One intriguing feature of the human communication system is the interactional infrastructure
it builds on. In both dyadic and multi-person interactions, conversation is highly
structured and organized according to set principles (Sacks et al., 1974). Human adult
interaction is characterized by a mechanism of exchange based on alternating (and
relatively short) bursts of information. In the majority of cases, only one person
tends to speak at a time and each contribution usually receives a response. What is
remarkable is the precise timing of these sequential contributions, resulting in gaps
between speaking turns averaging around just 200 ms (Stivers et al., 2009). From psycholinguistic
experiments, we know that the time it takes to produce even simple one-word-utterances
(min. 600 ms, Indefrey and Levelt, 2004) by far exceeds this average gap duration,
hinting at the complexity of the cognitive processes that must be involved (Levinson,
2013).
While the behavioral principles governing turn-taking in interaction have been researched
for some decades—primarily by scholars of conversation analysis—the cognitive underpinnings
of the human turn-taking system have long remained elusive. Recently, psycholinguists
have begun to explore the cognitive and neural processes that allow us to deal effectively
with the immensely complex task of taking turns on time. Amongst other things, this
has highlighted the anticipatory, predictive processes that must be at work, as well
as the different layers of processing allowing production planning and comprehension
to take place simultaneously (de Ruiter et al., 2006; Magyari and de Ruiter; Bögels
et al., 2015). These insights mesh well with the conversation analytic literature
that has illuminated the interactional environments in which individual turns are
embedded: their sequential organization and the use of conventionalized linguistic
constructions allow for the projection of upcoming talk, as well as for the recognition
of points of possible completions in the turn which make transition to the next speaker
relevant (Sacks et al., 1974; Ford and Thompson, 1996; Schegloff, 2007). The articles
in this Research Topic bring together these as yet largely independent lines of research
to elucidate our understanding of turn-taking from multiple perspectives and aim to
foster future synergies.
In addition to exploring the adult psycholinguistic machinery and its workings, researchers
have begun to wonder how and when the required cognitive and social processes mature
in children, as well as how they compare to those in other species. Levinson (2006)
proposed that human beings are inherently social and interactive in orientation. He
argues that an “interaction engine” may lie at the heart of children's early predisposition
for turn-taking. Likewise, this particular human capacity might explain the strong
cultural universals in the structure of human interaction as well as the striking
commonalities and differences in communication systems brought about by the course
of evolution.
The present Research Topic provides a collection of experimental and observational
empirical studies using qualitative and quantitative approaches, complemented by articles
offering reviews, opinions, and models. They aim to inform the reader about the most
recent advances in our endeavor of unraveling the workings of the human turn-taking
system in communicative interaction. The contributions are organized into six sections:
(1) Foundations of turn-taking, (2) Signals and mechanisms for prediction and timing,
(3) Planning next turns in conversation, (4) Effects of context and function on timing,
(5) Turn-taking in signed languages, and (6) Development of turn-taking skills.
Foundations of turn-taking
The articles in this section outline models of human turn-taking, specify the interaction
of the various psycholinguistic processes that underlie our ability to take conversational
turns on time, and test the applicability of human turn-taking models to non-human
animal species. Levinson and Torreira review behavioral and cognitive findings specifying
the parameters of the processes underlying the human turn-taking system. This empirical
evidence is synthesized into a model claiming that intention ascription and response
planning begin as early as possible during the incoming turn, running through all
the serial stages of speech production à la Levelt (1989) before the response is launched,
triggered by turn-final cues. Garrod and Pickering propose a model that specifies
two processes. The first is based on the entrainment of brain oscillations that allow
listeners to predict when the incoming turn will end. The second is constrained by
the first and based on covert imitation, allowing listeners to determine the intention
conveyed by the incoming turn. The final article in this section addresses the phylogenetic
development of turn-taking skills. Henry et al. look at the European Starling's turn-taking
behavior, finding evidence for both temporal and structural regularities, the influence
of the immediate as well as the wider social context in which turns are produced,
and of emitter-specific factors influencing the behavior—thus pointing toward strong
similarities with some of the features shaping turn-taking in humans. In addition,
they provide comparisons with other starling species, leading the authors to argue
for turn-taking behavior having co-evolved in close interdependency with social structure.
The empirical studies collected in the rest of this Research Topic support various
components of these proposed turn-taking models while in places being at odds with
some of the claims made. As much as the current volume is a summary of the state-of-the-art
in the field, it also aims to stimulate future research that will help us piece together
the parts of the remarkable puzzle that human turn-taking poses.
Signals and mechanisms for prediction and timing
One of the central debates on the cognitive processes involved in turn-taking focuses
on the role played by prediction. Part of this debate is the issue of which kinds
of cues adults may use for predicting the end of turns, allowing them to come in on
time. The article by Riest et al. further advances this debate by testing, in three
offline experiments, the relative contribution of syntactic, and semantic information
to turn-end anticipation. It shows that, while both types of information are essential,
adults rely predominantly on the latter. The article by Holler and Kendrick builds
on this work by using eye-tracking technology to investigate the responses of observers
directly immersed in a conversational setting. The data show that observers' eye movements
toward next speakers are not random but guided by points of possible completion in
current turns, thus revealing interactants' sensitivity and orientation toward the
semantic, syntactic, prosodic, and pragmatic information that becomes available as
turns unfold. The article by Hiroko zooms into the projective power of specific lexicogrammatical
particles in Japanese (wa, mo, and tte). These become available to listeners as turns
unfold in conversation and often allow next speakers to predict the content of ongoing
turns. Himbert et al. throw light on yet another source of information that speakers
in interaction may use for timing their turns: their analysis demonstrates that interlocutors
adapt their turn-taking rhythms to one another, which they argue is facilitated by
the alignment of semantic and syntactic processes.
