It Walks Like a Duck, Talks Like a Duck, . . . but Is it a Duck? Making Sense of Substantial Similarity Law as it Applies to User Interfaces

• Publication year: 1992

UNIVERSITY OF PUGET SOUND LAW REVIEWVolume 16, No. 1FALL 1992

It Walks Like a Duck, Talks Like a Duck, . . . But Is It a Duck? Making Sense of Substantial Similarity Law as it Applies to User Interfaces

Ellen M. Bierman(fn*)

In copyright law, a plaintiff must prove copyright infringement through proof of valid copyright ownership and copying. Copying may be proved through circumstantial evidence of access to the copyrighted material and "substantial similarity" between the protected work and the allegedly infringing work. In the Ninth Circuit, the case law has created confusion about how to apply the substantial similarity test to different kinds of subject matter, especially software user interfaces. Moreover, recent cases do not comport with the original Ninth Circuit test announced in Sid and Marty Krofft Television Prods. Inc. v. McDonald's Corp.(fn1); the test may "walk like a substantial similarity test and talk like the Krofft test," but it is not clear that the same results are achieved. This Comment addresses these recent Ninth Circuit cases, explains why they are nevertheless desirable, and examines how the court should apply substantial similarity analysis to user interfaces in the future.

I. Introduction

Congress enacted copyright law, which grants limited monopolies to authors in the exclusive use of their writings, to further the constitutional mandate of promoting science and the useful arts.(fn2) Copyright law also seeks to balance two competing social interests: (1) rewarding an individual's creativity in order to encourage progress; and (2) enabling others to use and build upon the fruits of such creativity as soon as possible.(fn3) To balance these competing goals, copyright law rewards and protects creativity by limiting other individuals' rights to use an author's creation. However, copyright protection is limited to the author's expression-the ideas embodied in the creation are freely available for public use.(fn4)

In light of these goals, Congress and the courts have developed a set of principles and doctrines that define copyrightable subject matter and that limit protection within such subject matter to the incident expression. Incident expression is expression that is not essential for the realization of an idea.

The United States Copyright Act explicitly defines the subject matter that can be protected.(fn5) The Act is supplemented by doctrines such as the idea/expression dichotomy,(fn6) merger, and scenes a faire, all of which limit the protectable matter to the author's original and incident expression.(fn7) Only original and incident expression is protectable by copyright law; otherwise, an author would indirectly receive a monopoly on the underlying idea because no one else could use the idea without including the author's expression.

Application of these doctrines and principles has not always been consistent as copyright law has evolved to embrace new technologies, such as computer software. Few people would disagree that computer software is copyrightable subject matter.(fn8) However, courts continue to struggle with the scope of protection appropriate for different parts of computer software, such as the screen displays and user interfaces.(fn9) In addition, courts struggle with the application of traditional copyright doctrines to software programs.

Typically, courts confront these issues under the umbrella of the "substantial similarity" analysis. Courts use substantial similarity analysis to infer improper appropriation when the expression contained in two works is so alike that one appears to be copied from the other.(fn10) In deciding whether a work is substantially similar to another, a court must use various copyright doctrines(fn11) that define and limit protectable elements of the infringed work.

In general, different courts apply different versions of the substantial similarity test. The Ninth Circuit's version of the substantial similarity test is particularly difficult to apply to user interfaces for two reasons: First, the application of copyright law to user interfaces is inherently problematic. Second, recent developments in the case law have obfuscated the test.

The first difficulty in applying the substantial similarity test to user interfaces relates to the inherent dual nature of such software: the mixed functional and aesthetic nature of user interfaces makes it difficult to separate protectable from unprotectable elements. On the one hand, a user interface serves the fundamental purpose of enabling a user to communicate with the software (and the underlying computer) in order to accomplish specific tasks. Functionally essential elements of the interface that are necessary embodiments of procedures, processes, and ideas, are specifically excluded by the copyright statute.(fn12) In general, utilitarian works are given a limited scope of copyright protection.(fn13)

On the other hand, the presentation of a user interface may have aesthetic purposes; it may differentiate one software product from another with similar capabilities by providing different visuals or behavior. In addition, the user interface may provide a "mood" for the software that entices a user to choose a particular system or that makes the system appear easy to use.(fn14) To the extent that user interface elements exhibit aesthetic expression, they should be protectable like other literary and visual works.

The second difficulty in applying the substantial similarity test to user interfaces, especially under Ninth Circuit case law, is that the substantial similarity test has evolved to a point of confusion.(fn15) Because of the divergent case law, it is no longer obvious which elements the trier of fact may take into account when determining substantial similarity. For example, several recent decisions applying the substantial similarity test to factual and functional works have precluded the trier of fact from examining anything other than the protected expression when judging the works as a whole for similarity.(fn16) It is not clear from these cases whether user interfaces should be treated like functional works for this purpose.(fn17)

In addition, as a result of the divergent case law, the court's role in the substantial similarity test seems to have changed. For example, recent Ninth Circuit decisions have allowed courts to examine the similarity of expression between works with the aid of expert testimony and detailed analysis before submitting the issue to a trier of fact.(fn18) Moreover, one decision applied this new principle directly to user interface software infringement and implied that this principle should be applied to all subject matters.(fn19)

Thus, the Ninth Circuit case law has created confusion about which aspects of the substantial similarity test apply to which kind of subject matter. Moreover, these cases do not comport with the original Ninth Circuit test laid down in Sid and Marty Krofft Television Prods. Inc. v. McDonald's Corp.(fn20) However, this Comment asserts that changes embraced by these cases are necessary and desirable to promote the goals of copyright law and advocates a more uniform test for achieving more uniform results.

Towards that end, this Comment recommends how courts should apply the substantial similarity analysis to user interfaces. Specifically, this Comment (1) delineates the state of the law in the Ninth Circuit and explains how the recent changes should be interpreted with respect to user interfaces; (2) establishes an analytic framework for evaluating proposed substantial similarity tests through the enumeration of a set of goals specific to user interfaces; and (3) uses this analytic framework to evaluate and endorse a test that applies traditional copyright doctrine in a logical and consistent manner.

To accomplish these objectives, the remainder of this Comment is divided into four sections. Section II lays out the traditional substantial similarity test under Krofft and discusses how the test has been modified by recent cases. This section also addresses the possible application of these modifications to user interfaces and describes a recent decision involving user interfaces.(fn21) Because courts have sufficiently deviated from the Krofft test, because the Ninth Circuit has recently addressed the confusion with respect to user interfaces, and because there is at least one user interface case currently before the court, a rare opportunity exists for the Ninth Circuit to clarify the substantial similarity test in general, and as it applies to user interfaces.(fn22)

Section III of this Comment sets up an analytic framework for evaluating any proposed revisions of the test. This section lays out a set of goals that should be addressed by a substantial similarity test from the user interface perspective. These goals include the following: (1) promote standardization and compatibility; (2) foster competition; (3) account for the dual functional and aesthetic role; (4) enable fine differentiation where limited protection is available; (5) provide useful guidelines to developers and designers; (6) enable consistent application of principles; and (7) enable fair resolutions.

Section IV then identifies and compares the approaches that the Ninth Circuit could adopt. One approach consists of tests that are peculiar to the subject matter protected. Some recent...