What is it about a crisis that causes people to get creative and think expansively? And just how bad does a crisis have to get before we start seeing new possibilities?
It’s possible that I’m still stuck on a metaphor for distributed networks, the haunted image from RAND Networks in the late 1960s developed in response to possible communications shut-downs after a nuclear crisis:
In a recent interview with Wired magazine, Paul Baran discussed his vision of how the new technology might be used. “Around December 1966, I presented a paper at the American Marketing Association called ‘Marketing in the Year 2000.’ I described push-and-pull communications and how we’re going to do our shopping via a television set and a virtual department store. If you want to buy a drill, you click on Hardware and that shows Tools and you click on that and go deeper.” While residing on the other side of the spectrum of emergency-planning, this prediction of Baran’s foretold the future of home shopping, not the future of education or crisis management. But Baran clearly would have been aware of Marshall McLuhan’s work, and I am also interested in these seldom-cited projections of possibilities onto television as the precursors of the Internet.
The general interest I hold about technology is in the close examination of crisis, and specifically dismantling debt. The word “crisis” by itself does not mean much – Jean Anyon would say that it’s abused about as much as the word “awesome” (missing you, Jean!).
Much of my desire to explore these issues of higher education in the wake of economic crisis and student loans comes from the book DIY U: Edupunks, Edupreneurs, and the Coming Transformation of Higher Education (2010) by Anya Kamenetz. Concerns about quality and affordability in the new mainstream of higher education are addressed head-on, and any prior assumptions about traditional hierarchies and categories dissolve. She wonders if given diversity in “human capital and meritocracy, race and class – can we build a system that works for everybody?” (Kamenetz 2010). Kamenetz believes that there are several trends guiding the transformation of higher education, including:
The 80/20 rule: Most of the growth in higher education over the next century will come from the 85 percent of students who are “nontraditional” in some way—say, older, working adults or ethnic minorities, and will increasingly will attend the 80 percent of institutions that are that are “nonselective,” meaning they accept the vast number of applicants, in mainstream universities as well as community or for-profit colleges.
The Great Unbundling: also describes a movement to de-couple university-achieved accreditation as “the great unbundling,” in which the logic of digital technology will compel institutions to specialize and collaborate, find economies of scale and avoid duplications. Cutting edge sciences and traditional liberal arts will flourish alike
Techno-hybridization: because studies have shown that students do a better job collaborating online if they meet in person even once. This has been traditionally-called “blended learning, too.
Personal Learning Networks and Paths: Self-directed learning will become increasingly important. Despite plenty of demand for the traditional collegiate experience, these will become only one of many options and entry points.
Reading that same book by Kamanetz last summer was crucial in formulating some of my personal theories about informal learning in museums. If possible future systems of learning will include mentors, peers, colleagues, and unbound opportunities to stretch one’s abilities or test personal theories – how can such relationships be replicated online? On thing is clear: the future response to an unending “crisis” in education must be open to more systems of alternative learning.
Other sources to examine this semester are just as pressing beyond Kamanetz’s book – as the dawn of my own personal “sunrise” semester into finally addressing my dissertation research head-on is also rising. This comes with the territory of leaving a full-time job to teach and become a full-time student for the first time in nearly twenty years, and so I am looking at some sources with renewed, wide-eyed interest:
The Future Perfect: The Case for Progress in a Networked Age (2012)
Theorizing with Friedrich Hayek in “Forests, Trees, and Intellectual Roots” by J. Bradford DeLong, and Hayek’s 1945 essay “The Use of Knowledge in Society,” from The American Economic Review.
And most importantly of all, a big break through: an archive I found that includes documentation about the hit TV show Sunrise Semester at New York University this week. Sunrise semester was a ground-breaking television show that first aired on CBS in 1957 and ran for over twenty years, attracting over 1.6 million eyeballs a day at its peak. The catch? It ran at 6:30am on weekday morning, and eventually lack of funding – coupled with a network push for entertainment and “morning news,” eventually led to the show’s demise.
I am slowly amassing a course list of the show’s earliest broadcasts, and some of the topics included philosophy (like a ten week class on Existentialism and Realism, all the way in 1958), biology, foreign languages, and mathematics.
It is possible that NBC also had a show similar to this called “Continental Classroom” which was on from October 6, 1958 until December 18, 1964.
