Irrelevant idiosyncratic acts as preparatory, conﬁrmatory ... · H. Keren et al. / Behaviour 150 (2013) 547–568 551 free-throws and weightlifting. For the free-throw task, ten

Behaviour 150 (2013) 547–568 brill.com/beh

Irrelevant idiosyncratic acts as preparatory,confirmatory, or transitional phases in motor behaviour

Hila Keren a, Joel Mort b, Pascal Boyer c,d, Omri Weiss a and David Eilam a,∗

a Department of Zoology, Tel-Aviv University, Ramat-Aviv 69978, Israelb 711th Human Performance Wing, US Air Force Research Laboratory, WPAFB, OH, USA

c Department of Psychology, Washington University, St. Louis, MO, USAd Department of Anthropology, Washington University, St. Louis, MO, USA

*Corresponding author’s e-mail address: [email protected]

Accepted 23 February 2013

AbstractMotor behaviours typically include acts that may seem irrelevant for the goal of the task. Theseunnecessary idiosyncratic acts are excessively manifested in certain activities, such as sports orcompulsive rituals. Using the shared performance (commonness) of acts as a proxy for theirrelevance to the current task, we analysed motor behaviour in daily tasks, sport-related tasks,and obsessive-compulsive disorder (OCD) tasks. For each task, these motor behaviours comprisedcommon acts that were performed by all the individuals, and idiosyncratic acts that were performedby only some individuals. In all three tasks there was a temporal section that included all thecommon acts (termed ‘body’). This body section was preceded by a sequence of idiosyncraticacts that we termed ‘head’, and was followed by another sequence of idiosyncratic acts that wetermed ‘tail’. While both head and tail sections were relatively short in the daily tasks, the headwas relatively long and the tail largely absent in sport-related tasks, which have a definite end andhigh stakes. In contrast, OCD behaviour had a relatively long tail. In light of these results, wesuggest that the head is a preparatory phase and the tail a confirmatory phase. The head may beviewed as a warm-up phase for the pragmatic section of the task (‘body’), and the tail as a cool-down phase. Finally, we suggest that rituals may be viewed as a descendant of pragmatic activities,which differentially feature a greater terminal phase of idiosyncratic acts in OCD, and an extendedinitial phase of idiosyncratic acts in sport rituals.

Keywordssport rituals, motor routines, OCD rituals, displacement activity, adjunctive behaviour.

© 2013 Koninklijke Brill NV, Leiden DOI:10.1163/1568539X-00003071

548 Irrelevant idiosyncratic acts in motor behaviour

1. Introduction

Although motor behaviour is usually goal-directed, it may involve acts thatseem irrelevant to the goal. For example, displacement activities in ethologyand adjunctive behaviour in psychology refer to movements (acts) that occuroutside the appropriate behavioural context to which they belong function-ally, and that appear intermittently in the midst of another ongoing behaviour(Immelmann & Beer, 1989; Fraley, 2003). Similarly, daily motor tasks thatare performed regularly during everyday human life, such as getting dressed,making coffee, preparing breakfast, driving to work, etc., comprising well-established behaviours that have been shaped by repeated performances,seem to be executed without much attentional control, while also involv-ing parameters that can change from one task performance to the next (Ruhet al., 2005; Patsenko & Altmann, 2010). Indeed, despite featuring an obvi-ous goal, daily motor routines also incorporate a component of idiosyncraticacts that do not seem relevant to the goal of the routine (Keren et al., 2010).Performance of overt unnecessary acts is a salient feature of rituals (Boyer &Liénard, 2006). These could also be daily motor tasks that have become rit-ualized through the application of strict rules, such as ‘walk on the sidewalkwithout stepping on the lines’ (Boyer & Liénard, 2006). Ritualized behaviourseems to have become divorced from its original function and instead targetsan alternative goal such as preventing harm (Boyer & Liénard, 2006). Ritualsappear in a variety of domains and life stages, such as childhood, coming-of-age, pregnancy or parenthood (Evans et al., 2002; Abramowitz et al., 2003).Rituals are also prevalent in sport (Singer, 2002; Czech et al., 2004; Cot-terill et al., 2010), where they may take the form of what is thought of asthe superstitious behaviour (Lobmeyer & Wasserman, 1986) that character-izes specific individuals, similar to their fingerprints. Religious traditions arealso composed of ritualized behaviours: for example, religious circumcision,burial, the Jewish Bar Mitzvah or the Catholic Confirmation. Rituals alsopredominate the behaviour of obsessive-compulsive disorder (OCD) patientswho repeatedly perform salient cleaning, checking, ordering and hoardingrituals according to strict rules (Bloch et al., 2008; Markarian et al., 2010;Zor et al., 2011a). Indeed, many OCD patients are preoccupied with activ-ities that are intended to diminish their illusionary fear of potential dangerfrom contamination, contagion or risk to kin. Being preoccupied in such ac-tivities, the behaviour of OCD patients becomes a continual set of ritualsthat neutralize normal functioning. Nevertheless, rituals are not necessarily

H. Keren et al. / Behaviour 150 (2013) 547–568 549

pathologic and, as noted, they are also prevalent in normal life activities suchas sports and religion. Moreover, routine daily motor tasks are also carriedout in a stereotypic form that may seem reminiscent of rituals. Consequently,one of the aims in the present study is to compare sport rituals, daily tasks,and OCD rituals, and to uncover the similarities and differences among them.

