Risk compensation theory and bicycle helmets – Results from an experiment of cycling speed and short-term effects of habituation

It has been suggested that the safety benefits of bicycle helmets are limited by risk compensation. The current study contributes to explaining whether the potential safety effects of bicycle helmets are reduced by cyclists’ tendency to cycle faster when wearing them (as a result of risk compensation), and if this potential reduction can be associated with a change in perceived risk. A previous study (Fyhri & Phillips, 2013) showed that non-routine helmet users did not increase their speed immediately after being given a helmet to wear, while routine helmet users cycled more slowly. The current study tests whether the previously found reduction in speed in response to helmet removal – as an indirect indicator of risk compensation – could be established in non-routine helmet users, after a period of habituation while cycling with a helmet.We did this by conducting a randomized crossover trial, in which we used GPS-derived speed calculations and self-reported risk perception. To test the effect of habituation, we used a design where each participant took part in two rounds with a break between and each round having two trips. We collected the data in June 2015. Non-routine helmet users (N = 31) were recruited in the field (along cycle routes in Oslo), and through a sample drawn from the Falck National register of bicycle owners. In the first phase of the study, all participants were asked to complete a test route (2.4 km downhill) with and without a helmet. In the second phase of the experiment, conducted after 1.5–2 h, the same participants again completed the test route with and without a helmet. In the time between the first and second phases of the experiment, all participants were given helmets, and told to use them on a predefined bicycle route.Habituation to the helmet between the first and second phases of the experiment did not produce any decrease (with helmet removal) in speed, on top of the habituation that occurred while cycling down the hill (the order effect). Mean speed difference for cycling with/without a helmet before the break was −0.76 km/h, after the break this difference was 0.32 km/h; 95% CIs [−0.5, 2.9] and [−0.9, 1.5]. We argue that risk compensation is an unlikely effect of using a bicycle helmet, and probably cannot explain any adverse effects related to helmet legislation.     

Barriers and facilitators of bicycle helmet use among children and their parents

Despite the fact that bicycle helmet use protects against head injuries, helmet use rate is still low even in countries with high concern for traffic safety. Earlier research shows that helmet use declines with age and that helmet use is low especially among teenagers. The aim of the present study was to investigate barriers and facilitators of helmet use among primary and secondary school pupils and their parents. Identical surveys were conducted among school children (n = 235) and their parents (n = 106). Children’s and adults’ responses concerning cycling, helmet use, helmet ownership, risk assessment and barriers and facilitators were compared and separate regression analyses conducted. Helmet use rate was lower among pupils than adults and they scored higher in most of the barrier items. The results of regression analyses showed that among children, age, gender, barriers and facilitators predicted helmet use while among adults only frequency of cycling and barriers were related to helmet use. Among children, the strongest correlates of not using a helmet were the belief of not needing a helmet and wish to use a cap or a hat instead. Having a helmet wearing as a habit and feeling safer were the strongest correlates of using helmet. Among adults, the strongest correlates of not using a helmet were “helmet looks ridiculous”, “just going to short trip” and riding close to home while the strongest correlate of using a helmet was the habit of helmet use. It was concluded that targeting the barriers in helmet wearing campaigns might work better both among children and adults than emphasising the benefits at least among Norwegian child and adult cyclists.     

A model of factor analysis: Reasons for using a helmet in a sample of non-competitive Italian cyclists

