Phone Usage Patterns Research Articles

Preference Pattern for Mobile Phone and Conventional Tools in Task Performance by Students of Delta State University, Abraka, Nigeria

Abstract Mobile phones have become very popular among people in different countries of the world and apart from the traditional role of making and receiving of calls; they have been adopted for several other uses. Its use for those activities tends to pose challenge to the conventional media tools that are used traditionally to perform those activities. The study thus aims at determining the pattern of mobile phone usage by students of Delta State University, Abraka; their preference pattern for mobile telephone and conventional media tools in carrying out certain activities; and the implication of their use of mobile telephone on conventional media toolsThe study adopted the Technology Acceptance Model (TAM), which explains how a person comes to accept and use an information technology. Survey and questionnaire were used as the research method and instrument respectively. The data were analyzed with descriptive statistics. The study found that the students preferred using mobile phones to perform tasks that were originally performed with conventional media tools; and the use of mobile phone by the students also suggested a diminishing patronage of conventional media tools. The study recommends that providers of those conventional media tools should improve on their services to avoid losing patronage, and they should make their products and services adaptable to mobile phone users in order to boost patronage.

Potential for mobile health (mHealth) prevention of cardiovascular diseases in Kerala: A population-based survey

BackgroundIndia's southern state of Kerala stands at the forefront of India's epidemic of cardiovascular disease (CVD), among other non-communicable diseases (NCDs). Mobile phone use in healthcare (mHealth) has shown promise in India, including NCDs. However, suitability and acceptability of m-Health interventions is poorly researched, particularly in rural settings. Objectives(1)To explore mobile phone usage patterns in rural Kerala (Ernakulam).(2)To explore acceptability of mHealth delivery of health promotion and CVD prevention. MethodsA questionnaire regarding mobile phone usage and possible use in healthcare was verbally administered in five primary health centres and by home visits in five village councils (“panchayats”) of Ernakulam, Kerala. Adults who spoke Malayalam or English, with access to a mobile phone were recruited by convenience sampling in partnership with accredited social health activists (ASHAs). Quantitative data analysis was conducted using SPSS software. Results262 participants were recruited. 87% routinely used and 88% owned a mobile phone. 92% were willing to receive mHealth advice, and 94% favoured mobile medication reminders. 70.3% and 73% preferred voice calls over short messaging service (SMS) for delivering health information and medication reminders, respectively. 85.9% would send home recorded information on their blood pressure, weight, medication use and lifestyle to a doctor or ASHA. 75.2% trusted the confidentiality of mHealth data, while 77.1% had no concerns about the privacy of their information. ConclusionsThe majority of this population approve mHealth interventions. While further investigation of mHealth as a health education tool is warranted, SMS interventions may fail to maximise equity and penetration across all patient groups.

Predicting Negative Emotions Based on Mobile Phone Usage Patterns: An Exploratory Study.

BackgroundPrompt recognition and intervention of negative emotions is crucial for patients with depression. Mobile phones and mobile apps are suitable technologies that can be used to recognize negative emotions and intervene if necessary.ObjectiveMobile phone usage patterns can be associated with concurrent emotional states. The objective of this study is to adapt machine-learning methods to analyze such patterns for the prediction of negative emotion.MethodsWe developed an Android-based app to capture emotional states and mobile phone usage patterns, which included call logs (and use of apps). Visual analog scales (VASs) were used to report negative emotions in dimensions of depression, anxiety, and stress. In the system-training phase, participants were requested to tag their emotions for 14 consecutive days. Five feature-selection methods were used to determine individual usage patterns and four machine-learning methods were tested. Finally, rank product scoring was used to select the best combination to construct the prediction model. In the system evaluation phase, participants were then requested to verify the predicted negative emotions for at least 5 days.ResultsOut of 40 enrolled healthy participants, we analyzed data from 28 participants, including 30% (9/28) women with a mean (SD) age of 29.2 (5.1) years with sufficient emotion tags. The combination of time slots of 2 hours, greedy forward selection, and Naïve Bayes method was chosen for the prediction model. We further validated the personalized models in 18 participants who performed at least 5 days of model evaluation. Overall, the predictive accuracy for negative emotions was 86.17%.ConclusionWe developed a system capable of predicting negative emotions based on mobile phone usage patterns. This system has potential for ecological momentary intervention (EMI) for depressive disorders by automatically recognizing negative emotions and providing people with preventive treatments before it escalates to clinical depression.

