Semantic richness and the activation of concepts in semantic memory: Evidence from event-related potentials

Abstract

Semantic richness refers to the amount of semantic information associated with a concept. Reaction-time (RT) studies have shown that words referring to rich concepts elicit faster responses than those referring to impoverished ones, suggesting that richer concepts are activated more quickly. In a recent functional neuroimaging study, richer concepts evoked less neural activity, which was interpreted as faster activation. The interpretations of these findings appear to conflict with event-related potential (ERP) studies showing no evidence that speed of concept activation is influenced by typical semantic variables. Resolution of this apparent contradiction is important because the interpretation of 40 years of semantic-memory RT studies depends on whether factors such as semantic richness influence the duration of initial concept activation or later decision and response processes. Consistent with previous studies of the effects of semantic factors on ERP, the present study shows that richness influences the magnitude, but not the latency, of the P2 and N400 ERP components (which are early relative to behavioral responses), suggesting that effects of richness on RT reflect temporal effects on downstream decision or response mechanisms rather than on upstream concept activation.

The Price of Your Soul: Neural Evidence for the Non-Utilitarian Representation of Sacred Values

“…We also tested the possibility that sacred values involve concepts, like God, which have more meanings than mundane concepts such as dogs and cats. SR refers to the amount of semantic information contained in, or associated with, a concept in semantic memory [33] and has been previously associated with activation in VLPFC [34 -36]. To test the possibility that SR may be partially confounded with our measures of sacredness, we formulated an alternative model that controlled for the SR of the statements.…”

“…Given that many sacred values are also represented in legal doctrine, we sought to control for the possibility that participants were simply processing statements as lawful or not. [33]. SR has been previously associated with activation in VLPFC [34][35][36].…”

Electroencephalographic responses to SMS shortcuts

“…For instance, shortcuts are by definition shorter than words; they are less frequent, have fewer orthographic and phonological neighbours, and have fewer semantic associations than words. All these factors are known to affect electrophysiological responses to written stimuli (e.g., Assadollahi and Pulvermüller, 2001;Hauk et al, 2006;Holcomb et al, 2002;Holcomb, Kounios, Anderson, & West, 1999;Kounios et al, 2009;Van Petten and Kutas, 1990). …”

An integrated neural model of semantic memory, lexical retrieval and category formation, based on a distributed feature representation

“…First, in order to simulate real experimental results [such as event related potentials, which are commonly used to study the dynamics of semantic activation and priming, (Bermeitinger et al 2008;Deacon et al 2000;Kounios et al 2009)), or lexical-semantic integration (Graben et al 2008)] a more complex dynamics should be included in the network. In the present model, all neural units reach their activation state (either oscillatory or static) with a time constant of a few milliseconds, which is typical of the dynamics of individual neurons.…”