Teenagers are less likely to cooperate and put effort into their mother’s requests when they are said in a controlling tone of voice, researchers have found.
Speaking to a son or daughter in a pressurizing tone is also accompanied by a range of negative emotions and less feelings of closeness, a new study has discovered.
The experimental study involving over 1000 adolescents aged 14-15 is the first to examine how subjects respond to the tone of voice when receiving instructions from their mothers, even when the specific words that are used are exactly the same.
Lead author of the study Dr. Netta Weinstein, from Cardiff University, said: “If parents want conversations with their teens to have the most benefit, it’s important to remember to use supportive tones of voice.
It’s easy for parents to forget, especially if they are feeling stressed, tired, or pressured themselves.”
The study showed that subjects were much more likely to engage with instructions that conveyed a sense of encouragement and support for self-expression and choice.
The results, whilst of obvious interest to parents, could also be of relevance to schoolteachers whose use of more motivational language could impact the learning and well-being of students in their classrooms.
“Adolescents likely feel more cared about and happier, and as a result, they try harder at school, when parents and teachers speak in supportive rather than pressuring tones of voice,” Dr. Weinstein continued.
The new study, published today in the journal Developmental Psychology, involved 486 males and 514 females, aged 14-15.
In the experiment, each of the subjects was randomly assigned to groups that would hear identical messages delivered by mothers of adolescents in either a controlling, autonomy-supportive, or neutral tone of voice.
Expressions of control impose pressure and attempt to coerce or push listeners to action. In contrast, those that express ‘autonomy support’ convey a sense of encouragement and support for listeners’ sense of choice and opportunity for self-expression.
Each of the mothers delivered 30 sentences that centered around schoolwork, and included instructions such as:
“It’s time now to go to school,” “you will read this book tonight,” and “you will do well on this assignment.”
After the delivery of the messages, each student undertook a survey and answered questions about how they would feel if their own mother had spoken to them in that particular way.
The findings showed that the tone of voice used by mothers can impact significantly on teenagers’ emotional, relational, and behavioral intention responses.
The study showed that subjects were much more likely to engage with instructions that conveyed a sense of encouragement and support for self-expression and choice.
Across most outcomes, adolescents who listened to mothers making motivational statements in a controlling tone of voice responded in undesirable ways.
In contrast, autonomy-supportive tones elicited positive reactions from listeners as compared to listening to mothers who used a neutral tone of voice to deliver their motivational sentences.
Co-author of the study Professor Silke Paulmann, of the University of Essex, added: “These results nicely illustrate how powerful our voice is and that choosing the right tone to communicate is crucial in all of our conversations.”
The researchers now intend to take their work a step further by investigating how tone of voice can impact physiological responses, such as heart rates or skin conductance responses, and how long lasting these effects may be.
Funding: The study was funded by the Leverhulme Trust and involved researchers from Ghent University and the University of Essex.
Emotional signals can convey information about rules to children (Dix, 1991; Weiner, Graham, Stern, & Lawson, 1982). Mothers of infants have reported and expressed different emotional reactions to moral harm violations (when infants are harming others) than to pragmatic violations (when infants create inconvenience, e.g. by spilling food) (Dahl & Campos, 2013; Dahl, Sherlock, Campos, & Theunissen, 2014; see also Cole & Tan, 2015; Honig & Chung, 1989). Emotional signals may be especially important during early childhood, when children’s linguistic understanding is limited (K. C. Barrett & Campos, 1987; Kochanska, 1994). Yet, these emotional signals only influence the development of rule conceptions insofar as children perceive and make use of the emotional signals (Walle & Campos, 2012). If a child were oblivious to the differences in her mother’s reactions to moral and pragmatic violations, the child could not use such differences to guide future behavior (for instance in guessing whether the she might get away with a violation) or understand differences between rules (for instance that hitting causes pain, whereas spilling merely causes minor inconvenience) (Dahl & Kim, 2014; Dunn & Munn, 1985; Smetana, 1989). The present research investigated how caregivers’ vocal prohibitions of moral and pragmatic transgressions influence behavioral reactions in infancy (Study 1) and interpretations of social events in preschool age (Study 2).