I have hit an incredible set of archives from NYU this week that makes me certain that Sunrise Semester is the big sleeper hit in distance learning – and will fill the historical gap between early correspondence courses in the late 1890s (such as the Independent Correspondence Course aimed at miners and draftsmen, founded in 1896). Just all notes and scribbles. The best kind.
Never one to say no to a free conference (and certainly not one to say no to a free conference that is also being held in my own backyard over at CUNY), this weekend I attended the conference Theorizing the Web – the 2013 edition. A chance to consider questions like “is the internet a separate reality?” and “does the web reproduce or topple those in power?” alongside classmates and other really smart people can’t really spell a bad weekend at all.
Opening night on March 2 popped off with a massively inspiring firehose attempt to take apart the idea of who “free speech” protects and why. The title of the opening plenary was Theorizing the Web: Free Speech for Whom? and sought to face down some of the discussions that are missing about race and class when theorizing about social surveillance and digital diplomacy. The panel – Jessie Daniels, danah boyd, Adrian Chen and Zeynep Tufekci offered examples as diverse as #muslimrage – a meme that tenuously vacillates between irony and, well rage – and efforts to expose ViolentAcrez – a creepy racist perv troll on Reddit. A favorite example of mine was ways in which 4chan users pwned Oprah’s chokehold on our attention economy by releasing false stories about known pedophile groups.
The conference, now in its third year, seeks to examine power, inequality and domination on the web – and the opening night delivered in this regard. What part of acting under the cloak of anonymity allows bad behavior online? What is it about our need to hold individual users accountable… and then lets the community itself be blameless? Do we out everyone online – not just the pervs and racists, but the sloppy and the mean who can’t hold themselves back from posting? The panel urged the audience to stop blaming the technology, and to pull the power back into the hands of every day people that have the responsibility to model better behavior, both online and offline. Are WE all responsible? In this case, there was an academic we in the room, and the air felt real heavy for a millisecond.
Many of us couldn’t help but feel blown away by danah boyd as she spoke out against the apathy in ripping teens who say stupid things on the internet, about bullying in general, and how we are all implicated if we sit back and don’t do anything to elevate the conversation higher. Confession here that I think I’ve held an academic crush on her since her 2002 study on Facebook and Myspace – at a time I was managing teen programs in a contemporary art museum in Boston. Class lines bifurcated along who was using Facebook to promote our events, who was using Myspace, and why they were reaching such separate – dare I say segregated, teen audiences. I think she has consistently spoken on behalf of young people in ways that matter, and often when they cannot.
So for a moment, the answer was a resounding yes about the blame game; we are all implicated whether we liked it or not. Chen posited that old addage that you can behave any way you like online “cos it’s private” might actually be left over “from a really ancient time when the internet was run by all white guys.” Duh. So does that mean we blame ourselves? danah spoke particularly eloquently about why we all must adopt a “professorial” role to educate beyond the immediate, limited social circles we reach via our Twitter followers. She gestured to us, sitting in the audience, that there was too much brain power in the room to ignore our potential to expand our reach.
After last night’s panel, it became clear to me that there aren’t many places of resistance at CUNY against teaching, learning and theorizing why we can’t all contribute to make the internet just be a little bit better, together.
Today was Saturday afternoon, and so I had to run up to the library stacks over the break – as today also surfaced a new running list of what can only be tagged with <what am I not reading now, but really should be>, followed by a head smack. I never go into those stacks, and today I did in earnest. With special thanks to someone at #TtW13 for posting this – as clearly I wasn’t the only one hopeful to capture this screenshot:
I hit the streets outside CUNY last night ready to kick an edupunk signpost – stoked that I live in New York City, that I can sit and watch the discomfort of academics as we remind ourselves where we hit gaping caverns between what we think and write about, and what the heck else the rest of the world is actually doing in their everyday lives.
I then felt the weight of so much more responsibility as I walked the stacks this afternoon, in the midst of the Theorizing the Web conference. The HD-live stream and our comfy auditorium chairs are a privileged place to sit and contemplate our work, at any moment. Such conversations can feel rather disconnected. The IRL actions of academics are only just beginning to index some of the more practical applications in urban education, yet operates separately from the systems of learning that actually might go down in cities. And especially in a city like this one.