Despite a high degree of variability among different rituals, several char-acteristics are shared throughout: formality, repetition, redundancy, stereo-typy, invariance, causal opaqueness and goal demotion (Rappaport, 1999).These characteristics make it easy to intuitively distinguish rituals from otherbehaviours (Boyer & Liénard, 2006; Liénard & Boyer, 2006). Moreover,ritualized behaviour, especially in OCD, seems to be time-consuming andirrational in terms of cost/benefit analysis. Nevertheless, the above criteriaare mostly subjective and the study of rituals is still in need of a method-ology by which to qualitatively define and quantitatively measure featuressuch as goal demotion, which predominate rituals. In light of both the di-versity of content and commonness of performance, the present study wasaimed at deconstructing motor behaviour in OCD, in sport-related tasks andin daily motor tasks, to its constituent components, in order to uncover anyqualitative and quantitative similarities or/and differences among them, in anattempt to understand what are rituals and why, when and how often theyoccur (Eilam et al., 2006; Zor et al., 2009a, b; Keren et al., 2010; Eilam &Mort, 2013).

A key problem for such analysis lies in how to evaluate the relevance ofeach act to the goal of the task. Specifically, when an OCD patient brushesher/his teeth, how is one to assess the subjective impression that certainacts performed by the patient are unnecessary for the tooth brushing? Inthe present study, we adopted the method of using shared performance ofacts (commonness) as a proxy for their relevance. In OCD, the relevance(or necessity) of an act to the task could be assessed by comparing the per-formance of an OCD patient with the performance of a matched non-OCDindividual who was requested to perform the same task. It, thus, becomespossible to distinguish between acts that were performed by both the patientand the non-OCD individual, and to consider these as common acts that arerequired for the task (pragmatic or ‘functional’ acts). In contrast, acts thatwere performed only by the OCD patient or the non-OCD individual may beconsidered as unnecessary for the task (non-pragmatic or ‘non-functional’acts), as demonstrated in the completion of the task by the other individual


without performing these acts (Zor et al., 2009a, b; Eilam et al., 2012). Inthe same vein, the commonality of acts can be used as a proxy to assess theirrelevance in daily and sport-related tasks: the more individuals performingan act in the context of the same task, the more relevant is this act to thattask. Conversely, the fewer times that an act is performed by different in-dividuals performing the same task, the less relevant is this act (Keren etal., 2010). Following this concept, in this research we analyzed OCD be-haviour, sport-related tasks (basketball free-throws and weightlifting) andseveral daily tasks (donning a shirt, making coffee, locking a door, starting acar, putting on shoes, lighting a cigarette). By comparing OCD rituals, nor-mal rituals (e.g., in sports) and normal motor activities, we sought to answerthe following questions: (i) what are the structural components of these mo-tor tasks; (ii) what might be the value of uncommon idiosyncratic acts thatare not directly functional for the tasks; (iii) how do idiosyncratic acts varyamong OCD, sport-related tasks and daily tasks; and (iv) is there a structuralindication for OCD rituals being a descendant of normal rituals such as sportrituals or daily motor routines?

2. Methods

2.1. Participants

2.1.1. OCD patients and their matching controlsThis part of the study was approved by the Helsinki Committee of GehaMental Health Center and the Institutional Helsinki Committee at Tel-AvivUniversity. Eight male and two female adult out-patients, meeting DSM-IV(APA, 2000) and SCID criteria for OCD with insight, and having compul-sions with obvious motor rituals, were videotaped at their homes, wherethey routinely perform compulsive rituals. Y-BOCS scores, ages and de-tailed diagnoses are given in the Appendix. After describing the study tothe subject, a written informed consent was obtained. A matched healthy(non-OCD) individual of similar age and gender was asked to perform thesame task that was performed by the OCD patient. For example, if a patientdescribed his/her behaviour as ‘lighting a cigarette’, the respective controlwas requested to ‘light a cigarette’.

2.1.2. Sport-related tasksThese were extracted from public-domain video-clips of two sport-relatedtasks that featured a repeated performance by the same individual: basketball


free-throws and weightlifting. For the free-throw task, ten adult active pro-fessional basketball players were chosen according to the availability of theirfree-throw shootings in publicly competitive games. For weightlifting, weused video recordings of ten adult weightlifters competing in the Olympicsand championships.

