Parts, partonomies, and taxonomies.

Partonomies, such as body parts, like taxonomies, such as the animal kingdom, are hierarchical organizations of knowledge based on an asymmetric, transitive relation, part of or kind of. This article reports exploratory work on children's partonomic knowledge, and the relation between partonomic knowledge and use of taxonomic organization. Because parts are elements of both appearance and function, shared parts may facilitate the transition from classification based on perception to classification based on function. Children were more likely to group taxonomically when instances shared parts than when instances did not share parts. For adults, parts rated "good" are functionally significant as well as perceptually salient, for example, the seat of a chair. Perceptually salient parts—those affecting shape or large ones—were detected faster by younger children than were less salient parts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Retraction of Hard, Lozano, and Tversky (2006).

Reports a retraction of "Hierarchical encoding of behavior: Translating perception into action" by Bridgette Martin Hard, Sandra C. Lozano and Barbara Tversky (Journal of Experimental Psychology: General, 2006[Nov], Vol 135[4], 588-608). All authors retract this article. Co-author Tversky and co-author Hard believe that the research results cannot be relied upon; Sandra C. Lozano takes full responsibility for the need to retract this article. (The following abstract of the original article appeared in record 2006-20327-007.) People encode goal-directed behaviors, such as assembling an object, by segmenting them into discrete actions, organized as goal-subgoal hierarchies. Does hierarchical encoding contribute to observational learning? Participants in 3 experiments segmented an object assembly task into coarse and fine units of action and later performed it themselves. Hierarchical encoding, measured by segmentation patterns, correlated with more accurate and more hierarchically structured performance of the later assembly task. Furthermore, hierarchical encoding increased when participants (a) segmented coarse units first, (b) explicitly looked for hierarchical structure, and (c) described actions while segmenting them. Improving hierarchical encoding always led to improvements in learning, as well as a surprising shift toward encoding and executing actions from the actor's spatial perspective instead of the participants' own. Hierarchical encoding facilitates observational learning by organizing perceived actions into a representation that can serve as an action plan. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Event structure in perception and conception.

Events can be understood in terms of their temporal structure. The authors first draw on several bodies of research to construct an analysis of how people use event structure in perception, understanding, planning, and action. Philosophy provides a grounding for the basic units of events and actions. Perceptual psychology provides an analogy to object perception: Like objects, events belong to categories, and, like objects, events have parts. These relationships generate 2 hierarchical organizations for events: taxonomies and partonomies. Event partonomies have been studied by looking at how people segment activity as it happens. Structured representations of events can relate partonomy to goal relationships and causal structure; such representations have been shown to drive narrative comprehension, memory, and planning. Computational models provide insight into how mental representations might be organized and transformed. These different approaches to event structure converge on an explanation of how multiple sources of information interact in event perception and conception. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Body partonomy: How children partition the human body.

Concepts of 7 body parts and their relationships were assessed among 94 Ss from 4 age groups (3, 4, and 5 yrs and undergraduates) and 10 additional adults. The youngest Ss tended to assume that each familiarly labeled part was distinctly identified and unrelated to other labeled parts, and they exhibited peculiarly underextended conceptions of the body and face. This tendency is similar to J. Anglin's (1977) report that children are less likely to include familiarly named objects in superordinate categories. Older Ss recognized "parts of" relations at all levels of the hierarchy, but tended to have greater difficulty with nonimmediate relations between parts of parts of parts. Discussion focuses on differences between classificatory, collective, and partonomic hierarchies. It is suggested that the development of partonomic concepts is less a product of inherent conceptual complexity and more a product of experience and perceptual boundaries. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The internal representation of pitch sequences in tonal music.

Examines how humans optimally form hierarchies, using a model based on the assumptions that tonal music is solely the product of human processing systems, and that pitch sequences are retained as hierarchical networks. At each level of the hierarchy, elements are organized as structural units in accordance with gestalt principles such as proximity and good continuation. Further, elements that are present at each hierarchical level are elaborated by further elements to form structural units at the next-lower level, until the lowest level is reached. Processing advantages include the following: (a) redundancy of representation, (b) use of distinct alphabets at different structural levels, and (c) representations formed in accordance with the laws of figural goodness. (73 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Learning artificial grammars with competitive chunking.

When exposed to a regular stimulus field, for instance, that generated by an artificial grammar, subjects unintentionally learn to respond efficiently to the underlying structure (G. A. Miller [1958]; A. S. Reber [see PA, Vol 42:8911]). We explored the hypothesis that the learning process is chunking and that grammatical knowledge is implicitly encoded in a hierarchical network of chunks. We trained subjects on exemplar sentences while inducing them to form specific chunks. Their knowledge was then assessed through judgments of grammaticality. We found that subjects were less sensitive to violations that preserved their chunks than to violations that did not. We derived the theory of competitive chunking (CC) and found that it successfully reproduces, via computer simulations, both Miller's experimental results and our own. In CC, chunks are hierarchical structures strengthened with use by a bottom-up perception process. Strength-mediated competitions determine which chunks are created and which are used by the perception process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hierarchical encoding of behavior: Translating perception into action.

