Social Motivation in Schizophrenia: What’s Effort Got to Do With It?

Abstract

Background and Hypothesis

Social motivation, defined as the fundamental human desire to seek out, engage in, and maintain interpersonal bonds, has become a growing area of research in schizophrenia. The major focus has been on understanding the impact of social reward-related processes. An obvious but rarely acknowledged fact is that social interactions, much like other goal-directed acts, require the exertion of effort. In this Review Article, we argue that social motivation in schizophrenia can be conceptualized through the lens of an established framework: effort-based decision-making (EBDM).

Study Design

We conducted a literature review on social reward processing in schizophrenia, then extended these findings by applying concepts and insights from the literature on EBDM to the study of social motivation.

Study Results

Within the EBDM framework, decisions about whether or not to pursue social interactions are bound by cost/benefit calculations. That is, people do not pursue social behaviors when the estimated “cost” of the required effort outweighs the anticipated “benefit” or reward. We propose that people with schizophrenia are less likely to engage in social interaction compared with healthy samples because they: (1) underestimate the benefits of relationships (based on expectations of reward/punishment), (2) overestimate the effort costs associated with social interaction, and/or (3) fail to integrate cost-benefit information in an optimal manner.

Conclusions

EBDM is an especially promising framework of social motivation that goes beyond the current focus on social reward processing to include a focus on effort.

Introduction

Social impairment is a hallmark of schizophrenia and is one of the main components of functional disability in the disorder. This impairment is partly explained by deficits in social abilities and competence, including social cognition and social skills.^1–3 In the past decade, there has been an increasing focus on social motivation, defined as the human desire to seek out, engage in, and maintain interpersonal relationships.⁴ Substantial knowledge gaps exist in our understanding of what causes social motivation deficits in schizophrenia.⁵

In this Review Article, we argue that social motivation in schizophrenia can be conceptualized through the lens of an established framework: Effort-based decision-making (EBDM). In making this argument, we first review the literature on social reward processing in schizophrenia, then apply concepts and insights from the EBDM literature to the study of social motivation. We provide recommendations for research aimed at elucidating the impact of effort on social behaviors in schizophrenia. Lastly, we consider profiles based on the EBDM framework and potential treatment directions.

Historical Background: Social Anhedonia

Disruptions in social motivation have been documented since the seminal writings of schizophrenia by both Kraepelin⁶ and Bleuler.⁷ These impairments, now commonly referred to as “asociality,” are characterized by a reduction in social drive due to decreased interest in forming close relationships.⁸ Rado theorized that anhedonia, defined as the reduced capacity to experience pleasure, was central to social deficits in schizophrenia.⁹ Meehl expanded on this hypothesis, speculating that what we clinically observe as social anhedonia is actually a deficit in reinforcement learning.¹⁰ He argued that people learn social ambivalence over the course of the illness due to a decreased sensitivity to positive social outcomes (eg, reduced approach to companionship, intimacy), and they learn interpersonal fear and aversiveness (ie, high social avoidance) due to an intact sensitivity to negative social outcomes (eg, rejection, conflict).

Meehl’s theory on social anhedonia has had a substantial influence on the way we assess social motivation via self-reports¹¹ and clinician-rated negative symptom interviews.^12,13 These instruments consistently show that people with schizophrenia have elevated trait levels of social disinterest that are stable over time and clinical status,^14,15 and are important vulnerability markers of schizophrenia-spectrum liability.¹⁶ Until recently, research on social motivation in schizophrenia has focused on the reduced subjective experience of social pleasure, and less work has focused on altered reinforcement learning as a basis for reduced social motivation.

Social Reward Processing in Schizophrenia

Modern conceptualizations of motivation from affective neuroscience allow us to disentangle its relevant components and explain how hedonic experiences are translated into goal-directed behaviors. The NIMH’s Research Domain Criteria include a “positive valence” systems domain, outlining reward-related processes that are relevant for understanding approach motivation. Research on social reward in schizophrenia can be categorized into 3 subprocesses: (1) reward responsiveness, (2) reward learning, and (3) reward valuation. The vast majority of work on reward processing and motivational impairments in schizophrenia has involved nonsocial contexts,^17,18 but recent efforts are extending this work to social contexts.^5,19

