Procedural learning of unstructured categories

Abstract

Unstructured categories are those in which the stimuli are assigned to each contrasting category randomly, and thus there is no rule-or similarity-based strategy for determining category membership. Intuition suggests that unstructured categories are likely to be learned via explicit memorization that is under the control of declarative memory. In contrast to this prediction, neuroimaging studies of unstructured-category learning have reported task-related activation in the striatum, but typically not in the hippocampusresults that seem more consistent with procedural learning than with a declarative-memory strategy. This article reports the first known behavioral test of whether unstructured-category learning is mediated by explicit strategies or by procedural learning. Our results suggest that the feedback-based learning of unstructured categories is mediated by procedural memory.

Dopamine dependence in aggregate feedback learning: A computational cognitive neuroscience approach

“…In addition, several studies have shown that switching the response keys interferes with performance of a categorization task known to recruit procedural learning (i.e., information-integration categorization) but not with performance in a task known to recruit declarative memory (i.e., rule-based categorization; Ashby et al, 2003; Maddox et al, 2004; Maddox, Glass, O’Brien, Filoteo, & Ashby, 2010; Spiering & Ashby, 2008). Crossley et al (2012) showed that switching the locations of the response keys interfered with unstructured categorization performance but not with performance in a rule-based categorization task that used the same stimuli. Thus, feedback-mediated unstructured category learning seems to include a motor component, as do other procedural-learning tasks.…”

“…First, several neuroimaging studies of unstructured category learning found task-related activation in the striatum, as one would expect from a procedural-learning task, and not in the hippocampus or other medial temporal lobe structures, as would be expected if the task was explicit (Lopez-Paniagua & Seger, 2011; Seger & Cincotta, 2005; Seger et al, 2010). Second, Crossley, Madsen, and Ashby (2012) reported behavioral evidence that unstructured category learning is procedural. A hallmark of procedural learning is that it includes a motor component.…”

Frontoparietal networks involved in categorization and item working memory

“…For each participant, eight stimuli were randomly assigned to category “A” and eight were randomly assigned to category “B.” This type of categorization task is sometimes referred to as arbitrary, or unstructured because the stimuli are randomly assigned to category and do not include any intentional within-category similarities. Unstructured tasks rely on procedural knowledge to a similar degree as structured implicit categorization tasks (Crossley, Madsen, & Ashby, 2012), and recruit similar cortical and striatal systems (Seger, Dennison, Lopez-Paniagua, Peterson, & Roark, 2011; Seger, Peterson, Cincotta, Lopez-Paniagua, & Anderson, 2010). The remaining stimuli were used in the Item condition.…”

How may the basal ganglia contribute to auditory categorization and speech perception?

“…Because of this orientation, previous studies have indicated the basal ganglia in category learning regardless of the presence of category structure. These studies have not differentiated or directly compared the process of learning structured categories that require integration of multiple dimensions vs. arbitrary/unstructured category exemplars randomly distributed without any specific category boundaries (Seger and Cincotta, 2005; Cincotta and Seger, 2007; Seger et al, 2010; Lopez-Paniagua and Seger, 2011; Crossley et al, 2012), although different category input distributions can have a notable impact on sensory processing and learning (Wade and Holt, 2005; Holt and Lotto, 2006; Lim et al, 2013). …”