The cocktail party problem: What is it? How can it be solved? And why should animal behaviorists study it?

“[17] Mark A Bee and Christophe Micheyl.”

“Manifestations of auditory streaming have been observed in various nonhuman species, including birds, fish, and monkeys, suggesting that streaming is a fundamental aspect of auditory perception, which plays a role in adaptation to diverse ecological environments (Bee and Micheyl, 2008; Fay, 1998, 2000; Hulse et al., 1…”

“J Speech Lang Hear Res 52(5):1230–1240.”

“Other social animals such as birds and rodents demonstrate a similar ability (Bee and Micheyl, 2008); for instance, mother mice respond to distinct pup calls when several are calling at once (Geissler and Ehret, 2002).”

“Although the results of some of these studies were reviewed in earlier publications [3–12], during the past two years, several new findings have emerged.”

“Auditory masking as a result of this situation will decrease the discrimination and/or detection of behaviorally relevant signals, depending on the degree of signal (spectral) overlap (Riede 1997; Wollerman and Wiley 2002; Brumm and Slabbekoorn 2005; Bee 2007; Bee and Micheyl 2008; Schmidt and Römer 2011).”

“The first alternative is unlikely, however, because increases in call duration increase the time-bandwidth product of the sound, allowing greater temporal integration time for receivers, which is likely to increase detectability of the call (Bee & Micheyl, 2008).”

“Biotic and abiotic sources of environmental noise can constrain acoustic communication, for example, by making signals more difficult to detect and recognize (Narins & Zelick 1988; Klump 1996; Brumm & Slabbekoorn 2005; Bee & Micheyl 2008).”

“Whether it is the buzzing of our surroundings or on-going conversations, our minds are bombarded by endless streams of auditory signals [e.g., (Conway et al., 2001; Denham and Winkler, 2006; Jaaskelainen et al., 2007; Micheyl et al., 2007); reviewed in (Bee and Micheyl, 2008; Winkler et al., 2009)].”

“By comparison with humans, we know relatively little about sound source perception in nonhuman animals (Hulse 2002; Bee & Micheyl 2008).”

“…males of many anuran species are confronted with the challenge of detecting, locating and discriminating conspecific males in breeding aggregations (Bee & Micheyl, 2008; Richardson & Lengagne, 2010) or environments that hamper propagation and transmission of acoustic signals (Boeckle, Preininger,…”

“Following previous studies (Bush et al. 2002; Schul & Bush 2002; Beckers & Schul 2004 ), I computed phonotaxis scores for each masking condition as a percentage by dividing the mean latency from Reference 2 and Reference 3 by a female’s latency to respond to the target signal in the particular masked condition of inte…”

“Fortunately, in a broad evolutionary sense, the cocktail party problem can be viewed as a speechspecific example of a much more general communication problem that is encountered, and solved, by many nonhuman animals (Bee and Micheyl, 2008; Hulse, 2002).”

“Comparable studies on animals in different taxa have shown that they have to solve rather similar problems, in particular those that live in larger aggregations and social groups [9], [10], [11], (see Bee and Micheyl for an excellent review dealing with cocktail party-like problems in animal communication [12]).”

“Similarly, the neuronal computations required to recognize communication signals embedded in noise are not well understood although it is known that humans [6] and other animals [7] excel at this task.”

“The perceptual mechanisms by which nonhuman animals solve cocktail-party-like problems potentially include abilities to exploit various spectral, temporal and spatial cues (Hulse 2002; Bee & Micheyl 2008).”

“For the acoustic domain, animals use numerous adaptations to maintain information transfer despite signal masking, which involves both special perception and production mechanisms (Klump 1996; Brumm & Slabbekoorn 2005; Bee & Micheyl 2008).”

“As acoustic signals such as individual anuran advertisement calls are difficult to localize in a chorus situation (Bee & Micheyl, 2008; Richardson et al., 2010), or in environments (e.g. dense vegetation) that hamper the propagation and transmission of acoustic signals (Wells & Schwartz, 1982;…”

“an offspring in the midst of a loud chorus [3,4].”

