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Impossible figures are striking examples of inconsistencies between global and local perceptual structures, in which the overall spatial configuration of the depicted image does not yield a coherent three-dimensional object. In order to investigate whether structural “impossibility” is an important perceptual property of depicted objects, we used a category formation task in which subjects were asked to divide pictures of shapes into groups that seemed most natural to them. Category formation is usually unidimensional, such that sorting is dominated by a single perceptual property, so this task can serve as a measure of which dimensions are most salient. In Experiment 1 , subjects received sets of 12 line drawings consisting of six possible and six impossible objects. Very few subjects grouped the figures by impossibility on the first try, and only half did so after multiple attempts at sorting. In Experiment 2 , we investigated other global properties of figures: symmetry and complexity. Subjects readily sorted objects by complexity, but seldom by symmetry. In Experiment 3 , subjects were asked to draw each of the figures before sorting them, which had only a minimal effect on categorization. Finally, in Experiment 4 , subjects were explicitly instructed to divide the shapes by symmetry or impossibility. Performance on this task was perfect for symmetry, but not for impossibility. Although global properties of figures seem extremely important to our perception, the results suggest that some of these cues are not immediately obvious or salient for most observers.

Cognitive control processes are central to adaptive behavior, but how control is applied in a context-appropriate manner is not fully understood. One way to produce context-sensitive control is by mnemonically linking particular control settings to specific stimuli that demanded those settings in a prior encounter. In support of this episodic reinstatement of control hypothesis, recent studies have produced evidence for the formation of stimulus-control associations in one-shot, prime-probe learning paradigms. However, since those studies employed perceptually identical stimuli across prime and probe presentations, it is not yet known how generalizable one-shot stimulus-control associations are. In the current study, we therefore probed whether associations formed between a prime object and the control process of task-switching would generalize to probe objects seen from a different viewpoint (Experiment 1 ), to different exemplars of the same object type (Experiment 2 ), and to different members of the object category (Experiment 3 ). We replicated prior findings of one-shot control associations for identical prime/probe stimuli. Importantly, we additionally found that these episodic control effects are expressed regardless of changes in viewpoint and exemplar, but do not seem to generalize to other category members. These findings elucidate the scope of generalization of the episodic reinstatement of cognitive control.

The ability to represent knowledge at the category level promotes the transfer of learning. How this ability integrates with basic forms of conditioned learning is unknown but could explain why conditioned fear is overgeneralized after aversive experiences. We examined the impact of stimulus typicality—an important determinant of category-based induction—on fear learning and generalization. Typicality is known to affect the strength of categorical arguments; a premise involving typical exemplars (e.g., sparrow) is believed to apply to other members, whereas a premise about atypical exemplars (e.g., penguin) generalizes more narrowly to similar items. We adopted this framework to human fear conditioning and found that fear conditioned to typical exemplars generalized more readily to atypical members than vice versa, despite equal feature overlap across conditions. These findings have implications for understanding why some fearful events lead to broad overgeneralization of fear whereas others are regarded as isolated episodes.

Classic studies of human categorization learning provided evidence that high-variability training in the prototype-distortion paradigm enhances subsequent generalization to novel test patterns from the learned categories. More recent work suggests, however, that when the number of training trials is equated across low-variability and high-variability training conditions, it is low-variability training that yields better generalization performance. Whereas the recent studies used cartoon-animal stimuli varying along binary-valued dimensions, in the present work we return to the use of prototype-distorted dot-pattern stimuli that had been used in the original classic studies. In accord with the recent findings, we observe that high-variability training does not enhance generalization in the dot-pattern prototype-distortion paradigm when the total number of training trials is equated across the conditions, even when training with very large numbers of distinct instances. A baseline version of an exemplar model captures the major qualitative pattern of results in the experiment, as do prototype models that make allowance for changes in parameter settings across the different training conditions. Based on the modeling results, we hypothesize that although high-variability training does not enhance generalization in the prototype-distortion paradigm, it may do so when participants learn more complex category structures.

Purpose Semantic feature analysis (SFA) is a naming treatment found to improve naming performance for both treated and semantically related untreated words in aphasia. A crucial treatment component is the requirement that patients generate semantic features of treated items. This article examined the role feature generation plays in treatment response to SFA in several ways: It attempted to replicate preliminary findings from Gravier et al. (2018), which found feature generation predicted treatment-related gains for both trained and untrained words. It examined whether feature diversity or the number of features generated in specific categories differentially affected SFA treatment outcomes. Method SFA was administered to 44 participants with chronic aphasia daily for 4 weeks. Treatment was administered to multiple lists sequentially in a multiple-baseline design. Participant-generated features were captured during treatment and coded in terms of feature category, total average number of features generated per trial, and total number of unique features generated per item. Item-level naming accuracy was analyzed using logistic mixed-effects regression models. Results Producing more participant-generated features was found to improve treatment response for trained but not untrained items in SFA, in contrast to Gravier et al. (2018). There was no effect of participant-generated feature diversity or any differential effect of feature category on SFA treatment outcomes. Conclusions Patient-generated features remain a key predictor of direct training effects and overall treatment response in SFA. Aphasia severity was also a significant predictor of treatment outcomes. Future work should focus on identifying potential nonresponders to therapy and explore treatment modifications to improve treatment outcomes for these individuals. Supplemental Material https://doi.org/10.23641/asha.12462596.

