Archives of Design Research

Typically, when developing a product in industry, companies create a document that contains information related to the target market, broad constraints, and project objectives. This document is often called the design brief (Ulrich, 2012; Sadowska and Laffy, 2017). Based on this document, product development teams establish a clear set of design specifications, which spell out in precise, measurable details information related to what the product should be and do in terms key features and expected deliverables. For instance, a design constraint might indicate quantifiable limits in the product size for a specific purpose (e.g., diameter, weight). However, design constraints could also be positioned in terms a qualitative aesthetic or sensory requirement that a future product is required to possess. However, little is yet known of how these different design constraints affect the outcomes of product design. In this study, we investigate how design outcomes are derived when two different sets of design constraints are provided to two groups of designers.

Research on the relationship between design process and constraint has been conducted in various fields. For example, Onarheim’s (2012) work in the field of engineering design explored how design constraints affect creativity in the product development process. Likewise, the current study illustrates how designers may exhibit constraint-oriented tendencies to invent creative strategies to overcome initial constraints. In this context, the current paper empirically examines how the provision of specific constraints at the start of design ideation may implicate the design outcome. In doing we aim to understand how design constraints, provided at the beginning of a new product development process relate to and inform both outcomes and the means through which they are arrived. This knowledge has the potential to support the appropriate positioning of constraints through an understanding of how they may influence the direction of design development and the eventual outcome.

For the purposes of the current empirical study we focus upon two types of design constraint, ergonomic and aesthetic. Ergonomics refers to a discipline of study that explores user interact with the environment, adopting measurable and objective methods to understand humans/product interactions (International Ergonomics Association., 2014). On the other hand, design aesthetics are associated with subjective feelings and emotional responses perceived through the senses and relate to more subjective sensory-emotional values (Zangwill, 2008).

These two design constraints have been chosen because, although both differ in theirprioritisation of design features (i.e. ergonomic function, aesthetic product attributes), both are often considered significantly important to product design. Previous studies have confirmed these two factors as important to commercial success (Nayak, 2015). In addition, it has been noted that ergonomics and aesthetics are important factors for innovation. For example, Rampino's (2011) theoretical model of product design innovation positions the three, related elements of innovation as: Form, Mode-of-Use, and Technology (Rampino, 2011). The Mode-of-Use construct has clear relation to ergonomic considerations in its focus upon innovation through different and improved use.

However, this doesn’t mean that two attributes; ergonomics and aesthetics may be considered to be in opposition and/or mutually exclusive. Both may, in fact factors complementary one another. The current study thus explores how the imposition of the constraints may implicate conceptual design outcomes as experimental conditions. These are thus used in our attempt to examine how design constraints may influence conceptual design outcome.

This pursuit of improved function often relates to and is informed by objective data on human beings’ sensory and cognitive abilities (cognitive ergonomics), together with anthropometric measures (physical ergonomics). In contrast, Form is described as a more subjective lever related to human emotion. The Rampino (ibid) model of product innovation further describes these two levers as resulting in either Aestheticor of Use innovations. In this sense we position ergonomic design constraints as related to the objective, quantifiable requirements of design. In contrast our aesthetic dimension described the more subjective, qualitative and emotional needs of design.

This paper reports a study aimed at examining the influence of design constraint, used during the design process, upon conceptual design outcomes. Towards this end we position Ergonomic and Aesthetic constraints as constructs to examine their influence. Towards these aims, we identified the following research question: How does the provision of ergonomic or aesthetic design constraints affect the quality and novelty of conceptual design outcomes?

Here we define quality as the extent to which outcomes have the potential to provide excellence in achieving functional requirements. For example, the concept’s ability to support ease of scooping, comfort and convenience on storing, washing and practical application (scooping ice-cream). Quality also refers an ability to arouse positive emotion and stimulate improved user experience through the use of appropriate, aesthetically pleasing and/or emotionally stimulating forms, materials and composition of forms. Novelty is defined as the extent to which a concept design provides departures from a product archetype, on both functional and aestheticdimensions (i.e. how similar or different is the product’s function and/or aesthetic when compared to a typical ice-cream scoop). In defining novelty as construct to measure dependent upon the independent variables ergonomic and aesthetic designconstraints, we realise a required subjectivity in assessment of novelty by the user. That is, degree of novelty is, to an extent, dependent upon one’s own experience of ice-cream scoops and scooping ice-cream. However, we attempted to control for this subjectivity through our sampling approach to product evaluations at phase three of the empirical study.

