When memory fails, intuition reigns: midazolam enhances implicit inference in humans

People often make logically sound decisions using explicit reasoning strategies, but sometimes it pays to rely on more implicit "gut-level" intuition. The transitive inference paradigm has been widely used as a test of explicit logical reasoning in animals and humans, but it can also be solved in a more implicit manner. Some researchers have argued that the hippocampus supports relational memories required for making logical inferences. Here we show that the benzodiazepene midazolam, which inactivates the hippocampus, causes profound explicit memory deficits in healthy participants, but enhances their ability in making implicit transitive inferences. These results are consistent with neurocomputational models of the basal ganglia-dopamine system that learn to make decisions through positive and negative reinforcement. We suggest that disengaging the hippocampal explicit memory system can be advantageous for this more implicit form of learning.     

When adjunction fails

The rule of adjunction is intuitively appealing and uncontroversial for deductive inference, but in situations where information can be uncertain, the rule is neither needed nor wanted for rational acceptance, as illustrated by the lottery paradox. Practical certainty is the acceptance of statements whose chances of error are smaller than a prescribed threshold parameter, when evaluated against an evidential corpus. We examine the failure of adjunction in relation to the threshold parameter for practical certainty, with an eye towards reinstating the rule of adjunction in some restricted forms, by observing the conditions under which the overall chance of error of the joint statements can be variously bounded.     

Logical competence and transitive inference in young children

Five-year-old children were trained on the length relationships between the adjacent members of a five-term series of sticks. They were then tested on their abilities (1) to judge the length relationships between nonadjacent pairs of the series, and (2) to incorporate an unseen novel stick into the series through inference. Children who were trained with sticks of markedly different lengths succeeded on the first test but not the second; they apparently relied on memory for the absolute lengths of the sticks. Children in the other groups succeeded on both tests. The critical factor in inducing the use of seriation and transitivity seemed to be the elimination of alternative solutions.     

Developmental change on a five-term transitive inference

Three experiments are reported which utilize the five-term transitive inference task developed by P. E. Bryant and T. Trabasso (Nature (London) 1971, 232, 456–458). In Experiment I, preschool children (mean age = 4 years 8 months) required fewer trials to learn the premises and showed a higher proportion of correct responses on the inferences when the presentation order was serial (i.e., AB, BC, CD, DE) throughout training as compared to when a nonserial presentation order (i.e., BC, DE, AB, CD) was used. In Experiments II and III, preschool (mean age = 4 years 7 months), second grade (mean age = 7 years 8 months), fourth grade (mean age = 9 years 9 months), and college students (mean age = 18 years 11 months) were administered the nonserial presentation version of the five-term transitive inference. An ontogenetic decrease in trials to learn the premises and corresponding increase in proportion correct on both premises and inferences was observed. A developmental model specifying changes at two stages of constructing an internal linear order is proposed to explain the results.     

When discounting fails: An unexpected finding

Two studies were designed to investigate the effects of prior information about plausible causes on subsequent attributions. In the Experiment 1, prior information was given about an internal and an external cause. It was predicted and found that the stronger an expectancy for a behavior, the more the behavior would be attributed to the cause that formed the basis of the expectancy. It was also predicted that (1) for facilitative causes, the stronger the expectancy based on a given cause, the less the behavior would be attributed to other causes (discounting), and (2)for inhibitory causes, the stronger the expectancy, the more the behavior would be attributed to other causes (augmenting). These predictions were not supported. It was suggested that discounting and augmenting did not occur because subjects had been given information about both causes which "locked in" their attributions to each cause. To test this explanation, a second study was undertaken in which observers were given information about only one cause. The results of Experiment 2 indicated that discounting and augmenting may only occur for attributions to causes about which no prior information is available.     

Solving distant analogies reduces belief-based responding in transitive inference

ABSTRACT

Previous research demonstrated that relational processing in transitive inference problems can be disrupted by belief-based content. Given the premises, The horse is larger than the goat, and The goat is larger than the elephant, accepting the valid conclusion, The horse is larger than the elephant suggests use of relational processing whereas accepting the invalid conclusion The elephant is larger than the horse indicates belief-based responding. This research examined whether solving analogies influenced participants’ reliance on belief-based or relational processing. Participants generated solutions to either distant analogies (e.g. nose:scent::antenna: ______) or near analogies (e.g. nose:scent::tongue:______) before evaluating the conclusions of transitive inference problems that were valid (V) or invalid (I) and believable (B), unbelievable (U) or neutral (N). Solving distant analogies eliminated belief-based responding (possibly reflecting improved inhibitory control) and facilitated relational responding on VU problems.     