2.1.3. Daily motor tasksThis part of the study was approved by the Institutional Helsinki Commit-tee at Tel-Aviv University. Six daily tasks were chosen according to theirhigh prevalence and commonality in everyday life: donning a button shirt,making coffee, starting a car, putting on shoes, locking a door, and lightinga cigarette. Each daily task was performed by ten healthy adult volunteers(5 women and 5 men, age 25–50 years) who were recruited from the generalpublic by personal invitation from the researcher. Participants were askedto perform on-camera an everyday task (lighting a cigarette, making coffee,etc.) in their usual manner.

Altogether, the study comprised 10 OCD tasks and 10 non-OCD tasks,100 basketball free-throws (10 per player), 30 tasks of weightlifting (3 perweightlifter), 50 daily tasks (10 individuals per task) and 30 tasks for donninga button shirt (3 per each of the 10 individuals), as detailed below.

2.2. Design and procedure

2.2.1. OCD tasks and their matching controlsA psychiatrist and the researcher arrived at the patient’s home, describedthe research and again requested the patient’s consent to participate and tobe videotaped. The patient was then videotaped by the researcher with ahand-held camera for 1–2 h. After the session the patient was asked to ratethe degree of similarity between the videotaped ritual and their off-cameracompulsion. All patients reported a medium or high degree of similarity. Itshould be noted that once patients started to perform their behaviour, theperformance took over and they paid no further attention to the observer orthe camera but only to performing the ritual itself.

2.2.2. Sport-related tasksOne-hundred video-clips of successful free-throws, by 10 professional play-ers (10 per player) and 30 video-clips of successful weightlifting, by 10professional weightlifters (3 per weightlifter) were extracted from publiclyaired league games or Olympics games and weightlifting championships. We


used these videos with no experimentation, no intervention/involvement, andwithout revealing the identity of the basketball players/weightlifters.

2.2.3. Daily tasksUpon agreeing to perform one of the chosen daily tasks on camera, the vol-unteer was briefed on the purpose of the study, signed an informed consentdocument, and was then video-recorded with a hand-held camcorder (Pana-sonic SDR-H20) while performing the selected daily task. The participantswere then asked to rate the degree of similarity between the video sessionand their usual off-camera performance of the same task. All volunteers re-ported a medium to high degree of similarity. Each recording session tookless than 30 min. A total of 60 episodes of daily tasks were collected (10 foreach daily task). The individuals who performed the ‘donning a shirt’ taskwere requested to repeat it after one week and again after two weeks (totalof three repetitions for each volunteer).

2.3. Data acquisition and analysis

Video files were analysed by dividing each task into the objects/locationsat which the task took place, and the acts performed at each of these ob-jects/locations (Zor et al., 2009a; Eilam et al., 2012). Briefly, each task wasdefined as the set of acts that the individual performed in order to accom-plish it. In OCD and daily tasks the individual performing the task notifiedthe researcher when they started the task and when they had accomplishedit. In sport-related tasks, the beginning and end of the task were determinedby the researcher as follows: a free-throw started when the referee whistledto award it, and ended when the shot was made (since all instances were ofmade free-throws). A weightlifting task started when the weightlifter steppedinto the arena and ended when he released the weights. Thus, in both sporttasks, the end signal was set to an objective event that is apparent to boththe observer and the players. Everyone knows that the task is over and thatwhat follows is not related directly to task performance (celebrating, goingback to defence, etc.). In contrast, for the normal individuals performing adaily task and for the OCD patients, there was no such objective terminationsignal, and we had to rely on their subjective announcement that the job wasdone. The mental state of the individual who after donning a shirt smoothesit around the belt, folds the sleeves, or observes her/his image in the mirror,is that this is part of the task. Moreover, OCD patients who lack a sense of


task completion (a presumed mechanism of the disorder) continued to per-form the unnecessary acts. Accordingly, the mental state in OCD rituals andin normal individuals performing daily motor tasks is that it is not over untilthey say it is over. In contrast, both the sportsmen and the observer knowwhen the task is over due to an explicit external end signal. Following thisconcept, we did not consider the behaviour after the ball had left the hands infree-throws or the weight was released in weight-lifting, unless these subse-quent acts were performed within the task objects/locations (ball, weights).A few such acts occurred only in weightlifting, but not in free throws.

Once the beginning and end of each motor task were set, the analysis fo-cused on two spatio-temporal domains: (i) objects or locations by means ofwhich the task was executed (such as tooth-brush, door-knob, ball, shirt, but-tons, etc.); and (ii) the acts performed with each of these objects/locations.The acts were the basic operational unit of the task. For example, some ofthe acts (and the operative ‘object’) in donning shirt were fasten (a ‘but-ton’), stretch (the ‘collar’ or the ‘side of the shirt’), and insert (arm into a‘sleeve’). Some of the acts in free throws were bounce (the ‘ball’), wipe (the‘face’ with jersey), nodding (the ‘head’), etc. Accordingly, a task includedall the acts performed with the objects and/or at the locations within the taskstart and stop points, as defined above. We listed the acts that comprisedeach task, and scored them during slow-motion playback using Observer,a behavioural encoding and analysis software (Noldus Information Tech-nologies, Wageningen, The Netherlands).

