The role of time preference and perspective in socioeconomic inequalities in health-related behaviours
The role of time preference and perspective in socioeconomic inequalities in health-related behaviours
Abstract and Keywords
This chapter shows how social inequalities affect the way people think about the future, and through this affect their decisions to engage in health-destroying behaviours like smoking or avoiding health check-ups. In high-inequality societies, those on the lowest rungs of the socioeconomic ladder may not feel much incentive to plan for the long term, and as a result end up living in worse health when they get older. This can act as a drag on the public's health more broadly. The chapter discusses how time preference and time perspective have been understood by both economists and psychologists, describes the theoretical reasons why time preference and perspective may be related to both SEP and health-related behaviours and briefly reviews the evidence relating to these relationships.
Pervasive socioeconomic inequalities in health and disease have been consistently reported within and between populations (Mackenbach et al, 1997; Acheson, 1998). While epidemiologists are adept at describing these relationships, evidence for interventions that can achieve whole-scale reduction of socioeconomic inequalities in health remains scarce (Arblaster et al, 1996; Gunning-Schepers and Gepkens, 1996; Alvarez-Dardet and Ashton, 2005). Socioeconomic differences in behaviours that influence health, such as smoking, diet and uptake of screening and vaccination programmes, play an important role in overall inequalities in health (Marmot et al, 1997), but there remains little understanding of why socioeconomic patterning of these behaviours persists and what can be done about it.
In 1995, Charlton and White proposed that the key links between socioeconomic position (SEP) and health-related behaviours are ‘choice, autonomy and long termism’ (Charlton and White, 1995, p 235). The concept they referred to as ‘long termism’ is more commonly termed ‘time preference’ or ‘time perspective’ and describes how individuals value and orientate themselves towards the future and how this influences their behaviour. The hypothesis that time preference and perspective may play a role in the link between socioeconomic factors and health-related behaviours is potentially important in terms of both understanding and developing interventions to reduce socioeconomic inequalities in health-related behaviours but remains under-researched.
Here I discuss how time preference and time perspective have been understood by both economists and psychologists, describe the theoretical reasons why time preference and perspective may be related to both SEP and health-related behaviours and briefly review the evidence relating to these relationships. I present a new conceptual model of the possible relationship between SEP, time preference and perspective, and health-related behaviours. I conclude that public health may have much to gain from integrating these economic and psychological concepts (p.10) in its understanding of inequalities and that this is an area ripe for public health interventional development. Although previous reviews have collated evidence on the economic concept of time preference and health-related behaviours (Chapman, 2005), and the psychological concept of time perspective and alcoholism (Hulbert, 1988), no previous work has provided a comprehensive overview of both economic and psychological concepts and proposed that both may play a role in socioeconomic inequalities in health-related behaviours.
What are time preference and time perspective?
In general, it has been found that individuals would prefer to receive a gain today rather than in the future, and suffer a loss sometime in the future rather than today. Furthermore, the value of a future gain or loss, when looked at from the perspective of the present day, is somewhat less than that which will be realised once the future date is reached. Thus, for example, if individuals are asked to state what value of prize today would be equally attractive as a prize of £1,000 a year from today, the answer is, generally, somewhat less than £1,000. As the delay to the attainment of the prize increases, the current value of the delayed prize decreases, generally in a hyperbolic fashion (Mazur, 1987). This variation in preference for events according to time delay is referred to by economists as time preference and the rate at which the value of future prizes decreases over time the discount rate. The higher the discount rate, the more rapidly the value of delayed events decreases over time. Thus, increased time preference and discount rates indicate less preference for future events and more preference for present events (see Figure 2.1).
(p.11) Although the phenomenon of time preference appears to be pervasive, discount rates vary between and within individuals according to the value of loss or gain considered (lower values are generally discounted more), the nature of that loss or gain (health is generally discounted less than money) and whether a loss or gain is considered (gains are generally discounted more than losses) (Baker et al, 2003). Given the known variability in time preference among individuals according to a number of factors, it is also possible that time preference varies according to both SEP and health-related behaviours.
In contrast to the economic focus on value over time, psychologists have focused on how often, and in what way, individuals consider past, present and future events when making behavioural decisions. A number of different concepts with a temporal dimension have been proposed (see Box 2.1). While all related in terms of their inclusion of a temporal perspective, these concepts are not all necessarily direct proxies of the time preference and perspective concept. While acknowledging the differences between the various terms listed in Box 2.1, I seek here to highlight the similarities, rather than the differences, and refer to the common time dimension of these psychological concepts using the general term ‘time perspective’.
