Douglas L. Nelson

The English Lexicon Project.

The English Lexicon Project is a multiuniversity effort to provide a standardized behavioral and descriptive data set for 40,481 words and 40,481 nonwords. It is available via the Internet at elexicon.wustl.edu. Data from 816 participants across six universities were collected in a lexical decision task (approximately 3400 responses per participant), and data from 444 participants were collected in a speeded naming task (approximately 2500 responses per participant). The present paper describes the motivation for this project, the methods used to collect the data, and the search engine that affords access to the behavioral measures and descriptive lexical statistics for these stimuli.

The University of South Florida free association, rhyme, and word fragment norms

Preexisting word knowledge is accessed in many cognitive tasks, and this article offers a means for indexing this knowledge so that it can be manipulated or controlled. We offer free association data for 72,000 word pairs, along with over a million entries of related data, such as forward and backward strength, number of competing associates, and printed frequency. A separate file contains the 5,019 normed words, their statistics, and thousands of independently normed rhyme, stem, and fragment cues. Other files providen × n associative networks for more than 4,000 words and a list of idiosyncratic responses for each normed word. The database will be useful for investigators interested in cuing, priming, recognition, network theory, linguistics, and implicit testing applications. They also will be useful for evaluating the predictive value of free association probabilities as compared with other measures, such as similarity ratings and co-occurrence norms. Of several procedures for measuring preexisting strength between two words, the best remains to be determined. The norms may be downloaded fromwww.psychonomic.org/archive/.

Pictorial Superiority Effect.

Pictures generally show superior recognition relative to their verbal labels. This experiment was designed to link this pictorial superiority effect to sensory or meaning codes associated with the two types of symbols. Paired-associate stimuli consisted of simple pictures or of their labels, with list items selected either from the same conceptual category or from different conceptual categories. In addition, schematic or visual similarity among the pictures was either high or low. At two rates of presentation equal amounts of conceptual interference were produced for pictures and their labels. High schematic similarity eliminated the pictorial superiority effects at the slow rate and completely reversed it at the fast rate. These results suggest that the meaning representations for simple pictures and their labels may be identical, and that the pictorial superiority effect is related to the qualitative superiority of the sensory codes for pictures.

Processing implicit and explicit representations

This article summarizes the results of a 15-year research program dedicated to understanding how implicitly activated memories affect remembering and proposes a model for describing such influences. Implicit memories are manipulated by varying the number of associates preexperimentally linked to test cues or to studied words. Assumptions of the model specify when implicit memories of various types are likely to contribute to performance in various tasks. The main assumptions are that encoding involves both explicit and implicit processing components and that these components provide mutually exclusive sources of information during testing. Experiments designed to evaluate the exclusivity assumption are reported, and implications of the findings for several theoretical frameworks are discussed.

What is free association and what does it measure

This paper reports the results of a study of free association in which participants were asked to produce the first two words to come to mind. The findings were used to estimate the reliability of indices of strength and set size for different types of items and to model free association as a retrieval task. When confined to first responses, reliability was generally high for both indices, particularly for words with smaller sets of associates and stronger primaries. When second responses were included, reliability declined. A second response added new but weak items to the set, and, when the primary associate was not produced on the first opportunity, it tended not to be produced on the second. Relative to when multiple responses are requested, first-response free association provides more reliable indices of the relative strength and set size for a word’s strongest associates. A model of free association assuming that a strength distribution underlies each response provided a good fit to the data.

The University of South Florida homograph norms

Norms were collected to determine the relative dominance of different meanings of homo-graphic words. Forty-six subjects wrote down the first word that came to mind for each of 320 homographs. Each homograph, the number of times each meaning was given, and the specific associates are made available. In addition, correlations with other norms are presented.

What is the connection between true and false memories? The differential roles of interitem associations in recall and recognition

Veridical memory for presented list words and false memory for nonpresented but related items were tested using the Deese/Roediger and McDermott paradigm. The strength and density of preexisting connections among the list words, and from the list words to the critical items, were manipulated. The likelihood of producing false memories in free recall varied with the strength of connections from the list words to the critical items but was inversely related to the density of the interconnections among the list words. In contrast, veridical recall of list words was positively related to the density of the interconnections. A final recognition test showed that both false and veridical memories were more likely when the list words were more densely interconnected. The results are discussed in terms of an associative model of memory, Processing Implicit and Explicit Representations (PIER 2) that describes the influence of implicitly activated preexisting information on memory performance.

Word concreteness and word structure as independent determinants of recall

Abstract Theorists attribute concreteness effects to differences in imagability, context availability, or to differences in associative structure. Imagability explanations assume that subjects are more likely to generate images for concrete than for abstract words and context availability explanations assume that contextual information is more accessible for concrete words. Structural explanations assume that concrete words have smaller associative sets than abstract words making them easier to recall, or they assume the opposite view, that concrete words have larger and more densely connected sets making them easier to recall. The purpose of this paper was to evaluate contradictory structural explanations. The results of a correlational study involving over 2000 words and three recall experiments involving manipulations of concreteness and structure indicate that these attributes are uncor-related and have independent effects. Neither structural view adequately explains the findings.

Implicit memory: effects of network size and interconnectivity on cued recall.

Previous findings have indicated that the recall of a recently studied word is affected by how many associates it has in long-term memory (set size). The purpose of these experiments was to determine whether recall is also affected by the connectivity of these associates. Studied words were preselected to represent combinations of set size and connectivity and, in different experiments, recall was cued with extralist or intralist cues and with cues sharing few or many associates with the studied words. Effects of study time, encoding context, and levels of processing were also investigated. The results indicated that recall was more likely for words with smaller associative sets and for words with more interconnected sets of associates. These findings demonstrate that the recall of a recently presented word in the presence of a retrieval cue is affected by both the size and organization of its implicitly activated associative structure.

Spreading activation or spooky action at a distance

How do preexisting connections among a words associates facilitate its cued recall and recognition? A spreading-activation model assumes activation spreads to, among, and from a studied words associates, and that its return is what strengthens its representation. An activation-at-a-distance model assumes strengthening is produced by the synchronous activation of the words associates. The spread model predicts that connections among the studied words associates will have a greater effect on memory when more of its associates return activation. The distance model predicts that total connections are important, not their direction. The results of cued recall experiments supported the distance model in showing that that connections among the associates facilitated recall regardless of the number of returning connections.