It should be noted that parsing the continuum of specific behaviour into itsaction-space and the acts performed in each object/location within this spacewas also a criterion for setting the start and end of the task. Such parsingwas also applied by others when developing analytic tools for the study ofbehaviour (e.g., the ‘Observer’ and the ‘J-Watcher’ software for behaviouralanalyses). According to this parsing, the post-throw activity of basketballplayer was not in the action-domain of the task (the ‘paint area’) and wasperformed without the main object (the ball); the same applies for weightlifting. This was not the case in donning a shirt or in OCD rituals, in whichindividuals continued interacting with the same objects/locations with whichthey had interacted during the entire task. Accordingly, the activity beforetaking a free throw included the acts the player performed when taking upposition on the free-throw line (the action space) even if he had not yetreceived the ball.


2.4. Statistical analysis

A two-way ANOVA with repeated measures was used in most comparisons,where the between-group factor was the task (OCD, sport, or daily tasks) andthe within-group factor was the number of acts or act type. None of the testedparameters deviated significantly from normal distribution, as verified by aKolmogorov–Smirnov test. Proportion data were transformed into arc-sinusof their square root. Statistical analysis was performed using STATISTICA8 software, with α set to 0.05.

3. Results

3.1. Common and idiosyncratic acts in OCD, sport and daily tasks

Figure 1 depicts side-by-side the set of acts that comprised the behaviour ofan OCD patient filling his dog’s water bowl, and the same behaviour per-formed by the control non-OCD individual. The acts are listed in order ofappearance from top to bottom, with the common acts that were performed

Figure 1. The sequence of acts displayed by an OCD patient when filling his dog’s waterbowl, and the sequence of acts of a non-OCD individual displaying the same behaviour. Actsare listed from top to bottom. The middle column presents the acts that are common to boththe OCD and non-OCD individuals. The acts performed only by the OCD individual aredepicted in the left-hand column and the acts performed only by the control individual aredepicted in the right-hand column.


Table 1.The number of common acts and idiosyncratic acts (mean ± SE) is depicted in the table forOCD and their matching non-OCD controls, for both sport rituals and six daily motor tasks.

Common acts Idiosyncratic acts

OCD 20.5 ± 4.8 (54%) 17.4 ± 4.0Non-OCD controls 9.3 ± 1.5 (90%) 1.1 ± 0.6Sports

Free throws 1.0 ± 0.0 (20%) 4.9 ± 0.2Weightlifting 11.7 ± 0.2 (40%) 18 ± 1.0

Daily tasksDonning shirt 7.1 ± 0.1 (48%) 8.1 ± 0.5Lighting cigarette 7.1 ± 0.1 (61%) 4.7 ± 0.6Making coffee 17.4 ± 0.2 (45%) 21.4 ± 1.2Starting car 7.3 ± 0.2 (66%) 4.1 ± 0.7Locking door 6.5 ± 0.30 (90%) 0.8 ± 0.3Putting on shoes 12.0 ± 0.7 (57%) 9.1 ± 0.8

These data include repetition on acts (not the act repertoire) and, therefore, means for com-mon acts had a standard error despite the similar repertoire of common acts. The percentageof common acts out of the total acts (common + idiosyncratic) is depicted for each task nextto the common acts data.

by both the patient and the control given in boldface in the middle column.The idiosyncratic acts of the OCD patient are depicted in the left-hand col-umn, and the idiosyncratic acts of the control in the right-hand column.The common acts are considered as necessary for task completion and theidiosyncratic acts as unnecessary, as reflected in their absence in the perfor-mance of the task by the other individual. This dichotomy into common andidiosyncratic acts was preserved in all OCD rituals, sport rituals and dailytasks (Table 1). As can be seen in the table, idiosyncratic acts constituted aconsiderable part of the act repertoire.

At the time of videotaping, OCD patients were requested to display thetask that was recently prevalent in their behaviour. Their behaviour com-prised various tasks (see the Appendix), and these were compared with theirmatched control. Accordingly, each act could be performed by both OCDpatients and the control individual (common act) or by only one of them (id-iosyncratic act). In contrast, in sport-related tasks and daily tasks, for eachtask we had 10 individuals performing the same behaviour and, theoretically,an act could be performed by 1, 2, 3, 4 and up to 10 individuals. Neverthe-less, the definitions for common and idiosyncratic acts were strictly applied


