We present statistical analyses of the large‐scale structure of 3 types of semantic networks: word associations, WordNet, and Roget's Thesaurus. We show that they have a small‐world structure, characterized by sparse connectivity, short average path lengths between words, and strong local clustering. In addition, the distributions of the number of connections follow power laws that indicate a scale‐free pattern of connectivity, with most nodes having relatively few connections joined together through a small number of hubs with many connections. These regularities (...) have also been found in certain other complex natural networks, such as the World Wide Web, but they are not consistent with many conventional models of semantic organization, based on inheritance hierarchies, arbitrarily structured networks, or high‐dimensional vector spaces. We propose that these structures reflect the mechanisms by which semantic networks grow. We describe a simple model for semantic growth, in which each new word or concept is connected to an existing network by differentiating the connectivity pattern of an existing node. This model generates appropriate small‐world statistics and power‐law connectivity distributions, and it also suggests one possible mechanistic basis for the effects of learning history variables (age of acquisition, usage frequency) on behavioral performance in semantic processing tasks. (shrink)

This paper shows how the dream archive and search engine on DreamBank.net, a Web site containing over 22,000 dream reports, can be used to generate new findings on dream content, some of which raise interesting questions about the relationship between dreaming and various forms of waking thought. It begins with studies that draw dream reports from DreamBank.net for studies of social networks in dreams, and then demonstrates the usefulness of the search engine by employing word strings relating to religious and (...) sexual elements. Examples from two lengthy individual dream series are used to show how the dreams of one person can be studied for characters, activities, and emotions. A final example shows that accurate inferences about a person’s religious beliefs can be made on the basis of reading through dreams retrieved with a few keywords. The overall findings are similar to those in studies using traditional forms of content analysis. (shrink)

Novice designers produced a sequence of sketches while inventing a logo for a novel brand of soft drink. The sketches were scored for the presence of specific objects, their local features and global composition. Self‐assessment scores for each sketch and art critics' scores for the end products were collected. It was investigated whether the design evolves in an essentially random fashion or according to an overall heuristic. The results indicated a macrostructure in the evolution of the design, characterized by two (...) stages. For the majority of participants, the first stage is marked by the introduction and modification of novel objects and their local and global aspects; the second stage is characterized by changes in their global composition. The minority that showed the better designs has a different strategy, in which most global changes were made in the beginning. Although participants did not consciously apply these strategies, their self‐assessment scores reflect the stages of the process. (shrink)

Dream reports from 21 dreamers in which a metamorphosis of a person-like entity or animal occurred were coded for characters and animals and for inner states attributed to them (Theory of Mind). In myths and fairy tales, Kelly and Keil (1985) found that conscious beings (people, gods) tend to be transformed into entities nearby in the conceptual structure of Keil (1979). This also occurred in dream reports, but perceptual nearness seemed more important than conceptual nearness. In dream reports, most inanimate (...) objects involved in metamorphoses with person-like entities were objects such as statues that ordinarily resemble people physically, and moreover represent people. A metamorphosis of a person-like entity or animal did not lead to an increase in the amount of Theory of Mind attribution. We propose that a character-line starts when a character enters a dream; properties and Theory of Mind attributions tend to be preserved along the line, regardless of whether, metamorphoses occur on it. (shrink)

Empirical studies largely support the continuity hypothesis of dreaming. Despite of previous research efforts, the exact formulation of the continuity hypothesis remains vague. The present paper focuses on two aspects: the differential incorporation rate of different waking-life activities and the magnitude of which interindividual differences in waking-life activities are reflected in corresponding differences in dream content. Using a correlational design, a positive, non-zero correlation coefficient will support the continuity hypothesis. Although many researchers stress the importance of emotional involvement on the (...) incorporation rate of waking-life experiences into dreams, Hartmann formulated the hypothesis that highly focused cognitive processes such as reading, writing, etc. are rarely found in dreams due to the cholinergic activation of the brain during dreaming. The present findings based on dream diaries and the exact measurement of waking activities replicated two recent questionnaire studies. These findings indicate that it will be necessary to specify the continuity hypothesis more fully and include factors which modulate the incorporation rate of waking-life experiences into dreams. Whether the cholinergic state of the brain during REM sleep or other alterations of brain physiology are the underlying factors of the rare occurrence of highly focused cognitive processes in dreaming remains an open question. Although continuity between waking life and dreaming has been demonstrated, i.e., interindividual differences in the amount of time spent with specific waking-life activities are reflected in dream content, methodological issues have limited the capacity for detecting substantial relationships in all areas. Nevertheless, it might be concluded that the continuity hypothesis in its present general form is not valid and should be elaborated and tested in a more specific way. (shrink)

Aggregating snippets from the semantic memories of many individuals may not yield a good map of an individual’s semantic memory. The authors analyze the structure of semantic networks that they sampled from individuals through a new snowball sampling paradigm during approximately 6 weeks of 1-hr daily sessions. The semantic networks of individuals have a small-world structure with short distances between words and high clustering. The distribution of links follows a power law truncated by an exponential cutoff, meaning that most words (...) are poorly connected and a minority of words has a high, although bounded, number of connections. Existing aggregate networks mirror the individual link distributions, and so they are not scale-free, as has been previously assumed; still, there are properties of individual structure that the aggregate networks do not reflect. A simulation of the new sampling process suggests that it can uncover the true structure of an individual’s semantic memory. (shrink)

As humans, we frequently engage in mental time travel, reliving past experiences and imagining possible future events. This study examined whether similar factors affect the subjective experience associated with remembering the past and imagining the future. Participants mentally “re-experienced” or “pre-experienced” positive and negative events that differed in their temporal distance from the present , and then rated the phenomenal characteristics associated with their representations. For both past and future, representations of positive events were associated with a greater feeling of (...) re-experiencing than representations of negative events. In addition, representations of temporally close events contained more sensorial and contextual details, and generated a stronger feeling of re-experiencing than representations of temporally distant events. It is suggested that the way we both remember our past and imagine our future is constrained by our current goals. (shrink)

Daydreaming appears to have a complex relationship with life satisfaction and happiness. Here we demonstrate that the facets of daydreaming that predict life satisfaction differ between men and women , that the content of daydreams tends to be social others , and that who we daydream about influences the relation between daydreaming and happiness variables like life satisfaction, loneliness, and perceived social support . Specifically, daydreaming about people not close to us predicts more loneliness and less perceived social support, whereas (...) daydreaming about close others predicts greater life satisfaction. Importantly, these patterns hold even when actual social network depth and breadth are statistically controlled, although these associations tend to be small in magnitude. Individual differences and the content of daydreams are thus important to consider when examining how happiness relates to spontaneous thoughts. (shrink)

As humans, we frequently engage in mental time travel, reliving past experiences and imagining possible future events. This study examined whether similar factors affect the subjective experience associated with remembering the past and imagining the future. Participants mentally “re-experienced” or “pre-experienced” positive and negative events that differed in their temporal distance from the present , and then rated the phenomenal characteristics associated with their representations. For both past and future, representations of positive events were associated with a greater feeling of (...) re-experiencing than representations of negative events. In addition, representations of temporally close events contained more sensorial and contextual details, and generated a stronger feeling of re-experiencing than representations of temporally distant events. It is suggested that the way we both remember our past and imagine our future is constrained by our current goals. (shrink)