘extrapolator’s circle’. At the same time, when the problems with mechanistic knowledge have been addressed, such knowledge can and should be used to mitigate (nothing can entirely solve) the problem of extrapolation.     

Dimensionality and correlates of problem solving: the use of the Problem Solving Inventory in the Chinese context.

The dimensional structure of the Problem Solving Inventory (PSI) was investigated using data collected from a sample of 499 Chinese university students in teacher training. While the original three-factor model provided poor fit to the data, the revised two-factor model provided more adequate fit but failed to consider a PSI construct tapped in the original PSI formulation. The newly constructed PSI scales based on the present data provided viable alternative scales reflecting constructs of self-efficacy, rational coping and dysfunctional coping. These newly developed problem-solving scales were predictive of indices of psychological adjustment in terms of depression, burnout, and perceived self-efficacy toward helping others. The use of the PSI in the Chinese context is discussed.     

Overshadowing of a context aversion by a novel incentive in operant conditioning

Two experiments examined the processes underlying the suppression of instrumental behaviours by lithium in rats, as reported by Meachum (1988 and this issue). Experiment 1 examined whether presenting a novel sucrose solution prior to lithium chloride administration would overshadow aversion learning to either the stimuli of the operant chamber or to familiar food pellets. After lever pressing had been established, and in the absence of responding, animals received free deliveries of a novel sucrose solution, familiar food pellets, or both, or they were exposed to only the cues of the operant chamber, prior to lithium injections. Lever pressing for food pellets was then assessed. It was found that the animals receiving the novel sucrose, either alone or with the familiar food pellets, pressed more for pellets than either the group receiving only food pellets or the group exposed to only the context. In addition, there was no appreciable difference in the response rates between the context-only group and the group that received the familiar food pellets. These outcomes were interpreted in terms of the novel sucrose overshadowing aversion learning to the context. Experiment 2 investigated whether in fact aversive contextual conditioning could be obtained using the present parameters. This was accomplished by directly manipulating the contexts. In this experiment animals were trained to lever press in two distinctive contexts. Subsequently, one context was paired with the novel sucrose, and the second was experienced in the absence of reinforcement prior to toxicosis. During a subsequent non-reinforced test it was found that responding in the context paired with the novel sucrose was considerably higher than responding in the context that was experienced alone. These findings stand in contrast to the taste-mediated contextual potentiation observed when a consumatory response is used to assess aversive contextual conditioning.     

Young children's use of a delayed video representation to solve a retrieval problem pertaining to self

The experiments reported here were concerned with the development of delayed self-recognition. Children were videotaped playing a game and were marked covertly with a sticker on their forehead while doing so. The findings, of both a cross-sectional sample and a prospective longitudinal one, revealed that 3- but not 2.5-year-old children reached to remove this sticker reliably during video playback only after they had been trained to use the video to guide their search for an object that was not directly visible to the unaided eye. It appears that by 3 years of age children understand that their briefly delayed self video-representation is related to their present self. In contrast, while 2.5-year-olds can use delayed video information to locate objects in space that cannot be seen by the unaided eye, they cannot use this type of information to locate an object that pertains to a part of self that is not directly visible, such as a sticker on one's hair. The findings are discussed in terms of the emergence of an extended sense of self.     

How to solve a mechanical problem: the relevance of visible and unobservable functionality for kea

Animals sometimes succeed quickly in solving a mechanical problem that is a modification of one they have previously learnt to solve. However, they may do so by attending to the visible features of the relevant physical dimension without knowing its causal functionality, if that is not directly perceivable. This kind of problem solving can be tested by simultaneously offering two mechanical devices with the same visual features but different inherent appropriateness for problem solving. Here, we provide data collected by following this procedure for the first time in a bird species. Captive kea, Nestor notabilis, a parrot species highly interested in the affordances of objects, were offered a mechanical problem in which they had to remove a baited tube from one of two upright poles where removal was blocked at the end of one pole but not the other. With extended but not with restricted exploration of a baseline apparatus, the kea immediately succeeded in removing the tube from an apparatus that had modified pole ends when they were able to visually observe (without touching) that one of these ends would block tube removal but the other would not. However, when the kea were allowed to explore two poles that had a removable and a fixed obstruction where the difference in function was not visible, they preferred the removable one during unbaited exploration but failed afterwards to push a tube to the end of the pole with the loose structure during subsequent baited test trials. Thus, in spite of the speed with which the kea learnt the tasks, there was no indication that they understood the underlying unobservable causal structure of the problem.     

