Dual systems Competence ←-→ Procedural processing: A relational developmental systems approach to reasoning

Many current psychological models of reasoning minimize the role of deductive processes in human thought. In the present paper, we argue that deduction is an important part of ordinary cognition and we propose that a dual systems Competence ←-→ Procedural processing model conceptualized within relational developmental systems theory offers the most coherent and productive framework for integrating and explaining the sometimes conflicting findings on the development of deductive reasoning across the lifespan. This model invokes a distinction that is quite similar to, though not identical with, the system 2–system 1 dichotomy employed in other dual systems models. In addition, the Competence ←-→ Procedural processing model maintains the more specific distinction between algorithmic and reflective subsystems of system 2. In this account, the algorithmic system is represented as a kind of mental logic while the reflective system is the seat of practical and epistemic self-regulation, including emergent epistemic and metalogical norms. While the proposed systems of mind often appear as split-off component features in other dual systems models, relational developmental systems theory conceives of them as the highly complex and relationally integrated outcome of a self-organizing and self-regulating adaptive developmental process.     

The grim reasoner: Analytical reasoning under mortality salience

The human species enjoys uniquely developed capacities for analytical reasoning and rational decision making, but these capacities come with a price: They make us aware of our inevitable physical death. Drawing on terror management theory and dual-process theories of cognition, we investigate the impact of mortality awareness on analytical reasoning. Two experiments show that experimentally induced thoughts of death impair analytical reasoning performance, just as cognitive load would. When made aware of their own mortality, reasoners allocate their executive resources to the suppression of this disturbing thought, therefore impairing their performance on syllogisms that require analytic thought. This finding has consequences for all aspects of rational thinking that draw on executive resources, and calls for an integrated approach to existential psychology and the psychology of rational thought.     

Lexical representation of schwa words: two mackerels, but only one salami

The present study investigated the lexical representations underlying the production of English schwa words. Two types of schwa words were compared: words with a schwa in poststress position (e.g., mackerel), whose schwa and reduced variants differ in a categorical way, and words with a schwa in prestress position (e.g., salami), whose variants differ in a noncategorical way. Participants named pseudohomophones and matched pseudowords corresponding to schwa and reduced variants of these words. Results revealed an advantage for pseudohomophones over matched pseudowords for both variants of poststress schwa words but only for schwa variants of prestress schwa words. As the pseudohomophone advantage is assumed to reflect the activation of a phonologically matching stored phonological representation, these results suggest that both variants of poststress schwa words are lexically represented while only schwa variants of prestress schwa words are. This result extends the proposal that words with two categorically distinct variants are stored in the production lexicon with 2 representations to another language and demonstrates that this 2-lexeme account does not generalize to pronunciation variants differing from one another in a noncategorical fashion. This finding challenges one of the widely shared assumption of generative models of word production: that content words have only 1 phonological representation. On the other hand, it provides further evidence in favor of another fundamental assumption of these models: that lexical representations are abstract sets of segments rather than fully detailed exemplars.     

Abductive reasoning in neural-symbolic systems

Abduction is or subsumes a process of inference. It entertains possible hypotheses and it chooses hypotheses for further scrutiny. There is a large literature on various aspects of non-symbolic, subconscious abduction. There is also a very active research community working on the symbolic (logical) characterisation of abduction, which typically treats it as a form of hypothetico-deductive reasoning. In this paper we start to bridge the gap between the symbolic and sub-symbolic approaches to abduction. We are interested in benefiting from developments made by each community. In particular, we are interested in the ability of non-symbolic systems (neural networks) to learn from experience using efficient algorithms and to perform massively parallel computations of alternative abductive explanations. At the same time, we would like to benefit from the rigour and semantic clarity of symbolic logic. We present two approaches to dealing with abduction in neural networks. One of them uses Connectionist Modal Logic and a translation of Horn clauses into modal clauses to come up with a neural network ensemble that computes abductive explanations in a top-down fashion. The other combines neural-symbolic systems and abductive logic programming and proposes a neural architecture which performs a more systematic, bottom-up computation of alternative abductive explanations. Both approaches employ standard neural network architectures which are already known to be highly effective in practical learning applications. Differently from previous work in the area, our aim is to promote the integration of reasoning and learning in a way that the neural network provides the machinery for cognitive computation, inductive learning and hypothetical reasoning, while logic provides the rigour and explanation capability to the systems, facilitating the interaction with the outside world. Although it is left as future work to determine whether the structure of one of the proposed approaches is more amenable to learning than the other, we hope to have contributed to the development of the area by approaching it from the perspective of symbolic and sub-symbolic integration.