When phonology fails: orthographic neighbourhood effects in dyslexia

Both cerebral hemispheres contain phonological, orthographic and semantic representations of words, however there are between-hemisphere differences in the relative engagement and specialization of the different representations. Taking orthographic processing for example, previous studies suggest that orthographic neighbourhood size (N) has facilitatory effects in the right but not the left hemispheres. To pursue the nature of this asymmetric N effect, in particular whether there are individual differences in such specialisation, we examined N in a case of developmental dyslexia, FM. We first describe the nature of his difficulties, which are mainly severe phonological deficits. Employing the divided visual field paradigm with FM revealed a greater sensitivity in the right than in the left hemisphere to orthographic variables, with a significant inhibitory N effect in the left, but not right hemisphere. Such inhibition, to a lesser degree, was found among a group of adults with dyslexia but not among age-matched normal readers. We argue that enhanced sensitivity to orthographic cues is developed in some cases of dyslexia when a normal, phonology-based left hemisphere word recognition processing is not achieved. The interpretation presented here is cast in terms of differences between people with dyslexia and typical readers that originate in the atypical way in which orthographic representations are initially set up.     

Relational framework improves transitive inference across age groups

Transitive inference is a complex task, conducive to the use of multiple strategies. We investigated whether transitive inference accuracy can be improved by biasing strategy choice towards a proposition-based approach that relies on the extraction of relations among stimuli. We biased strategy choice by using familiar stimuli with known relations that tap prior knowledge. Semantic information led to increased accuracy for younger and older adults, and increased awareness of stimulus relations. Increased age was associated with reduced awareness. Awareness accounted for the variability in performance accuracy to a greater extent than age, as aware older and younger adults showed similar accuracies on all conditions. The current work indicates that age differences in performance can be minimized by providing semantically meaningful stimuli that bias participants to use a relational proposition-based approach.     

When cross-modal spatial attention fails

There is now convincing evidence that an involuntary shift of spatial attention to a stimulus in one modality can affect the processing of stimuli in other modalities, but inconsistent findings across different paradigms have led to controversy. Such inconsistencies have important implications for theories of cross-modal attention. The authors investigated why orienting attention to a visual event sometimes influences responses to subsequent sounds and why it sometimes fails to do so. They examined visual-cue-on-auditory-target effects in two paradigms--implicit spatial discrimination (ISD) and orthogonal cuing (OC)--that have yielded conflicting findings in the past. Consistent with previous research, visual cues facilitated responses to same-side auditory targets in the ISD paradigm but not in the OC paradigm. Furthermore, in the ISD paradigm, visual cues facilitated responses to auditory targets only when the targets were presented directly at the cued location, not when they appeared above or below the cued location. This pattern of results confirms recent claims that visual cues fail to influence responses to auditory targets in the OC paradigm because the targets fall outside the focus of attention. (PsycINFO Database Record (c) 2008 APA, all rights reserved).     

When culture fails: coping with cultural trauma

The research into the phenomenon of cultural trauma is growing as the effects of historical transformations are recognized and analysed. The concept of cultural trauma and the analytic concept of the cultural complex is a suitable theoretical approach for this research. The Lithuanian experience of cultural trauma after the historical shifts indicates the importance of the interplay between societal and individual factors in coping with trauma. Academic psychotraumatological studies carried out at Vilnius University indicate a stronger traumatic experience by people who are survivors of direct political repression and even intergenerational transmission of trauma, but this group also seems to demonstrate an intergenerational transmission of resilience. Paradoxically, from a long‐term perspective, the victims of direct repression seem to have suffered less than the people who accommodated to the regime, and this applies also to their offspring. Analysis in terms of overcoming cultural trauma indicates that society is gradually integrating historic traumatic experiences, although a healthy cultural identity has not yet been restored.     

When festinger fails: Prophecy and the watch tower

Within its history, the Watch Tower has often set dates for the coming of Christ's millennial reign. The ability of Jehovah's Witnesses to endure the failure of these interpretations of Biblical prophecy reveals the power of the Watch Tower to withstand what would seem to be fatal challenges to its system of belief. In what has become a classic study, the social psychologist Leon Festinger has argued that such disconfirmations of prophecy lead only to deepened conviction and increased proselytism to persuade others that the original belief was correct. Applying Festinger's hypothesis to the prophetic speculation of the Watch Tower, I argue that his model fails to recognize how complex organizations and systems of belief shape responses to disconfirmed prophecy. Indeed, the history of Jehovah's Witnesses demonstrates that organizational structure and ideology constitute crucial variables for any analysis of reaction to prophetic failure. It is the very power of the Watch Tower as a millenarian movement that allows not only the rationalization of disconfirmation but the retrospective denial of the prophecy itself.     