The Construction of Moral and Pragmatic Rules through Social Interactions
By preschool age, children endorse and distinguish between a variety of rules. In the third year, they are view moral prohibitions as more generalizable and less alterable than social conventions (e.g. dress codes or codes of politeness) (Smetana & Braeges, 1990; Smetana, Jambon, Conry-Murray, & Sturge-Apple, 2012). In the fourth year, children also provide different justifications for different judgments about violations, for instance justifying judgments about moral violations with references to rights and welfare of individuals and judgments about pragmatic violations with references to inconvenience or material disorder (Dahl & Kim, 2014; Nucci & Weber, 1995; Smetana, 1985; Tisak & Turiel, 1984). At this age, children can also protest when others commit violations and react differently to different types of violations (Killen & Smetana, 1999; Rakoczy, Warneken, & Tomasello, 2008; Schmidt, Rakoczy, & Tomasello, 2012; Smetana, 1989; Vaish, Missana, & Tomasello, 2011; for a review, see Smetana, Jambon, & Ball ).
Theorists have proposed that children develop an understanding of and concern with moral and other rules through differentiated social experiences (Killen & Smetana, 2015; Smetana et al., 2014; Turiel, 1983). For instance, children experience that physical harm is painful (most directly experienced when they themselves are the victim) and often elicits signs of distress or protest from the victim, pragmatic violations elicit references to disorder or property damage, and often require someone to clean up, and conventional violations do not have immediate consequences and tend to elicit references to rules or authorities (Dahl & Campos, 2013; Killen & Smetana, 1999; Nucci & Turiel, 1978; Smetana, 1989; Tisak, Nucci, & Jankowski, 1996).
The experiential origins of rule distinctions in the transition from infancy to preschool age has received little attention. Most research on children’s experiences with rule violations has involved older children and, accordingly, focused on the linguistic content of reactions to violations (e.g. explicit references to harm or rules) (see Smetana, 2013). As noted, young children’s limited linguistic abilities may prevent them from understanding parents’ commands and explanations regarding violations (Fenson et al., 1994; Kaler & Kopp, 1990; Kochanska, 1994; Kuczynski, Kochanska, Radke-Yarrow, & Girnius-Brown, 1987). Moreover, there has been little research on how children use their social experiences with different types of prohibitions to guide their behavior (e.g. comply with the prohibition, Study 1) and interpretation of prohibitions (e.g. infer the nature of the event being prohibited, Study 2).
Others’ emotional reactions to rule violations may be particularly important for the early development of children’s reactions to prohibitions. As noted, some studies have found that mothers have different emotional reactions to infants’ moral and pragmatic violations (Dahl & Campos, 2013; Dahl et al., 2014). Dahl and his colleagues (2014) analyzed both mothers’ responses to naturally occurring violations in the family homes and to videotaped infant violations. In the latter paradigm, mothers were shown short video clips of infants engaging in violations, for instance hitting a sibling, and asked to respond to these video clips using a standardized phrase (“No, don’t do that.”). Dahl and his colleagues found that mothers were especially likely to respond to moral violations with intense firm-stern (anger-like) vocalizations, whereas positive tones of voice, termed warm-comforting (loving) or playful-playing (joyful), were more common in response to pragmatic violations. Situational differences in caregiver responses to infants’ moral and other violations are also seen in other verbal and non-verbal behaviors (Dahl & Campos, 2013; Smetana, 1989; Zahn-Waxler & Chapman, 1982).
The differences in mothers’ vocal and other responses reflect mothers’ different conceptions of moral and pragmatic violations. Mothers rate discouraging infants from harming others as more important than discouraging infants from spilling or breaking things, and mothers provide different justifications for moral and pragmatic rules (Dahl & Campos, 2013; Dahl et al., 2014; Smetana, Kochanska, & Chuang, 2000). Thus, if young children perceive and make use of differences in caregivers’ emotional reactions to violations, this information could help them (1) decide which prohibitions are particularly important to caregivers (e.g. prohibitions of moral violations, such as harming others) and which prohibitions children may be able to ignore without major consequences (e.g. prohibitions against pragmatic violations, such as making a mess) and (2) grasp differences between moral and pragmatic violations.