Planning next turns in conversation
The contributions in this section explore some of the cognitive processes involved
in preparing next turns in conversation. Applying a cutting edge statistical approach
(“random forests”) to data from a large conversational corpus, Roberts et al. explore
the value of both psycholinguistic factors (e.g., word frequency and syntactic complexity)
and conversational structures (e.g., the sequential relationships between turns) as
explanatory factors when modeling the timing of turns in conversation. Their results
show that both sets of factors significantly contribute to explaining variation in
turn timing. Torreira et al. study pre-answer in-breaths in a dialogue setting using
insights from acoustic and inductive plethysmography recordings. They demonstrate
that the occurrence of an in-breath is dependent on the length of an answer, suggesting
that answers are planned prior to these in-breaths. Since the pre-answer in-breaths
in their data were launched close to the end of question turns, the data provide evidence
for the concurrence of comprehension and next utterance planning.
Effects of context and function on timing
Three articles investigate the interplay of turn-taking rules with other principles
shaping human behavior in specific conversational contexts. Kendrick shows that turns
dealing with problems of speaking, hearing, and understanding (i.e., other-initiations
of repair) are governed by different timing principles and can thus break the common
pattern of minimal gaps between turns. As the analysis reveals, the longer gaps characteristic
of repair sequences tend to be used by participants as opportunities to either allow
the producer of the trouble source to resolve the issue before repair is initiated,
to allow themselves to resolve their problems in understanding before initiating repair,
or to signal problems in understanding through visual displays (e.g., eyebrow raise)
before initiating repair verbally. The article by Gardner and Mushin provides evidence
from Garrwa, an indigenous Australian language, for turns that are followed by substantially
longer gaps than one would ordinarily expect based on prior work on English conversations.
In these cases, however, it is not repair that drives the longer turn transition times;
the environment in which they occur is slow-paced conversation, appearing to reduce
the pressure for gap minimization. Stevanovic and Peräkylä discuss perspectives on
the intersection of two different systems of temporal organization, that of turns
at talk and that of emotional reciprocity—the former favoring sequential organization,
the latter affording simultaneity and immediate uptake through emotional contagion
and mimicry.
Turn-taking in signed languages
The research presented in this section investigates the principles of turn-taking
and sequence organization in signed languages where communication is constrained to
the visual modality. De Vos et al. analyze the timing of turns in Sign Language of
the Netherlands (NGT), showing that the timing of turns in signed conversation looks
remarkably similar to that of spoken interaction (i.e., with minimal gaps and minimal
overlaps) when considering not simply onset and offset of manual movements but individual
movement phases (preparations, strokes, retractions). Girard-Groeber examines turn-taking
principles in multi-party conversations in Swiss German Sign Language (DSGS), focusing
on the occurrence of overlaps. She, too, finds striking similarities with spoken interactions:
the examples provided illustrate a strong orientation to the “one at a time” principle,
an orientation of participants toward points of possible completion in the sign stream,
and a set of principles that appear to determine deviations from this rule (such as
repair initiations or strong disagreements). Manrique and Enfield focus on a particular
type of turn transition environment—other-initiated-repair—in Argentine Sign Language
(LSA), thus complementing Kendrick's work on repair in spoken interaction (this volume).
However, their focus is on how repair is elicited in visual question-answer sequences
rather than on the timing of turns in the repair environment, revealing the frequent
use of a visual display form termed the “freeze-look.” Next to clearly unique features,
the three articles point toward some striking similarities regarding the timing and
organization of turns in spoken and signed languages.
Development of turn-taking skills
Convergent findings regarding principles governing turn-taking across languages in
different modalities hint at the possibility of a shared cognitive infrastructure
underlying all human communicative interaction. This cognitive infrastructure may
also account for the ease with which young children appear to acquire the necessary
skills to interact with others. The contributions included in this section focus on
the acquisition of turn-taking in very young infants and in children as they start
to master spoken language. The first two articles suggest that temporal turn-taking
skills are learned early on in infancy. Gratier et al. demonstrate that already at
8–21 weeks babies are active participants in, as well as initiators of, turn-taking
sequences, but also that at this early stage of development mothers play a core role
in the timing of turns by adapting their behavior to the infant. Hilbrink et al. provide
a longitudinal study showing that turn-timing skills continue to develop continuously
from 3 to 18 months, with some regressive slowing down as language comprehension kicks
in around the “9 month revolution” (Tomasello, 2008). Clark and Lindsey provide a
case study of one child's (1;4-3;5 years) verbal and gestural responses to questions.
The pattern they find nicely fits with the temporal slowing down in vocal turn-timing
caused by the challenge of having to master language—while verbal responses often
occurred with long delays, the child frequently produced gestural responses preceding
speech. The following two articles examine children's use of linguistic cues for anticipating
upcoming next turns when observing dyadic conversations. Keitel and Daum find that
three but not 1 year olds are able to make use of intonational cues for predicting
upcoming next turns. In line with this, Lammertink et al. find that 2 year olds make
use of prosodic cues for predicting upcoming next turns, but that they make use of
lexicosyntactic cues, too, even weighing these more strongly—just like adults do.
Funding
The authors were supported through the Max Planck Gesellschaft and European Research
Council (Advanced grant #269484 INTERACT awarded to SCL) during the preparation of
the editorial and the research topic as a whole.
Conflict of interest statement
The authors declare that the research was conducted in the absence of any commercial
or financial relationships that could be construed as a potential conflict of interest.