The objective of the target article is to present a new theoretical perspective on the psychology of cleansing, which posits the physical action of cleaning as a procedure of separation between two entities, e1 (e.g., failure/success) and e2 (e.g., one's self). This procedure results in attenuation/elimination processes of the effects of the former (e1) on the latter (e2).
In our view, the theoretical account proposed by Lee and Schwarz (L&S) needs to be enriched by considering the limited capacity of the human executive control system (Schmeichel, Reference Schmeichel2007). Threats to the self (e.g., negative emotions and intrusive thoughts) load executive control processes (Cohen, Mor, & Henik, Reference Cohen, Mor and Henik2015; Curci, Lanciano, Soleti, & Rimé, Reference Curci, Lanciano, Soleti and Rimé2013). Crucially, Kalanthroff et al. (Reference Kalanthroff, Aslan and Dar2017) recently demonstrated that physical cleansing reduces the detrimental effect of threatened morality on two executive processes: conflict monitoring and response inhibition. Therefore, physical cleansing appears to unload executive control processes, which are involved in top-down, goal-related behavior (Lavie, Reference Lavie2010). Indeed, cleansing may exert its effects through the embodied processes involved in physical actions, which improve cognitive performance and problem-solving and reduce cognitive load (Chum, Bekkering, Dodd, & Pratt, Reference Chum, Bekkering, Dodd and Pratt2007; Schaefer, Lövdén, Wieckhorst, & Lindenberger, Reference Schaefer, Lövdén, Wieckhorst and Lindenberger2010; Skulmowski & Rey, Reference Skulmowski and Rey2017; Wagner Cook, Yip, & Goldin-Meadow, Reference Wagner Cook, Yip and Goldin-Meadow2012; Wilson, Reference Wilson2002).
We propose that L&S's predictions about the effectiveness of cleansing-mediated separation are dependent on individual differences in the available amount of executive resources. In support of this, de Los Reyes et al. (Reference de Los Reyes, Aldao, Kundey, Lee and Molina2012) found that post-decisional dissonance (i.e., aversive feeling triggered by a choice between two similarly valued alternatives) is not eliminated by means of handwashing in compromised decision makers (healthy individuals with high levels of anxiety, intolerance toward uncertainty, and rumination) versus non-compromised individuals. On the contrary, Reuven, Liberman, and Dar (Reference Reuven, Liberman and Dar2014) showed that the association between physical cleansing and the reduction of moral discomfort is particularly strong in individuals diagnosed with obsessive-compulsive disorder (OCD) as compared with healthy controls.
These results may appear inconsistent with one another, as both samples are characterized by excessive negatively-valenced cognitions (rumination in anxious individuals and obsessive thoughts in OCD). We propose a load-dependent role of cleansing as a procedure whose efficacy is related to an individual's current amount of available executive resources. Consequently, the differential load charged to the executive control system in the two aforementioned populations (high in compromised decision makers and low in OCD, see below) represents a plausible candidate to explain the inconsistent effects of cleansing actions (de Los Reyes et al., Reference de Los Reyes, Aldao, Kundey, Lee and Molina2012; Reuven et al., Reference Reuven, Liberman and Dar2014).
Excessive negatively-valenced cognition can take the form of rumination, consisting of intrusive thoughts related to past or possible future events (Nolen-Hoeksema, Wisco, & Lyubomirsky, Reference Nolen-Hoeksema, Wisco and Lyubomirsky2008). A recent meta-analysis reported a negative association between rumination and the functioning of core executive functions such as inhibition and set-shifting (Yang, Cao, Shields, Teng, & Liu, Reference Yang, Cao, Shields, Teng and Liu2017). Rumination is also associated with deficits in executive processing (Watkins & Brown, Reference Watkins and Brown2002), cognitive control (Joormann, Levens, & Gotlib, Reference Joormann, Levens and Gotlib2011), attentional control (Daches, Mor, Winquist, & Gilboa-Schechtman, Reference Daches, Mor, Winquist and Gilboa-Schechtman2010), working memory (Joormann & Gotlib, Reference Joormann and Gotlib2008), inhibition (Joormann, Reference Joormann2006), and goal disengagement (van Randenborgh, Hüffmeier, LeMoult, & Joormann, Reference van Randenborgh, Hüffmeier, LeMoult and Joormann2010) (see Whitmer & Gotlib, Reference Whitmer and Gotlib2013). The sample used by de Los Reyes et al. (Reference de Los Reyes, Aldao, Kundey, Lee and Molina2012) was characterized by high levels of anxiety, which is known to impair executive function (Shields, Moons, Tewell, & Yonelineas, Reference Shields, Moons, Tewell and Yonelineas2016), storage and processing capacity of working memory (Darke, Reference Darke1988; Moran, Reference Moran2016), and attentional control (Eysenck, Derakshan, Santos, & Calvo, Reference Eysenck, Derakshan, Santos and Calvo2007; Forster, Elizalde, Castle, & Bishop, Reference Forster, Elizalde, Castle and Bishop2015). This evidence, suggesting that rumination and anxiety contribute to loading executive functions, could explain the absence of cleansing-related effects in this sample (de Los Reyes et al., Reference de Los Reyes, Aldao, Kundey, Lee and Molina2012).