IntroductionThe increased bicycle use for transport as an alternative to motorized vehicles has by now become a common occurrence in all Italian cities. Even though the benefits of using a helmet to protect against trauma in bicycle accidents have been demonstrated, its use is still limited. The objective of this study is to analyse those motivations for helmet wearing that can influence their adoption.MethodsData was gathered through an online questionnaire in collaboration with the Federazione Italiana Amici della Bicicletta (Italian Federation of Friends of the Bicycle), a recreational cyclists association.Motivations to use a helmet were investigated using a factorial analysis model. Factors were analysed through a points allocation system and compared according to gender, area of residence and whether the cyclist was a helmet-enthusiast.ResultsThe sample was made up of 1781 individuals, with a declining participation rate from North to South; 63% of respondents were men.Three factors were identified from the sample: helmet use as a safety benefit; helmets being perceived as a hindrance; and helmet used out of habit as well as to follow the virtuous example of friends and/or acquaintances during cycling outings. The major kinds of evidence are: regarding gender, differences in the perception of a helmet as a hindrance (p < 0.001) and its use out of habit (p < 0.001); as for area of residence, differences in the perception of a helmet as a hindrance (p = 0.01) and its use out of habit (p < 0.01); as regards being a helmet-enthusiast, differences were found for all the factors (p < 0.01).ConclusionsThese results contribute to understanding the scenario that affects motivational beliefs through facilitating or deterring cyclists from using a helmet during recreational cycling. The evidence suggests how to argue the helmet use discussion among Italians. In such a homogeneous population of respondents in terms of passion for cycling, opinions on helmet use were dissimilar from the point of view of both its perception and the subsequent motivation for using it.Exploring perceptions and motivations on helmet use is a key element in understanding cyclists’ behaviour in order to characterize different users. A combination of friends/peer influence, reduction in the perception of helmets as a hindrance, and reinforcing of safety could represent the starting point for planning interventions.     

The effects of protective helmet use on physiology and cognition in young cricketers

Many studies have reported physiological and cognitive decrements following heat stress. Of particular concern in cricket are the possible negative effects of sustained protective helmet use, as this leads to an increase in heat‐related stress. Correct and rapid decision making, and focused attention are essential for efficient performance whilst batting, and it is possible that helmet usage could impair such processes. In a repeated‐measures, randomized crossover study, physiological, self‐report, and cognitive measures were taken from 16 teenage cricketers before and after moderately intense (batting) exercise. Participants underwent the assessments twice, once while wearing a standard protective helmet, and again, when not wearing a helmet (counterbalanced). While helmet use did not lead to significant physiological changes, wearing a helmet led to some cognitive impairments in attention, vigilance and reaction times. These preliminary findings could have significance for cognitively demanding sports (and perhaps military and industrial settings) in which participants perform cognitively demanding operations under conditions of physical exercise whilst wearing protective helmets. Additional factors of hydration, exercise duration, and helmet design are discussed. Copyright © 2004 John Wiley & Sons, Ltd.     

Disparity of motorcycle helmet use in Nepal – Weak law enforcement or riders' reluctance?

Like many low- and middle-income countries, Nepal is experiencing a massive motorization, predominantly from increased use of motorcycles which is driving a surge in road-related injuries and fatalities. Motorcycles and their riders have been identified as a focal point for road traffic injury prevention measures. While helmet use is mandatory for both motorcycle drivers and passengers, fines for helmet non-use are only levied on drivers, not on passengers, and it is unclear how this unequal enforcement translates to helmet use rates in Nepal. Hence, a video-based observation on motorcyclists’ helmet use was conducted alongside a questionnaire survey on fatalism, perceived police enforcement, risk-taking personality, and perceived usefulness of helmets. For the observation and questionnaire survey, seven rural and urban sites were selected from all seven provinces of Nepal, representing varied populations, road environments, and elevations. The observation of the helmet use behavior of 2548 motorcycle riders revealed an alarming picture of helmet use in Nepal. While more than 98% of observed motorcycle drivers in Nepal used a motorcycle helmet, less than 1% of observed passengers did so. Interviews of 220 riders show that the absence of a fine for helmet non-use by passengers is accompanied by an unawareness of the traffic law, where only 11.8% of respondents knew about the mandatory helmet use law for passengers. Unhelmeted riders had a significantly higher attribution of road related crashes to fate, compared with riders that used a helmet. Results of this study can serve as an evidence base for revisions of Nepal’s Vehicle and Transportation Management Act in regard to traffic rule enforcement and fines. They further show the global importance of comprehensive regulation on safety related behaviors of road users. The feasibility of more comprehensive enforcement is discussed against the background of helmet availability for passengers.     

