1. Introduction
Use of laser light pointers (LLPs) for play and to stimulate species-typical hunting behavior is popular with many cat guardians. Interactive play between human and cat using an LLP would appear to meet two of the five pillars of a healthy feline environment [
1]: allowing for an enjoyable shared interaction between human caretaker and their cat, and potentially providing an opportunity for exercise in the form of species-typical, normal hunting behaviors. Hyman [
2] has suggested that a primary reason why cats enjoy laser light play involves the light’s motion. Citing research from Tremoulet and Feldman [
3,
4], he notes that the nature of the motion (e.g., frequent changes in speed and direction, appearing to ‘react’ to the cat’s movements) is a critical component of the perception of animacy (i.e., that the laser light ‘prey’ is alive). The appearance of goal-directed behavior on the part of the light (e.g., ‘avoiding’ the cat, ‘hiding’ behind furniture etc.) adds to this perception, similar to the “wolfpack effect” described by Gao et al. [
5], in which multiple triangles ‘chasing’ a single moving circle are perceived as animate when the triangles remained oriented (pointed) towards the circle as it moves.
However, LLP play alone does not allow cats to complete the hunting sequence; essentially, the cat can never ‘catch’ the prey. It has been suggested that this may trigger frustration and stress, common contributors to feline behavioral problems, including compulsive behaviors [
6,
7]. Thus, in theory at least, using LLPs to play with cats could contribute to the development of compulsive behaviors. Compulsive behaviors are usually brought on by conflict, and appear abnormal because they are repetitive, exaggerated or sustained, and displayed out of context [
8]. In cats, common signs of a compulsive disorder include oral behaviors such as overgrooming, self-directed aggression (such as chasing/chewing the tail), and hallucinatory behaviors such as staring at shadows or chasing light reflections [
9].
Treatment for feline compulsive disorders (FCD) often includes the identification and removal of things that cause (motivational) conflict, frustration, and stress [
9]. Complete resolution of FCDs is uncommon, although treatments (including medications) are often used to decrease the frequency or severity of the behavior, thereby increasing quality of life of the effected animal [
10,
11]. Providing environmental enrichment is another important component of treatment, designed to decrease stress and the risk for developing stress-related behavior problems [
1,
6,
12,
13]. A common recommendation for enrichment involves interactive play with toys. To maintain the enrichment value (in addition to the physical exercise benefits) of LLP play, while minimizing the risks of frustration, many experts recommend a modification to this type of play [
14,
15]. This modification consists of ending LLP play by having the light land on a small toy that resembles catchable prey (e.g., a stuffed toy mouse) [
16], or a high-value food treat. In their recommendations for environmental enrichment for indoor cats, Herron and Buffington [
17] list laser toys as an ‘appropriate toy’ given their ability to simulate the natural predatory sequence, but caution that the “general rule among behaviorists about light-beam games is that they should always be followed by the presentation of a treat or toy to reward the cat for the extensive ‘hunt’ and to prevent frustration” (p. 5).
To our knowledge, however, the use of LLPs for play, including the potential protective value of this recommendation for reducing the risk of frustration or the development of compulsive behaviors, has never been tested. Behavior problems are a significant risk factor for relinquishment and euthanasia of domestic cats [
7,
18], and even without these tragic end points, often negatively impact animal welfare, especially when they are a result of stress or anxiety [
7]. Additionally, compulsive behaviors can interfere with normal behaviors and damage the human-animal bond [
19]. As noted by Amat et al. [
20], compulsive behaviors are among the top five cat owner complaints. The negative impact of compulsive behaviors makes it important to identify any type of activity that might increase their prevalence.