Recent research demonstrates that the relationship between an acoustic dimension and speech categories is not static. Rather, it is influenced by the evolving distribution of dimensional regularity experienced across time, and specific to experienced individual sounds. Three studies examine the nature of this perceptual, dimension-based statistical learning of artificially accented [b] and [p] speech categories in online word recognition by testing generalization of learning across contexts, and testing the effect of a larger word list across which learning is induced. The results indicate that whereas learning of accented [b] and [p] generalizes across contexts, generalization to contexts not experienced in the accent is weaker even for the same speech categories [b] and [p] spoken by the same speaker. The results support a rich model of speech representation that is sensitive to context-dependent variation in the way the acoustic dimensions are related to speech categories.

Purpose: Reporting of outcome and experience measures is critical to our understanding of the effect of intervention for speech sound disorders (SSD) in children. There is currently no agreed-upon set of measures for reporting intervention outcomes and experiences. In this article, we introduce the Speech Outcome Reporting Taxonomy (SORT), a tool designed to assist with the classification of outcome and experience measures. In a systematic search and review using the SORT, we explore the type and frequency of these measures reported in intervention research addressing phonological impairment in children. Given the integral relationship between intervention fidelity and intervention outcomes, reporting of fidelity is also examined. Method: Five literature databases were searched to identify articles written or translated into English published between 1975 and 2020. Using the SORT, outcome and experience measures were extracted and categorized. The number of intervention studies reporting fidelity was determined. Results: A total of 220 articles met inclusion criteria. The most frequently reported outcome domain was broad generalization measures (n = 142, 64.5%), followed by specific measures of generalization of an intervention target (n = 133, 60.5%). Eleven (5.0%) articles reported measures of the impact of the phonological impairment on children's activity, participation, quality of life, or others. Twenty articles (9.1%) reported on parent, child, or clinician experience or child engagement. Fidelity data were reported for 13.4% of studies of interventions. Conclusions: The measurement of intervention outcomes is challenging yet important. No single type of measure was reported across all articles. Through using tailored measures closely related to intervention targets in combination with a universal set of measures of intelligibility, the impact of phonological impairment on children's lives, and the experience of receiving and providing intervention, researchers and clinicians could work together to progress insights and innovations in science and practice for children with SSD.

In the olfactory literature there is considerable debate about how differences in olfactory receptors across different species map onto variations in perceptual acuity and performance. Although humans have fewer functional olfactory receptors than most other mammals, it has been suggested that linguistic and cognitive abilities help compensate for this apparent deficit and enhance discriminative abilities, particularly through humans’ ability to categorize sensory stimuli into conceptual categories. However, previous research suggests that non-human animals can learn complex categories, involving multiple perceptual dimensions, indicating that they can discriminate complex odor stimuli without language. We investigated generalization over complex olfactory categories by examining rats' discrimination of wine varieties, a challenging task for humans that has been suggested to rely heavily on human-specific linguistic, cognitive and categorization abilities. Nine rats were trained in an olfactory discrimination task (go/no-go) using a specific wine variety (Riesling or Sauvignon Blanc from different winemakers) as the S + . Rats were then tested using novel wines of the same varieties in unrewarded probe trials to assess their abilities to correctly assign instances of wine to specific categories. Interestingly, all nine rats successfully learned to discriminate the two varieties, and most rats generalized within two test trials to novel wines of the same varieties. We explore the implications of our results for olfactory concept formation and categorization more generally.

Reference point approaches have dominated the study of categorization for decades by explaining classification learning in terms of similarity to stored exemplars or averages of exemplars. The most successful reference point models are firmly grounded in the associative learning tradition—treating categorization as a stimulus generalization process based on inverse exponential distance in psychological space augmented by a dimensional selective attention mechanism. We present experiments that pose a significant challenge to popular reference point accounts which explain categorization in terms of stimulus generalization from exemplars, prototypes, or adaptive clusters. DIVA, a similarity-based alternative to the reference point framework, provides a successful account of the human data. These findings suggest that a successful psychology of categorization may need to look beyond stimulus generalization and toward a view of category learning as the induction of a richer model of the data.