For a Friday night, and for all the nights I’ve tried to get home, late and exhausted, running between my full time job and my full time doctoral studies — last night, I was ready to fist pump the air. Hells, yea, CUNY. I get it, you’ve always had a radical history. But thank you for bringing the BADA$$ES together this weekend. We all needed this level of thoughtfulness and discussion led by a call to action to make new moves. There is plenty more work to be done, and it needs to be done by all of us.
If I were to leave art-speak out for a moment and address larger issues of access and education within institutional practice, I wonder what would happen to the shift in balance about stories that get told (or not told) within institutional practice. I am in search of questions that provoke new opportunities afforded by unprecedented amounts of cultural data now available on the web, that in turn is directly informing seemingly provocative ways to analyze larger questions of digitized cultural heritage in institutions.
Sometimes I wonder if we should just measure everything that can be measured, just to see what happens. If you can talk about it, you can measure it. Somehow, such a reductive approach makes me believe that just as data sets get bigger and bigger and more reliant on predominant digital traces, there is a simultaneous push against voices that don’t get heard. Just because we’re examining bigger data doesn’t mean it’s discerning data.
As institutions are considering new approaches that include “open” and “shared authority” online, what other ways can we also seek to expand institutional practice to become more inclusive and expansive in its reach, and how can it occur in real-time? How can we meet real-world challenges in the context of the institution to represent missing voices, and how can we engage the power of big data to facilitate change? And, finally – what would such a shift look like in the hands of artists working in the institution?
This really struck me was attending the opening of the 1993 show last week – and I happened to visit the “Age of Abstraction show from 1910-1929. Lev Manovich and I were talking about what it means to look at the entirety of cultural production from a single year, and possible ways to understand culture by taking such a narrow slice of New York history. What do we learn by leaving so much else out? What can be understand by examining such a sliver of history in a city like New York that can be extrapolated for deeper analysis? Dividing the data in the context of a museum space is really fascinating to me, and opens new questions for education and curatorial practice.
I’m not an expert on that 1993 show that just opened last week at the New Museum, but their pointed look at the 20th year anniversary of the Whitney Biennial has definitely pointed viewers towards considerations about how art production in general just looked so different back then. Maybe we weren’t spending all of our time on email or snapping photos with our phone cameras… and yet maybe there are just so many more places and contexts and types of institutions that can show work now in 2013 that we cannot help but look backwards in a wave of nostalgia.
And while we both acknowledged that this isn’t truly possible because we could never ever track down all those mix tapes of our 1990s youth! (Although I wish we could…) New possibilities now abound to consider “cultural production” as a massive data set that could be analyzed to help us connect or understand influences that simply not visible before. This, in turn, might lead us to some kind of higher understanding about relevance, about perceived value, about culture and maybe even why more of it has become digitized, whether we like it or not.
I’d like to argue that this only slightly expands the role of the traditional institution, and museums, cultural organizations and other institutions will become tapped to fill in the void that is being left by traditional modes of schooling. I believe it is time for us to think through how our fields could work together to expand the educational role of the institution – and inject ourselves into larger cultural relevance. This may happen through informal learning systems that exist outside of school, through apprenticeship models about art-making, through online learning unafraid to address the culture of “critique.” We can’t predict what the future holds. But here are some possibilities:
– Institutions could study societal shifts through shifts marked in social media and social computing (i.e., beyond merely sophisticated analysis through Twitter that mark connections between audiences and viewers)
– Institutions could help detect large-scale cultural patterns not visible in normative possibilities of display, exhibition or catalog
– Institutions could present move inclusive understanding of cultural history, and include more voices that are typically under-represented
– Institutions could position themselves to map cultural variability and diversity.
The skeptic in me is always going to say that the more data we are able to collect, the more we will find how much we continually leave out – immigrant experiences, the undocumented, and any other euphimisms for marginalized communities that academics like to name.
The goal should always be about moving towards more inclusive understandings of cultural history and point to predictors using larger cultural patterns that we can trace and back up with data. What’s the line then between, say, an archive fetish and a top-level analysis? At what point, do we become seduced by too much data, and lose our ability to recognize encroaching data-blindness?
I’m not sure, but I sure loved those directional speakers that showered audio from the early 1910s at MoMA’s Age of Abstraction show. Totally worth it.