This study examines the potential relationship between the use of LLPs for play with companion cats and the occurrence of excessive or abnormal repetitive behaviors (ARBs) often linked to diagnosis of feline compulsive disorder (FCD). Our primary hypothesis was that there would be a relationship between the use and frequency of laser light play and reported ARBs. We were also interested in examining how common use of LLP play is in cat guardians; their attitudes towards this type of toy (i.e., reasons they chose to use or not use LLPs); whether or not they were familiar with the recommended modification for LLP play and employed this strategy (e.g., ending the game by providing a toy or treat); and whether or not reported ARBs had any impact on the human-animal bond.
2. Materials and Methods
An online, anonymous, cross-sectional survey was developed using Qualtrics (Qualtrics, Inc., Provo, UT, USA). The survey was designed, reviewed, and tested by the co-investigators and their colleagues. The survey was pre-tested by eight individuals for ambiguity and/or potentially missing or inappropriate response options, with revisions made based on the results of this testing. The final survey and study design were approved by the Colorado State University Institutional Review Board (IRB # 21-10566H). Survey respondents were recruited between February 2021–April 2021 via social media (Facebook, Twitter, Instagram).
Adult (18 years or older) participants who were the current guardians and primary caretakers of at least one adult cat (at least one year of age), and had owned the cat for at least 6 months, were recruited for the study. Guardian demographics were collected (e.g., country, age group, gender, education level, number of cats in the household). A series of questions from a published survey [
21] measuring the relationship between cat and guardian were included. The Pet Relationship Scales (PRS) consists of 22 self-report items organized into three subscales, “Affectionate Companionship,” “Equal Family Member Status,” and “Mutual Physical Activity”. For this study, questions from the Affectionate Companionship subscale with an additional three items (“I consider my cat a member of the family,” “I have considered relinquishing my cat because of his/her behavior” (reverse coded), and “My cat provides me comfort during difficult times” were included. Possible total scores for the Affectionate Companionship subscale range from 8–48, with higher scores indicating a closer bond. Cronbach’s alpha for the PRS Affectionate Companionship subscale in our study was 0.755.
Next, respondents were asked a series of questions about their cat, including characteristics of the cat (such as age, sex/reproductive status, whether the cat is an indoor or outdoor cat, and whether the cat is declawed). They were next asked how often their cat displayed behaviors that might indicate compulsive tendencies (spins or tail chases, chases lights and shadows, fixates on a specific toy, stares obsessively at lights or reflections, overgrooms him/herself) [
8], using a 7-point Likert scale anchored by 1 = never and 7 = multiple times a day. The survey was not directed at cat guardians experiencing behavior problems with their cats; recruitment materials only mentioned wanting to understand how people played with their cats. The list of behaviors came before any other questions besides demographic questions (and the order of the behaviors was randomized). Note that in the survey, we did not define “obsessive”, instead allowing respondents to interpret the term in the most common sense, i.e., excessive, resembling an obsession (see
Supplementary Materials for the complete survey). For each such behavior noted, respondents were then asked to report how the behavior impacted them and/or the cat (e.g., negatively impacts the cat’s quality of life; negatively impacts the bond we have; does not affect me at all). They could select all answers that applied. They were next asked how easy it is to redirect their cat when doing each of these behaviors using a 4-point Likert scale (from 1 = very easy to 4 = very challenging). Guardians were also asked to indicate if their cat had ever been treated by a veterinarian for any compulsive behaviors, and if they had ever sought help for excessive fear/anxiety, aggression, or “inappropriate” elimination exhibited by their cat.