The role of traffic law enforcements in the relationship between cultural variables and traffic fatality rates across some countries of the world

The aims of the present study were to investigate whether cultural variables are related to law enforcements as well as traffic fatality rates and to examine the role of law enforcements of five risk factors for road safety (i.e., national speed law, national drink-driving law, national motorcycle helmet law, national seat-belt law, and national child restraint law) in the relationship between cultural variables and traffic fatality rates across countries of the world. The aggregated data of the study included Hofstede’s cultural dimensions, Schwartz’s value dimensions, law enforcements of five risk factors for road safety, gross national income per capita, and traffic fatality rates for 97 countries of the world. The results showed that most of the cultural variables were associated with law enforcements of five risk factors for road safety and traffic fatality rates of countries. By bootstrapping, among Hofstede’s cultural dimensions, it was found that the indirect effects of long-term orientation (LTO) on fatality rates (FR) through speed, helmet, and child restraint enforcements were significant, separately. Among Schwartz’s value dimensions, the indirect effects of embeddedness on fatality rates through speed and child restraint enforcements were significant, separately. Intellectual autonomy had also significant indirect effects on fatality rates via speed and child restraint enforcements, separately. Finally, it was found that the indirect effects of affective autonomy on fatality rates through speed and helmet enforcements were significant, separately.     

Determinants of standard motorcycle safety helmet usage among child pillion riders

The World Health Organization stressed that compliance with the use of safety helmet could significantly reduce the risk of injury by 72% and the probability of death by 39%. In Malaysia, the enforcement of the safety helmet legislation significantly reduced 30% of motorcycle crash fatalities in Malaysia. The aim of this study is to explore the use of motorcycle helmets and the determinants of standard helmet usage among child pillion riders. A cross-sectional survey of 200 adult riders accompanied by the child pillion riders aged 6–12 years old from Klang, Selangor, was conducted. The proper use of the helmet among the respondents and the child pillion riders was observed and recorded. A questionnaire was used to assess socio-demographic background and awareness of the use of child safety helmets. The data was analyzed using SPSS version 23. Only 3% of child pillion riders use standard child safety helmets, while 37% wear standard adult motorcycle helmets. Adult riders who were married, female, always wear helmets, have a higher household income and travel a long distance, are more likely to use a standard motorcycle helmet for their child pillion riders. Knowledge on Standard Certification (SIRIM) label and its importance, awareness of the campaign on child safety helmets, police enforcement, understanding the safety of toy/game helmet use have been identified as additional determinants of standard helmet use among child pillion riders. This study recommends prospective studies with continuous road safety educations programs that integrate behavioural change approaches to enhance the use of standard motorcycle helmets among the child pillion riders in Malaysia.     

Rhesus monkeys (Macaca mulatta) demonstrate robust memory for what and where,but not when,in an open-field test of memory

We adapted a paradigm developed by Clayton and Dickinson (1998), who demonstrated memory for what, where, and when in scrub jays, for use with rhesus monkeys. In the study phase of each trial, monkeys found a preferred and a less-preferred food reward in a trial-unique array of three locations in a large room. After 1 h, monkeys returned to the test room, where they found foods placed as during study. Twenty-five hours after the study phase monkeys again searched the room, but now the preferred food was replaced with a distasteful food remnant, while the less-preferred food was still present. Although monkeys remembered the locations of the foods for up to 25 h, they did not learn that the preferred food was available after the short, but not after the long delay. Thus, monkeys demonstrated long-term memory for the type and location of food but failed to demonstrate sensitivity to when they acquired that knowledge.     

Impact of a comprehensive safety program on bicycle helmet use among middle-school children

A bicycle helmet program was evaluated in three middle schools using a multiple baseline across schools design. Two of the three schools had histories of enforcement of helmet use. During baseline many students riding their bikes to and from school did not wear their helmets or wore them incorrectly. A program that consisted of peer data collection of correct helmet use, education on how to wear a bicycle helmet correctly, peer goal setting, public posting of the percentage of correct helmet use, and shared reinforcers, all of which were implemented by the school resource officer, increased afternoon helmet use and afternoon correct helmet use in all three schools. Probe data collected a distance from all three schools indicated that students did not remove their helmets once they were no longer in close proximity to the school, and probe data collected in the morning at two of the schools showed that the behavior change transferred to the morning.     