Differential effect of one versus two hands on visual processing

Hand position in the visual field influences performance in several visual tasks. Recent theoretical accounts have proposed that hand position either (a) influences the allocation of spatial attention, or (b) biases processing toward the magnocellular visual pathway. Comparing these accounts is difficult as some studies manipulate the distance of one hand in the visual field while others vary the distance of both hands, and it is unclear whether single and dual hand manipulations have the same impact on perception. We ask if hand position affects the spatial distribution of attention, with a broader distribution of attention when both hands are near a visual display and a narrower distribution when one hand is near a display. We examined the effects of four hand positions near the screen (left hand, right hand, both hands, no hands) on both temporal and spatial discrimination tasks. Placing two hands near the display compared to two hands distant resulted in improved sensitivity for the temporal task and reduced sensitivity in the spatial task, replicating previous results. However, the single hand manipulations showed the opposite pattern of results. Together these results suggest that visual attention is focused on the graspable space for a single hand, and expanded when two hands frame an area of the visual field.     

Both non-symbolic and symbolic quantity processing are important for arithmetical computation but not for mathematical reasoning

This study investigated whether numerical processing was important for two types of mathematical competence: arithmetical computation and mathematical reasoning. Thousand eight hundred and fifty-seven Chinese primary school children in third through sixth grades took eight computerised tasks: numerical processing (numerosity comparison, digit comparison), arithmetical computation, number series completion, non-verbal matrix reasoning, mental rotation, choice reaction time, and word rhyming. Hierarchical regressions showed that both non-symbolic numerical processing (numerosity comparison) and symbolic numerical processing (digit comparison) were independent predictors of arithmetical computation but neither was a predictor of mathematical reasoning (assessed by number series completion). These findings suggest that the cognitive basis of mathematical performance varies depending on the type of mathematical competence measured.     

Multiple layers of information processing in deductive reasoning: combining dual strategy and dual-source approaches to reasoning

The idea that inferential performance cannot be analyzed within a single model has been suggested within two theoretical contexts. The dual strategy model suggests that people reason using different approaches to processing statistical information. The dual-source model suggests that people reason probabilistically using both statistical information and some intuition about logical form. Each model suggests that people have different approaches to processing information while making inferences. The following studies examined whether these different forms of information processing were equally present during reasoning. Participants were given a series of problems designed to distinguish counterexample from statistical reasoners. They were then given a series of MP or AC inferences for which identical statistical information was provided. Results show that MP inferences were considered to be deductively valid more often than equivalent AC inferences. The effect of logical form was independent of reasoning strategy, and of relatively equivalent size for both counterexample and statistical reasoners. The second study examined explicitly probabilistic inferences, and showed smaller effects of logical form and of reasoning strategy, although with a complex set of interactions. These results show that understanding the way that people use information when making inferences requires a multidimensional approach.     

In two minds: dual-process accounts of reasoning

Researchers in thinking and reasoning have proposed recently that there are two distinct cognitive systems underlying reasoning. System 1 is old in evolutionary terms and shared with other animals: it comprises a set of autonomous subsystems that include both innate input modules and domain-specific knowledge acquired by a domain-general learning mechanism. System 2 is evolutionarily recent and distinctively human: it permits abstract reasoning and hypothetical thinking, but is constrained by working memory capacity and correlated with measures of general intelligence. These theories essentially posit two minds in one brain with a range of experimental psychological evidence showing that the two systems compete for control of our inferences and actions.     