The next series of questions pertained to the use of an LLP, defined as any form of play that involves light, such as a pen light or flashlight. They were first asked if they play with their cat using an LLP, with response options including no, have never used; no, used to but no longer use; rarely (less than once a month); some (less than once a week); fair amount (2–3 times/week); frequently (more than three times a week); and daily. For those who did not currently use an LLP (not currently or ever), they were asked to select all reasons why they do not use them (e.g., “I am afraid of hurting my cat’s eyes”; “my cat does not like laser pointers”; etc.). Those guardians who indicated they currently do play with an LLP (or have in the past) were asked to select the reasons why (e.g., my cat seems to enjoy it; it is an easy way to play with my cat). They were then asked if they let their cat ‘catch’ something at the end of the play session (for example, by ending the game with the laser landing on a food treat or favorite stuffed mouse or toy). Additionally, they were asked how long the cat continues to look for the light when the game is over, and the cat’s typical behavior at the end of the LLP play session (e.g., goes to sleep; seems agitated or upset, etc.); and, if these behaviors are similar or different than when finished with other forms of play. They were asked if they feel their cat benefits from the LLP play, as well as if they think their cat suffers any negative effects of LLP play. All respondents were also asked to indicate, by selecting from a series of statements, what they had heard about LLPs (e.g., laser pointers are a good way to exercise your cat, laser pointers can lead to obsessive cat behavior).
In addition, respondents were asked to report the total amount of time they spend with their cat over the span of an entire day either playing with an LLP, in other forms of play, or cuddling/sitting together/petting, on a 7-point Likert scale (with 1 = less than 5 min and 7 = more than 5 h). Guardians were also asked to report how bonded they felt with their cat during each of these types of interactions using a 5-point Likert scale (with 1 = much less bonded, 5 = much more bonded).
Descriptive statistics were calculated to characterize guardians’ views of LLP play and their cats’ behaviors. Kruskal–Wallis (KW) nonparametric analyses of variance were used to explore the relationship between specific behaviors and LLP play. We next performed a multiple linear regression analysis using a total compulsive behavior score (the sum of reported compulsive behaviors significantly associated with LLP play) as the response variable. Results of the exploratory KW analysis were used to guide the selection of predictors for the multiple regression model. Potential predictor variables in the model included: LLP play [never used; used to use but no longer; rarely used (less than once a week); frequently used (at least 2–3 times a week)]; total number of cats living in the home (1, 2, >2); cat variables including age, sex, indoor/outdoor; guardian variables including age (18–29, 30–39, 40–49, 50 and older), gender, country, and bond score. Because LLP play was the largest predictor of potentially compulsive ARBs, separate chi-square analyses were next performed for each of the associated ARBs. Significance level (α) was set at p = 0.05 and all tests were two-tailed. Data were analyzed using SPSS (IBM, Armonk, NY, USA).
4. Discussion
In this study, significant associations were found between the frequency of LLP play and the occurrence of all surveyed ARBs, with the exception of overgrooming, in owned companion cats. The strongest patterns were seen for behaviors which may be connected to LLP play: chasing lights or shadows, staring “obsessively” at lights or reflections, and fixating on a specific toy (
Table 4 and
Table 5). As these results are correlational, we cannot state that LLP play causes ARBs in companion cats; given the intrinsically rewarding nature of play, it may be that individual cats who enjoy laser play are motivated to look for more of this activity in other light sources or reflections (or vice versa). Over half of respondents who reported that their cat engaged in shadow or light chasing stated that it was easy to redirect the cat into another behavior, which could argue against a truly compulsive behavior in those cats (
Figure 2). Nonetheless, frequency of LLP play was the strongest predictor of ARBs in the multiple regression model (
Table 6), and guardians who frequently used LLPs for playing with their cats were more likely to report ARBs in their cats than others who did not use LLPs, or who used them less frequently (
Table 5). While significant, the low R
2 of the regression model likely reflects the high variability among both cats and their human guardians, and suggests that other intrinsic and extrinsic factors contribute to the development of ARBs in companion cats.
The lack of association between frequency of LLP play and overgrooming may be due to the diverse causes of this type of behavior in domestic cats. Grooming is a normal behavior in cats, and while grooming can also function as a displacement behavior during stress and conflict [
22], underlying medical causes are often the primary cause of such self-directed trauma in cats [
10,
23]. It is perhaps also important that overgrooming was the behavior that guardians reported having the most difficulty in redirecting to other behaviors (
Figure 2).
