Mulkay, Gilbert and Woolgar (1975) suggest a more incremental model of scientific branching. A new research network may emerge following the migration of researchers who are attracted by unsolved problems or developments, outside, but related to, their present research area, especially where theories and techniques transfer readily to another problem area. This sets off a cycle of exploration, unification, and decline/displacement. Over time, the availability of new techniques, theory and advances in research may lead to increased acceptability of a new or less favored perspective within the wider scientific community. Theoretical advances may provide a means of reconciling disparate results and views within an integrative framework. These developments suggest the possibility of increased convergence among differing perspectives, exploration of joint areas of concern and the potential resolution of formerly anomalous results and problems. An increase in the volume and relevance of published research in a problem area, or its greater visibility through publication in more widely read journals, also may result in changing patterns of citation and greater density of ties among researchers. Reaction from neighboring areas may be hostile, in which case revolution is possible, or receptive, resulting in relatively fluid interactions between the emerging and other, more established networks.
Various social factors affect the innovation process such as branching in a scientific community: organizational and network characteristics (e.g., occupational diversity which provides new sources of information and innovation, stratification which may foster or inhibit the emergence of a new research area, professional activity which provides both access to new ideas as well as avenues for diffusion and acceptance of an emerging research area, and external accountability such as grant funding), and individual characteristics (e.g., knowledge about the new research area gained from formal and informal communication, innovativeness, and expectations about the rewards of migrating toward a new research area) (Rogers, 1983).
The most commonly accepted explanations for dyslexia have revolved around a linguistic/phonological deficit theory (a difficulty in decoding words) or a visual perceptual deficit hypothesis (involving problems in processing visual stimuli), hotly debated in the Journal of Learning Disabilities in the late 1970s. By the mid-1980s, the research began to coalesce around a small set of general conclusions that are endorsed by the vast majority of researchers (Stanovich, 1985, p. 67; Stein, 1991; Vellutino, 1987). In recent years, however, there has been renewed interest in the visual perceptual component of reading disability (e.g. Eden, et al., 1995; Kruk, 1991; Lehmkuhle, et al., 1993) following advances in the neurobiological, genetic, cognitive and neuropsychological aspects of dyslexia (Galaburda, 1993). It is likely that these efforts were spurred in large part by a major increase in federal funding of research into the biological basis of learning disabilities (Lyon, 1991).
All members (100%) of the co-citation Neuroscience block at T3 reported a current research interest in neuropsychology and related problem areas. This compares with only 40% of researchers in the Phonological block at that time period. Those in the Phonological block at T3 were correspondingly more likely to be interested in topics related to language problems (40% vs. 20%) and education/learning (60% vs. 20%). There was no significant difference between blocks in members' self-reported involvement in disabilities research.
Neuroscience members are significantly more likely to hold the M.D. degree (36% vs. 9%) and/or to have a background in specialized areas of biology (28% vs. 0%). Members of the Phonological block are more likely to have a background in education (32% vs. 8%) and to have been active on the editorial boards of two of the primary journals concerned with learning disabilities. Overall, the editorial activities of the researchers in the study group are distinguished by their tremendous diversity.
Figure One shows the two-dimensional plot of co-citation data for T3, with block structure superimposed upon them. Individuals who are located closely together are perceived by citing authors in a similar way. Individuals closest to the center of the plots have the lowest co-citation levels. These include younger researchers, migrants who may not have published extensively on topics related to dyslexia at the time period in question, those who are no longer active in the area, and those who are active in the informal but not the formal dyslexia network. Those furthest to the right on the plot are the more established researchers in the field. Among the phonological group are such highly cited individuals as Stanovich, Isabelle Liberman and Torgesen. Those consistently grouped in the neuroscience block include Pennington, Smith, and Stein, who have published on such topics as genetics and visual processing.
The data suggest that dyslexia researchers in the late 70s were fairly clearly divided into "insiders" and "outsiders". The insiders can be characterized as somewhat mixed groups of researchers having a primarily phonological or neuroscience orientation, respectively. The outsiders consist of those with some interest in topics pertaining to vision as well as those who were not yet active in the problem area. Many of the outsiders were relatively young and possess a variety of backgrounds. They were not co-cited with the insiders and were not co-cited with each other very much. In sum, they appear to fit the definition of marginal scientists as discussed by Gieryn and Hirsch (1977, p. 91).