According to W. Terrence Gordon’s introduction in the critical edition of Understanding Media: The Extensions of Man (1964, 1994), Gordon tells the story of how McLuhan began to write a Claude Bissell, then-president of University of Toronto in 1958, was only vaguely aware “that an English professor toiling away in a remote corner of the campus was beginning to enjoy a reputation for his work on media” (Gordon 477). That English professor, none other than Marshall McLuhan. At that point, the U.S.-based National Association of Educational Broadcasters (NAEB) had approved McLuhan’s proposal for a study of media during his sabbatical year in 1958. And so, NAEB project #69 was launched.
McLuhan called it “Vat 69,” a caldron where he tossed in as many ideas as he could seize, hoping to eventually turn his study into a book. Later, his enthusiastic but frustrated editors for the original edition of Understanding Media would innocently believe that he also intended to give his subject a more orderly treatment.
I am curious to learn more about Project 69, or “Vat 69,” because this is where McLuhan also started developing a bit of an attitude against teachers.
The NAEM apparently set McLuhan to designing a teaching method and syllabus for introducing secondary school students to the nature and effects of media. With sponsorship from both the NAEB and the United States Office of Education, McLuhan’s research focused on interviews with educators and a program of media-testing conducted with the help of the Ryerson Polytechnic Institute in Toronto. He began to work as soon as possible, heading to Philadelphia to study with Harry Skornia, then professor of radio and television broadcasting University of Illinois at Urbana and president of the NAEB, and with author Gilbert Seldes.
It was clear that the project would absorb McLuhan fully, with a final report scheduled for submission at the end of his sabbatical year in June 1960. But he had a sample syllabus ready (text is in the book Understanding Media) before the end of 1959. As an objective for prospective courses, he gives priority to examining the following:
– the interaction of media
– the nature of print
– and new electronic technologies
McLuhan later admitted (Gordon 1994) that he himself emphasized that he had neither a theory nor a point of view – only percepts and probes.
He points out that achieving increased awareness of the forms of media is not an end in itself but provides a means of anticipation and control.
Linguistics, and the organizing pattern imposed on experience by language – was made into “the medium is the message,” a far cry from what “the medium is the message” meant when McLuhan said it to reassure worried broadcasters with extinction by television.
He castigated educators for insulating themselves against cultural change by taking shelter in bureaucratic structures. Ouch!
Since he was gearing up for his sabbatical anyway, it was probably a time for him to get reflective on why teachers and teacher education as a field might be resistant to new modes of learning.
His writing seems to evolve from metaphor; in fact, his entire life’s work came from Poe, James Joyce, and other Renaissance writers. He was an English professor because there was no “comparative media studies” or other such fields of study that he, himself, is later credited for beginning.
Heavy credit to W. Terrance Gordon and his revised preface to Understanding Media is due, as I have never seen that particular study researched or documented elsewhere.
So it’s a journal entry now, not a thesis, not even an outline. Did some great reading today. Manuel Castells (2012) and an essay by Rosalind Williams on “crisis.”
It’s prompted an essay I’ve always wanted to write: “the crisis of crisis.” Which means that crisis doesn’t really exist anymore. Foucault would have described the language gap as a “semantic vacuum” (1970). We’ve entered a time in which we hold an impossibility to describe the times we are in; one crisis spills over to another. (I love her analogy to the Macondo, Gabriel Garcia-Marquez’ fictional Mexican town that vaporizes into a sea of dust, and the parallels between fiction and the actual code name of that busted oil rig in the Gulf of Mexico that wouldn’t stop spilling its oil). A spill, spillonomics, spill-o-distaster. Crisis, meta-crisis, “fiscal cliff,” which implies slow-moving, cartoon-like, and in free-fall.
(At the time of this writing, my 2013 paycheck has already been deducted, overnight and just like that. Now I pay more into social security that may not be there when I retire, without having voted on it, nor have I really been told about the alternatives). Crisis of economics now results in an ongoing crisis of civic trust.
Marshall McLuhan will also feature prominently in my thesis. It’s an ill-fated but otherwise sealed-deal that I learned that the anniversary of his death falls on New Years Eve, and so I was thinking a lot about him this week.
i’ve also been thinking about networks. Decentralized, distributed networks originally envisioned in response to nuclear threat. RAND corporation, ARPA net, all conceived against the backdrop of very specific threats to our own existence. We abstractly could probably rationalize and understand nuclear threat, or at least – we could practice drills to fight it, build bunkers to protect ourselves.