“More recently, it has started to attract the interest of both animal behaviorists and neuroscientists (for reviews, see Carlyon 2004; Micheyl et al. 2007b; Snyder and Alain 2007; Bee and Micheyl 2008; Fay 2008; Shamma and Micheyl 2010).”

“Additional studies of source segregation in the context of animal communication stand to reveal a great deal about the mechanisms and evolution of sensory systems and their role in generating adaptive behaviors [13].”

“This is a general problem in hearing, and it is a specific biological analogue of the human ‘cocktail party problem’ [2].”

“[11]; [12]).”

“This could also allow her to discriminate the courting male's sound pattern from the noisy environment of the vocalizing flock mates and provide an example of ‘spatial release from masking’ (Bee & Micheyl, 2008).”

“Signal masking is a ubiquitous problem in animal communication, because individuals must often communicate in the presence of noise (Brumm & Slabbekoorn 2005; Bee & Micheyl 2008).”

“These and other examples in animal communication have many parallels to the classic cocktail party problem, i.e., recognizing speech in complex acoustic environments (Cherry, 1953; Brémond, 1978; Hulse et al., 1997; Bee and Klump, 2004; Bee and Micheyl, 2008).”

“Spatial partitioning, on the other hand, involves divergence in the locations from which the signal is emitted (Hodl, 1977; Bee, 2008).”

“mask one-another[42,60–62].”

“The natural behaviors of many non-human animals indicate that they also regularly encounter and solve problems of auditory stream segregation in their daily lives (reviewed in Hulse 2002; Bee and Micheyl 2008).”

“1 is a psychoacoustic phenomena, which refers to the remarkable ability of the human auditory system to selectively attend, recognize and extract meaningful information from a complex auditory signal, where interfering sounds are produced by competing talkers [7]–[9].”

“…neural mechanisms in different species including humans (for recent reviews, see Carlyon, 2004; Micheyl et al., 2007; Snyder and Alain, 2007; Bee and Micheyl, 2008; Shamma and Micheyl, 2010), on the development of conceptual and computational models accounting for psychophysical and…”

“Incorporating temporal context could also help separate concurrent singers (the cocktail party problem [7]).”

“Most laboratory studies play back ambient noise from a single or two speakers, creating an acoustic situation that is quite different from the natural one, where there are multiple sound sources, each at a different location (Bee and Micheyl 2008).”

“84).”

“…the precise location of individuals, relative to structural elements of the environment as well as other signalers, should be especially important in determining the extent to which receivers can assess important features of communication sounds (Schwartz and Gerhardt 1995; Bee and Micheyl 2008).”

“Compared to our understanding of how humans perceive speech in noisy settings, however, we know little about how nonhuman animals solve evolutionarily analogous problems (Bee and Micheyl, 2008; Hulse, 2002).”

“Both may be essential for the reception of auditory signals in humans and other animals (Bee and Micheyl 2008).”

“Despite similarity with the human “cocktail party problem,” a phenomenon that describes the difficulty we have following a single conversation in multi-talker social environments (Cherry 1953; Bronkhorst 2000; McDermott 2009), few studies have investigated mechanisms that allow nonhuman animals to solve parallel probl…”

“This preference for calls out of synchrony is assumed to be a general strategy across anuran species, given that females select signals in aggregations where overlapping signals impose a cognitive challenge for localizing and discriminating individual signals [7,37].”

“However, evolution by natural selection has solved biological analogs of the human cocktail party problem numerous times [3, 8].”

“The receiver must (1) perceptually group sequences of temporally separated signal units and (2) integrate simultaneous harmonic (or quasi-harmonic) sounds produced by a given signaller, often in the presence of interfering biotic and abiotic sounds1.”

“In our experiment, test subjects were presented with playback of three opposite-sex birds differing in their familiarity: (1) their partner, (2) a familiar and (3) an unfamiliar individual.”

“…body of experimental data on auditory streaming in humans, and neuroscientists are starting to explore the neural basis of this phenomenon in both humans and nonhuman animals, the evidence for auditory streaming in animals remains limited (for recent reviews, see Bee & Micheyl, 2008; Fay, 2008).”

