Apple designer Jonathan Ive took over some of Forstall's responsibilities and had "made his distaste for the visual ornamentation in Apple's mobile software known within the company". With the announcement of iOS 7 at WWDC in 2013, Apple officially shifted from skeuomorphism to a more simplified design, thus beginning the so-called "death of skeuomorphism" at Apple. Other virtual skeuomorphs do not employ literal images of some physical object; but rather allude to ritual human heuristics or heuristic motifs, such as slider bars that emulate linear potentiometers and visual tabs that behave like physical tabbed file folders. Another example is the swiping hand gesture for turning the "pages" or screens of a tablet display. Virtual skeuomorphs can also be auditory. The shutter-click sound emitted by most camera phones when taking a picture is an auditory skeuomorph. Retrofuturism incorporates spatial motifs from previous iterations of the future; especially visions of electro-industrialism. This is frequently incorporated in retrowave or synthwave illustrations. Skeumorphic time is closely linked with metamodernism. Skeuomorphic design seems to be preferred by older recipient groups often referred to as digital immigrants while digital natives tend to favor flat design over skeuomorphisms. However, younger people are still able to understand the signifiers that skeuomorphic design employs. A better user experience could be measured for each respective design philosophy among digital natives and immigrants. Although it is often proven that digital immigrants are more likely able to perceive and understand all available functions in an application, it has been found out that some affordances that do not have direct signifiers e.g. the function to flip pages in an ebook by simple swiping from right to left are less likely to be found by older users. However, all associated Functions should be included when a certain metaphor is used. For example users are likely to feel frustrated when trying to pull a file into the trash bin only to find out that this gesture does not delete the file. An argument in favor of skeuomorphic design is that it makes it easier for those familiar with the original device to use the digital emulation by making certain signifiers to affordances stronger. Interactions with computer devices are mostly cultural and learned. Once a process is learned and adopted in a society, it develops persistence. Proposals for change, especially radical change, often result in debate between proponents and opponents. Don Norman describes this process as a form of cultural heritage.