Six designer participants were recruited for the design workshop studies and divided into two groups: Ergonomic Group and Aesthetic Group. We then ran three design workshop sessions with two participants each. Each session took 2.5~3 hours to complete. Participants all possessed a bachelor's degree in industrial design and had experience working on Industry related design projects of one year or more. As part of their education, all had taken product design studio courses which cover creating design concepts, visualizing, and design skills. Four females and two males participated (Avg. age: 24.8, SD=1.36), with all participants enrolled onto a graduate industrial design programme at the authors’ home institution.

Because the two design constraints used within the current study are derived from ergonomic and aesthetic considerations, it was important to identify a product where both ergonomics and aesthetics are of particular importance. Following the online learning course undertaken by Karl (2017), ice-cream scoop was selected as product for the Design Workshops at phase one of the empirical study. In terms both aesthetic and ergonomic design considerations, contemporary products often consider both practical and emotional factors in design towards ice-cream, its branding and sale. For example, the ice-cream producers, Haagen-Dazs, employ a brand image implying luxury and high-quality (Newlands, 2016). In such contexts, their products need to exemplify their brand image through careful consideration of product personality derived from form, colors, material and finishes.

Figure 2 Haagen-Dazss premium Ice-cream Boutique (Haagen-Dazs, 2018)

From a more functional perspective, scooping ice-cream can often cause stress fracture of the hand. Previous studies reveal that strain injuries represent a significant portion of worker’s compensation claims in retail ice-cream outlets (Dempsey, 2000). Thus, design towards improved ice-cream scoops provided both opportunities for aesthetic and ergonomic considerations in pursuit of improved quality.

Three key terms were provided to the Ergonomic Group: ergonomic, practical, and ease-of-use. At the start of the workshop guidelines were provided for designing an ice-cream scoop through the application of ergonomic knowledge and design principles (Figure 3). The appropriate handle diameter, angle available, and grip-types were provided for this purpose.

Figure 3 Workshop materials provided to participants: Ergonomic design group (above), aesthetic design group (below).

We also introduced how the goals of ergonomic design may be met, including relevant example cases of best practice in ergonomic design; i.e. OxO Good Grips by OxO/Smart Design (Smart Design, 2017). The OxO Good Grips/Smart Design reference was provided as a classic example of a focus upon functional improvement in pursuit of universal design.

In contrast, the provided keywords within the aesthetics workshop were: high-value, desirability and beauty. Again, example cases were provided to participants; the Alessi Familiy Follows Fiction kitchen range (Alessi, 2017). The Alessi kitchenware range is often cited in the literature as example of meaning change in design (Verganti, 2009). That is, the Alessi range aimed to elicit motional response from users, where before kitchen products had been sold on utilitarian reasons of usefulness to the task at hand. In this sense the Alessi examples were provided as indicative of emotional design, drawing upon product aesthetic to elicite motive response (Norman, 2004).

In both cases, possible contexts for product use were also provided as examples (Figure 3).

Due to time constraints, designers participating in the workshops were required to communicate their ideas through one concept board and a low-fidelity prototype. However, the completeness and detail of these submissions differed dependent upon the groups. Therefore, it was necessary to standardise the quality of design outcomes derived from each of the workshop sessions. To do this, the researchers produced 3D models, rendered 3D images, and prototypes based upon design outputs. The aim was to express the characteristics of the concepts designed by the participants. In an attempt to ensure the designers’ intent was maintained as far as possible during the process of refinement, the refined designs were subjected to a validation session with the original designers. The extent to which the designs reflected original intent was discussed and revisions made as appropriate. Figure 4 provides an illustrative example of a design refinement expressed through a 3D CAD (Computer Aided Design) model and prototype.

Figure 4 Example design refinements

To further help illustrate the designs, we made introduction videos to help evaluators understand how to hold and use the scoops. The concept sketches originally submitted by the designers contained a rough overview of how to hold and use each scoop design (Figure 4). However, the fidelity was not constant, with some sketches difficult to understand. Therefore, we needed to make the fidelity of communication constant in terms how the scoops were designed to be used. Therefore, we recorded short (typically 10-15 seconds each) videos showing how to grip and use the scoop. Our researchers recorded each video using 3D printed prototypes. Each video recording provided a close-up of how to hold the scoop, including grip-type and scooping action. No actual ice-cream was scooped during the video recordings.