“Various species across disparate taxa must also identify and locate complex acoustic signals in multi-source environment”

“In the third section, therefore, we ask whether the confusion effect might also apply to situations in which multiple species use acoustic signals, a situation referred to as the “cocktail party effect” (Bee and Micheyl, 2008).”

“The perception of multimodal signal components with different times of arrival may be especially challenging when many signalers display at the same time and place, such as frogs calling from choruses or birds singing at dawn [31].”

“Understanding how listeners with normal hearing solve the cocktail party problem has remained a focus of study for over 50 years (e.g., see Bee & Micheyl, 2008; Bodden, 1993; Hafter et al., 2013; Wood & Cowan, 1995; Yost, 1997), in no small part because of its importance: difficulties in such…”

“…complex communication systems, such as anuran communication in which auditory stream analysis presents a particular problem (Farris et al., 2002; Bee and Micheyl, 2008), auditory filtering is important for discrimination of individual signalers and thus should result in strong selection…”

“Furthermore, auditory streaming has been found in multiple animal species (for a review, see Bee & Micheyl, 2008), suggesting that the phenomenon is quite general.”

“Meanwhile, this mechanism was found in different sensory systems of various species including insects (Levin and Miller, 1996; Spezia et al., 2008), frogs (Bibikov, 2002), mammals (Frisina et al., 1996; Lewis and Henry, 1995; Henry, 1999) and humans (Zhang-Cai et al., 2004; Zeng et al., 2000).”

“While noisy settings can impair intelligibility of speech sounds in humans (the cocktail party problem; Cherry 1953; Bee and Micheyl 2008) and signal detection and discrimination in non-human animals (Bee and Schwartz 2009; Schmidt and Römer 2011), receivers may improve their performance in noisy…”

“These constraints potentially act as sources of selection that can influence the evolution of how signals are designed (Boncoraglio and Saino, 2007; Ey and Fischer, 2009; Ryan and Kime, 2003), how signalers behave to produce signals in time and space (Brumm and Slabbekoorn, 2005; Ryan and Kime, 2003) and how the audit…”

“…Author M anuscript N IH -PA Author M anuscript commonly referred to as “auditory streaming”— is an active area of research for auditory psychophysicists, behaviorists, and neuroscientists (for reviews, see: Bee & Micheyl, 2008; Carlyon, 2004; Fay, 2008; Moore & Gockel, 2012; Snyder & Alain, 2007).”

“Obviously, group living animals may face the cocktail party problem, but also heterospecific signallers may contribute to a receiver’s perception problem (Bee and Micheyl 2008).”

“There have been several avian studies on the “cocktail party problem” (CPP; Cherry, 1953), which refers to the difficulties that humans (Homo sapiens) and other animals encounter when trying to communicate in noisy environments (recently reviewed in Bee & Micheyl, 2008).”

“…level differences (ILDs) is critical for sound localization and sound source separation in noisy environments (Hine et al. 1994; Roman et al. 2003; Bee and Micheyl 2008), understanding how these binaural spatial cues are processed is of clear interest both from a clinical and basic science…”

“Investigation into how nonhuman animals perceive acoustic signals in such environments is necessary to understand the potential diversity of mechanisms that have been evolutionarily exploited or derived to solve cocktail-party-like problems (Bee and Micheyl, 2008).”

“Yet, our brains can solve the blind source separation problem effortlessly (Bronkhorst, 2000; Asari et al., 2006; Narayan et al., 2007; Bee and Micheyl, 2008; McDermott, 2009; Mesgarani and Chang, 2012; Golumbic et al., 2013; Isomura et al., 2015).”

“The perceptual tasks faced by animals when they communicate in large aggregations are rather similar to the difficulties faced by humans when they attempt to understand speech in noisy social settings (Cherry, 1953; reviewed in Bee & Micheyl, 2008).”

“Signals may become muddled in noisy environments where many avian species are trying to communicate simultaneously, thus birds often need to be able to discriminate conspecific vocalizations from those of heterospecifics in order to communicate effectively (Bee & Micheyl, 2008).”

“In cases of spectral overlap between noise and signal, acoustic masking may occur, which results in a reduced ability of a receiver to detect and/or decode the signal (Dooling, 2004; Bee & Micheyl, 2008).”