Visual objects and Auditory Objects

From CNBH Acoustic Scale Wiki

In the description of perception to this point there has not been any need to use the terms “visual object” or “auditory object”; indeed, the description to this point might be said to be more about sensation than perception. The situation immediately begins to change, however, if I tell you that the first two calls are the species-specific communication sounds of (a) a Mongolar drummer fish, or Jamaica weakfish (Cynoscion jamaicensis) and (b) a North American bullfrog (Lithobates catesbeiana). They are the sounds used by males to declare their territories, to ward off other males and to attract females. If I play the sounds again with this knowledge in mind, you can probably imagine them puffing up to present themselves to their world. The third sound, (c), is a “coo call” from a macaque (Macaca mulatta), and it is anthropomorphically described as ‘a call emitted when the animal is foraging in the forest out of sight of other macaques, to elicit similar calls from other macaques within earshot, for mutual reassurance that they are not alone and there is no imminent danger’. Now if I play the sound again while you are thinking about the lonely macaque foraging nervously in the forest, this information will get attached to the call in your mind, and when auditory events acquire meaning, the more perceptual auditory scientists start to call them auditory objects, and this seems a reasonable distinction. The fourth sound, (d), provides a similar example; you may have already recognized that it is me saying the syllable /ma:/. You may not have recognized it because it was presented as an animal call in the context of other, clearly non-human, animal calls. Either way, the /ma/ now has added meaning, and some people would refer to it as an auditory object. In general, it seems useful and sensible to refer to the perception of an acoustic event that has no immediate interpretation or meaning, as an auditory event, and the perception of an acoustic event that is instantly perceived in terms of its meaning, as an auditory object. The main question in this regard seems to be the level of meaning below which we would agree to call it an auditory event and the level above which we would agree to call it an auditory object. One useful examples for thinking about the distinction between auditory objects and events occurs when you are listening intently to one source, say a friend speaking, in a multi-source environment, say a busy market with many people making ‘noise’, and you are successfully ‘ignoring’ the background sources. The individual acoustic events flowing from your friend are immediately interpreted as words, and so they are auditory objects; similar words from people you are ignoring, are acoustic events which produce activity in the auditory system up to the level at which they are ignored. As such they might be described as auditory events that do not progress to the level of processing where they would become auditory objects.