Indoor-only cats were more likely to display ARBs than cats allowed indoor/outdoor access (no outdoor-only cats were included in the data analysis). The link between outdoor access and reduced reports of ARBs cannot be explained with the data collected for this study, but possible contributing factors may include presence of stressors within the home for these cats (other cats, other animals, lack of enriched environment). Cats originally evolved to live an outdoor lifestyle, and indoor-only cats in particular may show increased stress from the presence of (incompatible) conspecifics, competition for resources, insufficient mental stimulation, and lack of physical exercise [
24]. Provision of some form of outdoor access is recommended by some cat welfare organizations [
25], and a number of studies have found that behavioral problems, such as unacceptable indoor elimination (often termed inappropriate elimination), destructive scratching, and aggression, as well as feline lower urinary tract disease (FLUTD) are more common in indoor-only cats vs. indoor/outdoor cats [
20,
26,
27,
28,
29,
30]. Compulsive behaviors are often seen in genetically-predisposed individuals exposed to chronic or recurrent stressors (motivational conflict, frustration, etc.), or whose behavioral needs are not adequately met [
8,
23].
Nearly half (45.5%) of the respondents in our study reported using LLPs to play with their cats; however, frequency of use was low for most survey respondents: approximately half (50.7%) of those who used LLPs with their cats, did so less than once a month. A small percentage of guardians, however, used LLPs frequently: 2.8% reported using them more than 3 times per week, and 3.2% reported using them daily. Similarly, when asked about how they interact with their cat regularly (e.g., by cuddling/petting, playing excluding LLP play, or playing with an LLP), guardians reported spending the least amount of time in LLP play: 73.8% reported spending less than 5 min per day in LLP play. In comparison, 62.1% of respondents reported playing in other ways with their cats for between 5 and 30 min per day, and 87.5% reported spending between 31 min and 5+ hours per day cuddling with or petting their cats.
Interestingly, the statement “Laser pointers can make cats frustrated if they do not get to ‘catch’ something at the end of play” was the statement reported as familiar to the greatest proportion of respondents (52.1%); yet only 35.6% of respondents reported following this advice. This was followed closely, however, by the statement “Laser pointers are a good way to exercise your cat” (47.1%), perhaps reflecting the current emphasis on providing both physical and mental exercise for companion cats, and partially explaining their use by a significant proportion of cat guardians. Only about one in five cat guardians reported familiarity with the statements “Laser pointers can lead to obsessive behavior” (18.6%) and “Too much laser pointer play can be bad for cats” (21.4%).
Many cats do, in fact, seem to enjoy LLP play; among guardians who did use LLPs to play with their cats, “My cat seems to enjoy it” was the most commonly reported reason why (54.0% of respondents). Guardians also commonly cited the exercise benefits for their cats, and the ease of playing with laser pointers with their cats, as reasons why they used these toys. The risk of development of compulsive behaviors was of less concern to cat guardians in the present study than was the risk of hurting their cat’s eyes (
Figure 4), and only 5.2% of guardians reported the fear of their cat developing “obsessive” behaviors as their reason for not using laser play. The most common reason, by far, that guardians chose not to use laser pointers with their cats was “I enjoy playing with my cats in other ways.”