In the early 80s, the co-citation network structure became far more intermingled. Researchers in general were more highly co-cited. The outsiders began to be absorbed into the neuroscience or phonological blocks, which have an even more mixed character than in T1. This intermingling reflects the somewhat heated debate in the literature on the validity of the visual perceptual approach to the study of dyslexia. Each subgroup was co-cited with itself, and one small group of outsiders remained isolated from the rest of the network.
By the late 80s-early 90s, the neuroscience-phonological orientation of blocks became far more clear. The outsiders appear to have been effectively absorbed into the larger network structure; researchers with an interest in vision were now a subset of the neuroscience block. Those in the neuroscience block were significantly more likely to have studied medicine or biology than their phonological counterparts, while many of those in the phonological block held graduate degrees in education. Members of the latter group also were more active on editorial boards related to learning disabilities. In brief, the co-citation data indicate that blocks reflecting an established (phonological) and an emerging hybrid (neuroscience/visual) perspective can be discerned.
Patterns in the literature had suggested that network analysis of the problem area would reveal separate blocks of phonological and visual researchers in the 70s and early 80s which over time converged, joined by outside "others" in the neurosciences. The actual findings were slightly more complex, but no less interesting. Co-citation analysis indicated that in the late 1970s, the outsiders included a preponderance of those with an interest in the visual aspects of dyslexia, as well as some migrants who were not yet involved in dyslexia research. In contrast, many of those with a neuroscience focus were relatively more central in terms of co-citedness than those from a vision perspective. The lively critique in the literature rendered the visual perspective far more visible than its citedness would seem to have warranted.
The concept of convergence might still be properly applied to some of the changes in the problem area over time, especially as regards the informal network and changes within the neuroscience-vision block. However, in a sense there appear to have been three alternative perspectives: phonological, neuroscience, and outsiders, with the latter including those with an interest in vision. The results suggest a convergence between the neuroscience and vision/outsider blocks, and a divergence between the phonological and neuroscience-vision blocks, each of which became more distinctly characterized and more closely connected with similar others. This pattern supports the description of scientific growth advanced by Mulkay et al. (1975): a period of exploration followed by unification. In the present case, two alternative branches appear to be evolving in the unification phase, although both are perhaps embedded in a more encompassing social network, in line with findings of Lievrouw et al. (1987).
Despite the differences in background and research interests of individuals in alternative blocks, the researchers in the dyslexia research network in many ways appear quite similar to one another, or alike in their differences. They are a diverse group in terms of their citizenship, institutional affiliations, where they studied, and their editorial affiliations. Some are more professionally active than others, but this appears to be linked less to research perspective than to professional age and stature. Although nearly all have received grant funding -- from a wide variety of funding agencies -- those in the neuroscience block were significantly more likely to have received grant funding from the National Institutes of Health (NIH). Few of the characteristics expected to influence innovativeness showed significant differences between blocks, so it is not surprising that there also was no difference between blocks in their members' reported willingness to change.
Members of different blocks do differ significantly from one another in their knowledge of research developments pertaining to neuroscience topics, their assessment of the importance of various skills to the study of dyslexia, and their attendance at conferences at which neuroscience topics are discussed. They communicate more with others within their block than with those outside it, but the more central researchers interact with a wider variety of colleagues than do those on the periphery.
The diversity of institutions represented in the problem area over time is remarkable. The 60 individuals for whom at least partial data was collected were affiliated with more than 170 institutions, and little obvious pattern of affiliation in training or research collaboration. The perception one gains is of little science, involving numerous distributed sites of research, rather than a limited number of dominant centers involving large numbers of researchers.
There was no significant difference in citizenship patterns between blocks at T1. But by T3, Neuroscience-vision members were significantly more likely to be citizens of countries other than the United States.
A Ph.D. degree and a major in psychology characterize the backgrounds of a majority of problem area researchers. Members of a block characterized more closely with the phonological perspective have been affiliated with significantly fewer institutions than those in a neuroscience block at both T1 (3.7 vs. 4.4) and T3 (3.6 vs. 4.9).
No significant differences were found among blocks -- at any point in time -- using any of the self-reported data concerning external accountability in the form of funded research projects. The data were also analyzed according to total number of NIH funded projects or subprojects related to reading disorders, as well as by total subproject dollar amounts between the years 1976-1993. However, at T3, the combined Neuroscience-vision block showed significantly higher grant activity than did the combined Phonological block (7.7 projects/subproject vs. 2.3; $851,830 vs. $313,439).