Abiding by the law when it does not exist: The case of the helmet bicycle law

To improve the safety of bicycle users, some countries have enacted, or considered enacting, mandatory helmet legislation. Of course, the enactment of such legislation in a country assumes that its citizens will be well-informed of it, and consequently, will use the helmet more frequently than before. However, in the survey described in this paper we found that many people are not aware of the legislation in force in their own country, or, even if they know, they may not necessarily behave as dictated by the law. Thus, the effects of mandatory helmet legislation may be somewhat different than desired or expected. Therefore, the goal of this paper is to ascertain the role of cyclists’ knowledge of the law in their country as a mediator between the law and the actual use of the helmet. Respondents from seventeen countries participated in an international survey about cyclists' habits, and answered questions about helmet legislation, and frequency of helmet use. The results indicate that the main effect of mandatory helmet legislation on the frequency of use of the helmet is mediated by the perception that such a law exists in their country—even when in fact sometimes it does not exist.     

Bicycle helmets – A case of risk compensation?

Several studies have shown that bicycle helmets have the potential of reducing injuries from accidents. Yet, no studies have found good evidence of an injury reducing effect in countries that have introduced bicycle helmet legislation. Two of the most promising explanations for why helmet laws do not work as intended are risk compensation and shifts in the cycle population as a response to the law.The present article investigates whether the lack of effect of helmet wearing laws is due to risk compensation mechanisms or population shifts (i.e. discouraging cyclists with the lowest accident risk, and thereby increasing the overall average risk per cyclist). A random sample of 1504 bicycle owners in Norway responded to a questionnaire on among other things helmet use, bicycle equipment use, accident involvement, cycling behaviour and risk perception. Data were analysed by using structural equation model (SEM). The results show that the cyclist population in Norway can be divided into two sub-populations: one speed-happy group that cycle fast and have lots of cycle equipment including helmets, and one traditional kind of cyclist without much equipment, cycling slowly. With all the limitations that have to be placed on a cross sectional study such as this, the results indicate that at least part of the reason why helmet laws do not appear to be beneficial is that they disproportionately discourage the safest cyclists.     

FUNCTIONAL ANALYSIS AND TREATMENT OF SEVERE PICA

A two-phase functional analysis of a profoundly retarded 19-year-old male's pica facilitated the design of an effective intervention containing no aversive components. In the first analysis, frequent staff-client interaction resulted in 25% and 66% less pica than limited and no interaction, respectively. Paradoxical effects were obtained in the second analysis, where no protective helmet resulted in 38% and 26% less pica than the helmet with face shield and helmet without face shield, respectively. On the basis of these analyses, limited interaction and no helmet conditions were combined in an effective, staff-implemented treatment at a medium-sized institution.     

An observational study of restraint and helmet wearing behaviour in Malaysia

Unrestrained and unhelmeted occupants are at increased risk of severe injury or death in the event of a crash, and there is evidence that children, particularly in low and middle income countries, have low restraint and helmet wearing rates.Roadside observations of occupants of passing vehicles (7247 cars, vans and taxis and 2897 motorcycles) in nearside lanes were made at seven selected road sites located around the Klang Valley (greater Kuala Lumpur) area representing a variety of demographic locations.The findings revealed an overall low rate of seat-belt wearing in vehicles (front seat drivers: 44.6%; front seat adult passengers: 33.8%; front seat child passengers: 11.8%; rear seat adult passengers: 5.2%; and, rear seat child passengers: 5.8%). For motorcyclists, the majority of adult riders and pillions wore helmets (93.4% and 85.8%, respectively), however a substantial proportion (40%) did not fasten their helmet properly. Of children observed on motorcycles, only 30.5% wore helmets.This study shows low seat-belt and helmet wearing rates, despite enactment of legislation that requires all vehicle passengers to be restrained and for all motorcyclists to wear helmets. This was particularly evident for children (front and rear seating positions) and rear seat adult passengers. It is suggested there is a general lack of awareness of safety and the benefits of restraint/helmet use, and lack of adequate and appropriate enforcement. The implications of the findings are discussed in terms of promoting restraint/helmets use, enforcement of legislation and implementation of technologies to increase appropriate restraint/helmet use.     