[Retraction Notice: A retraction for this article was reported in Vol 137(4) of Journal of Experimental Psychology: General (see record 2008-15679-005). All authors retract this article. Co-author Tversky and co-author Hard believe that the research results cannot be relied upon; Sandra C. Lozano takes full responsibility for the need to retract this article.] People encode goal-directed behaviors, such as assembling an object, by segmenting them into discrete actions, organized as goal-subgoal hierarchies. Does hierarchical encoding contribute to observational learning? Participants in 3 experiments segmented an object assembly task into coarse and fine units of action and later performed it themselves. Hierarchical encoding, measured by segmentation patterns, correlated with more accurate and more hierarchically structured performance of the later assembly task. Furthermore, hierarchical encoding increased when participants (a) segmented coarse units first, (b) explicitly looked for hierarchical structure, and (c) described actions while segmenting them. Improving hierarchical encoding always led to improvements in learning, as well as a surprising shift toward encoding and executing actions from the actor's spatial perspective instead of the participants' own. Hierarchical encoding facilitates observational learning by organizing perceived actions into a representation that can serve as an action plan. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Event perception: A mind-brain perspective.

People perceive and conceive of activity in terms of discrete events. Here the authors propose a theory according to which the perception of boundaries between events arises from ongoing perceptual processing and regulates attention and memory. Perceptual systems continuously make predictions about what will happen next. When transient errors in predictions arise, an event boundary is perceived. According to the theory, the perception of events depends on both sensory cues and knowledge structures that represent previously learned information about event parts and inferences about actors' goals and plans. Neurological and neurophysiological data suggest that representations of events may be implemented by structures in the lateral prefrontal cortex and that perceptual prediction error is calculated and evaluated by a processing pathway, including the anterior cingulate cortex and subcortical neuromodulatory systems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hierarchical Silica Nanostructures Inspired by Diatom Algae Yield Superior Deformability,Toughness, and Strength

A universal design paradigm in biology is the use of hierarchies, which is evident in the structure of proteins, cells, tissues, and organisms, as well as outside the material realm in the design of signaling networks in complex organs such as the brain. A fascinating example of a biological structure is that of diatoms, a microscopic mineralized algae that is mainly composed of amorphous silica, which features a hierarchical structure that ranges from the nano- to the macroscale. Here, we use the porous structure found at submicron length scales in diatom algae as a basis to study a bioinspired nanoporous material implemented in crystalline silica. We consider the mechanical performance of two nanoscale levels of hierarchy, studying an array of thin-walled foil silica structures and a hierarchical arrangement of foil elements into a porous silica mesh structure. By comparing their elastic, plastic, and failure mechanisms under tensile deformation, we elucidate the impact of hierarchies and the wall width of constituting silica foils on the mechanical properties, by carrying out a series of large-scale molecular dynamics (MD) simulations with the first principles based reactive force field ReaxFF. We find that by controlling the wall width and by increasing the level of hierarchy of the nanostructure from a foil to a mesh, it is possible to significantly enhance the mechanical response of the material, creating a highly deformable, strong, and extremely tough material that can be stretched in excess of 100 pct strain, in stark contrast to the characteristic brittle performance of bulk silica. We find that concurrent mechanisms of shearing and crack arrest lead to an enhanced toughness and are enabled through the hierarchical assembly of foil elements into a mesh structure, which could not be achieved in foil structures alone. Our results demonstrate that including higher levels of hierarchy are beneficial in improving the mechanical properties and deformability of intrinsically brittle materials. The findings reported here provide insight into general material design approaches that may enable us to transform a brittle material such as silicon or silica into a ductile, yet strong and tough material, solely through alterations of its structural arrangement at the nanoscale.     

Rhythm and pitch in music cognition.

Rhythm and pitch are the 2 primary dimensions of music. They are interesting psychologically because simple, well-defined units combine to form highly complex and varied patterns. This article brings together the major developments in research on how these dimensions are perceived and remembered, beginning with psychophysical results on time and pitch perception. Progressively larger units are considered, moving from basic psychological categories of temporal and frequency ratios, to pulse and scale, to metrical and tonal hierarchies, to the formation of musical rhythms and melodies, and finally to the cognitive representation of large-scale musical form. Interactions between the dimensions are considered, and major theoretical proposals are described. The article identifies various links between musical structure and perceptual and cognitive processes, suggesting psychological influences on how sounds are patterned in music. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mental animation: Inferring motion from static displays of mechanical systems.

Analyzed reaction time (RT) and eye-fixation data to investigate how people infer the kinematics of simple mechanical systems (pulley systems) from diagrams showing their static configuration. It is proposed that this mental animation process involves decomposing the representation of a pulley system into smaller units corresponding to the machine components and animating these components in a sequence corresponding to the causal sequence of events in the machine's operation. Although it is possible for people to make inferences against the chain of causality in the machine, these inferences are more difficult, and people have a preference for inferences in the direction of causality. The mental animation process reflects both capacity limitations and limitations of mechanical knowledge. (PsycINFO Database Record (c) 2010 APA, all rights reserved)