Young Children’s Use of Emotional Signals from Others
Past research suggests that young children would be able to perceive and make use of differences in caregivers’ vocal responses to moral and pragmatic violations. Infants show some ability to discriminate canonical (prototypical) facial and vocal expressions of different emotions, such as fear and anger, in the first year of life (Flom & Bahrick, 2007; Walker-Andrews, 1997). By the first birthday, infants are also able to regulate their behavior in response to emotional signals from others. Sorce, Emde, Campos, and Klinnert (1985) found that infants were less likely to cross a transparent surface covering a 30 cm drop-off when their mother displayed a fearful facial expression than when she displayed a joyful expression. Mumme, Fernald, and Herrera (1996) found evidence that infant responsiveness to negative vocal signals may be even more reliable than their responsiveness to facial expressions.
Several other studies have confirmed that, by late in the first year, infants perceive and make use of the distinction between canonical positive and negative emotional signals (e.g. Campos, Thein, & Owen, 2003; Hornik & Gunnar, 1988; Miyake, Campos, Kagan, & Bradshaw, 1986; Moses, Baldwin, Rosicky, & Tidball, 2001). By the middle of the second year, infants can integrate information about others’ observed emotional reactions with cues about what the person is attending to: After merely observing an adult getting angry at another person, 15- and 18-month-olds were more likely to avoid the anger-provoking action when the angry adult was present than when the adult was absent or distracted (Repacholi & Meltzoff, 2007; Repacholi, Meltzoff, Rowe, & Toub, 2014). However, evidence for differential responses to different canonical negative expressions (e.g. of fear and anger) is mixed (Gendler-Martin, Witherington, & Edwards, 2008; Walle & Campos, 2012).
During the preschool years, children become increasingly able to generate appropriate labels for canonical facial and, eventually, vocal expressions of positive and negative emotions (Nelson & Russell, 2011; Sauter, Panattoni, & Happé, 2013; Widen & Russell, 2010). However, children’s ability to adequately label emotional expressions is dramatically hampered if the situational context conflicts with the emotional expression (Aguert, Laval, Lacroix, Gil, & Le Bigot, 2013; Aguert, Laval, Le Bigot, & Bernicot, 2010; Morton & Trehub, 2001). In one study, when 4-year-olds heard sentences describing positive or negative events stated in either a positive or a negative tone of voice, they overwhelmingly relied on the content (nature of the event) rather than tone of voice (Morton & Trehub, 2001). For instance, when 4-year-olds heard the sentence, “My dog ran away from home,” they would typically guess that the speaker was sad, even if the speaker spoke in a positive tone of voice. By comparison, older children and adults give greater priority to the tone of voice when guessing the speaker’s emotional state.
One limitation of past research on children’s responses to emotional expression is the reliance on canonical vocal or facial expressions. These canonical emotional expressions are those used in studies demonstrating cross-cultural recognition of so-called basic emotions such as fear or anger (Ekman, 1992; Ekman et al., 1987; Laukka et al., 2013; Sauter, Eisner, Ekman, & Scott, 2010). However, in everyday life, emotional expressions often do not conform to these canonical patterns and instead show a great deal of contextual variability (Barrett, 2009; Russell, 2003). The existing evidence does not suggest that people typically show the canonical facial expressions of anger, fear, or joy when they are in the respective emotional state (see Fridlund, 1994). An angry person may yell at the perceived transgressor or refuse to talk to the person at all, while the expression of joy over success in sports is culturally variable and depends on whether the person is engaged in a social interaction (Matsumoto & Willingham, 2006; Ruiz-Belda, Fernández-Dols, Carrera, & Barchard, 2003). Campos, Dahl, and He (2010) refer to this as the principle of “equifinality” of emotional expressions: Any given emotion can be expressed in multiple ways.
The present research used as stimuli the types of vocal prohibitory signals that children encounter in everyday life rather than posed vocal signals. In doing so, these studies presented children with a task similar to tasks they face in everyday life: that of using naturally occurring caregiver vocalizations to guide their behavior (i.e. compliance, Study 1) and interpret caregiver messages (i.e. the nature of the transgression to which the caregiver is reacting, Study 2).
A second limitation of much past research on children’s responses to emotional expressions is the emphasis on discrimination or labeling rather than adaptive use (see Walle & Campos, 2012). Emotional signals from others do not just indicate others’ emotional states; they also provide information about others’ concerns, expectations, and intentions. Adaptive use of these signals may therefore involve actions that take the other person’s concerns, expectations, or intentions into account. For instance, as children grow older they respond to others’ distress not merely by themselves showing distress or concern, but also acting upon the cause of the other person’s concern, for instance by providing a blanket to a person who is cold (Hoffman, 2000; Svetlova, Nichols, & Brownell, 2010; Zahn-Waxler, Radke-Yarrow, Wagner, & Chapman, 1992).