New Tools for New Research in Psychiatry: A Scalable and Customizable Platform to Empower Data Driven Smartphone Research.

BackgroundA longstanding barrier to progress in psychiatry, both in clinical settings and research trials, has been the persistent difficulty of accurately and reliably quantifying disease phenotypes. Mobile phone technology combined with data science has the potential to offer medicine a wealth of additional information on disease phenotypes, but the large majority of existing smartphone apps are not intended for use as biomedical research platforms and, as such, do not generate research-quality data.ObjectiveOur aim is not the creation of yet another app per se but rather the establishment of a platform to collect research-quality smartphone raw sensor and usage pattern data. Our ultimate goal is to develop statistical, mathematical, and computational methodology to enable us and others to extract biomedical and clinical insights from smartphone data.MethodsWe report on the development and early testing of Beiwe, a research platform featuring a study portal, smartphone app, database, and data modeling and analysis tools designed and developed specifically for transparent, customizable, and reproducible biomedical research use, in particular for the study of psychiatric and neurological disorders. We also outline a proposed study using the platform for patients with schizophrenia.ResultsWe demonstrate the passive data capabilities of the Beiwe platform and early results of its analytical capabilities.ConclusionsSmartphone sensors and phone usage patterns, when coupled with appropriate statistical learning tools, are able to capture various social and behavioral manifestations of illnesses, in naturalistic settings, as lived and experienced by patients. The ubiquity of smartphones makes this type of moment-by-moment quantification of disease phenotypes highly scalable and, when integrated within a transparent research platform, presents tremendous opportunities for research, discovery, and patient health.

Utilizing Smartphones to Study Disadvantaged and Hard-to-Reach Groups

Mobile technologies, specifically smartphones, offer social scientists a potentially powerful approach to examine the social world. They enable researchers to collect information that was previously unobservable or difficult to measure, expanding the realm of empirical investigation. For research that concerns resource-poor and hard-to-reach groups, smartphones may be particularly advantageous by lessening sample selection and attrition and by improving measurement quality of irregular and unstable experiences. At the same time, smartphones are nascent social science tools, particularly with less advantaged populations that may have different phone usage patterns and privacy concerns. Using findings from a smartphone study of men recently released from prison, this article discusses the strengths and challenges of smartphones as data collection tools among disadvantaged and hard-to-reach groups.

Pattern of mobile phone usage and its effects on psychological health, sleep, and academic performance in students of a medical university

Background: Mobile phones have become increasingly popular in recent years, especially in young generation. Although these are convenient and useful, teenagers are becoming more and more dependent on them. Aims and Objective: This study was designed to assess the mobile phone usage pattern and its negative effects on psychological health, sleep, and academic performance in students of a medical university. Materials and Methods: A descriptive study was conducted on a total of 1,000 medical students aged between 17 and 24 years who were using mobile phone for at least 1 year. They were requested to fill a specially designed, self-administrated, pretested, questionnaire that comprised details of their frequency and pattern of using mobile phone and its effects on their psychological health, sleep-related behavioral issues, and academic performance. The data collected were statistically analyzed. Result: Among the total 1,000 students, all of them possessed their own mobile phone, with about 76.4% students having smart phones. Major purpose of using the phone was for communication, coordination of activities, and in emergency situations, while others were also using it for downloading games, music, videos, and for style. Nighttime usage of mobile phone was highly significantly (p < 0.0001) associated with difficulty in waking up, waking time tiredness, decline in study habits, difficulty in concentration, increase in missed classes, and going late for classes. Total time spent on mobile phones was significantly (p < 0.05) associated with waking time tiredness and difficulty in waking up and highly significantly (p < 0.001) with decline in study habits, increase in missed classes, and going late for classes. Conclusion: Besides the positive role of mobile phones in our daily lives, its overuse presents negative impact on psychological health, sleep, and academic performance of students. Hence, it is important to guide the students regarding efficient, safe, purposeful usage, and negative effects of mobile phones on health and environment.

Mobile Phone Usage and its Health Effects Among Adults in a Semi-Urban Area of Southern India.