also to the sport-related tasks and daily tasks, revealing that both of thesealso contained a major component of idiosyncratic acts (Table 1). A two-way ANOVA with repeated measures of the total number of each act type(common or idiosyncratic) in each task (OCD, Sport, Daily) revealed thatthere was no significant difference between them in the number of commonand idiosyncratic acts (F1,217 = 0.13; p = 0.72), but there was a signifi-cant difference between tasks (F2,217 = 29.0; p < 0.00001) and a significantinteraction between task and act types (F2,217 = 31.3; p < 0.00001). Theinteraction indicates that the ratio between common and idiosyncratic actsdiffered among the three behaviours. Indeed, an Tukey HSD test revealedthat in sport-related tasks, the number of idiosyncratic acts was significantlyhigher than the number of common acts. In addition the number of both com-mon and idiosyncratic acts in OCD tasks was significantly higher than boththese act types in sport and daily tasks (Table 1). Thus, whereas OCD tasksfeatured a high total number of idiosyncratic acts, sport-related tasks featuredfewer idiosyncratic acts, but these made-up a greater part (high percentage)of the total acts in sport tasks. This is probably why sport and OCD tasks areusually conceived of as rituals displaying certain overt activities that seemirrelevant to the task. Overall, motor tasks in OCD, sports and daily tasks in-corporated a component of unnecessary acts to the acts that were compulsoryfor task completion.

3.2. The temporal order of performing common and idiosyncratic acts

As can be seen in Figure 1, all the idiosyncratic acts of that specific OCD pa-tient were performed at the end of the task, after the set of common acts(left-hand column in Figure 1). In contrast, the idiosyncratic acts of thenon-OCD control individual occurred in between the common acts (right-hand column, Figure 1). This led to the question of the temporal order inwhich idiosyncratic acts occurred: at the beginning, the end, or through-out the tasks. Figure 2 depicts the acts in exemplary sequence for each ofthe motor tasks. As shown for the daily task (top), the common acts (opensquares) were preceded or followed by sets of idiosyncratic acts (filled cir-cles), with only a few idiosyncratic acts occurring in between the commonacts. Accordingly, we divided the entire task into three sections: (i) ‘head’,comprising the acts that preceded the first common act (accordingly, the headcomprised only idiosyncratic acts); (ii) ‘body’, starting with the first com-mon act and ending with the first performance of the last common act; and


Figure 2. The temporal order of performing common (1) and idiosyncratic (") acts in oneperformance of: (A) daily task (donning a button shirt); (B) one OCD task (preparing to leavehome); and (C) one sport-related task (weightlifting). The acts are presented from left to rightaccording to their temporal order of performance. Since the duration of acts by all individualsof this study did not significantly differ from each other (data not shown), the number of actsin each sequence also indicates its duration. Dashed vertical lines divide the sequence of actsinto the initial section (‘head’), which comprises only idiosyncratic acts, preceding the firstcommon act. The central section (‘body’) comprises all common and idiosyncratic acts untilthe first performance (repetition excluded) of the last common act. The last section (‘tail’)comprises the acts that followed the first performance of the last common act. The tail istypically idiosyncratic, comprising either idiosyncratic acts and/or repetition of previously-performed common acts. As shown, the OCD ritual (B) features an extension of the ‘tail’,while the sport-related task (C) features an extension of the ‘head’.

(iii) ‘tail’, including the acts that followed the first performance of the lastcommon act (accordingly, the tail comprised idiosyncratic acts and repeti-tion of previously-performed common acts). In this division, the body wasthe pragmatic (‘functional’) section since it included all the acts that weremost relevant for the task and, therefore, was necessary for task completion;whereas the head and tail sections were idiosyncratic and, therefore, non-pragmatic or unnecessary for task completion.

The exemplary OCD task (central section in Figure 2) illustrates thechange that occurred in OCD behaviour compared with daily tasks, with thetail becoming longer and comprising a major part of the task. Conversely,the sport-related tasks (bottom section in Figure 2) illustrate that the idiosyn-cratic head section constitutes a major part of the entire behaviour, and the


tail is absent. Act duration was relatively short in all tasks of all individu-als (OCD patients and non-clinical individuals and sportsmen) and, thus, thenumber of acts in each phase also represents phase duration.

The division into head, body and tail, as illustrated in Figure 2, was thenapplied to the sequence of acts in each performance of all the tasks, and themean (±SE) number of acts in OCD, sport and daily tasks was calculated.Since, by their nature, the tasks vary in the total number of acts (Table 1),the head, body and tail sections are depicted in Figure 3 as a percentageof the total number of acts. As shown in Figure 3, OCD tasks comprisea long tail and a short head. Sport-related tasks comprise a relatively longhead and the tail is largely absent, while daily tasks comprise a relativelyshort head and recognizable tail. Indeed, a two-way ANOVA with repeatedmeasures revealed a significant difference between OCD, sports and dailytasks (F2,87 = 3.9; p = 0.024), between the head, body and tail sections(F2,174 = 131; p < 0.0001), and a significant interaction of the tasks andtheir sections (F4,174 = 59; p < 0.0001). An HSD Tukey test revealed thatthe head in sport-related tasks was significantly longer than in OCD anddaily tasks, and the body was significantly shorter. The tail in OCD wassignificantly longer than in sport-related tasks. Altogether, the major sectionof daily tasks was the body, which was preceded by a short head and followed

Figure 3. The relative size of the ‘head’, ‘body’ and ‘tail’ sections of daily (top) OCD(middle) and sport (bottom) tasks. To facilitate comparison, the total duration of each taskwas considered as 100%, and the mean portion of the ‘head’, ‘body’, and ‘tail’ are depictedas the average (±SE) percentage of the total number of acts in each task. As shown, dailytasks comprised a long body with short head and tail, whereas in OCD tasks the tail was longand in sport tasks the head was long and the tail was short.


by a short tail, with the tail becoming longer in OCD and the head becominglonger in sports.