In the present study, the purpose was not merely to see whether young children could discriminate or label maternal vocal reactions to transgressions. The purpose was to see whether young children could make use of adult vocal prohibitive tones in deciding whether to continue a behavior (Study 1) and in determining the nature of the transgression to which an adult was responding (Study 2). The studies contrasted prohibitions against moral and pragmatic transgressions, since such prohibitions, in addition to being commonplace, are recognized by both preschoolers and parents as differing in both their justification and importance (Dahl & Kim, 2014; Dahl et al., 2014; Smetana et al., 2000).Go to:
Study 1: Infants’ Response to Prohibitive Vocal Tones
In Study 1, children (13-25-month-olds) were given the opportunity to approach a novel toy (a small, stationary humanoid robot). When children approached the toy, they heard a prerecorded vocal prohibition from their own mother responding to a videotaped, naturally occurring child transgression. The videotapes shown to mothers included either child harming someone else (moral condition) or creating mess or other inconvenience (pragmatic condition). Children’s responses to the playback of the recorded prohibitions were assessed by coding (1) whether they moved away from the prohibited toy after the playback, (2) whether they expressed negative emotion after the playback, and (3) whether they approached the toy in a subsequent phase when no prohibitions were played back.
We hypothesized that, over the course of the second year, children would become increasingly responsive to mothers’ vocal responses to moral violations, as reflected in an increased tendency to move away from the prohibited toy after prohibition, decreased tendency to display negative reactions after prohibitions, and increased tendency to avoid the prohibited object in the subsequent phase without prohibition. The hypothesized increase in responsiveness to vocal prohibitions of moral transgressions was based on (1) mothers’ emphasis on the prohibition against harm (Dahl & Campos, 2013; Dahl et al., 2014), children’s improved ability to make adaptive use of emotional signals from others during the second year (Gendler-Martin et al., 2008; Repacholi & Gopnik, 1997; Walle & Campos, 2014; Zahn-Waxler et al., 1992), and (2) general increases in behavioral inhibition during this period (Kaler & Kopp, 1990; Kopp, 1982). In contrast, we did not hypothesize increases in responsiveness to vocal prohibitions of pragmatic violations with age, as these prohibitions tend to be less stern and more positive (warm or playful) than prohibitions of moral violations (Dahl et al., 2014). Although infants grow more able to comply with parental prohibitions, we expected that infants would consider parental reactions to pragmatic violations as less serious, and hence be more likely to try to “push boundaries” after hearing such vocal reactions. Further supporting this prediction, mothers have reported that their infants complied more with prohibitions against harming others than with prohibitions against pragmatic violations (Smetana et al., 2000).
Our hypotheses do not imply a perfect association between transgression type (moral vs. pragmatic) and vocalization category (e.g. firm-stern vs. positive tones, such as warm-comforting or playful-laughing). First, the relation between transgression types and adult reactions is probabilistic, not deterministic. Along with average differences between parental reactions to different transgressions, there are also some similarities, with most types of transgressions eliciting commands and at least somewhat firm vocalizations (Dahl & Campos, 2013; Dahl et al., 2014; Smetana, 1989). Second, the vocalization categories developed by past research (Dahl et al., 2014) are unlikely to capture all of the relevant features of mothers’ prohibitive vocal tones. For instance, two vocalizations from the same mother may both be classified as firm-stern and yet, for a child who knows this mother, one vocalization may convey a highly negative reaction while the other vocalization may convey a mild reaction. For this reason, the vocalizations played back to the children in Study 1 were not chosen based on whether they fit into a given vocal category (e.g. firm-stern) but rather based on how each mother tended to respond to a given videotaped transgression type.
The final sample consisted of 119 mother-infant dyads. An additional 13 dyads were recruited, but their data could not be used for the following reasons: The child never approached the prohibited object and hence did not hear any vocal recordings (N = 4); the mother interfered with the procedures (N = 5); the child was distressed (N = 3); the study equipment malfunctioned (N = 1). Families were living in a large metropolitan area in the western United States and were recruited from a participant database maintained by the Institute of Human Development at the University of California, Berkeley. Fifty-eight percent of caregivers were European-American, 13% were Asian-American, 13% were Hispanic, were of other ethnicities.