Worldwide, mobile phone usage has been increased dramatically which could affect the health of the people. India has the second largest number of mobile phone users. However there are only few studies conducted in India to assess its effects on health. To determine the prevalence and pattern of mobile phone usage and to assess the relationship between certain selected health problems and mobile phone usage among adults. Community-based cross-sectional study was conducted in Kottakuppam, a town panchayat in Villupuram district of Coastal Tamil Nadu, Southern India. It is a semi-urban area with a population of about 16,000. Majority of the residents are Muslim by religion and belong to different socio economic status. The study was approved by the Institutional Ethics Committee. A total of 2121 study participants were interviewed by the pre-final medical students through house-to-house survey using a pretested structured questionnaire. The questionnaire included the variables such as socio demographic profile, mobile phone usage and pattern, selected health problems, perceived benefits and threats and blood pressure. Selected health problems included headache, earache, neck pain, tinnitus, painful fingers, restlessness, morning tiredness, tingling fingers, fatigue, eye symptoms, sleep disturbance and hypertension. Only 2054 were included for data analysis using SPSS 17 version. Proportions were calculated. Chi-square test was used to measure the p-value. The p-value < 0.05 was considered as statistically significant. The prevalence of mobile phone usage was 70%. Calling facility (94.2%) was used more than the SMS (67.6%). Health problems like headache, earache, tinnitus, painful fingers and restlessness etc., were found to be positively associated with mobile phone usage. There was negative association between hypertension and mobile phone usage. The prevalence of mobile phone usage was high. There was significant association between selected health problems and mobile phone usage. In future, higher studies are required to confirm our findings.

A cross sectional study to assess the effects of excessive use of smartphones among professional college going students

Background: Smart phones have now become an essential part of life. However, despite the convenience it brings to use, sometimes it might affect our daily life in a negative sense. The objective of the study was to explore the pattern of mobile phone usage among professional college going students in Indore, India also to examine the extent of addictive behaviour towards the usage of mobile phones. Methods: A total of 300 students of different streams having smartphones were surveyed regarding the usage of smartphone considered as population and simple random sampling technique was used. A well-structured and administered questionnaire was used to elicit the responses. The collected data were analysed with the help of various tools and techniques to draw meaningful inferences and conclusion which were obtained using Excel and some using SPSS. The study was conducted during September 2014 to December 2014. Results: In present study maximum number of the students used smartphone around 4 hours daily and mostly the use was for communication & social networking. Majority of students used their smartphone at home, thought that they used smartphone more than expectation, felt uncomfortable without their smart phone, got irritated by frequent notifications of smart phone and got angry when someone interrupts them while using smart phone. Conclusions: Most of the students felt that over uses of smartphones make their lives more sedentary, dry eyes and headache, feel disturbances in their sleep. Also, they spend excess money on mobile recharges although they prefer to use internet over their own creativity for any project.

Menace of mobile phone overuse: an emerging public health concern

Background: Mobile phones have become indispensible objects of necessity in the rapidly developing economies like India. They are part and parcel of our lives in the rapidly evolving digitalized era. In this scenario, a study was conducted to find out how are mobile phones are being utilized by undergraduate medical students of a premier medical school IMS, BHU. The objectives of the study were to find out the pattern of mobile phone usage by the students; to assess its role as an educational tool and to explore the issue of ‘problem mobile phone overuse’; if any, in the students. Methods: A pretested questionnaire was used to assess the response on various issues related to cell phone usage. 208 medical students out of total 309 from 3rd to 9th semester were the part of the study. For statistical analysis, data analysis was done by using Epi-info ver.7. Results: Almost 40% respondents did not refer any educational sites on their cell phones. 9% respondents felt that they should cut down their time on cell phone but they can’t (problem mobile phone overuse). 59% respondents felt that cell phone affects their studies negatively to a certain extent. Only 5% respondents used their cell phones as a learning aid . Conclusions: Cell phones do not seem to play a major role as far as their educational role is concerned rather it is more often used as an entertainment tool by the students. The issue of cell phone overuse is also a new emerging issue with over 9% students found to be affected.

Effects of Mobile Phone Use on Sexual behavior of Youth in Andhra Pradesh

Cell phones have gradually become an integral part of one's life. It is no astonish, which a comprehensive, research just released acknowledges mobile technology has coherently changed the style in which we truly love, live and work. Cell phones are now like mini computers and with gam consoles, high resolution still and video cameras, mailing systems, text messengers, carriers of fun and business information, helping within one's commercial and business transactions. The cell phone has made international long distance contacts easy, with ceaseless advance in technology, advanced and elaborated features added to the cell phones. In the past decade, mobile technology has altered the way youth communicate and interact with their peers. The development and modernization of this technology has made lives of youth easier and has brought about some problems and threats stemming from irresponsible use of mobile phones among teens and young adults. The whole youth population or student community is passing through chaos, disturbance and mental incapacitation. This study focuses on exploring the pattern of mobile phone usage among young adults in the State of Andhra Pradesh. It also attempts to examine the extent of sexual messaging and addictive sexual behavior through use of mobile phones. A face to face survey method was used to elicit the responses through a questionnaire. The survey was administered among 1200 students between the age group of 18-25 years. The data were analyzed with the help of statistical tools and techniques to draw meaningful inferences and conclusions.