Time preference, time perspective and socioeconomic position
A number of studies have reported a relationship between SEP and both time preference and time perspective, finding that more affluent individuals tend to be more future orientated than more deprived individuals (Freire et al, 1980; Fuchs, 1980; Leigh, 1986; Nurmi, 1987; Lawrence, 1991; Green et al, 1996; Bosma et al, 1999; Peetsma, 2000; Wardle and Steptoe, 2003; Guiso and Paiella, 2004; Jaroni et al, 2004; Dom et al, 2006; Gurmankin-Levy et al, 2006). Instances where this relationship has not been found are predominantly case-control studies comparing current and never drug users (Kirby et al, 1999; Chesson and Viscusi, 2000; Petry, 2003; Reynolds et al, 2003; Kirby and Petry, 2004; Ohmura et al, 2005). As case-control studies are designed to identify differences and similarities between cases and controls, rather than associations between two continuous variables (Rothman, 1986), these findings are unlikely to be robust.
The main proposed explanation of time preference centres around uncertainty. The future is inherently uncertain and no future loss or gain can be absolutely guaranteed. As such, a future, and therefore uncertain, gain has less value than a current, and therefore almost certain, one (Freire et al, 1980). This explanation immediately raises the potential that time preference may be socioeconomically patterned. High-income occupations with permanent contracts and pension provision are frequently described as ‘secure’ in contrast to the relative insecurity and uncertainty of low incomes, temporary employment and reliance on state benefits. With money in the bank it begins to be possible to plan for the future. Without such savings and guaranteed income streams the future is uncertain (p.12) (p.13) and making firm plans becomes harder (Freire et al, 1980; Lawrence, 1991). The influence of income on security and ability to plan for the future strongly suggests that time preference and perspective should be socioeconomically patterned.
Educational attainment has also been used as a marker of time preference (Chaloupka, 1991; Huston and Finke, 2003). It is suggested that delaying entry to the workforce in order to take part in further education is an investment-like behaviour with low income in the short term being traded for higher income prospects in the longer term (Munasinghe and Sicherman, 2005). As educational attainment is also a key marker of SEP (Krieger et al, 1997; Galobardes et al, 2006), this provides a further theoretical link between SEP and time preference and perspective.
A number of authors have suggested that time preference and perspective are learned traits with children growing up in less structured environments and experiencing less predictability being more likely to develop high discount rates and less orientation towards the future (Frank, 1939; Zimbardo and Boyd, 1999; Petry, 2002). The preceding discussion suggests a number of reasons why less affluent families may provide less certain environments. Given that SEP tracks through the lifecourse, with children tending to maintain the relative social position of the families they were born into throughout adulthood (Graham, 2002), this provides further reason to believe that there may be a persistent relationship between SEP and time preference and perspective.
Lastly, children from more affluent families may gain a more developed sense of the future because their futures are, to some degree, more planned than children from less affluent families. Affluent children may be more likely than deprived children to be expected to finish school and attend university – providing a clear plan for their future into their early twenties. In contrast, children from more deprived families may face expectations to leave school in their mid-teens and find a job – providing a clear plan only into the mid- or late teens (Nurmi, 1991).
Time preference, time perspective and health-related behaviours
Many health-promoting messages appeal to a desire to make the future better – or at least more healthy – encouraging us to adopt healthy behaviours now in order to safeguard our health in the future (Rakowski, 1986; Orbell and Hagger, 2006). Similarly, many health-related behaviours involve a trade-off between immediate pleasure and potential future health benefits (Fuchs, 1980; Finke, 2000; Piko et al, 2005). For example, eating a healthy diet involves avoiding pleasurable, but unhealthy foods in the short term and taking part in a regular exercise programme involves devoting time, energy and, in some cases, money in the short term – both in order to reduce the risk of a number of chronic diseases in the long term. Despite some current attempts to make healthy behaviours ‘fashionable’ and therefore attractive in the short term, the reality is that many behaviours have to be pursued for prolonged periods of time in order to bring health benefits and (p.14) those benefits are not certain. Thus, a rational decision to take part in healthy behaviours – for the purpose of health benefit – requires that value is placed on potential health benefit at some point in the future. Hence, it is highly plausible that time preference and perspective play a role in the decision to take part in healthy behaviours.