Reward Responsiveness

Reward responsiveness refers to the hedonic experience associated with reward receipt (consummatory pleasure or “liking”) and impending rewards (anticipatory pleasure or “wanting”).^20,21 Studies on social “liking” have utilized ecological momentary assessment (EMA) and laboratory tasks to assess positive affect following affiliative interactions. A recent meta-analysis of 26 studies found that people with schizophrenia exhibit a small, significant deficit in social consummatory pleasure compared with healthy controls (g = −0.38, 90% CI [−0.53, −0.22]).²² However, the degree of differences depended on the type of method used. Group differences were significant in the EMA studies but not in the standardized laboratory interactions. This suggests that people with schizophrenia have the capacity to experience social pleasure, but may have fewer opportunities for pleasant interactions in daily life.²³ A separate review found that people with schizophrenia experience positive affect when with others, but concurrently experience heightened negative affect and prefer to be alone.²⁴

Studies on social “wanting” have yielded mixed findings, potentially due to different assessment methods across studies. EMA studies have shown that people with schizophrenia report a desire for interpersonal connection,²⁵ expect enjoyment from future interactions,²⁶ and feel lonely in the absence of others,²⁷ although they report fewer social goals.²⁸ Moreover, people with schizophrenia report positive appraisals of past social interactions that predict the likelihood of future interactions.²⁹ Inpatients with schizophrenia similarly self-report a desire for social affiliation.³⁰ However, in the laboratory, people with schizophrenia experience elevated anticipation of negative emotion during social inclusion,³¹ and anticipate less pleasure in social interactions with smiling partners³² than healthy controls.

Few studies have pitted social and nonsocial stimuli and responses against each other. The incentive delay task has been used to study nonsocial reward anticipation in schizophrenia, and recently it has been adapted to contrast social and nonsocial rewards. Two studies, one behavioral³³ and one fMRI,³⁴ found that people with schizophrenia had deficits anticipating both social and nonsocial rewards compared with healthy controls. A third study used electroencephalography and measured separate event-related potentials for reward receipt and anticipation. People with schizophrenia showed less response to social vs nonsocial rewards compared with healthy controls, but only in the anticipation phase, and poorer social reward anticipation was associated with fewer real-world social behaviors.³⁵ A fourth study used a fMRI version of the incentive delay task with only social stimuli and similarly found anticipation deficits in schizophrenia vs healthy controls.³⁶ More research is needed in this area, but preliminary evidence suggests that people with schizophrenia may not anticipate as much pleasure from the prospect of social rewards compared with controls.

Reward Learning

Reward learning refers to the ability to learn about stimuli, actions, and contexts that predict positive and negative outcomes, and to use that feedback to modify behavior. Studies using reward learning paradigms with nonsocial rewards have consistently shown that people with schizophrenia have difficulty using positive outcomes to guide decision-making, but have less difficulty using negative outcomes.^37,38 Consequently, people with schizophrenia are less sensitive or less able to learn how to obtain rewards but successful in knowing how to avoid punishments.³⁹

There is increasing evidence that people with schizophrenia may have a deficit in the ability to use social cues to guide reward-seeking behavior. Two studies employed a gambling task to examine alterations in social vs nonsocial reward learning in schizophrenia. During the task, participants chose between differently colored slot machines that were associated with high likelihoods of positive (smiling face or monetary gain), neutral (neutral face or break even), or negative (scowling face or monetary loss) feedback. This task captures implicit probabilistic learning that is gradual and stimulus-driven. The first study utilized fMRI and found that people with schizophrenia showed reduced neural activation in areas associated with reward value representation to social but not nonsocial feedback compared with controls.⁴⁰ Despite these neural differences, both groups had similar behavioral performances across social and nonsocial conditions. In the second behavioral study,⁴¹ results showed that both schizophrenia and control groups performed better in the social vs nonsocial condition. Furthermore, the schizophrenia participants performed better when avoiding negative feedback, whereas controls performed better when obtaining positive feedback.

