Understanding nonverbal communication (NVC) is important in a range of situations and settings, from daily relationships to interrogations (Krauss et al. 1996). Research has shown that NVC includes both reflexive and nonreflexive movements of the body, which communicate an emotional message to others (Tamietto and De Gelder 2010). Correct interpretation of individuals’ emotional states and intentions is obviously important for effective communication; however, a particularly important area for NVC is in police and legal investigations. During a police interview or interrogation, investigators may implicitly or explicitly use NVC reading techniques to identify the concealment of emotions, which may indicate an intent to deceive or a line of questioning worth pursuing (Hartwig and Bond 2011; Mann et al. 2004). Behavioural cues of mental effort, memories and emotions are used by security personnel to identify behavioural ‘hot spots’ that indicate that a topic is worth considering and investigating further (Frank et al. 2008). Typically, research has focused on behaviours related to particular emotions or concealment of information (Ekman and O’Sullivan 1991). Sporer and Schwandt (2007) outline several reliable indicators of deception, such as nodding, movement of feet and legs and hand movements; however, they showed no systematic relationship between avoidance of eye contact and deception. However, researchers and professional practitioners in the field have suggested that clusters of behaviours are better indicators of changes in emotion and possible psychological discomfort, which may arise from attempting to deceive someone (DePaulo et al. 2003; Navarro and Karlins 2008, Navarro 2011; Vrij et al. 2004). The present research continues a more recent trend in NVC by investigating the possibility that it is not only discrete behaviours or clusters of movements that can be used to indicate emotion or distress but also the sequence that these movements occur in (Burgoon et al. 2014; Burgoon et al. 2015). Previous research that has focused on sequences of behaviour has used a software programme that detects patterns in time-ordered data. These T-patterns (see Casarrubea et al. 2015) are a multivariate approach to identifying temporal structure in behaviour. Burgoon et al. (2014), therefore, used a very similar statistical approach to the one taken in the current study; however, their series of studies focused on mock theft, cheating game behaviours and group discussions and deception. The current study uses a similar statistical approach, but with real-world deception.

Understanding and interpreting NVC typically start by identifying discrete, single behaviours, referred to as tells (Collett 2003; Ekman et al. 1991; Navarro and Karlins 2008). Hartwig and Bond (2011) outlined the leakage hypothesis as a means by which individuals leak informative tells while trying to conceal the truth. For instance, poker players who have become successful at reading NVC have the ability to identify particular behaviours of their opponents. This line of research, however, has limitations in terms of individual differences in the ability to mask emotion and deception (Blanck et al. 1981).

In contrast to looking at single behaviours or micro reactions, researchers have suggested that ‘clusters’ of behaviours are better indicators of changes in emotion and psychological distress, which may reflect attempts to deceive (DePaulo et al. 2003; Hartwig and Bond 2011; Navarro and Karlins 2008; Vrij et al. 2004). Therefore, simply recognising one single behaviour as an indication of emotions or lying is not completely reliable, though Hartwig and Bond (2011) highlight that while multiple cues may be better than single cues, individual behaviours still contribute a lot to the detection of deception. The cluster approach, which is based on more applied settings, outlines that NVC involves the changes of behaviours across the entire body (i.e., movement of feet, hands, face, etc.). This research has gained support from applied fields of forensic and investigative psychology and police work (Furnham and Taylor 2011). While the cluster approach has proven effective, there may be an additional step in terms of understanding the sequence of body movements. For instance, it may be possible that body movements occur in sequence (i.e., the feet change movement first, followed by the face). Research has shown that if an individual attempts to mask one behaviour, they may leak behaviours on other parts of their body (Ekman and Friesen 1969). Looking at patterns of behaviours in deceptive and truthful interactions has been previously researched by Burgoon et al. (2014, 2015). In their seminal research, patterns of nonverbal behaviour, across time, were analysed, showing clear differences between deceivers and truthful participants. Burgoon and colleagues’ research provides a clear foundation to begin future development in investigating patterns and sequences of behaviours, rather than individual behaviours or clusters. It is to this direction the present research builds on, by using real-world deceptive statements, rather than mock crime experiments.

Behaviour Sequence Analysis

Behaviour sequence analysis (BSA), also referred to as lag sequence analysis (LSA), is a useful method for understanding the dynamic relationship between progressions of behaviours and social interactions occurring over time (Beune et al. 2010; Keatley et al. 2016; Taylor et al. 2008). Sequence analysis typically involves three key stages (Clarke and Crossland 1985). First, unitisation involves taking a person’s whole response to a question and cutting it into discrete behaviours or events. Second, classification involves placing the behaviours or events into distinct categories that are functionally similar. Finally, analysis involves the statistical measurement of whether transitions between behaviours are occurring significantly above the level of chance. For example, if we imagine a simple chain of behaviours, question asked (category a), respondent shakes head (category b), respondent taps finger (category c) and respondent looks up and right (category d), first-order or lag-one behaviour sequence analysis tests whether ‘a-b’, ‘a-c’, b-c’ and ‘c-d’ pairs, for instance, are more or less likely to occur than by chance alone. Therefore, sequence analysis begins by first finding stimuli (e.g., video clips of individuals caught lying or telling the truth) that can be analysed. A coding scheme is then developed so that each individual behaviour shown in the stimuli can be categorised (e.g., ‘head-nod’, ‘eyes-looks down’). When an exhaustive and mutually exclusive list is developed, all stimuli are then coded. The sequence analysis then measures transitions between pairs of behaviours, to see if pairs occur above chance.

BSA is underpinned by Markov models, which involve studying transitions between behaviour pairs (Ivanouw 2007). The first event in a pairing is the antecedent (e.g., nods head); the second behaviour in a pair is the sequitur (e.g., taps finger). In the simplest form of BSA, the analysis determines whether the antecedent causes the sequitur to be more likely to occur, than expected by chance. Sequence analysis has been used in a variety of social interactions and behaviours, such as marital conflict (Gottman 1979), violent episodes between people (Beale et al. 1998; Turner and Clarke 2009) and rape cases, in relation to physical interactions (Fossi et al. 2005) as well as verbal interactions and strategies (Lawrence et al. 2010) between attacker and victim.

Present Study

The main aim of the current research is to provide a new method, behaviour sequence analysis, for understanding and researching NVC. Previous research has shown that the accuracy rates of trained professionals are modest, in terms of detecting deception through NVC techniques (Burgoon et al. 2014; Burgoon et al. 2015; Frank and Ekman 1997; Vauch et al. 2016). However, many NVC studies lack ecological validity (Richardson et al. 2000; Scriba et al. 1999). Although participants in lab-based experiments may be motivated towards an outcome, they are not at risk of major negative consequences for being exposed, as a criminal would be in a real investigation. Indeed, the absence of such high stakes might not produce a sufficient amount of anxiety or motivation for the person in question to display valid facial cues or NVC (Miller and Stiff 1993). Therefore, the current study used real-world recorded videos of people, rather than in a laboratory. The sample chosen were criminals, and/or people of high power, who were later unequivocally exposed as being guilty at the time of making the statements of innocence that were recorded and analysed. Owing to the nature of the current study, no formal hypotheses were made. However, it is likely that previous research into NVC will be supported as elements of larger sequences. There are also likely to be differences in the chains of behaviours exhibited between deceptive and truthful statements. Based on the research by Hartwig and Bond (2011) and Sporer and Schmidt (2007), behaviours related to head movements and hand movements are likely to be different between honest and dishonest statements, and clusters of behaviours are likely to occur, but with certain individual behaviours occurring more frequently in honest and dishonest statements.