Effects of daily morphine administration and deprivation on choice and demand for remifentanil and cocaine in rhesus monkeys

Choice procedures have indicated that the relative reinforcing effectiveness of opioid drugs increases during opioid withdrawal. The demand curve, an absolute measure of reinforcer value, has not been applied to this question. The present study assessed whether mild morphine withdrawal would increase demand for or choice of remifentanil or cocaine. Four rhesus monkeys chose between remifentanil and cocaine during daily sessions. Demand curves for both drugs were subsequently obtained. The effects of daily injections of 3.2 mg/kg morphine on both choice and demand for these drugs was assayed 3 and 20.5 hr after each morphine injection, and then during a postmorphine period. Three hours following morphine injections, choice of remifentanil over cocaine decreased and demand for remifentanil--but not cocaine--became more elastic. During morphine withdrawal (20.5 hr postinjection), choice of remifentanil increased and remifentanil demand became more inelastic in 3 of 4 monkeys. Cocaine demand also became more inelastic during this period. Four to five weeks following the morphine regimen, demand for both drugs was more inelastic relative to the initial determination. The results suggest that both the relative and absolute reinforcing effectiveness of remifentanil decreased following morphine administration and increased during morphine withdrawal. The absolute reinforcing effectiveness of cocaine also increased during morphine withdrawal. In addition, extended exposure to drug self-administration and/or exposure to the morphine regimen produced long-term increases in demand for both drugs.     

Bicycle helmet law does not deter cyclists in Finland

Bicycle helmet legislation (BHL) in Finland went into effect in January 2003 and applies to cyclists of all ages. There are no mechanisms to fine cyclists riding without a helmet; however, helmet wearing rates are 64% in Helsinki and 42% across Finland. Our aim was to discuss possible effects of BHL on cycling in Finland. We used data from the 1998/1999, 2004/2005 and 2010/2011 Finnish National Travel Surveys. Data across three surveys suggest cycling has declined from before to after BHL. In a 2004/2005 survey, however, only 0.063% (95% CI: 0.02–0.10%) of responders identified helmet use as their most important obstacle to cycling. It is unlikely BHL is a causal factor in the downward trend in Finnish cycling. Lack of cycling infrastructure and concerns for safety are much more common reasons given.     

Analysis of correlations between psychological factors and self-reported behavior of motorcyclists in Malaysia,depending on self-reported usage of different types of motorcycle facility

Segregated road lanes for motorcyclists are one of the practices implemented by the Malaysian authority to decrease the number of road crashes involving motorcycles. In this study, the motorcycle lanes are divided into three types, exclusive, inclusive, and paved shoulder. This study examined the correlations between motorcyclists’ psychological factors and their risky riding behaviors (speeding and neglecting to wear helmet), depending on self-reported usage of different types of motorcycle facilities. The psychological factors discussed in this study were: attitude, desire, perceived behavior control, moral obligation, perceived danger, fear of being caught, and perception of others’ behaviors toward the risky behaviors. Quantitative analyses, including Structural Equation Modeling, were used as the analytical tools. The results demonstrated the statistically significant relationship of exclusive road lanes’ usage on speeding behavior. However, no statistically significant correlation was found for segregated lanes’ usage on helmet wearing behavior. Psychological factors were found affecting the motorcyclists’ likelihood of performing the risky behaviors. However, these factors influence speeding and helmet wearing behavior differently. The study offers recommendations and theoretical contributions to explain the complex relationships among the uses of segregated lanes, riders’ psychological factors, and their risky behaviors.     