But networks are resolved, and have evolved – and now we cannot name the fear, the “one thing” we could now name that would set the disaster plan in motion. It’s fluid, like the Twin Towers flowing down into rubble like liquid, slow-moving, barely catching up as the brain realizes its own inability to process the horror.
Rosalind Williams, after being asked to give a 2012 talk on the “slow-moving disaster” of the economic melt-down, tracked New York Times headlines to get a grasp and a measure of how the fiscal crisis was written about in the press. The Great Recession was probably the most accurate in daring parallels between the Great Depression; a complicated system of credit and debt, further complicated by a really Black Tuesday on the market, caused a disruption of a delicate system to come tumbling down for a number of years. The problem now, it seems, is that we really just don’t know how far we can go.
One thing is for certain, back then as now: we’ve lost our civic trust in systems. A fiscal crisis results in perceptions of mismanagement, bloat, greed.
And so we turn to one of the most difficult questions in the midst of “a crisis of crisis:” can education save society?
In the spirit of New Year’s Eve and things that are scary and fiscal-cliffy: the above graph shows the NEA’s appropriations history in real and nominal dollars, along with an illustration of the actual percentage of the budget and party in control of the White House and Congress. (Looks like maybe the House of Representatives may be a bigger driver of the NEA budget than previously acknowledged?) And what the heck does that mean, as we stand on the precipice of the fiscal cliff tonight? Happy New Year’s Eve!
In a rare and performative act when pressed, I spent untold hours reading the table of contents of dissertations from past students that I admired these last few weeks, and my efforts were rewarded when I finally saw the first few pages of some future possibilities for chapter headings. The only sounds in the Mina Rees Dissertation Room were mine, scratching into an old-fashioned ledger notebook because keyboard clicks are not allowed. It’s my absolute most favorite place to work.
If I become more brave, this outline will include Chapter 5: Issues in Contemporary Art for Online Learning, and Chapter 6: Against the Commodification of Education. But I’m not acting that brave yet. I am meanwhile visualizing a tidy table of contents and the first few pages that look real to me. Most of all, I am imagining that first coverlet page with my initials signed in pencil. Those seem most real of all. Time to talk it into existence. Black heavy cover jacket and all.
[Title page, initialed in pencil]:
CENTRALIZED, DECENTRALIZED, DISTRIBUTED:
DISRUPTIVE TECHNOLOGY IN URBAN EDUCATION
by Rosanna Noelle Flouty
A dissertation submitted to the Graduate Faculty in Urban Education in partial fulfillment of the requirements for the degree of Doctor of Philosophy, The City University of New York
[blank page, p ii]
All Rights Reserved
[Manuscript approval signature page, p iii]
This manuscript has been read and accepted for the Graduate Faculty in Urban Education in satisfaction of the dissertation requirement for the degree of Doctor of Philosophy.” Date, Name, Signed, Chair of Examining Committee, Anthony Picciano, PhD Executive Officer, plus three readers on Supervision Committee, Names TBD, Signed, Dated.
THE CITY UNIVERSITY OF NEW YORK
[Abstract, p iv]:
CENTRALIZED, DECENTRALIZED, DISTRIBUTED:
DISRUPTIVE TECHNOLOGY IN URBAN EDUCATION
Rosanna Noelle Flouty
Advisor: Dr.____________ word count
[Dedication, p v]
[Acknowledgments p vi]
[Preface, p vii]
[Table of Contents] x
Approval Page iii
Chapter 1. Introduction: The Birth of MOOCs
Centralized, Decentralized, Distributed: The Conceptual Foundation
Setting the Stage: [ tk Defining Characteristics of Online Learning]
Overview of the Dissertation
Structure of the Dissertation
Chapter 2. Conceptual Theory:
Why [this theory? this study? What will we learn here? How will this impact the field?]
Marshall McLuhan’s Understanding Media: the Extensions of Man
Overview of the Dissertation
Chapter 3. DIY Education: Movements to be Free for Everyone, Everywhere
A Brief History of Distance Learning c. 1954-2001
Sunrise Semester and New York University c. 1954-1982
PBS YOU and the Demise of the Telecourse c. 1988-2001*
Chapter 4. Conceptual Theory:
A Brief History of Online Courses
Coursera, Udacity, Khan Academy
Disruptive Technology in Online Education
Edupunk and DIY U: Movements to Be Free
It trails off at the end… because it’s just not ready yet. But again, in efforts to work in public and to cease my shyness in writing this all down as soon as I am able, I have forced myself to hit the button, and post. The next ten days are crucial ones, but this is the first step.