Other evidence for social reward learning disruptions in schizophrenia comes from behavioral economics tasks, which are suggestive of decreased social reward learning but do not directly pit social rewards against nonsocial rewards. Studies using the Trust Game, a cooperative task played with computerized opponents, have shown that schizophrenia participants generally have difficulty using social rewards (reciprocation of trust by a social partner) to inform subsequent decisions about who to trust, compared with healthy controls.^42,43 Studies using the Ultimatum Game, a strategic bargaining task, have shown that people with schizophrenia were less likely than healthy controls to use positive and negative facial expressions from opponents to modify their decisions.^44,45

Reward Valuation

Reward valuation involves the processes by which the benefits of different prospective outcomes are evaluated relative to each other.⁴⁶ These calculations utilize mental representations of reward value to compare their relative worth, form preferences, and motivate decisions to approach or avoid certain options. Most of the work on reward valuation in schizophrenia has involved nonsocial rewards but there have been at least 2 studies that attempted to estimate the subjective value of social vs nonsocial rewards. One study⁴⁷ asked participants to select computerized opponents to play against in a game; opponents provided different rates of social (smiling expressions) and nonsocial (money) rewards. The results indicated that schizophrenia participants treated genuine smiles as significantly less rewarding than healthy controls, despite showing a similar preference for money. The valuation of social rewards was modestly correlated with clinician-rated motivational deficits. The second study involved a competitive auction game.⁴⁸ Participants made choices to win the auction and earn social “status” (social reward) or to lose the auction and avoid overbidding, thereby maximizing their monetary payoffs (nonsocial reward). Results showed that people with schizophrenia overbid less than healthy controls, suggesting a reduced motivation to pursue the social reward of winning vs retaining money.

Taken together, the research on social reward processing suggests that people with schizophrenia have some difficulty learning or recalling social reward representations, or at the very least, they are not translated into behavior.^17,47

Limitations of Current Knowledge: The Role of Effort

An obvious but rarely acknowledged fact in the schizophrenia literature is that social interactions, much like other goal-directed acts, require the exertion of effort to obtain rewards and avoid punishments.⁴⁹ The topic of poor social effort in schizophrenia was introduced in a review by Fulford and colleagues.⁵ Here we build upon their review, applying concepts and methods from the EBDM literature to understand how people with schizophrenia make decisions about whether or not to socially engage. Consistent with the previous review, we argue that people with schizophrenia exhibit reduced social motivation partly because they do not exert enough effort to seek our pleasurable social activities in daily life as comparison groups. This idea is supported by research suggesting that people with schizophrenia have fewer relationships and daily social interactions,⁵⁰ spend more time doing nothing,²⁶ and less time initiating and engaging in personal conversation.²³ Importantly, this reduced effort is a separate consideration from whether there is sufficient desire for connection.

There are several reasons why people with schizophrenia may be less likely to exert social effort. First, people with schizophrenia may have fewer opportunities for positive social interactions. Many individuals have restricted or sparse social networks,⁵¹ and consequently, social rewards may be undervalued due to the low probability of obtaining them. Second, people with schizophrenia may also be more likely to receive social “punishments.” Many individuals have social skill deficits that create uncomfortable interactions.⁵² Negative social experiences and the stigmatization of mental illness may result in demoralization and the development of negative attitudes about social interactions.⁵³ People with schizophrenia could then withdraw from others due to a hostile attributional bias.⁵⁴

What is Effort-Based Decision-Making?

EBDM involves making a choice about whether a desired outcome is worth the effort required to obtain it.^55–57 Individuals conduct a cost/benefit analysis to make this determination (figure 1). The benefit and cost of an action are calculated separately, then are evaluated with regard to one another (the level of reward for the level of effort). The basis for a decision to take action is reflected in the following equation: (the expected benefit or outcome of the action) − (the expected cost or effort of the action) = net value of the action.⁵⁸ Rational decision-makers take action when the overall net value is positive (the benefit outweighs the cost) and do not take action when the net value is negative.

Fig. 1.

Cost-benefit analysis.⁵⁹ Adapted from Schiffmann et al., 2023

Benefit Calculations

The “benefit” of a social action is estimated from the expected outcome. The action must bring the individual closer to their social goal to be considered worthwhile. The action itself can be the goal when seeking intrinsic rewards (eg, socializing because it is enjoyable), but often the goal is to obtain extrinsic rewards (eg, ­socializing to gain status, approval, or belonging). An outcome becomes increasingly more valuable the greater the magnitude of the reward, the greater the need for the reward (eg, seeking connection when lonely), and the higher probability that the reward will be obtained. Rewards are also more valuable when they are received immediately.⁶⁰

We note that the expected outcome of a social action can include both positive and negative aspects. For example, when socializing with a new person, there is a possibility that the interaction will be positive and rewarding (eg, leading to a friendship), or negative and punishing (eg, leading to embarrassment or rejection). The rewarding aspects of the potential outcome must be greater than the punishing aspects for it to be considered a benefit.