Influences of task concreteness upon transitive responding in humans

The derivation of the conclusion Anna is bigger than Mary from the premises Anna is bigger than Paul and Mary is smaller than Paul is considered an instance of transitive deduction. For a non-verbal presentation, the premise statements were here transformed into a multiple operant discrimination task. Adult subjects were trained with overlapping pairs of a six-member stimulus series (A+B–, A+C–, C+D–, D+E–, E+F–; +: choice rewarded, choice penalized). A computer game-type presentation that hid the actual problem structure from the subjects was employed. The effects of varying the presentation style of the task on the objective performance and the structure awareness of subjects were investigated. A first experiment used random polygons as stimuli and the relations between them were only signalled by the above reinforcement allocations. In a second experiment the stimuli were cartoon figures additionally involved in a dominance hierarchy that was suggested graphically. A third experiment used named items that were related through visible size differences in addition to the reinforcement allocations but was otherwise like an experiment using an abstract format reported by Werner et al. (1992). In all experiments a similar proportion of subjects responded transitively when subsequently tested with the pairs BD, BE and CE by preferentially choosing stimulus B or C. Each subject subsequently filled in a questionnaire, completed a stimulus ordering exercise, and was interviewed to find out whether they were explicitly aware of the stimulus hierarchy underlying each of the tasks. Although the proportion of subjects revealing an explicit transitive responding increased together with the concreteness of the stimuli and their relations across the experiments, the objective performance in terms of choice accuracy did not vary. The accuracy performance on tests could be accurately simulated with a modification of a simple conditioning model. It is concluded that an implicit mode of processing may underlie many instances of transitive responding in humans even when explicit task understanding is reported.     

Depth of processing: When the principle of congruity fails

Two factors, level of processing (Craik & Lockhart, 1972) and congruity (Schulman, 1974), known to have large effects on the recall of experimenter-provided responses to questions, were examined in a series of five incidental learning experiments using subject-generated responses. The data show that manipulation of level of processing has the same effect on recall of subjectgenerated responses as it does on experimenter-provided responses. However, the effect of congruity is reversed for subject-generated responses. The data suggest that the difficulty of generating unrelated responses (“incongruous“ items) may account, at least in part, for the failure of the “principle of congruity“ with subject-generated responses.     

Comparatives,logical structures,and encoding in a transitive inference task

Four- to five-year-old children were asked questions on length involving single or double comparatives in a transitive inference task. The number of comparatives varied within or across pairs. The pairs of sticks were colorcoded. Initial pair-wise discrimination training on four adjacent pairs from a five-stick array with only verbal feedback was followed by tests, without feedback, on all possible pairs. When both comparatives were used, Ss learned adjacent pairs faster and more often reached criterion than when only one comparative term was used in training. In testing, Ss were successful on transitive inference tests only when the double-comparative relation was used within pairs during training. Retraining with visual feedback increased the number of Ss solving the inference test only in this condition. The findings are discussed in terms of how children may use processes other than logical operations to make transitive inferences.     

Belief-based and analytic processing in transitive inference depends on premise integration difficulty

Three experiments investigated belief-based versus analytic processing in transitive inference. Belief-based and analytic processing were inferred from conclusion acceptance rates for problems with conclusions that were either valid or invalid and believable or unbelievable. Premise integration difficulty was manipulated by varying premise integration time (Experiment 1), premise presentation order (Experiment 2), and the markedness of the relational terms in the premises (Experiment 3). In all the conditions, reasoning accuracy and rated confidence were lower on conflict problems, where belief-based and analytic processes yielded different responses. Participants relied more on analytic processing and less on belief-based processing in conditions in which premise integration was easier. Fluid intelligence and premise integration ability predicted analytical reasoning on conflict problems after reasoning on the no-conflict problems was controlled for. The findings were related to three dual-process models of belief bias. They provide the first evidence of belief bias in transitive inference.     

Implicit definition and the application of logic

The paper argues that the theory of Implicit Definition cannot give an account of knowledge of logical principles. According to this theory, the meanings of certain expressions are determined such that they make certain principles containing them true; this is supposed to explain our knowledge of the principles as derived from our knowledge of what the expressions mean. The paper argues that this explanation succeeds only if Implicit Definition can account for our understanding of the logical constants, and that fully understanding a logical constant in turn requires the ability to apply it correctly in particular cases. It is shown, however, that Implicit Definition cannot account for this ability, even if it draws on introduction rules for the logical constants. In particular, Implicit Definition cannot account for our ability to apply negation in particular cases. Owing to constraints relating to the unique characterisation of logical constants, invoking the notion of rejection does not remedy the situation. Given its failure to explain knowledge of logic, the prospects of Implicit Definition to explain other kinds of a priori knowledge are even worse.