Idea/Expression Distinction in Determining Substantial Similarity in Copyright Litigation



For the past 4 years I have been teaching a copyright litigation seminar at Cornell Law. Rather than use a textbook I wrote my own. I prepared nine primers dealing with key issues in copyright litigation. The primers are not exhaustive but are instead designed to introduce a copyright topic as simply as possible. I will be posting all nine under a tab entitled Copying Learning Center on this blog (now being redesigned) after the newly-designed blog launches.

This is the initial primer dealing with the distinction between idea and expression in copyright litigation. Infringement results when defendant’s work is substantially similar to plaintiff’s work. But the similarity between the two works must concern the expression of ideas, not the ideas themselves. Understanding the elusive distinction between idea and expression and how it is applied will aid in determining whether a work has been infringed.

Now to the primer.

In determining the elements of a copyrighted work that may be protectable, §102(b) of the Copyright Act requires the exclusion of the idea described, explained, illustrated, or embodied in plaintiff’s work. Copyright protects only plaintiff’s expression of the idea.

The Policy Underlying the Idea/Expression Dichotomy

The idea/expression dichotomy, as it is often called, “strike[s] a definitional balance between the First Amendment and the Copyright Act by permitting free communication of facts while still protecting an author’s expression.” Harper & Row, Publishers, Inc. v. Nation Enters., 471 U. S. 539, 556 (1985). Because creators are denied a monopoly over their ideas, others are free to use and build on them, Feist Publications, Inc. v. Rural Telephone Service Co., Inc., 499 U.S. 340, 349-50 (1991). Further, courts reason to give creators a monopoly over ideas would reduce their incentives to transform them into protectable expressions. See Apple Computer, Inc. v. Microsoft, 35 F.3d 1435, 1443 (9th Cir. 1994) (“[S]imilarities derived from the use of common ideas cannot be protected; otherwise, the first to come up with an idea will corner the market.”).

But the line between an unprotected idea and its protected expression is not clear. As Judge Hand stated in Peter Pan Fabrics, Inc. v. Martin Weiner Corp., 274 F.2d 487, 489 (2d Cir. 1960), “no principle can be stated as to when an imitator has gone beyond copying the ‘idea,’ and has borrowed its ‘expression.’ Decisions must therefore inevitably be ad hoc.” Judge Hand years before in Nichols v. Universal Pictures Co., 45 F2d. 119, 121 (2d Cir. 1930), famously offered this guidance when attempting to define the idea:

Upon any work, and especially upon a play, a great number of patterns of increasing generality will fit equally well, as more and more of the incident is left out. The last may perhaps be no more than the most general statement of what the play is about, and at times might consist only of its title; but there is a point in this series of abstractions where they are no longer protected, since otherwise the playwright could prevent the use of his ‘ideas,’ to which, apart from their expression, his property is never extended.

Some Guidelines When Distinguishing Between the Idea and Expression

Although the terrain between idea and expression is uncertain, here are some broad guidelines, which vary depending on the subject matter involved.

An idea may refer to the work’s animating concept. See Goldstein, Goldstein on Copyright § Supp.) (“Goldstein”). For example, when a new iPhone is released, the concept of advertising it in various forms of social media is a unprotectable idea. But the original combination of elements in a video containing that ad would be a protectable expression.

For literary works ideas might be the building blocks. The building block ideas will typically be the work’s theme, plot, stock characters and settings, as well … as a work’s title,” Id. See Berkic v. Crichton, 761 F.2d 1289, 1293 (9th Cir. 1985) (“No one can own the basic idea for a story. General plot ideas are not protected by copyright law; they remain forever the common property of artistic mankind.”) Thus, the theme of a book about an aging baseball player in his last days in the major leagues would be its idea.

With visual works such as photographs, the creative choices concerning subject matter, pose, lighting, camera angle and perspective are, by themselves, unprotectable ideas. But in combination these elements may be protectable. See Rentmeester v. Nike, Inc., 883 F.3d 1111, 1119 (9th Cir. 2018), cert. denied, 139 S. Ct. 1375 (2019) (“What is protected is the photographer’s selection and arrangement of the photo’s otherwise unprotected elements.” If sufficiently original, the combination … [of these elements] receives protection”). Id.

Rogers v. Koons, 960 F.2d 301 (2d Cir.), cert. denied, 506 U.S. 934 (1992), is an example of when the combination of these elements may be protectable. Their plaintiff created a photo of a couple holding eight puppies. Defendant, an appropriation artist, admitted during discovery he asked his Italian artisans to copy the photo and reproduce it in a sculpture.

Idea:Expression Distinction Koons Plaintiff

In finding infringement, the Court of Appeals stated:

What is protected is the original or unique way that an author expresses those ideas, concepts, principles or processes. Hence in looking at these two works of art to determine whether they are substantially similar, focus must be on the similarity of expression of an idea or fact, not on the similarity of the facts, ideas or concepts themselves.

Id. at 308.

Rogers added:

Thus, had appellant [Koons] simply used the idea presented by the photo [created by Rogers], there would not have been infringing copying. But here Koons used the identical expression of the idea that Rogers created; the composition, the poses, and the expressions were all incorporated into the sculpture [the infringing work].