3.3. In sport and daily tasks, idiosyncratic acts dichotomized into those thatwere consistent within individuals but varied among individuals, and thosethat also varied within individuals

While the common acts, by definition, were performed by all individuals,idiosyncratic acts could either vary or be preserved among repeated perfor-mances of the same task by the same individual. Consequently, we analyzedrepeated performances of each of the 10 performing individuals for onedaily task (donning-shirt) and in both the sport tasks (weightlifting and free-throws). We did not have access to repeated performances of OCD taskssince an inherent drawback with the OCD patients was that, for variousreasons, they did not agree to display the tasks repeatedly. Therefore, thissection refers to only the two sport-related tasks and one daily task.

For each individual, whether a basketball player, a weightlifter or a shirt-donner, we classified the idiosyncratic acts into two types: (i) ‘personal acts’that were performed in all repetitions of the task by that individual; and(ii) ‘sporadic acts’ that were performed only in some of the repetitions bythat individual (Figure 4A). The mean proportion of each of these act typesin each of the tasks that were performed repeatedly is depicted in Figure 4B.As shown, the idiosyncratic acts were almost equally divided into personaland sporadic acts. A two-way ANOVA with repeated measure revealed asignificant difference between daily and sport-related tasks (F2,157 = 685;p < 0.0001), a significant difference between common, personal and spo-radic acts (F2,314 = 21.8; p < 0.0001), and a significant interaction betweentask and act type (F4,314 = 31.4; p < 0.0001). In each of the three tasks(donning-shirt, free-throw, weightlifting), there was no significant differencebetween personal and sporadic acts (Tukey HSD test). Altogether, threetypes of acts characterised each sport or daily task: (i) common acts thatwere performed in all the repetitions of all individuals; (ii) personal actsthat were consistent within individual performance but varied among indi-viduals; and (iii) sporadic acts that varied among and within individuals.The idiosyncratic portion was equally comprised of personal and sporadicacts.


(A)

(B)

Figure 4. (A) The acts that comprise motor tasks and the categorization of acts accordingto the commonness and consistency in their performance between and within individuals.(B) The mean (±SE) proportion of each act-type during repeated performance of donningshirt, free throws and weightlifting tasks.

4. Discussion

4.1. Preparatory, confirmatory, or transitional role as the possiblefunctions of idiosyncratic acts

In the present study, OCD rituals, sport rituals and daily motor tasks weredeconstructed into the sequential order of their structural units — acts. It wasfound that the common acts, which were the most relevant for these motortasks and, thus, considered as pragmatic (‘functional’), converged together


in a section of the sequence of acts that we termed ‘body’. The body sectionwas either preceded and/or followed by sections of idiosyncratic acts (termed‘head’ and ‘tail’, respectively). While common acts were performed by allthe individuals who performed the same task, idiosyncratic acts were specificto particular individuals, not performed by others and, therefore, consideredas less relevant, or non-pragmatic (‘non-functional’) for that task, as reflectedin its completion by the other individual without performing these acts. The‘body’, thus, constituted the functional section since it included all the actsnecessary for task completion, whereas the head and tail sections were notpragmatically necessary for task completion. When compared with dailymotor routines, OCD rituals included a longer tail section and sport rituals alonger head section.

We suggest that the ‘head’ is a preparatory section and the ‘tail’ a con-firmatory section, with both serving to ensure that the task is performedproperly. Accordingly, the accumulation of idiosyncratic acts before thepragmatic common acts (the head) in sport rituals is a preparatory phase.The preparatory head section is reminiscent of the ‘pre-performance routine’that is “a systematic sequence of task-relevant thoughts and actions which anathlete engages in systematically prior to his or her performance of a specificsports skill” (Moran, 1996). This is an effective way to achieve attentionalfocus, concentration and control, and these in return may increase the rate ofsuccess (Lobmeyer & Wasserman, 1986; Czech et al., 2004). In daily rou-tines, the head section is minor, perhaps since these tasks are not a salientwin-or-lose issue, unlike most sport tasks and, therefore, do not necessitatea major preparatory phase.