When two actions are easier than one: How inhibitory control demands affect response processing

Numerous studies showed that the simultaneous execution of multiple actions is associated with performance costs. Here, we demonstrate that when highly automatic responses are involved, performance in single-response conditions can actually be worse than in dual-response conditions. Participants responded to peripheral visual stimuli with an eye movement (saccade), a manual key press, or both. To manipulate saccade automaticity, a central fixation cross either remained present throughout the trial (overlap condition, lower automaticity) or disappeared 200 ms before visual target onset (gap condition, greater automaticity). Crucially, single-response conditions yielded more performance errors than dual-response conditions (i.e., dual-response benefit), especially in gap trials. This was due to difficulties associated with inhibiting saccades when only manual responses were required, suggesting that response inhibition (remaining fixated) can be even more resource-demanding than overt response execution (saccade to peripheral target).     

At one with our actions,but at two with our bodies

Jennifer Hornsby's account of human action frees us from the temptation to think of the person who acts as ‘doing’ the events that are her actions, and thereby removes much of the allure of ‘agent causation’. But her account is spoiled by the claim that physical actions are ‘tryings’ that cause bodily movements. It would be better to think of physical actions and bodily movements as identical; but Hornsby refuses to do this, seemingly because she thinks that to do so would be to endorse the so–called ‘standard causal story’. But Hornsby misses a possibility here, for we can insist on this identity claim without endorsing the standard story if we embrace an account which parallels the disjunctive account in the philosophy of perception. This will leave us with a picture of physical action that saves the insights of Hornsby's account without succumbing to its distortions.     

Memory indexing of sequential symptom processing in diagnostic reasoning

In diagnostic reasoning, knowledge about symptoms and their likely causes is retrieved to generate and update diagnostic hypotheses in memory. By letting participants learn about causes and symptoms in a spatial array, we could apply eye tracking during diagnostic reasoning to trace the activation level of hypotheses across a sequence of symptoms and to evaluate process models of diagnostic reasoning directly. Gaze allocation on former locations of symptom classes and possible causes reflected the diagnostic value of initial symptoms, the set of contending hypotheses, consistency checking, biased symptom processing in favor of the leading hypothesis, symptom rehearsal, and hypothesis change. Gaze behavior mapped the reasoning process and was not dominated by auditorily presented symptoms. Thus, memory indexing proved applicable for studying reasoning tasks involving linguistic input. Looking at nothing revealed memory activation because of a close link between conceptual and motor representations and was stable even after one week.     

Sensible reasoning in two tasks: Rule discovery and hypothesis evaluation

The hypothesis testing skills of undergraduates were measured in two tasks: the 2-4-6 rule discovery task in which students generate and assess hypotheses, and a hypothesis evaluation task, which requires only the assessment of hypotheses. The results of Experiments 1 and 2 show that the students consistently employed a disconfirmation strategy when assessing hypotheses, but employed a counterfactual inference strategy when they also were required to generate the hypotheses. The results of Experiment 3 suggest that the selection of the hypothesis testing strategy reflected a balance between the logical requirements of the task and the desirability of possible outcomes. Taken together, the findings support a more consistent picture of human rationality across tasks, and suggest alternatives to accounts of confirmation bias.     

Automatic-heuristic and executive-analytic processing during reasoning: Chronometric and dual-task considerations

Human reasoning has been shown to overly rely on intuitive, heuristic processing instead of a more demanding analytic inference process. Four experiments tested the central claim of current dual-process theories that analytic operations involve time-consuming executive processing whereas the heuristic system would operate automatically. Participants solved conjunction fallacy problems and indicative and deontic selection tasks. Experiment 1 established that making correct analytic inferences demanded more processing time than did making heuristic inferences. Experiment 2 showed that burdening the executive resources with an attention-demanding secondary task decreased correct, analytic responding and boosted the rate of conjunction fallacies and indicative matching card selections. Results were replicated in Experiments 3 and 4 with a different secondary-task procedure. Involvement of executive resources for the deontic selection task was less clear. Findings validate basic processing assumptions of the dual-process framework and complete the correlational research programme of K. E. Stanovich and R. F. West (2000).     