Although there is strong theoretical reason why time preference and perspective may be important in determining many different health behaviours, the majority of the empirical evidence on the ability of time preference and perspective to predict health behaviours has focused on addictive behaviours. Many studies have now reported that people who use substances such as heroin, cocaine, alcohol and tobacco in an addictive manner have higher discount rates than individuals who do not (Hornik, 1990; Madden et al, 1997; Vuchinich and Simpson, 1998; Bickel et al, 1999; Bretteville-Jensen, 1999; Kirby et al, 1999; Mitchell, 1999; Petry and Casarella, 1999; Chen, 2001; Petry, 2001, 2002, 2003; Odum et al, 2002; Baker et al, 2003; Coffey et al, 2003; Sato and Ohkusa, 2003; Kirby and Petry, 2004; Reynolds et al, 2004; Ohmura et al, 2005; Dom et al, 2006). In addition, there is consistent evidence of a cross-sectional relationship between psychological measures of time perspective and use of addictive substances (Sattler and Pflugrath, 1970; Alvos et al, 1993; Businelle, 1996; Allen et al, 1998; Petry et al, 1998; Vuchinich and Simpson, 1998; Keough et al, 1999; Chen, 2001; Klingemann, 2001; Wills et al, 2001; Levy and Earleywine, 2004; Robbins and Bryan, 2004; Peters et al, 2005; Piko et al, 2005), with only two known studies failing to report the predicted relationship (Murphy and DeWolfe, 1985–86; Chesson and Viscusi, 2000).
Much less work has explored the relationship between measures of time preference and perspective and non-addictive health-related behaviours. While condom use and other safer sexual practices appear to be associated with more orientation towards the future (Rothspan and Read, 1996; Agnew and Loving, 1998; Dorr et al, 1999; Aronowitz and Morrison-Beedy, 2004; Bryan et al, 2004; Appleby et al, 2005), time preference was not strongly associated with acceptance of an influenza vaccine or adherence with hypertension or cholesterol medication prescriptions (Chapman and Coups, 1999; Chapman et al, 2001). Other behaviours such as fruit and vegetable intake and regular physical activity are inconsistently related to measures of time preference and perspective (Mahon and Yarcheski, 1994; Mahon et al, 1997, 2000; Finke, 2000; Hamilton et al, 2003; Huston and Finke, 2003; Wardle and Steptoe, 2003; Nagin and Pogarsky, 2004) but few of these studies used well-established, or validated, measures of time preference or perspective and behavioural measures were frequently crude and sample sizes small.
Gaps in the literature, methodological problems and next steps
The evidence reviewed thus far, along with the well-established relationships between SEP and both addictive and non-addictive health-related behaviours, is summarised in a new conceptual model shown in Figure 2.2. In this figure, (p.15) solid arrows represent established relationships and the dotted arrow represents a hypothesised relationship that may be an area of fruitful future investigation.
There is substantial evidence that time preference and perspective are socioeconomically patterned and that addictive behaviours are associated with increased time preference and less orientation towards the future. Given the strength of the evidence, these relationships are represented with solid arrows in Figure 2.2. While there is good theoretical reason to believe that other, non-addictive, health-related behaviours are associated with time preference and perspective, this relationship has received little attention in the literature. Due to the current absence of evidence on this relationship (rather than evidence of absence of a relationship), it is represented by a dotted arrow in Figure 2.2. As there is good evidence (not reviewed here) that SEP is a causal determinant of health-related behaviours, these relationships are shown with unidirectional arrows in Figure 2.2. However, the direction of causation, if any, between SEP and time preference and perspective, and between time preference and perspective and health-related behaviours is not known and these relationships are, therefore, shown with bidirectional arrows in Figure 2.2.
The current gaps in the literature highlighted by Figure 2.2, along with a number of others, are now discussed in turn.
Time preference, time perspective and socioeconomic inequalities in health-related behaviours
Although all of the individual relationships shown in Figure 2.2 have been subject to at least some empirical testing, few attempts have been made to study the whole pathway. In the cases where time preference and perspective have been investigated as potential mediators of the relationship between SEP and health-related behaviours, it has been found that time preference or time perspective statistically accounts for some, but not all, of the relationship between SEP and health-related behaviours (Fuchs, 1980; Hornik, 1990; Keough et al, 1999; Picone et al, 2004; Appleby et al, 2005). Further work using well-established measures of (p.16) time preference and perspective, SEP and health-related behaviours is, therefore, required to determine if a causal pathway exists linking SEP and health-related behaviours through time preference and perspective.
Lack of longitudinal data
To date, a substantial proportion of published research on time preference and perspective in relation to health behaviours has relied on case-control studies of substance users versus non-users where time preference or perspective is measured after behavioural patterns are well established. Although these studies provide useful preliminary evidence, they cannot provide any evidence on causality. Furthermore, even if a causal association is assumed, case-control studies provide no information of the direction of causality – is time preference a constant factor within individuals that determines their behaviours, or do individuals alter their time preference in order to be consistent with the behaviours they currently perform? The existing, scant, longitudinal data provide evidence for both possibilities (Henik and Domino, 1975; Reynolds et al, 2003, 2004).