Inference of demographic attributes based on mobile phone usage patterns and social network topology

Mobile phone usage provides a wealth of information, which can be used to better understand the demographic structure of a population. In this paper, we focus on the population of Mexican mobile phone users. We first present an observational study of mobile phone usage according to gender and age groups. We are able to detect significant differences in phone usage among different subgroups of the population. We then study the performance of different machine learning (ML) methods to predict demographic features (namely, age and gender) of unlabeled users by leveraging individual calling patterns, as well as the structure of the communication graph. We show how a specific implementation of a diffusion model, harnessing the graph structure, has significantly better performance over other node-based standard ML methods. We provide details of the methodology together with an analysis of the robustness of our results to changes in the model parameters. Furthermore, by carefully examining the topological relations of the training nodes (seed nodes) to the rest of the nodes in the network, we find topological metrics which have a direct influence on the performance of the algorithm.

The Role of Mobile Phone Technology in Understanding and Preventing Suicidal Behavior.

In this editorial, we discuss how mobile phone technology has the potential to move the field forward in terms of understanding suicide risk as well as laying foundations for the development of effective treatments/interventions. We have focused on mobile health technology given the rapid growth of mobile health approaches in suicide prevention (De Jaegere & Portzky, 2014; Mishara & Kerkhof, 2013) and psychological research more generally (Myin-Germeys et al., 2009; Nock, Prinstein, & Sterba, 2009; Palmier-Claus et al., 2011) and because mobile phone use is ubiquitous, with 75% of the world having access to a mobile phone (Kay, 2011). (aut. ref.)

Why Don't Farmers Use Cell Phones to Access Market Prices? Technology Affordances and Barriers to Market Information Services Adoption in Rural Kenya

Providing smallholder farmers with agricultural information could improve economic development, by helping them to grow more crops, which they could then sell for more money. Widespread mobile phone ownership in Africa means that, for the first time, there is a realistic opportunity to deliver pertinent information to remote farmers throughout the continent. Efforts to harness the potential of mobile phones include the development of agricultural market information services (MIS) – applications that send farmers crop pricing information via short message service or SMS. These services promote economic development among some farmers in the developing world, but not yet in rural Kenya. To understand what factors impede the adoption of these services, we qualitatively studied Kenyan farmers’ mobile phone usage patterns and their interactions with MFarm, a commercially available MIS. Using affordance theory to guide our analysis, we discovered a mismatch between the design of MIS and smallholder farmers’ perceptions of their mobile phones’ communication capabilities. We use these findings to motivate a design agenda that encourages software developers and development practitioners to adopt an ecological perspective when creating mobile applications for sub-Saharan Africa's rural farmers. Strategies for implementing this approach include reconsidering the design of mobile phones, and developing innovative educational interventions.

The phantom in my pocket: Determinants of phantom phone sensations

This study investigated the prevalence and antecedents of the so-called phantom phone sensations (PPS) phenomenon – the false perception that one’s cell phone is ringing, vibrating, or blinking. While previous studies have already addressed the impact of personality traits and cell phone usage patterns on the likelihood of experiencing phantom phone sensations, we were interested in additionally addressing the impact of situational context factors. An online questionnaire assessed especially cell phone usage patterns (e.g., frequency of cell phone usage), personality traits (e.g., Big Five, need for popularity), and contextual factors (e.g., awaiting a call, being in a noisy environment). Analyses ( N = 249; 137 female) revealed that the majority of participants (83.5%) have experienced phantom phone sensations. Multivariate analysis methods indicated that, in particular, contextual factors regarding the social situation (awaiting a call) along with cell phone usage patterns are predictive for the experience of phantom phone sensations. Moreover, age was also found to have a high predictive value.