Mechanisms of contextual control when contexts are informative to solve the task

An experiment was conducted using a human instrumental learning task with the goal of evaluating the mechanisms underlying the deleterious effect of context-switching on responding to an unambiguous stimulus when contexts are informative to solve the task. Participants were trained in a context-based reversal discrimination in which two discriminative stimuli (X and Y) interchange their meaning across contexts A and B. In context A, discriminative stimulus Z consistently announced that the relationship between a specific instrumental response (RI) and a specific outcome (O1) was in effect. Performance in the presence of stimulus Z was equally deteriorated when the test was conducted outside the training context, regardless of whether the test context was familiar (context B) or new (context C). This result is consistent with the idea that participants code all the information presented in an informative context as context-specific with the context playing a role akin to an occasion setter.     

How to solve the problem of phenomenal unity: finding alternatives to the single state conception

The problem of phenomenal unity (PPU) consists in providing a phenomenological characterization of the difference between phenomenally unified and disunified conscious experiences. Potential solutions to PPU are faced with an important challenge (which Tim Bayne calls the “explanatory regress objection”). I show that this challenge can be conceived as a phenomenological dual to what is known as Bradley’s regress. This perspective (i) facilitates progress on PPU by finding duals to possible solutions to Bradley’s regress and (ii) makes it intelligible why many characterize phenomenal unity in terms of the existence of a single global conscious state. I call this latter view the “single state conception” (SSC). SSC is superficially attractive, because it seems to provide a solution to the phenomenological dual to Bradley’s regress, but should still be rejected, because (1) it does not solve PPU; (2) instead, it creates more problems; (3) these problems can be avoided by alternative conceptions of phenomenal unity.     

Concrete problems in the abstract deontic selection task - and how to solve them

The abstract deontic selection task was introduced by Cheng and Holyoak with the aim of demonstrating that people possess abstract reasoning schemas for processing deontic rules about what an individual must, must not, may, or need not do. Solving this task requires people to detect possible rule violators. The average solution rate across several studies, while being substantially higher than that with abstract nondeontic tasks, did not reach the level obtained with concrete deontic tasks. A task analysis based on the deontic principles by Beller uncovers several problems with the formulation of the original task. They concern the presentation of the deontic rule as well as the instructions (focusing on rule following) and result in a specific selection behaviour. Three experiments replicate the difficulties with the original task and show that task performance increases when the formulation problems are resolved. The best performance was obtained with a task that combined a genuine violation detection instruction with a genuine permission rule. Interestingly, permissions are weak deontic rules that, if taken literally, cannot be violated in a deontic sense. Therefore, people must interpret these rules as implying a strong deontic constraint (i.e., a ban), which then constitutes the basis for solving the task. The results provide novel insights into the interpretation of deontic rules and into the role that these content-specific, but abstract, tasks can play for the study of reasoning processes.     

Integration of information during problem solving due to a meaningful context of learning

Ninety-seven subjects memorized nine associations among six interlocking elements that were presented as links among nonsense letters, connections among spies with word code names (after Hayes, 1966), or airline flights among major US cities. On tests of problem solving and true-false judgments, the letters group and the words group performed nearly identically; however, relative to these two groups, the cities group performed worse or about the same on short recall problems and much better on longer problems requiring chunking of learned information. The conditions and effects of a meaningful learning context for problem solving were discussed.     

Using sound to solve syntactic problems: the role of phonology in grammatical category assignments.

One ubiquitous problem in language processing involves the assignment of words to the correct grammatical category, such as noun or verb. In general, semantic and syntactic cues have been cited as the principal information for grammatical category assignment, to the neglect of possible phonological cues. This neglect is unwarranted, and the following claims are made: (a) Numerous correlations between phonology and grammatical class exist, (b) some of these correlations are large and can pervade the entire lexicon of a language and hence can involve thousands of words, (c) experiments have repeatedly found that adults and children have learned these correlations, and (d) explanations for how these correlations arose can be proposed and evaluated. Implications of these phenomena for language representation and processing are discussed.     

Opioid mechanisms are involved in the disruption of arcaine-induced amnesia by context pre-exposure

Previous exposure to the training context disrupts glutamatergic N-methyl-d-aspartate receptor (NMDAr) antagonist-induced amnesia, indicating that novelty is necessary for such an amnestic effect. While there are reports that novelty-related release of opioids cause amnesia, no study has addressed whether the amnestic effect of NMDAr antagonists involve opioid mechanisms. In this study we investigated whether pharmacological manipulation of the opioid system immediately after context pre-exposure alters the amnestic effect of arcaine, a NMDAr antagonist. Adult male Wistar rats were habituated (pre-exposed) to a fear conditioning training apparatus or to a different context (open field). Immediately after pre-exposure, animals were injected with saline or naloxone (0.5 mg/kg, i.p.) or anti-beta-endorphin antibody (1:500, i.c.v.). Forty eight hours after pre-exposure session, all animals were subjected to fear conditioning acquisition protocol and saline or arcaine (30 mg/kg, i.p.) was administered immediately after training. Testing was carried out 24 h later, and freezing responses due to re-exposure to the training apparatus were recorded. Pre-exposure to the training apparatus prevented the impairment of memory induced by post-training arcaine. Administration of naloxone or anti-beta-endorphin antibody, immediately after pre-exposure to the training apparatus, reinstated the amnesic effect of post-training arcaine. The results suggest that endogenous opioid mechanisms are involved in the pre-exposure-induced loss of the amnestic effect of arcaine.     