Further, rigorous longitudinal work that explores the effect of behaviour change on time preference and perspective, and the effect of time preference and perspective on behaviour change, will be necessary to help establish a causal relationship and the direction of causality between time preference and perspective and health-related behaviours.
Problems with definition and measurement
Along with the wide variety of concepts that have some relation to the time preference and perspective concept (Box 2.1) there has been wide variation in methods of measurement. A number of different choice tasks (Green et al, 1994; Chesson and Viscusi, 2000; Chapman et al, 2001), personality inventories (Strathman et al, 1994; Zimbardo and Boyd, 1999) and other tasks (Freire et al, 1980; Leigh, 1986) have been developed that purport to measure time preference, time perspective and related concepts. While some of the personality inventories have been subject to ample psychometric testing (Strathman et al, 1994; Zimbardo et al, 1997; Zimbardo and Boyd, 1999; D'Alessio et al, 2003), and money choice tasks appear to produce results in line with a variety of theoretical predictions (Mazur, 1987), without a clear conceptualisation of the phenomenon under study it is almost impossible to confirm construct validity.
Other proxies that have been proposed and used as measures of time preference or time perspective include smoking (Chaloupka, 1991; Munasinghe and Sicherman, 2000; Fersterer and Winter-Ebmer, 2003; Huston and Finke, 2003; Munasinghe and Sicherman, 2005), educational attainment (Chaloupka, 1991; Huston and Finke, 2003), spending patterns (Barsky et al, 1997; Komlos et al, 2004; Picone et al, 2004) and predicted longevity (Wardle and Steptoe, 2003; Nagin and Pogarsky, 2004; Picone et al, 2004). However, these all have limitations in the context of (p.17) socioeconomic inequalities in health-related behaviours – educational attainment is a common marker of SEP (Krieger et al, 1997; Galobardes et al, 2006), spending patterns and longevity are strongly associated with SEP (Drever and Whitehead, 1997) and smoking is a key health-related behaviour. The development of both an integrated definition of the concept of time preference and time perspective, and a measurement instrument that incorporates both economic and psychological perspectives, is therefore required to enable good-quality and policy-relevant, multidisciplinary work to be performed in this area.
Developing health-promotion interventions
From a public health perspective, the finding that time preference and perspective play a role in mediating the relationship between SEP and health-related behaviours is only of interest if it can be used to help promote wider uptake of healthy behaviours – particularly among individuals from the most deprived groups. Two approaches have been taken to making use of time preference and perspective in the area of health-promotion interventions.
On the basis that there is some evidence of a cross-sectional relationship between health behaviours and time preference and perspective, a few researchers have attempted to promote healthy behaviours by manipulating time perspective. These manipulations generally take the form of asking participants to focus on the future benefits of healthy behaviour, or the negative thoughts they may experience after engaging in unhealthy behaviours, and have led to some short-term success in behavioural change (Richard et al, 1996; Murgraff et al, 1999; Hall and Fong, 2003). Longer-term studies are required to determine if such interventions lead to sustained alteration in both time preference and perspective and behaviour.
A second body of work has proposed that the effectiveness of health-promoting messages may vary with an individual's time preference or perspective. There is some evidence that those with more future-orientated time perspectives respond better to traditional health-promoting interventions that focus on future benefits of behaviour while those with more present-orientated time perspectives respond better to messages that stress the short-term benefits of behaviour (Orbell et al, 2004; Ouellette et al, 2005; Orbell and Hagger, 2006). The obvious conclusion is that tailoring health-promotion messages to the time perspective of the subject may be more effective than a ‘one-size-fits-all’ approach – similar to the tailoring of health-promotion messages to individuals’ stage of change proposed by the transtheoretical model (Prochaska and DiClemente, 1982).
In this chapter I have proposed that attitudes towards the future, encapsulated in the concepts of time preference and perspective, may play a role in mediating the pervasive link between SEP and health-related behaviours. Strong theoretical reasons why time preference and perspective should be both associated with SEP (p.18) and predictive of health-related behaviours have been presented. The evidence reviewed here confirms a link between SEP and time preference and perspective and between addictive behaviours and time preference and perspective. Further work is required to confirm that time preference and perspective are associated with non-addictive health-related behaviours and that time preference and perspective are on the causal pathway between SEP and health-related behaviours. Some preliminary work suggests that interventions to alter time perspective or tailor health-promotion interventions according to recipients’ time preference may be effective in achieving behaviour change. Public health specialists may have much to gain by integrating these psychological and economic concepts into their understanding of socioeconomic inequalities in health and health-related behaviours.
Many thanks to Professors Cam Donaldson, Martin White and Andrew Steptoe for providing critical comments on previous drafts of this chapter. The author is supported by a UK MRC Special training Fellowship in Health Services and Health of the Public Research.
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