In the present study, 89.5% of cat guardians reported at least one potentially-problematic behavior in their cats. This percentage is in line with earlier work [
31] in which cat guardians were asked to report whether certain behaviors, typically perceived as undesirable, were exhibited by their cat; note that these percentages are typically higher than those reported in studies looking at (for example) case reports from veterinary behavior practices. The behavior problems for which guardians most sought help included “inappropriate” elimination (14.6%), excessive fear/anxiety (10.4%), and aggression (7.0%). Only 5.8% reported that their cat had been treated by a veterinarian for an “obsessive” behavior, although this percentage is higher than reported in other studies (3.5% reporting compulsive behaviors in Amat et al. [
20]; 3% reporting overgrooming/self-harming in Wassink-van der Schot et al. [
32]). Nonetheless, cat guardians in this study appeared largely unbothered by these behaviors: ~94–97% reported the behaviors such as chasing lights or shadows, staring at lights or reflections, or fixating on a specific toy, did not bother them at all. The notable exception to this pattern was overgrooming: over half the respondents who reported this behavior stated that it did affect them, citing reasons such as “the behavior requires veterinary care (for medication, etc.)” and the behavior “negatively impacts (my cat’s) quality of life” (
Figure 3). It is possible, given the link between serious behavior problems and relinquishment or euthanasia of pet cats, that cats with severe compulsive disorders were missing from our survey data; in which case, any existing relationship between LLP play and ARBs could be underestimated in our results. Despite this, however, less than 1% of respondents reported that any of these behaviors negatively impacted their bond with their cat, and no guardians reported that overgrooming impacted this bond. The mean score for the affectionate companionship subscale of the PRS for respondents in this study was 37.12 (range 9–48); this mean is higher than that reported for pet guardians in Kafer et al. [
21] (30.24 for females and 27.88 for males).
Taken as a whole, our results suggest that LLP toys are used by a substantial proportion of cat guardians in the US, Canada and U.K. to play with their cats. However, frequency of use is relatively low, as is duration of time spent playing with LLP toys, when compared to time spent in other shared activities. Many guardians were familiar with potential risks of using LLP toys to play with their cats, and some (35.6%) followed the common advice to end the game by allowing their cat to “catch” a more tangible “prey” item. However, for many, the perceived (and possibly real) benefits to their cat (enrichment, physical exercise, enjoyment by the cat) appeared to outweigh any potential risks of this type of play.
It is concerning, therefore, that we did find a significant association between frequency of laser play and all forms of ARB, except overgrooming, and that LLP play was the largest predictor of ARBs. Overall, the more frequently LLP toys were used, the more likely guardians were to report ARBs. Although correlational, these results support concerns that LLP toys may be associated with the development of compulsive behaviors in cats, warranting further research into their risks.
Three possible limitations of the study should be considered. First, in common with many studies based on guardian reports, the ability of these guardians’ to correctly identify the behaviors asked about on the survey, and their accuracy in recollecting frequencies of play and behavior, may vary. For example, it is possible that some of the “compulsive” behaviors reported by guardians may have been learned/attention-seeking behaviors [
9] seen only in the presence of the guardian; we do not have information on whether these cats also performed the behaviors outside of the guardians’ presence (i.e., supporting the true compulsive nature of the behaviors). Second, we did not investigate in detail other characteristics of guardians’ play styles with their cats (for example, other forms of active or hunting-type play, such as chasing string or feather wands), nor the timing of use of LLP play relative to when guardians’ first observed the ARBs; thus, we cannot comment on potential relationships between these types of play and development of ARBs in companion cats, including whether the reported ARBs predated or followed initial use of LLPs, as has been suggested elsewhere (14). We also cannot establish the ‘threshold’ at which laser play might be problematic. Third, the majority of respondents in the present study were women (88.5%) with a university degree (78.6%). This gender imbalance is a common challenge for survey-based studies which recruit participants through social media, as in the present study. Herzog [
33] notes that women tend to show higher levels of positive behaviors and attitudes towards animals, although the effect sizes of gender differences in the human-animal attachment studies he reviewed ranged from none to small. Respondents in our study scored slightly higher on affectionate attachment than participants in an earlier study using the same scale; this may be due to the predominance of women in our study. If true, then it is possible that the other bond-related measures in our study (such as the fact that most guardians in our study reported that the ARBs did not bother them, and that these behaviors had essentially no negative impact on their bond with their cat) may be somewhat higher than in the general cat-owning population. This in turn would underscore concern for the impacts of laser light toys on frequency of some types of ARBs in pet cats.