This thread is one of three that I will post based on curiosity I hold for the following three areas:
a) documented attempts, sometimes badly, to replicate or simulate in-person learning experiences in an online environment
b) methods in which MOOCs are pushing into univeristies, and why they might just be too early to start monetizing
c) how liberal arts education should and should not be emulated online
I’ve started here has to do with curiosity about curiosity, and mainly personal leanings toward a general motivation about learning enivornments. What creates the desire to learn? Always holding curiosity about definitions and root etymologies, I’ll start here with a crowd-sourced definition for curiosity:
n. pl. cu·ri·os·i·ties
1. A desire to know or learn.
2. A desire to know about people or things that do not concern one; nosiness.
3. An object that arouses interest, as by being novel or extraordinary: kept the carved bone and displayed it as a curiosity.
4. A strange or odd aspect.
5. Archaic Fastidiousness.
I get the first one, A desire to know or learn. It’s broad, it’s open. Most humans have it, and it’s pretty innate in other animals like cats, dogs, and monkeys, too. For curiosity’s sake, it’s actually pretty hard to satisfy one’s curiosity by simply ignoring something that is curious.
The rest of the Wikipedian definition of curiosity is fuzzier, such as an interest or desire to know about people or things that do not concern one; nosiness. Nosiness and one can trace the entomology to the word relic or artifact – which is to say, things that are odd. The use of the word strange or odd as an aspect of curiosity is troubling to me, because even not used pejoratively, odd points to that which is occasional or strange. The anomalies and outliers peak our curiosity.
Which means: curious people arouse curiosity. Those that are curious, seem curious.
Curiosity and the ability to satisfy curiosity implies that there are opportunities to learn. And learn about people and things that are not like us. Curiosity leads to desire, which leads to experience. Experience leads to learning and understanding. And in turn, opportunities to learn can create more curious people.
Bless Wikipedia for turning me onto this definition of curiosity and its mechanics. If the word comes from Latin curiosus “careful, diligent, curious,” akin to cura “care”), then they share a parallel root for the word “curate,” a museum term, often and arguably misused in various contexts, notably online. But the word cura, “to care” is open enough to be just that: I care, therefore I can.
Looking at ways that curiosity behaves on our brains, then we can then travel down the path of attention, drive, arousal – all areas of study that point to larger parts of our brain’s cognition that we don’t know very much about yet. We just know when we feel it, or that we feel something.
So what makes someone curious enough about an online course to take one? If it’s not for credit, and not for a degree or a grade? What could be possibly make someone curious about something, curious enough to spend online time learning about something, that does not “concern” someone?
Do we value curiosity? Scientists value curiosity, and so do artists. But what about being curious also makes it odd?
More to the point: how can online learning nurture curiosity? Can it? My ability to hit CTRL+N and Google something is as natural as the way I blink. My curiosity about curiosity led me down the Wikipedian rabbit hole of crowd-sourced definitions, and I didn’t dare cross-check Wikidictionary, although I remain curious about how they might compare. How many Google searches must begin with, “Just for the sake of curiosity, I went ahead and looked this up…”
Curiosity is primal and urgent, and for some, one of the sole motivators to learn something new. How do we nourish the desire to learn something new, and to learn something that is not about ourselves?
I’ll posit that immediate acts that “satisfy our curiosity” lead to deeper curiosity beyond our immediate selves, and towards things, people and places that do not concern us. And toward things that concern others. Deeply. The oddness lies in thinking about something other than ourselves.
Does curiosity lead to empathic choices? Can curiosity make the world a better place when we aren’t just curious about ourselves?
See also: http://en.wikipedia.org/wiki/Curiosity; http://en.wikipedia.org/wiki/Odd, “Odd is an adjective denoting the quality of being unpaired, occasional, strange or unusual, or a person who is viewed as eccentric.”
Technology means “the processes by which an organization transforms labor, capital, materials, and information into products and services of greater value.”
– Clayton M. Christensen, The Innovator’s Dilemma (1995)