Cost Calculations

The expected “cost” is an estimation of the resources that will be allocated to perform a social action, including the commitment of effort. Social effort can be physical, cognitive, or financial, just as with nonsocial effort. In the example of socializing, physical or financial effort could include someone’s travel to a social location, as well as opportunity cost (ie, time and effort that could have been dedicated to something else). There is also a cognitive cost associated with the interaction in the form of listening, paying attention, and recognizing and responding to social cues. Effort calculations can be influenced by defeatist beliefs – negative thoughts about one’s ability to successfully perform social behaviors. The more the expected effort, the higher the cost.

Maximizing Net Value

After doing the cost/benefit calculations for a social action, individuals compare the net value of the action among a set of alternative actions. Given a choice between two actions that result in equal rewards, rational people will choose the action that requires less effort (law of least effort).⁶¹ For example, given the choice to talk to a friend or a stranger, most people would choose to talk to their friend (if the net value is greater than the alternative action). If the choice is between the social action (talking to a stranger) and doing nothing (walking away), then the social action is engaged only when its net value is positive compared with doing nothing.

EBDM in Schizophrenia

Nonsocial EBDM

The EBDM framework has been applied to understand nonsocial contexts in schizophrenia. Over the past decade, research from several laboratories has shown that people with schizophrenia are less willing than healthy controls to expend physical effort (eg, key presses, handgrip squeezing) and cognitive effort to obtain monetary rewards on performance-based tasks.^55–57 Reduced effort on these tasks is sometimes associated with motivational deficits measured by clinician-rated interviews and EMAs,⁵⁶ as well as defeatist beliefs.⁶² Effort aversion can stem from an overestimation of effort costs^57,63 and/or a failure to integrate cost-benefit information in an optimal manner.⁶⁴

Applying EBDM to a Social Context

As mentioned above, EBDM is rarely applied to social contexts. If a social behavior is physically effortful, or if a social cognitive process is mentally demanding, people may choose not to socially engage. There are individual differences in effort sensitivity, defined as the amount of effort an individual is willing to exert for a potential reward. Studies with healthy controls demonstrate that effort sensitivity influences social behaviors, and there might be a core neural circuit that guides both social and nonsocial effort-based decisions involving the dorsal anterior cingulate cortex, ventral striatum, basolateral amygdala, ventromedial prefrontal cortex, anterior insula, and dorsolateral prefrontal cortex.^49,65

Below we summarize studies of EBDM in a social context with healthy samples and autism. There are only a handful of tasks. This is partly due to the challenge of designing ecologically valid paradigms. Standardized laboratory tasks offer experimental control over confounding variables, such as differences in social opportunities, but they are only proxies for real-world interactions, and social rewards may not be as salient. Despite this challenge, social EBDM paradigms still show promise for indexing real-world social behavior.

Social vs Nonsocial EBDM Paradigms

A social vs nonsocial EBDM task has been employed in the autism literature.^66–69 During the task, participants choose which type of movie they want to watch, social (faces with either direct or averted gaze) or nonsocial (object), for different levels of effort (button presses). In one study,⁶⁶ people with autistic traits showed a preference for nonsocial vs direct eye gaze movies when effort levels were equal, but picked the easier option when effort was not equal. In contrast, people with autism showed a preference for nonsocial vs direct-eye gaze movies, regardless of the relative effort required.⁶⁶ Both of these findings differed from healthy controls, who preferred the direct eye gaze movies vs nonsocial movies when effort was equal, and the less-effortful option when it was not. To the best of our knowledge, no social vs nonsocial EBDM tasks have measured decisions to exert effort to avoid punishment. This is an area for future task development.