Teaching Bayesian reasoning in less than two hours

The authors present and test a new method of teaching Bayesian reasoning, something about which previous teaching studies reported little success. Based on G. Gigerenzer and U. Hoffrage's (1995) ecological framework, the authors wrote a computerized tutorial program to train people to construct frequency representations (representation training) rather than to insert probabilities into Bayes's rule (rule training). Bayesian computations are simpler to perform with natural frequencies than with probabilities, and there are evolutionary reasons for assuming that cognitive algorithms have been developed to deal with natural frequencies. In 2 studies, the authors compared representation training with rule training; the criteria were an immediate learning effect, transfer to new problems, and long-term temporal stability. Rule training was as good in transfer as representation training, but representation training had a higher immediate learning effect and greater temporal stability.     

Self-construal and the processing of covariation information in causal reasoning

Causal induction provides a nice test domain for examining the influence of individual-difference factors on cognition. The phenomena of both conditionalization and discounting reflect attention to multiple potential causes when people infer what caused an effect. We explored the hypothesis that individuals with an independent self-construal are relatively less sensitive to context (other causes) than are individuals with an interdependent self-construal in this domain. We found greater levels of conditionalization and data consistent with discounting for participants in whom we primed an interdependent self-construal than for participants in whom we primed an independent self-construal.     

Watching diagnoses develop: Eye movements reveal symptom processing during diagnostic reasoning

Finding a probable explanation for observed symptoms is a highly complex task that draws on information retrieval from memory. Recent research suggests that observed symptoms are interpreted in a way that maximizes coherence for a single likely explanation. This becomes particularly clear if symptom sequences support more than one explanation. However, there are no existing process data available that allow coherence maximization to be traced in ambiguous diagnostic situations, where critical information has to be retrieved from memory. In this experiment, we applied memory indexing, an eye-tracking method that affords rich time-course information concerning memory-based cognitive processing during higher order thinking, to reveal symptom processing and the preferred interpretation of symptom sequences. Participants first learned information about causes and symptoms presented in spatial frames. Gaze allocation to emptied spatial frames during symptom processing and during the diagnostic response reflected the subjective status of hypotheses held in memory and the preferred interpretation of ambiguous symptoms. Memory indexing traced how the diagnostic decision developed and revealed instances of hypothesis change and biases in symptom processing. Memory indexing thus provided direct online evidence for coherence maximization in processing ambiguous information.     

Neural signatures of number processing in human infants: evidence for two core systems underlying numerical cognition

Behavioral research suggests two cognitive systems are at the foundations of numerical thinking: one for representing 1-3 objects in parallel and one for representing and comparing large, approximate numerical magnitudes. We tested for dissociable neural signatures of these systems in preverbal infants, by recording event-related potentials (ERPs) as 6-7.5 month-old infants (n = 32) viewed dot arrays containing either small (1-3) or large (8-32) sets of objects in a number alternation paradigm. If small and large numbers are represented by the same neural system, then the brain response to the arrays should scale with ratio for both number ranges, a behavioral and brain signature of the approximate numerical magnitude system obtained in animals and in human adults. Contrary to this prediction, a mid-latency positivity (P500) over parietal scalp sites was modulated by the ratio between successive large, but not small, numbers. Conversely, an earlier peaking positivity (P400) over occipital-temporal sites was modulated by the absolute cardinal value of small, but not large, numbers. These results provide evidence for two early developing systems of non-verbal numerical cognition: one that responds to small quantities as individual objects and a second that responds to large quantities as approximate numerical values. These brain signatures are functionally similar to those observed in previous studies of non-symbolic number with adults, suggesting that this dissociation may persist over vast differences in experience and formal training in mathematics.     

Dual hemispheric processing in a letter matching task

It has been reported that performance on recognition, detection, and matching tasks is enhanced if stimuli are projected to both sides of the visual field rather than to one side alone (Dimond, 1972). The present study investigated the claim that this phenomenon is due to the distribution of the burden of perceptual processing between the hemispheres. Three experiments were carried out using a matching paradigm in which RT and response errors were recorded. In all experiments, subjects were required to match two letters that were displayed separately on either side of a central fixation point (bilateral presentation) or were displayed together on the same side of the visual field (unilateral presentation). It was found that although lateral interference between adjacent stimuli was significantly implicated in the phenomenon, a strong residual effect, which could be tentatively ascribed to hemispheric mechanisms, remained in relation to letter name matches. It is argued that a model based on parallel hemispheric decision processes provides a better account of the data than does one based upon the notion of distributed perceptual processing.