We suggest that the ‘tail’ is a confirmatory section that follows the bodysection. In daily routines, donning-shirt for example, the task has no explicitend, and the apparent tail comprises an activity of checking and confirm-ing that the task was properly performed. In OCD rituals, the tail was long,comprising mostly idiosyncratic acts that are less relevant to the task (goal)of the ritual and, thus, transmitted a sense of excessive non-functionalityin OCD rituals. These idiosyncratic acts were accompanied by repetition ofpreviously-performed common acts that were directly linked to the task (e.g.,re-checking that a door is locked) (Zor et al., 2011b). We suggest that thelonger tail in OCD rituals is due to its confirmatory nature. Indeed, OCDpatients are preoccupied in repeatedly and excessively performing specific


daily activities (APA, 2000). It was suggested that the underlying mecha-nism in OCD is incompleteness, or the lack of a ‘just right feeling’ or ‘satietysignal’, which indicates that the task has been properly completed (Summer-feldt, 2004; Wahl et al., 2008). The long tail section in OCD patients is inagreement with its confirmatory role, and in accordance with the notion ofincompleteness (Szechtman & Woody, 2004; Boyer & Liénard, 2006). Forfurther discussion of OCD rituals and incompleteness from the clinical per-spective, see Zor et al. (2011b).

The ‘confirmatory’ function of the tail may also explain why, in thepresent study, the tail section was largely absent in the sport tasks. In bothbasketball free-throws and weightlifting the clear termination, in either suc-cess or failure, makes the confirmatory phase unnecessary. Perhaps the ges-tures of celebration or disappointment that frequently appear after the strictend in sports should also be considered as a tail. However, these acts are per-formed in a different action domain, comprising acts that did not appear inthe head and body sections. For example, in free-throws, the ball, which wasthe object with which the player performed the task, is no longer availableto the player. In contrast to such sport-related remote acts, the tail in dailytasks and in OCD comprised either repetition of acts that were performedduring the head and body sections, or acts performed in the relevant actiondomain. For example, in the donning-shirt task, the tail comprised acts likeadjusting the collar or observing the wearer’s reflection in the mirror. Thus,while tail activity in OCD rituals and everyday tasks took place in the sameaction-domain of the head and body sections, sport-related tasks typicallydid not include a tail but, rather, a post-task activity in other action-domains.Due to the success-or-failure nature of sport-related tasks, their subsequentpresumed tail activity could not be confirmatory as in everyday tasks (orOCD), but rather constituted celebratory or disappointment gestures. Takingtogether the above characteristics, the prevalence of head and tail sections inmost tasks attests that these too have an adaptive value as preparatory andconfirmatory constitutes, even if their role is more psychological than prag-matic.

The ‘head’ and ‘tail’ amalgamations of idiosyncratic acts that seem lessrelevant to the current behavioural task is in agreement with a recent studyof ring-tailed lemurs (Lemur catta), providing evidence that such irrelevantactivities may facilitate transitions in behaviour (Buckley & Semple, 2012).Specifically, acts that may seem irrelevant to the ongoing behaviour are also


prevalent in animal behaviour, especially primates. These have been termed‘displacement activities’, considered out of context in relation to the pre-ceding and subsequent behaviours (Tinbergen, 1952; Immelmann & Beer,1989). Following the hypothesis that displacement activities enable the in-dividual to switch from one motivational state to another, it was found that,indeed, these irrelevant activities occur more frequently around changes inbehaviour (Wilz, 1970; Root-Bernstein, 2010; Buckley & Semple, 2012).Similarly, it could be argued that the head and tail sections are respectivelyaimed at building up the motivation required for a specific task, and thencooling down before switching to another task. These natural sections in mo-tor tasks are independently exaggerated in rituals. In OCD the long cooling-down phase is required in order to confer a feeling of task completion. Insport rituals, a long building-up phase is required in order to disconnect fromthe previous task and concentrate on the pragmatic performance of the im-pending task.

4.2. Idiosyncratic acts as either behavioural fingerprints or an adaptiveoutlet

Motor tasks featured three components of act types: (i) a ‘common (prag-matic) component’, which included the acts necessary for task completion;(ii) a ‘personal component’, which included the acts that characterize theperformance of a specific individual; and (iii) a ‘sporadic component’, whichincluded acts that vary among both individuals and repetitions. The questionarises as to the adaptive value and importance of each act type. The commonacts are those necessary for task completion, and none of the tested individ-uals in each task ever accomplished the task without performing these acts.These acts are, therefore, intrinsic to the task and are identified with its func-tion. For example, the acts ‘inserting arm into sleeve’ and ‘fastening a button’are essential for ‘donning-shirt’. The pragmatic component is, thus, the coreof the task; and the question arises as to why are there also idiosyncraticcomponents.

The idiosyncratic personal component comprised acts that were consis-tently preserved over repetition of the task by the same individual but variedamong individuals. These acts were not necessary for the task since other in-dividuals accomplished the same task without them. The numerous personalacts observed in sport-related tasks (37 ± 7% of the total acts) enable un-mistakable assignment of a specific performance to a specific player/athlete.