Social EBDM Paradigms

Although not directly contrasting social to nonsocial stimuli, some paradigms have tried to merge EBDM procedures with socially relevant stimuli. These paradigms were developed in nonclinical samples, but could be extended to clinical samples, like schizophrenia. One example is a task where individuals chose between completing an empathy task (eg, empathizing with the emotional state of strangers) or another activity (eg, describing facial features of strangers).⁷⁰ Across a series of studies,^70,71 nonclinical participants were less likely to choose the empathy task due to the effort cost. Participants were more willing to empathize with loved ones than with strangers.⁷² Another example of a task with socially relevant stimuli found that nonclinical individuals were more willing to exert effort (button presses) to view attractive vs unattractive face images.⁷³

Other Relevant Paradigms

Other studies in nonclinical samples have utilized strategic games to measure effort exertion in different social contexts. In one task, participants squeezed a handgrip to earn money in 3 conditions: while playing individually, in collaboration with a human or a computer, and in competition with a human or computer.⁵⁸ Results indicated that participants exerted more effort in the competitive vs collaborative condition. However, participants tried harder when collaborating with another human vs a computer. EBDM tasks can measure effort chosen (what someone is willing to do based on “perceived effort”) and effort exerted (what someone actually does or “actual effort”)⁷⁴. Other EBDM tasks examine decisions when earning rewards for oneself vs others,^74,75 which may be useful in understanding altruism or prosocial motivation in schizophrenia. Alternative methods of studying social effort in schizophrenia without decision-making have involved self-report questionnaires,^76,77 and effort exertion following social encouragement.⁷⁸

Applying Computational Models

Computational models have been applied to nonsocial EBDM tasks in schizophrenia⁶⁴ and depression^79,80 to discriminate between reduced reward sensitivity and heightened effort sensitivity. A similar approach could be taken to test individual differences in social motivation subprocesses (see profiles described below). This would require experimental conditions that measure effort-based decisions to both gain social rewards and avoid punishments. Since these methods have not yet been tested in social EBDM tasks, this remains an important direction for future research.

The Role of Social Competence

Beyond the cost and benefit computations that are used to evaluate the net value of a social interaction, one also needs to consider the impact of social competence—the overall ability to achieve social goals and mastery of social skills. When making cost/benefit estimations, individuals take into account what they must do (social skills) and what they think they can do easily (appraisals of their social competence). For healthy controls with high social competence, most social interactions are relatively easy and require little effort expenditure. However, social interactions are inherently more challenging for people with schizophrenia who, on average, have lower social competence.⁸¹ In these conditions, people with schizophrenia need to expend greater amounts of effort to achieve their social goals and obtain social rewards. Healthy controls generally try harder on difficult vs easy tasks until the task seems impossible, at which point they give up.⁸² This point likely occurs sooner for people with schizophrenia when evaluating social interactions, especially those with defeatist beliefs.⁸³

Social Motivational Profiles

Within the EBDM framework, there are important individual differences in social motivation based on (1) how much one values social interactions, or finds them rewarding/punishing (benefit), (2) how effortful one finds the interactions (cost), and (3) how accurate one is in making cost/benefit calculations. Below we outline 5 profiles based on variations of the subjective preference towards reward and effort. These profiles are illustrative examples and not an exhaustive list (figure 2). They are not specific to schizophrenia, although people with schizophrenia may fall into the maladaptive categories more than the general population. Social experiences (and the degree of success and enjoyment) shape beliefs about the value of social interactions that then influence future choices and the type of profile someone adopts. Expectations for social interactions, and desires for social connections, can change dynamically over time. Social profiles likely become more fixed in chronic schizophrenia than first-episode psychosis.

Fig. 2.

Social motivational profiles.

Profile #1- Social Indifference

Individuals underestimate the “benefit” of social action because social interactions are not rewarding. Reduction in social pleasure may occur due to neurobiological differences in social reward sensitivity.⁸⁴ Over time, individuals might be socially apathetic and passively withdraw from others (low social approach).⁸⁵ Social effort only occurs when the expected payoff is estimated to be large and/or highly probable.