Children were recruited in three different age groups: 13.0–15.0 months (N = 46, Mage = 14.4 months), 18.0–20.0 months (N = 37, Mage = 19.3 months), and 23.0–25.0 months (N = 36, Mage = 24.1 months).
Video recordings shown to mothers
The experimental stimuli in Study 1 were video clips obtained from Dahl et al. (2014, see original article for additional details). Video clips showed infants engaging in moral (harming others), prudential (doing something that threatened child well-being), or pragmatic (creating inconvenience) transgressions. Each clip lasted 2–5 seconds. At the end of each clip, the final image frame was frozen for another three seconds, giving mothers additional time to respond. In the present study, only mothers’ responses to moral and pragmatic clips were used (see Introduction).
Mothers were randomly assigned to receive one of three sets of video clips containing 12 clips (four moral, four prudential, and four pragmatic). For each video set there were also six extra clips (two moral, two prudential, and two pragmatic), to be used if a mother did not respond to one or more of the four initial clips in the corresponding category (see Procedures below).
Although only vocal responses to either moral or pragmatic clips (depending on condition, see Procedures) were considered for playback to the child, all sets contained clips of moral, pragmatic, as well as prudential events. This variation in the nature of events was included to reduce the likelihood that mothers noticed the similarity of the clips (e.g. that they all contained a child harming someone), which could have drawn their attention to the study hypotheses.
Recording and playback set-up
The mothers’ vocalizations were recorded using a microphone positioned approximately 6 inches from the mothers’ mouths. For playback to the child, a speaker was placed behind the mothers’ chair in the area with the prohibited object (Figure 1). The speaker volume was adjusted so that the mean volume of each vocalization was 74dB, as measured by a sound meter placed immediately in front the speaker.
Target object (prohibited toy)
The target object that the child would be prohibited from touching was a small humanoid robot (Chicco Baby Space). The toy was attached to a 10 lb weight to prevent the child from moving the toy.
Children from each age group were randomly assigned to hear a vocalization elicited by a moral or pragmatic video clip, yielding a 3 (age group: 13–15, 18–20, 23–25 months) by 2 (condition: moral, pragmatic) between-subjects design.
The experiment had three phases: A recording phase (during which the mother’s vocalizations were recorded), a prohibition phase (during which the mother’s vocalizations were played back to the child when the child approached the prohibited object), and a no-prohibition phase (during which the child could approach the prohibited object, but no vocalizations would be played back).
Experimenter 1 (E1) told mothers that the study was about how children use commands from others to guide their behavior. Importantly, E1 made no mention of the three categories of child transgressions depicted in the video, nor about the hypothesized role of vocal tones. Mothers were told to respond vocally to these clips as if they were telling the child not to do whatever the child was doing, using the phrase, “No, don’t do that.” The phrase was shown visually to mothers so as not to lead mothers to say the phrase in a particular way. The researcher emphasized that the mother should not vocalize if the clip showed a behavior upon which they would not normally intervene.
The recording session took place in a separate room, while Experimenter 2 (E2) and the child stayed in the original warm-up room (to prevent the child from hearing the mothers’ vocalizations). In order to avoid auditory clipping effects, E1 adjusted microphone gain while the mother repeated the phrase into the microphone before beginning the recording. Mothers were randomly assigned to view one of the three video sets. Mothers first watched the twelve initial clips in the assigned set. If a mother had failed to respond to one or more of the twelve ordinary clips, she was then shown extra clips in the same category (up to two extra clips per each category). All mothers thus watched between 12 and 18 clips total.