Excessive negatively-valenced cognition can also take the form of obsessions that, together with repetitive behaviors or mental acts (compulsions), characterize OCD (American Psychiatric Association, 2013). According to the “habit hypothesis” (Graybiel & Rauch, Reference Graybiel and Rauch2000), in OCD striatal circuit dysfunction favors the expression of a routinized, habitual sequence of actions (Gillan et al., Reference Gillan, Papmeyer, Morein-Zamir, Sahakian, Fineberg, Robbins and De Wit2011, Reference Gillan, Apergis-Schoute, Morein-Zamir, Urcelay, Sule, Fineberg and Robbins2015), resulting in a reduced need for executive resources for their generation/inhibition (over-practiced behaviors are known to reduce cognitive load; Haith and Krakauer, Reference Haith and Krakauer2018). Moreover, compulsions may partially relieve the detrimental effects of obsessions on executive processes (Starcevic et al., Reference Starcevic, Berle, Brakoulias, Sammut, Moses, Milicevic and Hannan2011) by reducing anxiety, which impairs executive function (Moran, Reference Moran2016; Shields et al., Reference Shields, Moons, Tewell and Yonelineas2016). In agreement, recent studies on individuals with OCD found an absence of deficit in sustained attention (Milliery, Bouvard, Aupetit, & Cottraux, Reference Milliery, Bouvard, Aupetit and Cottraux2000), enhanced action-monitoring processes (Gehring, Himle, & Nisenson, Reference Gehring, Himle and Nisenson2000; Hajcak & Simons, Reference Hajcak and Simons2002), executive hyper-control (Bucci et al., Reference Bucci, Mucci, Volpe, Merlotti, Galderisi and Maj2004), lack of impairment in decision making (Johansen & Dittrich, Reference Johansen and Dittrich2013), and a superior performance in information gathering (Hauser et al., Reference Hauser, Moutoussis, Iannaccone, Brem, Walitza, Drechsler and Dolan2017) and in automatic versus controlled response inhibition (Wolff, Chmielewski, Buse, Roessner, & Beste, Reference Wolff, Chmielewski, Buse, Roessner and Beste2019). These findings, suggesting that in patients with OCD compulsions seem to unload executive functions, could explain why cleansing-related separation effects appear preserved in this population.
The aforementioned evidence may illustrate why individuals high in anxiety and rumination (with supposedly overloaded executive functions) do not fully benefit from the cleansing-related separation effects. In this population, although physical cleansing allows executive resources to unload, separation might be less efficient, as these resources are already partially recruited for coping with intrusive thoughts/emotions. Conversely, the inverse mechanism is proposed for OCD: obsessions overload the executive system (Abramovitch, Dar, Hermesh, & Schweiger, Reference Abramovitch, Dar, Hermesh and Schweiger2012) but compulsions, particularly the cleaning-related ones (Starcevic et al., Reference Starcevic, Berle, Brakoulias, Sammut, Moses, Milicevic and Hannan2011), may partially relieve the detrimental effects of obsessions on executive functions. Also, because compulsions are thought to be supported by a habit system (Burguière, Monteiro, Mallet, Feng, & Graybiel, Reference Burguière, Monteiro, Mallet, Feng and Graybiel2015; Gillan & Robbins, Reference Gillan and Robbins2014), fewer executive resources are needed for their implementation, and the available resources can be dedicated to separation procedures. In line with these findings, attentional control deficits in anxiety disorders are associated with perseverative worry, whereas in OCD this association is not significant (Armstrong, Zald, & Olatunji, Reference Armstrong, Zald and Olatunji2011).
To conclude, we propose that the cleansing-mediated separation effect introduced by L&S is load-dependent: cleaning actions reset the influence of a prior event (e1) on a subsequent one (e2), only when sufficient executive resources can be dedicated to the separation procedure. In this frame, the efficacy of the separation procedure may depend on individual executive load.
The objective of the target article is to present a new theoretical perspective on the psychology of cleansing, which posits the physical action of cleaning as a procedure of separation between two entities, e1 (e.g., failure/success) and e2 (e.g., one's self). This procedure results in attenuation/elimination processes of the effects of the former (e1) on the latter (e2).
