Perceived danger associated with a property modulates cross category generalization.

Identifying projectable predicates is a key issue in understanding inductive inference. It is proposed that looking into the evolutionary psychology literature for adaptive properties may be one useful approach. One hypothesis that emerges from this literature is that properties that signal danger or harm should be more salient than properties that do not. Two studies are carried out to test this hypothesis. In study 1 participants were presented with a scenario involving the discovery of novel animals, for which there was incomplete information. Three types of properties (a harmful property, a neutral property, a beneficial property) were associated with animals in one (base) category and participants were asked to indicate strength of generalization of the property to a target within the category, and to a target across to another category. In the second experiment, the procedure was repeated, but in addition, subjects were also explicitly asked to indicate whether the base and target belonged to the same or different categories. Study 1 showed that the harmful property was more projectable compared to the beneficial and neutral properties. Study 2 reconfirmed this and further showed that it also promoted excessive generalization across categories. The results suggest that examination of adaptations identified by evolutionary psychologists may be a useful source of insight in the study of inductive inference. Supplementary Information: The online version contains supplementary material available at 10.1007/s11571-022-09793-3.

The Neural Mechanisms of Cognitive Control in the Category Induction Task.

According to the conflict monitoring hypothesis, conflict monitoring and inhibitory control in cognitive control mainly cause activity in the anterior cingulate cortex (ACC) and control-related prefrontal cortex (PFC) in many cognitive tasks. However, the role of brain regions in the default mode network (DMN) in cognitive control during category induction tasks is unclear. To test the role of the ACC, PFC, and subregions of the DMN elicited by cognitive control during category induction, a modified category induction task was performed using simultaneous fMRI scanning. The results showed that the left middle frontal gyrus (BA9) and bilateral dorsal ACC/medial frontal gyrus (BA8/32) were sensitive to whether conflict information (with/without) appears, but not to the level of conflict. In addition, the bilateral ventral ACC (BA32), especially the right vACC, a part of the DMN, showed significant deactivation with an increase in cognitive effort depending on working memory. These findings not only offer further evidence for the important role of the dorsolateral PFC and dorsal ACC in cognitive control during categorization but also support the functional distinction of the dorsal/ventral ACC in the category induction task.

What Is the Mechanism Underlying the Interleaving Effect in Category Induction: An Eye-Tracking and Behavioral Study.

Interleaved practice (i.e., exemplars from different categories are intermixed within blocks) has been shown to enhance induction performance compared to blocked practice (i.e., exemplars from the same category are presented sequentially). The main aim of the present study was to examine explanations of why interleaved practice produces this benefit in category induction (known as the interleaving effect). We also evaluated two hypotheses, the attention attenuation hypothesis and the discriminative-contrast hypothesis, by collecting data on participants' fixation on exemplars, provided by eye-tracking data, and manipulating the degree of discriminative-contrast. In Experiments 1 and 2, participants were instructed to learn the style of 12 new artists in blocked and interleaved practice in fixed-paced and self-paced learning conditions, respectively. We examined fixation durations for six positions (temporal sequence of exemplars presented in each block) using eye-tracking. The results of the two experiments, based on eye-tracking data, suggested that attention attenuation may not be the primary mechanism underlying the interleaving effect in category induction. In Experiment 3, we manipulated the degree of discriminative-contrast to examine the impact on the interleaving effect in category induction. The results showed that the main effect of the degree of discriminative-contrast was significant, and performance in the high-contrast condition was significantly better than those in the medium-contrast and low-contrast conditions. Thus, the current results support the discriminative-contrast hypothesis rather than the attention attenuation hypothesis.

Developmental Changes in Strategies for Gathering Evidence About Biological Kinds.

How do people gather samples of evidence to learn about the world? Adults often prefer to sample evidence from diverse sources-for example, choosing to test a robin and a turkey to find out if something is true of birds in general. Children below age 9, however, often do not consider sample diversity, instead treating non-diverse samples (e.g., two robins) and diverse samples as equivalently informative. The current study (N = 247) found that this discontinuity stems from developmental changes in standards for evaluating evidence-younger children chose to learn from samples that best approximate idealized views of what category members are supposed to be like (e.g., the fastest cheetahs), with a gradual shift across age toward samples that cover more within-category variation (e.g., cheetahs of varying speeds). These findings have implications for the relation between conceptual structure and inductive reasoning, and for the mechanisms underlying inductive reasoning more generally.

How the brain detects invariance and inhibits variance during category induction.

A stepwise category-learning task was designed to examine brain activation associated with invariance detection and variance inhibition during category induction (CI). Three stimuli were displayed sequentially and participants were asked to learn the target category based on the invariant feature among stimuli. The processes of invariance detection and variance inhibition were necessary during certain events; however, these processes were not required for other events. Functional magnetic resonance imaging (fMRI) results indicated that the processes of detecting invariant features and inhibiting variant features were associated with significant activation in the left prefrontal cortex, including the left superior frontal gyrus, middle frontal gyrus, and mid-ventrolateral prefrontal cortex, as well as other regions (e.g., bilateral parietal cortex and putamen). These findings confirmed the important role of the fronto-parietal network and striatum in the invariance detection of category learning.

Functional imaging of brain responses to different outcomes of hypothesis testing: revealed in a category induction task.

Functional magnetic resonance imaging (fMRI) was used to examine differences in brain activation that occur when a person receives the different outcomes of hypothesis testing (HT). Participants were provided with a series of images of batteries and were asked to learn a rule governing what kinds of batteries were charged. Within each trial, the first two charged batteries were sequentially displayed, and participants would generate a preliminary hypothesis based on the perceptual comparison. Next, a third battery that served to strengthen, reject, or was irrelevant to the preliminary hypothesis was displayed. The fMRI results revealed that (1) no significant differences in brain activation were found between the 2 hypothesis-maintain conditions (i.e., strengthen and irrelevant conditions); and (2) compared with the hypothesis-maintain conditions, the hypothesis-reject condition activated the left medial frontal cortex, bilateral putamen, left parietal cortex, and right cerebellum. These findings are discussed in terms of the neural correlates of the subcomponents of HT and working memory manipulation.