Knowledge of current developments in neuroscientific aspects of dyslexia research was assessed by asking respondents to indicate their familiarity with four publications. Choices ranged from 1 to 4, as follows: 1=don't know this reference; 2=have heard of or seen it, but haven't looked at the article or abstract; 3=have skimmed paper, read abstract; 4=have read full paper (or many of the proceedings papers). Factor analysis resulted in all four items loading highly on one factor (61% of variance explained; alpha = .78). The mean score was 2.7, suggesting a low degree of familiarity with the papers referenced. Members of the Neuroscience-vision block for both the formal (mean=3.2) and informal (3.1) networks were significantly more familiar with new research developments on neuroscientific aspects of dyslexia research than were members of the Phonological block (means = 2.3, 2.4, p<.001, p<.01).
The vast array of information available to scientists poses both an essential element in the research process and a burdensome problem. Maintaining currency with information directly relevant to one's research is a challenge, and seeking out published information in related areas -- particularly those less well indexed or less easily obtained -- may be beyond the reach of all but the most motivated. Similarly, maintaining interpersonal ties and attending conferences is demanding in terms of time, money and effort, and many individuals may need to restrict these activities to those individuals and events most critical to their work. However, more elite scientists appear more likely to maintain ties with a greater number and variety of contacts than the typical researcher, possibly due to greater grant funding that facilitates informal communication and wider exposure.
The results provide strong support for a gradual process of scientific change, consistent with many aspects of descriptions by Chubin (1976), Mulkay, Gilbert and Woolgar (1975), Gieryn (1978), Ziman (1987) and others. A variety of measures indicate that a less well-accepted perspective has gradually assumed greater respectability within this hybrid field, and that such change is ongoing.
Although innovativeness, professional activity, differences in expectations, and most aspects of diversity were found not to be associated with emerging perspective status, the study reinforced the importance of several other variables. These other variables included: (a) external accountability, (b) knowledge, (c) conference activity and (d) shared background. This is consistent with the principle of homophily -- the transfer of ideas occurs more easily among those with similar beliefs and education (Rogers, 1983, p. 274) -- and "selective exposure" as a necessary survival mechanism for scientists trying to cope with information overload. The results also support Mulkay et al.'s (1975) contention that entrants to an emerging field are likely to have special competence in knowledge or techniques which may be applicable within the new area (p. 193; see also Ziman, 1987, p. 102).
The availability of substantial grant funding may be sufficient to inspire, renew or redirect attention to an area closely related to one's present or primary sphere of interest, despite self-reports that suggest otherwise (Ziman, 1987, p. 106).
Researchers in the current study reported a mean of 2.4 broadly coded research topics, suggesting that involvement in several related areas may be characteristic of a hybrid field as it is with other fields (Gieryn, 1978; Ziman, 1987). Involvement in more than one research project may be a strategy employed to reduce the risk involved with any single project, or it may be a characteristic associated with more eminent researchers because of their greater access to research funds, colleagues and students (Hagstrom, 1965; Mulkay et al., 1975).
Overall, this study provided clear evidence for a process of gradual change -- as compared to revolution -- in this particular hybrid area, to add to a growing family of studies on the process of change in science.
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+--------------------------------------------+ | | | NEUROSCIENCE-VISION BLOCK | | | | LajRumGalHynDuf | | Woo Dua | | SheHug 1A | | SmiKin | | + Liv SatShs | | StePirShb Pav BakBen | | Def TalPen | | Bod | | Wim Rou | | VonMar Lov Rut | | Ede Den | | DiLBre | | Doe | | 1B Bry 2B Joh | | Fle | | Udd Fis + | | Stg | | McC Lyo | | Chf Ham | | McK | | Bos Hal Las Kvn Ols | | Ray Lia SieJor | | MorWonSeiKvlLeoMaf | VogShdVel | Gib WidTor | | StkLunLiiMav| | 2A BlaBra | | + + Chl | | | | PHONOLOGICAL BLOCK | | | +--------------------------------------------+ Bak=Neuroscience Sub-block 1A Bre=Neuroscience-vision Sub-block 1B Bla=Phonological Sub-block 2A Bos=Phonological Sub-block 2B
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