Profile #2- Social Fear

Individuals underestimate the “benefit” of social action because social interactions are punishing or threatening. People may be interested in relationships, but feel discouraged after unsuccessful attempts to interact with others. Subsequent decisions to pursue social interaction are influenced by their fear of rejection, hostility, and/or stigma.⁸⁶ Over time, individuals become aloof and reticent due to paranoia or social anxiety, and limit social effort (high social avoidance).⁸⁵

Profile #3- Social Effort Aversion

For these individuals, the “cost” of social action outweighs the “benefit.” Several factors contribute to heightened social effort sensitivity. First, there may be logistical barriers to social interaction, including financial hardship and geographic distance.⁸⁷ Second, individuals may be less willing to exert social effort due to both their social competence (the actual effort required) and/or their perceived judgments about their ability to succeed (ie, defeatist beliefs; “Why bother trying, I always fail”).⁸⁶ They may have perceptions of failure despite repeated efforts, leading to asocial beliefs (“Trying to make friends isn’t worth the effort it takes”).⁸⁸

Profile #4-Socially Competent and Sociable

Cost/benefit calculations about whether to pursue social action are accurate, consistent, and rational. Individuals are socially competent and friendly; they want close relationships and frequently expend effort to assertively engage in social interaction. Individuals adjust their effort and deploy different social skills to meet the demands of social interaction.

Profile #5- Socially Eccentric

Individuals with altered cost/benefit calculations make non-rational decisions about when to pursue social interaction. They want to form social connections and are willing to expend effort to form and maintain relationships, but they have difficulty adjusting effort levels to meet the demands of the interaction, possibly due to cognitive deficits.^64,89 For example, individuals may make the wrong choice about whether or not to approach someone (eg, when no reward is available), to avoid someone (eg, when a reward is available), or they have difficulty deploying specific social skills given the context. Because their social behavior is inconsistent and unpredictable, they may appear eccentric to others, and have relationships of variable quality and reciprocity.

Clinical Implications

As previously stated, individuals with schizophrenia may have reduced social motivation because they underestimate the value of social interaction (low benefit), overestimate the effort associated with social actions (high cost), or have disruptions in their cost-benefit calculations. All 3 factors represent modifiable treatment targets. Interventions could be tailored to the factor that is most impaired for each individual.

For individuals who underestimate benefits (“social indifference”/“social fear”), one potentially relevant psychosocial intervention is motivational interviewing and cognitive behavioral therapy, an evidence-based way to improve motivation in schizophrenia.⁹⁰ This intervention could help individuals resolve social ambivalence, articulate social goals, increase positive affect via behavioral activation, and challenge low pleasure beliefs about socialization via cognitive restructuring. Other potential interventions involve social pharmacology. Currently, several drugs are being tested as ways to increase the salience of rewarding social cues and to decrease sensitivity to threatening cues (see Bershad et al., this issue).

For individuals who overestimate costs (“social effort aversion”), one potentially relevant psychosocial intervention is Cognitive Behavioral Social Skills Training.⁹¹ Cognitive Behavioral Social Skills Training includes 3 modules, all of which could be adapted to address social effort aversion: (1) problem-solving strategies could be used to overcome logistical barriers to social interaction (actual effort), (2) cognitive strategies could be used to challenge defeatist beliefs (perceived effort), and (3) social skills training could help improve social competence to reduce difficulty and effort. Skills could be practiced in a low-stakes environments to build mastery, then be gradually applied to real-world interactions. Encouragement from peers and providers may also improve effort.⁷⁸

Lastly, there is not an obvious intervention for disrupted cost-benefit computations (“socially eccentric”), but cognitive strategies aiming to improve social decision-making could be useful. For example, means-ends analysis could help individuals determine which actions are needed to reach desired social outcomes.⁹² Means-ends analysis involves comparing the current state with the goal state; identifying sub-steps in working towards the goal; and inferring relationships between actions and goals.⁹³ Means-end analysis was previously applied as a way to achieve interpersonal goals in schizophrenia,⁹⁴ although it has not been a recent focus.

Conclusion

Our knowledge of social motivation in schizophrenia was previously limited by the paucity of assessment tools and narrow focus on social pleasure. Modern advances in empirical methods and frameworks of motivation have accelerated our efforts to better understand the reduced social drive observed in some people with schizophrenia. We argue that EBDM is an especially promising framework of social motivation that goes beyond the current focus on social reward to include a focus on effort. Before optimized interventions can be developed, this area requires fundamental knowledge that will involve the development of novel paradigms.

Funding

This work was supported by a VA Career Development Award (IK2CX002202-01 to LTC).