In our view, the theoretical account proposed by Lee and Schwarz (L&S) needs to be enriched by considering the limited capacity of the human executive control system (Schmeichel, Reference Schmeichel2007). Threats to the self (e.g., negative emotions and intrusive thoughts) load executive control processes (Cohen, Mor, & Henik, Reference Cohen, Mor and Henik2015; Curci, Lanciano, Soleti, & Rimé, Reference Curci, Lanciano, Soleti and Rimé2013). Crucially, Kalanthroff et al. (Reference Kalanthroff, Aslan and Dar2017) recently demonstrated that physical cleansing reduces the detrimental effect of threatened morality on two executive processes: conflict monitoring and response inhibition. Therefore, physical cleansing appears to unload executive control processes, which are involved in top-down, goal-related behavior (Lavie, Reference Lavie2010). Indeed, cleansing may exert its effects through the embodied processes involved in physical actions, which improve cognitive performance and problem-solving and reduce cognitive load (Chum, Bekkering, Dodd, & Pratt, Reference Chum, Bekkering, Dodd and Pratt2007; Schaefer, Lövdén, Wieckhorst, & Lindenberger, Reference Schaefer, Lövdén, Wieckhorst and Lindenberger2010; Skulmowski & Rey, Reference Skulmowski and Rey2017; Wagner Cook, Yip, & Goldin-Meadow, Reference Wagner Cook, Yip and Goldin-Meadow2012; Wilson, Reference Wilson2002).
We propose that L&S's predictions about the effectiveness of cleansing-mediated separation are dependent on individual differences in the available amount of executive resources. In support of this, de Los Reyes et al. (Reference de Los Reyes, Aldao, Kundey, Lee and Molina2012) found that post-decisional dissonance (i.e., aversive feeling triggered by a choice between two similarly valued alternatives) is not eliminated by means of handwashing in compromised decision makers (healthy individuals with high levels of anxiety, intolerance toward uncertainty, and rumination) versus non-compromised individuals. On the contrary, Reuven, Liberman, and Dar (Reference Reuven, Liberman and Dar2014) showed that the association between physical cleansing and the reduction of moral discomfort is particularly strong in individuals diagnosed with obsessive-compulsive disorder (OCD) as compared with healthy controls.
These results may appear inconsistent with one another, as both samples are characterized by excessive negatively-valenced cognitions (rumination in anxious individuals and obsessive thoughts in OCD). We propose a load-dependent role of cleansing as a procedure whose efficacy is related to an individual's current amount of available executive resources. Consequently, the differential load charged to the executive control system in the two aforementioned populations (high in compromised decision makers and low in OCD, see below) represents a plausible candidate to explain the inconsistent effects of cleansing actions (de Los Reyes et al., Reference de Los Reyes, Aldao, Kundey, Lee and Molina2012; Reuven et al., Reference Reuven, Liberman and Dar2014).
Excessive negatively-valenced cognition can take the form of rumination, consisting of intrusive thoughts related to past or possible future events (Nolen-Hoeksema, Wisco, & Lyubomirsky, Reference Nolen-Hoeksema, Wisco and Lyubomirsky2008). A recent meta-analysis reported a negative association between rumination and the functioning of core executive functions such as inhibition and set-shifting (Yang, Cao, Shields, Teng, & Liu, Reference Yang, Cao, Shields, Teng and Liu2017). Rumination is also associated with deficits in executive processing (Watkins & Brown, Reference Watkins and Brown2002), cognitive control (Joormann, Levens, & Gotlib, Reference Joormann, Levens and Gotlib2011), attentional control (Daches, Mor, Winquist, & Gilboa-Schechtman, Reference Daches, Mor, Winquist and Gilboa-Schechtman2010), working memory (Joormann & Gotlib, Reference Joormann and Gotlib2008), inhibition (Joormann, Reference Joormann2006), and goal disengagement (van Randenborgh, Hüffmeier, LeMoult, & Joormann, Reference van Randenborgh, Hüffmeier, LeMoult and Joormann2010) (see Whitmer & Gotlib, Reference Whitmer and Gotlib2013). The sample used by de Los Reyes et al. (Reference de Los Reyes, Aldao, Kundey, Lee and Molina2012) was characterized by high levels of anxiety, which is known to impair executive function (Shields, Moons, Tewell, & Yonelineas, Reference Shields, Moons, Tewell and Yonelineas2016), storage and processing capacity of working memory (Darke, Reference Darke1988; Moran, Reference Moran2016), and attentional control (Eysenck, Derakshan, Santos, & Calvo, Reference Eysenck, Derakshan, Santos and Calvo2007; Forster, Elizalde, Castle, & Bishop, Reference Forster, Elizalde, Castle and Bishop2015). This evidence, suggesting that rumination and anxiety contribute to loading executive functions, could explain the absence of cleansing-related effects in this sample (de Los Reyes et al., Reference de Los Reyes, Aldao, Kundey, Lee and Molina2012).