Socially meaningful vocal plasticity in adult Campbell's monkeys (Cercopithecus campbelli)

Campbell's monkeys (Cercopithecus campbelli) frequently exchange vocalizations, the combined-harmonic calls, with individuals responding to one another's calls. Previous work has shown that these calls can be grouped into several structural variants. Adult females differ in their variant repertoires, which may change during their adult life, particularly after changes in the group composition. Playback of females' currently produced variants triggered vocal responses from other group members, whereas the same females' former, no longer used variants and those of stranger females never did. In contrast, former variants caused long-term cessation of vocal behavior, whereas stranger variants had no effect. Data showed that monkeys were able to distinguish between the different types of variants, indicating that these calls form part of a long-term social memory.     

Oral self-administration of pentobarbital by rhesus monkeys: relative reinforcing effects under concurrent fixed-ratio schedules.

During daily 3-hr sessions, orally delivered pentobarbital solutions and water, or two separate pentobarbital solutions, were concurrently available to rhesus monkeys according to fixed-ratio schedules of mouth contacts with a spout. First water, and then each of four "comparison-concentration" pentobarbital solutions (0.0625, 0.25, 1, and 4 mg/mL), was successively available from one spout for a block of sessions under a fixed-ratio-64 (three monkeys) or fixed-ratio-16 (one monkey) schedule. Under an identically sized fixed-ratio schedule, deliveries of a "standard-concentration" pentobarbital solution were concurrently available from a second spout. The concentration of the standard solution remained unchanged throughout testing of the series of comparison solutions. Each of three pentobarbital concentrations (4, 1, and 0.25 mg/mL) in turn served as the standard concentration. Within each pair of concurrently available solutions, the higher drug concentration maintained more behavior than the lower concentration. Thus when monkeys were provided with concurrent access to different pentobarbital concentrations, relative reinforcing effects were directly related to drug concentration. Further, the amount of behavior maintained by a particular drug concentration was dependent on the concentration of the concurrently available drug solution. Thus, the relative effectiveness of a reinforcer in maintaining behavior is a function of both the reinforcer's magnitude and the availability of alternative reinforcers in the environment.     

Duck! Scaling the height of a horizontal barrier to body height

Recent research shows that the body is used to scale environmental extents. We question whether the body is used to scale heights as measured by real actions (Experiments 1 and 2) or by judgments about action and extent made from a single viewpoint (Experiments 3 and 4). First, participants walked under barriers naturally, when wearing shoes, or when wearing a helmet. Participants required a larger margin of safety (they ducked at shorter heights) when they were made taller. In follow-up experiments, participants visually matched barrier heights and judged whether they could walk under them when wearing shoes or a helmet. Only the helmet decreased visually matched estimates; action judgments were no different when participants’ eye height increased. The final experiment suggested that the change in matched estimates may have been due to lack of experience wearing the helmet. Overall, the results suggest that perceived height is scaled to the body and that when body height is altered, experience may moderate the rescaling of height.     

Effects of fornix transection on spontaneous and trained non-matching by monkeys

Three monkeys with fornix transection and three normal control monkeys performed a series of tasks which were variations of delayed non-matching. Experiment 1 showed that even at short retention intervals fornix transection impaired the spontaneous tendency to explore novel objects. Experiment 2 provided differential reward for non-matching and showed that the fornix-transected monkeys learned and performed non-matching normally even though the sample-match retention intervals were long throughout the experiment. Experiment 3 showed that non-matching performance was transiently more disrupted in fornix-transected than in normal monkeys when the testing procedure was changed, in a variety of ways, while maintaining the basic non-match rule. Experiment 4 required the monkeys to discriminate objects they had displaced from objects they had seen but not displaced; fornix transection produced in this task a substantial and stable impairment. These four experiments require a revised interpretation of the effects of fornix transection upon recognition memory and exploration. Particularly they contradict the hypothesis, suggested by previous experiments, that fornix transection produces a defect in discrimination of stimulus familiarity in long-term but not in short-term memory. They suggest rather that fornix transection impairs memory of instrumental responses.