But predicting how a court will define the idea and expression is especially difficult in visual arts cases. That is “because every observer will have a different interpretation,” Mannion v. Coors Brewing Co., 377 F. Supp. 2d 444, 458 (S.D.N.Y. 2005). Mannion added, “[i]n other words, those elements of a photograph, or indeed, any work of visual art protected by copyright, could just as easily be labeled ‘idea’ as ‘expression,’” Id. at 458-59.

With commercial products, the courts attempt to apply a similar analysis by separating the commonplace idea from its particularized expression. Thus, in Mattel, Inc. v. Goldberger Doll Manufacturing Co., 365 F.3d 133 (2d Cir. 2004), involving the alleged copying of plaintiff’s doll, the court reversed summary judgment in favor of defendants, stating:

Thus, Mattel’s copyright in a doll visage with an upturned nose, bow lips and widely spaced eyes will not prevent a competitor from making dolls with upturned noses, bow lips and widely spaced eyes, even if the competitor has taken the idea from Mattel’s example, so long as the competitor has not copied Mattel’s particularized expression. An upturned nose, bow lips and widely spaced eyes are the ‘idea’ of a certain type of doll’s face. That idea belongs not to Mattel but to the public domain…But Mattel’s copyright will protect its own particularized expression of that idea and bar a competitor from copying Mattel’s realization of the Barbie features.

Id. at 136

An example of a protectable, particularized expression in a product was the decision by defendant in crafting a fighting doll to overemphasize certain muscle groups, Mattel, Inc. v. Azrak-Hamway Int’l, Inc., 724 F.2d 357, 360 (2d Cir. 1983).

The Different Approaches Each Party Takes to The Idea/Expression Dichotomy

Creative advocacy matters in a substantial similarity fight. That is because how the court defines the idea and expression will impact the outcome. Here are the approaches defendants and plaintiffs usually take in this fight.

Defendant’s Approach

In response to a substantial similarity infringement claim, defendant typically attempts to have the court define the idea in particularized detail or at a low level of abstraction. In other words, defendant will argue the idea accounts for most, if not all, of the similarities between the two works. Defendants may also ask the court not to define protectable expression too broadly else future authors face a narrower body of ideas from which to borrow when creating.

If the court accepts a detailed definition of the idea, defendant is then able to more easily convince a court that the works at issue owe much of their similarity to that shared idea and that therefore defendant’s work is non-infringing.

Primer on Idea:Expression Distinction

Here are some examples where courts in substantial similarity litigation, having defined the idea in considerable detail, concluded defendant’s work had not infringed. In Reece v. Island Treasures Art Gallery, Inc., 468 F. Supp. 2d 1197, 1206 (D. Haw. 2006), the court defined the idea of plaintiff’s photograph as “a hula dancer performing an ike movement in the hula kahiko style from the noho position”—not generally as an image of a hula dancer.

Primer on Idea:Expression Distinction example

In Mattel, Inc. v. MGA Entertainment, Inc., 616 F.3d 904, 915 (9th Cir. 2010), the court defined the idea as dolls “depicting a young, fashion-forward female with exaggerated features, including an oversized head and feet”—as opposed to merely a young, female doll. In L.A. Printex Industries, Inc. v. Aeropostale, 676 F.3d 841, 850 (9th Cir. 2012), the Court stated that “[t]he idea [is] a floral pattern depicting bouquets and branches,” as opposed to merely stylized fabric designs.

Finally in Rentmeester, supra, the district court agreed with defendant the idea expressed in plaintiff’s photo was not simply “Michael Jordan about to dunk a basketball” but the much more detailed “Michael Jordan in a gravity-defying dunk, in a pose inspired by ballet’s grand-jeté,” 15 U.S.P.Q.2d 1449, 1453 (D. Or. 2015). The Ninth Circuit accepted that particularized definition of the idea when deciding that defendant’s works were non-infringing.

Plaintiff’s Approach

In contrast, plaintiff in substantial similarity litigation will typically attempt to have the court define the idea at a higher level of abstraction or generality, thereby permitting plaintiff to argue the similarities in the respective works arise from defendant’s appropriation of plaintiff’s expression, not its idea. In other words, plaintiff will attempt to show that, because there are many ways to convey the generalized idea, defendant could have created its work in any number of ways that bear no obvious similarities to plaintiff’s work. If defendant’s work nevertheless contains protectable elements similar to those in plaintiff’s work, plaintiff’s will then have a greater chance of convincing a court that the similarity in expression is infringing.

Thus, in Rogers v. Koons above, plaintiff might have described the idea of his photo as “two persons with 8 dogs on their laps.”

Further, in litigation involving the jeweled pin below, plaintiff will best be able to demonstrate substantial similarity by having the court define the work in abstract terms as simply a jeweled insect pin. In that case, such a pin can be expressed in a number of ways with any number and kinds of jewels. If defendant’s product contains a similar design with similar number of jewels arranged in a similar pattern, that similarity in expression is likely to be found infringing. See Goldstein, §2.3.2 (2013-1 Supplement). On the other hand, defendant will urge the court to define the work in detail as a butterfly insect pin with symmetrical wings adorned with multi-colored jewels.  The definition the court adopts may be outcome determinative.

Primer on Idea : Expression Distinction jeweled insect pin

No Better Way Has Been Found to Reconcile Copyright Protection with Competition

Despite the difficulties and uncertainties in applying the idea/expression dichotomy when determining substantial similarity in copyright litigation, courts continue to apply the distinction because courts have found no better way to balance the need to reward and protect copyrighted creations while allowing others to build on earlier works.

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