The six concepts, derived through the design refinement process, underwent professional evaluation by two design experts. The two experts had eight and five year’s industry experience respectively. Both held under and postgraduate degrees in the field of industrial design. During the evaluation session, experts evaluated each design concept through consideration of a design concept board, product introduction video and prototype.

In order to further assess the usability of the designed products, tubs of frozen ice-cream were provided during evaluation sessions. The expert participants were asked to evaluate the refined design outcomes through an open-ended evaluation approach, with conversation and discussion recorded for subsequent qualitative analysis. An evaluation sheet was also provided to assist in the assessment of the refined design outcomes based upon the review criteria of the Reddot design awards competition, with particular focus upon ergonomic and aesthetic evaluation (Reddot, 2017).This criteria includes 1) Degree of Innovation, 2) Aesthetic quality, 3) Functionality, 4) Emotional content, and 5) Impact. We included evaluation sheet in the appendix section [C5].

A further final question was added to specifically evaluate degree of innovativeness. The expert evaluation session lasted 75 minutes in total.

Figure 5 Expert evaluation session

While professional evaluation measured design quality, user evaluation was conducted to evaluate design outcomes from the potential user group. Fourteen potential users (6 female, 8 male, n=14, average age 24, SD=4.5) were recruited for a user-evaluation study. Design evaluation was conducted using concept boards, prototypes and video materials. Taken from the validated set of bipolar semantic differential scales (SDs) identified by Khalaj and Pedgley (2014), users were asked to assess design quality in terms form and usability. Table 1 illustrates the SD scales provided during the user evaluation.

Table 2 Compares design outcomes produced by the ergonomics group.

Group	Code	Design Features
Ergonomics Group	Ergo Scoop A	Design to reduce arm fatigue through two-handed use alternately. Inspired from climbing stick (Hiking pole).
	Ergo Scoop C	Rotating-blade concept to more easily scoop hard-frozen ice-cream.
	Ergo Scoop E	Scoop to minimise wrist-stress by reducing rotating action of users’ wrist.

In terms the ergonomic design group, as expected, participants focused on the usability of their ice-cream scoop designs. For example, the handle grip of Ergo Scoop A is designed to be used with both hands freely. The designer mentioned the application of insights from mountain climbing sticks. Further, the form of the pointed scoop end was designed to scoop frozen ice-cream easily. In terms Ergo Scoop C, the concept was designed to allow users to rotate the handle, which in turn rotated the scoop’s blade. The designer described this function as helping users scoop frozen ice-cream more effectively. As with Ergo Scoop A, Ergo Scoop C was designed to be operated through two-handed use for increased efficiency in power transmit. Ergo Scoop E, in contract, aimed to minimisewrist rotation during scooping.

Unsurprisingly, design outcomes derived from the Ergonomic Group showed various attempts to improve product use-function (grabbing and holding, grip-types, scooping method etc.). Conversely, Aesthetic Group design outcomes (Table 3) showed evidence to indicatesimilar usage characteristics (i.e. the standard scooping use-action) across the three concept designs submitted, with differentiation between concept derived from form, colour and materials.

Group	Code	Design Features
Aesthetics Group	Aes Scoop B	Streamlined ice cream scoop design.
	Aes Scoop D	Designed with a motif/metaphor of the form of a bird's beak Sharp, bird-like scoop-spoon.
	Aes Scoop F	Motif in material and form of Korean embroidery Meaning blessing and good luck.

As expected, the aesthetics group identified ideas towards the form and personality characteristics of their design concepts. For example, Aes Scoop B applied the theme of natural-curve, designed to combine two different materials with consideration of form composition. Aes Scoop D expressed a bird's beak motif with its use function of scooping hard ice cream. Likewise, Aes Scoop F was inspired by the traditional Korean craft product Amboori. Holistically, if the Ergonomics Group focused upon use-function aspects of their design concepts, the Aesthetic Group showed various attempts to explore forms and materials to derive novel product personality as driver for differentiation from an archetypal scoop design. Relatedly, a notable feature of Aesthetic Group design outcomes was the use of analogy/metaphor as inspiration for design. The final six refined design outcomes are illustrated in Figure 6.