Excessive negatively-valenced cognition can also take the form of obsessions that, together with repetitive behaviors or mental acts (compulsions), characterize OCD (American Psychiatric Association, 2013). According to the “habit hypothesis” (Graybiel & Rauch, Reference Graybiel and Rauch2000), in OCD striatal circuit dysfunction favors the expression of a routinized, habitual sequence of actions (Gillan et al., Reference Gillan, Papmeyer, Morein-Zamir, Sahakian, Fineberg, Robbins and De Wit2011, Reference Gillan, Apergis-Schoute, Morein-Zamir, Urcelay, Sule, Fineberg and Robbins2015), resulting in a reduced need for executive resources for their generation/inhibition (over-practiced behaviors are known to reduce cognitive load; Haith and Krakauer, Reference Haith and Krakauer2018). Moreover, compulsions may partially relieve the detrimental effects of obsessions on executive processes (Starcevic et al., Reference Starcevic, Berle, Brakoulias, Sammut, Moses, Milicevic and Hannan2011) by reducing anxiety, which impairs executive function (Moran, Reference Moran2016; Shields et al., Reference Shields, Moons, Tewell and Yonelineas2016). In agreement, recent studies on individuals with OCD found an absence of deficit in sustained attention (Milliery, Bouvard, Aupetit, & Cottraux, Reference Milliery, Bouvard, Aupetit and Cottraux2000), enhanced action-monitoring processes (Gehring, Himle, & Nisenson, Reference Gehring, Himle and Nisenson2000; Hajcak & Simons, Reference Hajcak and Simons2002), executive hyper-control (Bucci et al., Reference Bucci, Mucci, Volpe, Merlotti, Galderisi and Maj2004), lack of impairment in decision making (Johansen & Dittrich, Reference Johansen and Dittrich2013), and a superior performance in information gathering (Hauser et al., Reference Hauser, Moutoussis, Iannaccone, Brem, Walitza, Drechsler and Dolan2017) and in automatic versus controlled response inhibition (Wolff, Chmielewski, Buse, Roessner, & Beste, Reference Wolff, Chmielewski, Buse, Roessner and Beste2019). These findings, suggesting that in patients with OCD compulsions seem to unload executive functions, could explain why cleansing-related separation effects appear preserved in this population.
The aforementioned evidence may illustrate why individuals high in anxiety and rumination (with supposedly overloaded executive functions) do not fully benefit from the cleansing-related separation effects. In this population, although physical cleansing allows executive resources to unload, separation might be less efficient, as these resources are already partially recruited for coping with intrusive thoughts/emotions. Conversely, the inverse mechanism is proposed for OCD: obsessions overload the executive system (Abramovitch, Dar, Hermesh, & Schweiger, Reference Abramovitch, Dar, Hermesh and Schweiger2012) but compulsions, particularly the cleaning-related ones (Starcevic et al., Reference Starcevic, Berle, Brakoulias, Sammut, Moses, Milicevic and Hannan2011), may partially relieve the detrimental effects of obsessions on executive functions. Also, because compulsions are thought to be supported by a habit system (Burguière, Monteiro, Mallet, Feng, & Graybiel, Reference Burguière, Monteiro, Mallet, Feng and Graybiel2015; Gillan & Robbins, Reference Gillan and Robbins2014), fewer executive resources are needed for their implementation, and the available resources can be dedicated to separation procedures. In line with these findings, attentional control deficits in anxiety disorders are associated with perseverative worry, whereas in OCD this association is not significant (Armstrong, Zald, & Olatunji, Reference Armstrong, Zald and Olatunji2011).
To conclude, we propose that the cleansing-mediated separation effect introduced by L&S is load-dependent: cleaning actions reset the influence of a prior event (e1) on a subsequent one (e2), only when sufficient executive resources can be dedicated to the separation procedure. In this frame, the efficacy of the separation procedure may depend on individual executive load.
Acknowledgements
The authors would like to thank Anna Maria Borghi (Department of Dynamic and Clinical Psychology, Sapienza University of Rome and Istituto di Scienze e Tecnologie della Cognizione, CNR, Rome), Luca Tummolini (Istituto di Scienze e Tecnologie della Cognizione, CNR, Rome), and Matteo Candidi (Department of Psychology, Sapienza University of Rome and IRCCS Fondazione Santa Lucia, Rome) for their valuable and insightful comments on the manuscript.
Financial support
G.P. was funded by the BIAL Foundation Grant for Scientific Research (No. 276/18) and V.E. was funded by Sapienza Progetti di Ricerca H2020 “Sharetrain” (2018).
Conflict of interest
None.