After the recording session, the mother went back to the warm-up area and rejoined E2 and the child. Because there was some variability in whether mothers followed instructions and in whether recordings included extraneous sounds (e.g. extra words), it was necessary to standardize a procedure for selecting which of the recordings to play back to children. E1 listened to all the vocal recordings corresponding to the child’s condition. (For instance, if the child was in the moral condition, E1 would listen to all the mothers’ vocal responses to moral video clips.) For each clip, E1 determined whether the mother failed to use the standard phrase or the clip contained extraneous noises, rendering the clip unsuitable for playback. Since mothers typically had more than one suitable audio recording, a procedure was established for selecting the most intense audio recording from the most typical vocal category. Using the coding scheme developed by Dahl and his colleagues (2014), E1 classified the vocalizations as either firm-stern, playful-laughing, warm-comforting, or worried-scared and rated their intensity (see Dahl et al.  for definitions and sample sound clips). E1 then determined which category of emotional tone was the most common (the “modal category”), and selected the clip in the modal category with the highest intensity rating (on a scale from 1 to 4) that was not deemed otherwise unsuitable. E1 was trained until agreement with the main author on clip classification was 70%. Agreement was subsequently spot checked to ensure continued agreement. If two or more recordings in the same vocal category were equally intense and suitable, the experimenter randomly selected which clip to use. It is difficult to achieve high inter-rater agreement for categorization of vocal emotional tones on a single coding pass (see e.g. Shrivastav, Sapienza, & Nandur, 2005). However, some randomness in choice of recording was deemed acceptable since E1 was already choosing between vocalizations elicited by the target video clip (moral or pragmatic), and hence any of these clips were at least minimally suitable for testing the study hypotheses (except for clips that contained extraneous words or other sounds).
During the prohibition phase, the mother was seated in the chair in front of the speaker. To make it seem as if the played-back vocalizations were coming from the mother, the mother pretended to read a magazine during the prohibition phase, holding a magazine high enough to cover her mouth but not so high as to cover her eyes. This way, the child could not see that the mother’s mouth was not moving when a vocal recording was played back, yet the mother could in principle see whether the child approached the robot. The mother was instructed to remain in the chair throughout the phase, look at the magazine, and minimize her interactions with the child. Mothers were told that if the child insisted on interacting with them, they could redirect the child to two small toys (a green fabric cube and a yellow plastic star) located next to the chair. They were also told explicitly that they should not direct the child toward the robot.
On signal from E2, the mother put the child on the floor, which marked the beginning of the prohibition phase. E1 monitored the child’s movements through a video feed. Each time the child moved within a 2 × 2 foot square around the robot, E1 triggered a playback of the mother’s vocalization. If the child remained in the 2 × 2 foot square, E1 triggered another playback five seconds after the end of the last playback. Each child heard up to four playbacks. The prohibition phase ended 15 seconds after the 4th playback or after 4 minutes, whichever happened first. At the end of the prohibition phase, E2 brought the mother and the child back to the warm-up area.
Three minutes after the end of the prohibition phase, E2 brought the mother and child back to the area with the prohibited toy for the final phase of the study. As for the prohibition phase, the mother had been instructed sit down in the chair in front of the speaker, put the child down on the floor, and read a magazine for the duration of the phase, interacting as little as possible with the child. During the no-prohibition phase, no vocal recordings were played back to the child. The phase lasted two minutes.
Research assistants blind to the child’s experimental condition continuously coded the location of the child (inside prohibited area versus outside prohibited area) after the first playback until the end of the prohibition phase. The child’s location was also coded during the entire no-prohibition phase. In a second pass, a coder assessed whether the child showed vocal or facial signs of negative emotion between the end of the first playback until the end of the prohibition phase. Coders also assessed whether the child looked toward the mother at least once immediately before or after entering the prohibited area (social referencing). Twenty percent of the data were double-coded. Inter-rater agreement: Emotional tone of vocalization: Cohen’s κ = .63 (84% agreement), prohibition phase location coding: κ = 1.00 (100%), no-prohibition phase location coding: Pearson’s r = .95, prohibition phase negative emotion: κ = 1.00 (100%), social referencing: κ = .83 (93%).
Data were analyzed using Generalized Linear Models with age group, condition, and the age group by condition interaction as predictors (Fox, 2008). Hypotheses were tested using likelihood ratio tests. With regards to the child’s location in the prohibition phase, the dependent variable was whether children remained in the prohibited area from the first playback until the end of the prohibition phase. This dichotomous variable was analyzed using logistic GLMs (logistic link function, binomial error distribution). The presence of negative emotional signals after the first playback (a dichotomous variable) was also analyzed using logistic GLMs. The time children spent in the prohibited area during the no-prohibition was positively skewed, with some children spending no time in the prohibited area. To model these duration data, we modelled the number of seconds children spent in the prohibited area using Poisson GLMs (logarithmic link function, Poisson error distribution).
Netta Weinstein – Cardiff University
The image is adapted from the Cardiff University news release.
Original Research: Closed access
“Listen to your mother: Motivating tones of voice predict adolescents’ reactions to mothers”. Netta Weinstein et al.
Developmental Psychology doi:10.1037/dev0000827.