Accordingly, we suggest that this component serves as a form of behaviouralfingerprint. Players believe that performing a specific behaviour improvestheir performance, and this is a basic approach in sport psychology (Moran,1996; Singer, 2002; Weinberg & Gould, 2003; Cotterill et al., 2010). Thisprocess manifests itself in a variety of sport rituals, ranging from the clothesthat sportsmen wear, to the food they eat before competing, the warm-upthey perform and even the music to which they listen. All these rituals fea-ture a rigid performance and are considered as a way by which to achieveconcentration and disconnect from the stress of the situation (Eilam et al.,2006).

The question that remains regarding the structural components of motortasks is why there are ‘sporadic’ non-pragmatic acts that vary among indi-viduals and across the repeated performance of an individual, and, therefore,seem irrelevant to the task. In other words, what is the possible advantageof the inclusion of sporadic acts in task performance? The answer mightbe that they serve in preserving behavioural flexibility. This could be adap-tive for adjusting to possible changes in the environment. Indeed, a fullyautomatic performance may result in losing functionality or even in disaster,when there are environmental changes that require behavioural adjustment(Gersick & Hackman, 1990). An example of rigid behaviour that ignoredthe actual environmental conditions and resulted in functionality loss is pro-vided in water shrews that were used to jumping over a stone blocking theirusual path, and kept on jumping at this location even after the stone hadbeen removed (Lorenz, 1952). Another example is that of a parent who for-gets to drop off his baby at the daycare centre when this requires a deviationfrom his regular, automatic, route. This illustrates that even the (presumablyimportant) infant might get lost in automatic performance, since memoryis ‘cue-dependent’ and, in some cases, the cue is missed under the auto-matic performance (Shechter, 2001). The above examples illustrate that therequired correct response to changing circumstances can prove vital. We sug-gest that the adaptive value of the sporadic non-pragmatic acts lies in theretention of a certain flexibility, which interrupts the automated performanceand thereby enables the individual to adjust to changes in the environment.

4.3. Conclusions

The present study provides qualitative and quantitative analyses of OCD,daily and sport-related tasks. These were deconstructed spatio-temporally


according to the action space (locations or objects at which they took place)and the acts performed at each object/location. We found that there wereidiosyncratic acts that seemed unnecessary for the specific task, and suggestthat the function of these acts is more psychological than pragmatic. In OCD,idiosyncratic acts occurred mainly at the end of the ritual, in sports they usu-ally preceded the pragmatic task; and in daily tasks they occurred as briefbouts before and/or after the pragmatic phase of the task. Accordingly, ritu-als may be viewed as a descendant of pragmatic activities, which feature agreater terminal phase of idiosyncratic acts in OCD, and an extended initialphase of idiosyncratic acts in sport rituals. The lack of such analyses in thepast blurred the borders among the various forms of repetitive behaviours(Langen et al., 2011a, b). While the present study has focused on the formand structure of these motor tasks, further research is required in order touncover the underlying mechanisms of these motor behaviours. Moreover,the present findings are based on ten OCD rituals and their matching con-trols, two sport-related tasks and several daily motor tasks and, therefore,should be taken with caution when generalized to OCD rituals, sport ritualsand daily motor activity. Nevertheless, we have delineated the sections thatconstitute daily motor tasks (head, body, tail), as well as the exaggerationof one of these sections in sports and the exaggeration of another sectionin OCD. Furthermore, the finding that OCD behaviour substantially differsfrom sport-related tasks indicates that these behaviours that are consideredas rituals were derived from normal motor activity via different mechanisms.

Acknowledgements

We are grateful to the volunteers who participated in this study and to NaomiPaz for language editing. The study was sponsored by the Air Force Office ofScientific Research, Air Force Material Command, USAF, under grant num-ber FA8655-09-1-3107. The US Government is authorized to reproduce anddistribute reprints for governmental purpose notwithstanding any copyrightnotation thereon. D.E., P.B. and J.M. are Visiting Professors at the Depart-ment of OTANES, University of South Africa.

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Appendix.Details of the 10 OCD patients.

Patient Code Behaviour Gender Age Y-BOCS Diagnosisno.

1 AK Put-on shoes M 47 21 OCD; schizophrenia2 AS Lock a door M 31 19 OCD; hoarding3 HE Wash hands M 54 14 OCD; generalized anxiety

disorder; MDD; simplephobic disorder; panic;agorapgobia

4 IW Clean a sink M 20 24 OCD; schizophrenia; tics5 MD Clean a phone F 50 25 OCD with insight; MDD6 NA Wash hands M 21 38 OCD; MDD-p; BDD-p7 NZ Lock a car M 46 17 OCD; Phobic anxiety

disorder8 VH Go out from

homeF 68 22 OCD; compulsive

shopping; dysthymia;agrophobia; borderlinepersonality; MDD;hypochondriosis

9 AR Fill the dogwater-bowl

M 26 30 OCD; MDD; nail biting

10 II Fold a towel M 28 36(+) OCD; BDD;schizophrenia

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Irrelevant idiosyncratic acts as preparatory, conﬁrmatory ... · H. Keren et al. / Behaviour 150 (2013) 547–568 551 free-throws and weightlifting. For the free-throw task, ten