Figure 6 Designed outcomes.

Users evaluated the appropriateness of the six outcomes through two sets of SD scales (Khalaj and Pedgley, 2014) targeting both ergonomic (Usability SDs) and aesthetic (Form SDs) considerations (Table 4). The advantage of using the prescribed bipolar pairs was that they provided a common reference to ease comparison between designs. A two-tail t-test was run to examine if there were any significant differences in user responses between design concepts derived from the two groups (i.e. Ergonomic design concepts and Aesthetic design concepts). 14 participants evaluated the 6 ice-cream scoop designs in a repeated measures experiment using 12 SDs (Table 4).A mean score (x) for each of the 12 SD-scale response items was then derived through the sum of user responses to the three ergonomic designs across the 12 scales. This process was repeated for aesthetic designs. A t-test was then conducted to statistically compare the 12 mean scores for each of the two groups across the 12 SD-scale response items. Table 4 provides results including statistically significant difference (p < .05) in response towards the two groups of design outcomes across the 12 SD-scale response items.

3. 2. 1. Usability

Significant differences between Usability (ergonomic) response items U1, U2, U3 and U6 (Table 4) are further illustrated in Figure 7.

Figure 7 Differences between design outcomes, four Usability response items

Analyzed as a group, the three aesthetic design outcomes were evaluated significantly more positively compared to the ergonomic group in terms four response items related to product usability (Khalaj and Pedgley).Specifically, user participant responses indicated design concepts from the aesthetics group were assessed to be significantly more Clear(M=1.97, SD=0.9), Easy to use (M=2.5, SD=1.4), Comfortable (M=2.6, SD=1.3), and Reliable (M=2.3, SD=0.6). This was an unexpected result in that we assumed designs derived from the Ergonomic design sessions would attract more positive user response in termsusability aspects compared to the aesthetic derived designs. It may have been that, in their exploration and proposition of concepts that significantly departed from archetypal use-functions (i.e. two-handed use, twist and cut design, Ergo Scoop C) participants felt unsure of their ability to achieve their practical function. That is, in their pursuit of innovative use interventions, the ergonomic derived designs were seen as potentially less functional in their ability to achieve the goal of their intended use (i.e. scooping frozen ice-cream). This result was supported by findings from the expert session. If this was the case, it appeared the ergonomic design constraints, while stimulating pursuit of difference in use-function, the same difference may have stimulated feelings of uncertainty towards the radically different concepts’ ability to perform the intended task (ice-cream scooping).

Further, qualitative user responses indicated participants considered products of the aesthetics group similar to those that they generally thought of and had used. For example, Expert #2 suggested, “It looks a little ordinary, but it looks like a very well-made and luxurious product.” On the other hand, the difference from the typical design shown by the ergonomics group's pursuit of usability improvements, resulted in confusion in how the designs may be used, together with uncertainty around their effectiveness. In contrast, it was the typicality of the aesthetic concepts that stimulated more positive response towards usability.

3. 2. 2. Quality of Form

The comparative analysis of design concepts also showed significant differences between four Quality of Form response items (Figure 8).

Figure 8 Differences between design outcomes in terms 4 Form response items

Participants assessed design concepts derived from the Aesthetics Group as significantly more elegant (M=2.1, SD=0.9, conditions; t (82) =4.3, p=.000), organic (M=1.7, SD=0.4), asymmetrical (M=3.6, SD=2.2) and high-class (M=2.3, SD=0.9). While design concepts from the Ergonomics Group were evaluated as significantly more inelegant (M=3.3, SD=1.0), geometric (M=2.5, SD=1.4), symmetrical (M=2.8, SD=2.7), and low-class (M=3.1, SD=1.1).

This result indicated more positive responses towards the aesthetic derived concepts (i.e. elegant and high-class) compared to the Ergonomic designs. That is, in line with expectations, the user evaluation identified the aesthetic driven scoop concepts as more elegant and high-class, indicating the relation between guidelines proffered at the start of the aesthetic design sessions (i.e. the design should be high-value and beautiful). As expected, the user evaluation study indicated these requirements were translated to inform scoop design compared to the ergonomic design outcomes.