Miller (1956) summarized evidence that people can remember about seven chunks in short-term memory (STM) tasks. How- ever, that number was meant more as a rough estimate and a rhetorical device than as a real capacity limit. Others have since suggested that there is a more precise capacity limit, but that it is only three to five chunks. The present target article brings together a wide vari- ety of data on capacity limits suggesting that the smaller capacity limit is real. Capacity limits will be useful in analyses of information processing only if the boundary conditions for observing them can be carefully described. Four basic conditions in which chunks can be identified and capacity limits can accordingly be observed are: (1) when information overload limits chunks to individual stimulus items, (2) when other steps are taken specifically to block the recoding of stimulus items into larger chunks, (3) in performance discontinuities caused by the capacity limit, and (4) in various indirect effects of the capacity limit. Under these conditions, rehearsal and long-term memory cannot be used to combine stimulus items into chunks of an unknown size; nor can storage mechanisms that are not capacity- limited, such as sensory memory, allow the capacity-limited storage mechanism to be refilled during recall. A single, central capacity limit averaging about four chunks is implicated along with other, noncapacity-limited sources. The pure STM capacity limit expressed in chunks is distinguished from compound STM limits obtained when the number of separately held chunks is unclear. Reasons why pure capacity estimates fall within a narrow range are discussed and a capacity limit for the focus of attention is proposed.

/pdf/the-magical-number-4-in-short-term-memory-a-reconsideration-3704b9phuz.pdf

The magical number 4 in short-term memory: a reconsideration of mental storage capacity.

http://science.sciencemag.org/content/sci/201/4359/899.2.full.pdf

Phenomenology of perception.

https://psycnet.apa.org/journals/rev/88/5/375.pdf

An interactive activation model of context effects in letter perception: I. An account of basic findings.

From the Publisher:
The old opposition of matter versus mind stubbornly persists in the way we study mind and brain. In treating cognition as problem solving, Andy Clark suggests, we may often abstract too far from the very body and world in which our brains evolved to guide us. Whereas the mental has been treated as a realm that is distinct from the body and the world, Clark forcefully attests that a key to understanding brains is to see them as controllers of embodied activity. From this paradigm shift he advances the construction of a cognitive science of the embodied mind.

/pdf/being-there-putting-brain-body-and-world-together-again-31tt4y51ml.pdf

Being There: Putting Brain, Body, and World Together Again

This article describes the Dual Route Cascaded (DRC) model, a computational model of visual word recognition and reading aloud. The DRC is a computational realization of the dual-route theory of reading, and is the only computational model of reading that can perform the 2 tasks most commonly used to study reading: lexical decision and reading aloud. For both tasks, the authors show that a wide variety of variables that influence human latencies influence the DRC model's latencies in exactly the same way. The DRC model simulates a number of such effects that other computational models of reading do not, but there appear to be no effects that any other current computational model of reading can simulate but that the DRC model cannot. The authors conclude that the DRC model is the most successful of the existing computational models of reading.

DRC: a dual route cascaded model of visual word recognition and reading aloud.

Information, Natural Law, and the Self-Assembly of Rhythmic Movement

On peripheral and central processes in vision: inferences from an information-processing analysis of masking with patterned stimuli.

Actions must be controlled prospectively. This requires that the behavioral possibilities of surface layouts and events be perceived. In this article, the ontolog- ical basis for an understanding of prospective control in realist terms is outlined. The foundational idea is that of affordances and the promoted ontology is materialist and dynamicist. It is argued that research in the ecological approach to prospective control is ultimately the search for objective laws. Because lawfulness is equated with real possibility, this amounts to the study of the affordances (the real possibilities) underlying prospective control and the circumstances that actualize them. The ontological assumptions and hypotheses bearing on this latter proposal are articulated. It is suggested that critical evaluation of the identified ontological themes may benefit the experimental and theoretical study of perception in the service of activity.

Affordances and Prospective Control: An Outline of the Ontology

In this paper we pursue the argument that where a group of muscles functions as a single unit the resulting coordinative structure, to a first approximation, exhibits behavior qualitatively like that of a force-driven mass-spring system. Data are presented illustrating the generative and context-independent characteristics of this system in tasks that require animals and humans to produce accurate limb movements in spite of unpredictable changes in initial conditions, perturbations during the movement and functional deafferentation. Analogous findings come from studies of articulatory compensation in speech production. Finally we provide evidence suggesting that one classically-defined source of information for movement, namely proprioception, may not be dimension-specific in its contribution to coordination and control.

1 On the Concept of Coordinative Structures as Dissipative Structures: I. Theoretical Lines of Convergence*

By watching each other's lower oscillating leg, 2 seated Ss kept a common tempo and a particular phase relation of either 0 degrees (symmetric mode) or 180 degrees (alternate mode). This study investigated the differential stability of the 2 phase modes. In Experiment 1, in which Ss were instructed to remain in the initial phase mode, the alternate phase mode was found to be less stable as the frequency of oscillation increased. In addition, analysis of the nonsteady state cycles revealed evidence of a switching to the symmetric phase mode for the initial alternate phase mode trials. In Experiments 2 and 3, Ss were instructed to remain at a noninitial phase angle if it was found to be more comfortable. The transition observed between the 2 phase modes satisfies the criteria of a physical bifurcation--hysteresis, critical fluctuations, and divergence--and is consonant with previous findings on transitions in limb coordination within a person.

/pdf/phase-transitions-and-critical-fluctuations-in-the-visual-582qbqcwq0.pdf

Michael T. Turvey

Papers

Information, Natural Law, and the Self-Assembly of Rhythmic Movement

On peripheral and central processes in vision: inferences from an information-processing analysis of masking with patterned stimuli.

Affordances and Prospective Control: An Outline of the Ontology

1 On the Concept of Coordinative Structures as Dissipative Structures: I. Theoretical Lines of Convergence*

Phase transitions and critical fluctuations in the visual coordination of rhythmic movements between people.