Reenactment of televised content by 2-year olds: toddlers use language learned from television to solve a difficult imitation problem

Parents commonly label objects on television and for some programs, verbal labels are also provided directly via voice-over. The present study investigated whether toddlers' imitation performance from television would be facilitated if verbal labels were presented on television via voice-over or if they were presented by parents who were co-viewing with their toddlers. Sixty-one 2-year olds were randomly assigned to one of four experimental groups (voice-over video, parent video, parent video no label, parent live) or to a baseline control condition. Toddlers were tested with novel objects after a 24h delay. Although, all experimental groups imitated significantly more target actions than the baseline control group, imitation was facilitated by novel labels regardless of whether those labels were provided by parents or by voice-over on television. These findings have important implications for toddler learning from television.     

Beyond objectivity: The performance impact of the perceived ability to learn and solve problems

The purpose of this research was to develop and provide initial validation evidence for the performance impact of a measure of an individual's perceived ability to learn and solve problems (PALS). Building on the self-efficacy literature and the importance of learning and problem solving, the fundamental premise of this research was that PALS would significantly explain employee performance. In addition to demonstrating that PALS represented a distinct construct, PALS was a significant predictor of performance for managerial and entry-level employees in two different organizational contexts. Moreover, PALS explained additional variance in performance beyond general mental ability, personality, and similar constructs related to learning and problem solving.     

Eggs of a female Japanese quail are more likely to be fertilized by a male that she prefers

Male Japanese quail (Coturnix japonica) that conspecific females preferred in a 10-min, forced-choice test of affiliative preference were more likely than were males not preferred in such a test to fertilize females' eggs when subsequently mated with them, although preferred and nonpreferred males mated equally often with females. Further, the probability that a nonpreferred male would fertilize a female's eggs was significantly increased if she watched while he courted and mated with another female. The results indicate that in Japanese quail (a) affiliative preference reliably predicts females' choices of fathers for their offspring and (b) females may have some degree of control over whether the males with whom they mate actually fertilize their eggs.     

Children can solve Bayesian problems: the role of representation in mental computation

Can children reason the Bayesian way? We argue that the answer to this question depends on how numbers are represented, because a representation can do part of the computation. We test, for the first time, whether Bayesian reasoning can be elicited in children by means of natural frequencies. We show that when information was presented to fourth, fifth, and sixth graders in terms of probabilities, their ability to estimate the Bayesian posterior probability was zero. Yet when the same information was presented in natural frequencies, Bayesian reasoning showed a steady increase from fourth to sixth grade, reaching an average level of 19, 39, and 53%, respectively, in two studies. Sixth graders' performance with natural frequencies matched the performance of adults with probabilities. But this general increase was accompanied by striking individual differences. More than half of the sixth graders solved most or all problems, whereas one third could not solve a single one. An analysis of the children's responses provides evidence for the use of three non-Bayesian strategies. These follow an overlapping wave model of development and continue to be observed in the minds of adults. More so than adults' probabilistic reasoning, children's reasoning depends on a proper representation of information.     

Effects of different training histories upon manufacturing a tool to solve a problem: insight in capuchin monkeys (Sapajus spp.)

Animal Cognition - The emergence of novel behavior is a multilayered phenomenon that comprehends distinct processes. One such process is known as insightful problem solving. “Insight”...     

Converging on a new role for analogy in problem solving and retrieval: when two problems are better than one

People often fail to retrieve examples analogous to a current problem or situation. There is good evidence that comparing structurally matching cases facilitates subsequent analogical access. However, current approaches offer little at the time of memory search to promote retrieval of a routinely encoded analogous source. We adapted Gick and Holyoak's (1980, 1983) classic paradigm to investigate whether comparing two unsolved problems at test promotes retrieval of a single previously studied analogue. In Experiment 1, comparison of test problems facilitated analogical problem solving. Experiment 2 showed that comparison is the critical factor since solving two test problems separately proved ineffective. In Experiment 3, comparing two problems led to greater success for participants who read a prior analogous story than those who did not, demonstrating specifically that comparison facilitates retrieval. The three studies show that analogical access is powerfully determined by problem encoding. Implications for psychological theory and real-world applications are discussed.