All or none hypothesis: A global-default mode that characterizes the brain and mind.

Abstract

It is proposed that the mind and brain often work at a gross level and only with fine tuning or inhibition act in a more differentiated manner, even when one might think the domains being issued the global command should be distinct. This applies to disparate findings in cognitive science and neuroscience in both children and adults. Thus, it is easier to switch everything, or nothing, than to switch one thing (the rule one is following or which button to press) but not the other. It is easier to issue the same command to both hands than to move only one hand. If one needs to respond to the opposite (or antonym) of a stimulus, one is faster if the correct response is to the side opposite the stimulus. People tend to think of the nervous system as sending out very precise commands only to the relevant recipient, but it appears that often the command goes out more globally and then parts of the system need to be inhibited from acting on the command. Keywords task switching; bimanual coordination; Simon effect; card sort test; inhibition Developmental psychologists, neuroscientists, pediatricians, and teachers have long known that early in life the nervous system lacks precision in many ways, often functioning in a global, diffuse way. For example, when a young child intends to do something with only one hand, there is often motor overflow to the other hand. The nervous system command to do the action goes to both hands, lacking the intended precision that was for the command to go to one hand only. Bruner and I independently documented the frustration of infants and toddlers, who having forcefully pushed a lid up with both hands, intend to remove one hand to reach for a treat under the lid. That darn lid, though, keeps coming down because when the child lowers one hand, the other hand (the one that should be holding the lid up) comes down as well (Bruner, 1970;Diamond, 1990; see Figure 1). Here, the command "lower" has gone to both hands, though it was intended for only one hand. Such mirror movements of the limbs are not only seen in infants but are normal in children through at least 7 years of age (Abercrombie, Lindon, & Tyson, 1964;Lazarus & Todor, 1987;Mayston, Harrison, & Stephens, 1999).Another example of early lack of precision in neural communication is the underspecification of neuronal projections, earning them the name exuberant projections. The sensory areas initially project somewhat globally to the thalamus, so that some nonvisual inputs go to the visual thalamus (the lateral geniculate) and some nonauditory inputs go to the auditory thalamus (the medial geniculate), and conversely some early projections from the visual thalamus go to nonvisual areas, and some early projections from the auditory thalamus go to (Bhide & Frost, 1999;Cooper & Cowey, 1990;Frost, 1986;Ramoa & Yamasaki, 1996; D. K. Simon, & O'Leary, 1992;Sur, 1988;Sur, Garraghty, & Roe, 1988). The nervous system relies on projections that have gone to the wrong place being pruned away when they do not match up as well with the re...

Children's Task-Switching Efficiency: Missing Our Cue?

“…By contrast, there was no support for the popular idea (cf. Diamond, 2002Diamond, , 2009) that young children make rule-switching errors because they have difficulty inhibiting prepotent (i.e., previous) responses or representations. There was no correlation between any tests of inhibition and any measure of task-switching accuracy or speed in either younger (Experiment 1) or older (Experiment 2) children.…”

“…That literature, although centered on adults (e.g., Allport, Styles, & Hsieh, 1994;Meiran, 1996;Monsell, 2003), includes a growing number of studies on children (Cepeda, Kramer, & Gonzalez de Sather, 2001;Crone, Bunge, van der Molen, & Ridderinkhof, 2006;Gupta, Kar, & Srinivasan, 2009;Karbach & Kray, 2007, 2009). Task-switching tests also use bivalent, rule-or cue-dictated task reversals; however, children aged 5 years or older, unlike 3-and 4-year-olds, make few errors.…”

The processes underlying flexibility in childhood

“…It has been argued that it is easier to consistently inhibit a task rather than repeatedly inhibit/activate the same task (Diamond, 2009). However, the difference between requirements to switch only once or several times has been overlooked in the preschool literature.…”

Can Internalism and Externalism be Reconciled in a Biological Epistemology of Language?

“…As development occurs, such constraints set out and fix the demarcations between the linguistic modules or domains. But throughout the lifetime of individuals, such constraints as specified show a tendency of being modified and changed as the research in developmental genetics and developmental neuroscience shows (Karmiloff-Smith 1992, 1998Bates 1994Bates , 1997Bates , 1999Dabrowska 2004;Marcus 2004;Johnson and Morton 1991;Johnson et al 1993Johnson et al , 2009Fletcher and Miller 2005;Diamond 2002Diamond , 2007Diamond , 2009. What follows from this is that the constraints that warp the geometry of the architecture of language are always continually changing; they are dynamical in nature throughout ontogenetic and perhaps phylogenetic time scales.…”