Does spreading activation summate?

Summary Network models of semantic memory assume implicitly or explicitly that the degree of activation of a node is a monotonic function of the total amount of excitation reaching that node from all sources. For example, the activation level of the node representing apple should be greater if it is receiving excitation due to the activation of the nodes for fruit and pear than if only one of these neighboring nodes is activated. This notion was tested by presenting semantic primes 80 ms or 320 ms before a letter string (e.g., apple or ipple) requiring a lexical decision. The prime stimuli consisted of a pair of simultaneous items that were identical in the single prime condition (e.g., fruit/fruit or pear/pear) or different in the double prime condition (e.g., fruit/pear or pear/fruit), and were either related (target = apple) or unrelated (target = copper) to the target, or neutral. As predicted by the summation of semantic activation assumption of network models there was a larger priming effect (in the 320 ms SOA condition) following the simultaneous activation of two related nodes than following the activation of only one node.This research was supported by grants to the first author from the Natural Sciences and Engineering Research Council of Canada.     

Using tutoring systems to study learning: An application of HyperCard

HyperCard was used to develop a simplified tutoring system whose principles were based on a learning theory, and a genetics tutoring system was evaluated experimentally. Learning was studied by examining immediate versus delayed feedback after an error was made. Such tutoring systems aid in psychological studies of learning, because experimental variables can be easily manipulated. HyperCard provides a good vehicle for tutoring system development, since it requires no extensive programming skills.     

Computer Communication and Organizational Commitment: Tracing the Relationship in a City Government

Various theories and management policies suggest that there should be a positive relationship between communication and commitment to the organization. However, support for that relationship remains equivocal. We report the results of a questionnaire on communication and commitment filled out by 376 employees of a mid-sized city government. They were asked about the mode and frequency of their communications within the organization and about their commitment to the city government. Consistent with our hypotheses about the nature of computer-mediated communication, use of computer mail and bulletin boards predicted organizational commitment, but use of the telephone and paper modes of communication did not. In addition, those most likely to benefit from the immediacy and memory of computer communication—shift workers—evidenced a stronger relationship between computer mail use and commitment than did regular employees. Two mechanisms for mediating the relationship between communication and commitment were evaluated. Evidence supports active participation in communication as a mediating mechanism in the relationship between communication and commitment. The informational value of communication does not appear to be important in this regard.     

Parent-infant resemblance for general and specific cognitive abilities in the Colorado adoption project

Previous publications emanating from the Colorado Adoption Project have reported significant relationships between parental general cognitive ability (g) and infant Bayley MDI scores. The present study compared infant Bayley factor scores representing separable dimensions of infant cognition with parental general and specific cognitive abilities for 182 adoptive families and 164 nonadoptive families. Parent/offspring correlations between 12-month Bayley factors and parental cognitive abilities suggest only minimal relationships for both parental g and specific abilities. At 24 months, more parent/offspring resemblance was present; moreover, Bayley factors that were related to parental cognition tended to be related to parental g, not to specific abilities. The finding of significant parent/offspring relationships at 24 months between biological parents and their adopted-away infants, as well as between nonadoptive parents and their infants, suggests some genetic continuity from infancy to adulthood.