Hindistan Batı Bengal’de Kolkata Tıp Okulu öğrencileri arasında cep telefonu kullanma alışkanlıkları

Abstract Objective: Mobile phone usage has reached all ages across all segments of society, and its radiofrequency waves are an increasing concern among the general population. To find out the pattern of mobile phone usage among undergraduate medical students and their perceived symptoms and awareness about negative health effects due to their exposure to the radiofrequency waves. Methods: A descriptive type of epidemiological study was conducted among 295 undergraduate medical students in the Institute of Post Graduate Medical Education and Research, Kolkata, in August 2012 after obtaining Institutional Ethical Clearance. Data were collected by a pre-designed and pre-tested, semi structured questionnaire and analyzed with SPSS software, version 19.0. Results: Among the 1st semester students, browsing of the internet became the predominant activity; while listening to music and radio was the preferred activity among the 3rd, 5th and 7th semester students. In lecture class, 1st semester students (62.5%) switch off; 40.6% of 5th semester students receive and 63.63% of 7th semester students keep the phone in silence mode. Duration of mobile phone usage was maximum among students who perceived headache as a side effect of usage. About 62.3% study subjects cited accidents as a harmful effect, followed by lack of concentration. Conclusions: Regulatory bodies should lay down specific regulations and guidelines regarding mobile phone usage in class as well as during patient care. Further research is needed to comment on long term health outcome keeping in view its usage and popularity among younger people. Keywords: Mobile phone use, medical students, hazard awareness

Conventionalists, Connectors, Technoisseurs and Mobilarti: Differential profiles of mobile marketing segments based on phone features and postmodern characteristics of consumers

The high penetration of mobile phones amongst the South African population presents mobile phones as an attractive interactive marketing communication medium. This paper argues that the access and actual use of different phone device features can be productively used as a segmentation approach, which may enable marketers to be more effective in planning interactive marketing communication plans. This study, based on 330 students, developed segments derived from mobile phone usage patterns using cluster analysis. The outcome revealed four clusters that were named: Connectors, Conventionalists, Technoisseurs and Mobilarti. Connectors made daily use of a full range of communication functions. Conventionalists were inclined to limit their use of mobile phone features to talking and texting. Technoisseurs were found to use a whole range of sophisticated mobile phone facilities. Mobilarti were identified as a group of expert users; using the full range of functions available to them on their phones, despite recording the lowest percentage of smartphone ownership when compared to the other groups. These groups were further profiled by analysing attitudinal and behavioural variables pertaining to two newly developed postmodern dimensions, which were introduced in the study as mobile importance as an attitudinal aspect, and social transformation as a behavioural outcome. For marketers, an understanding of the proposed segments, as well as the differences in attitudes towards mobile importance and social transformation behaviours, coupled with typical financial and social realities of these segments, allow targeting strategies that are more clearly actionable.

P-76 * PROBLEMATIC MOBILE PHONE USE: A COMPREHENSIVE REVIEW OF MEASUREMENTS

Introduction. Potentially addictive mobile phone use has been studied scientifically during the last decade; however, very few revisions have been done with this recent cyberaddiction. A review has been prepared to observe conceptualizations commonly used defining facets on mobile phone dysfunctional use, and especially its measurement through valid psychometric tools. Method. A comprehensive review of the existing validated questionnaires is conducted and described in detail in order to detect common terminology and operational definitions, as well as psychometric properties (e.g., items, factor/s and validation techniques), specifications of the user's profile, the indicators usually used to measure the patterns of mobile phone usage, and the clinical criteria commonly used. Results & Conclusions. This poster will present a description of our revision through structured tables with the main psychometric characteristics of these scales, common problematic user's profile, usage indicators of this technology and its symptomatology, in order to highlight the main findings. Our objective is to determine, through an in depth review study, the measurements and main characteristics of problematic mobile phone use.

On emotional aspects in Mission‐Oriented Opportunistic Networks

In Mission‐Oriented Opportunistic Networks (MOONs), the human users, who possess the mobile devices, also participate as part of the network. In this study, the authors study an aspect of human–network interplay in MOONs, by considering the effects of human emotions on the network operations. This study differs from the related existing works, which focus on detecting emotions of the users based on their activities, for example, their smart phone usage patterns. The study uses Meftah's computational model of the emotions, which itself is based on Plutchik's model. The authors model the current emotion of any user as a function of the individual's previous state of emotion and the content of the messages received by them. Specifically, the authors consider how the variation in individual emotions affect the traffic generation rate in the network. Further, they model the scenarios in which the users switch off their devices’ radios, and their effects on the message delivery ratio. The results of performance evaluation show that the delivery ratio of the messages tends to zero because of increased traffic load and inactivity of the devices’ radios, which, in turn, calls for efficient traffic management and forwarding schemes.

Mobile phones: the next step towards healthcare delivery in rural India?

BackgroundGiven the ubiquity of mobile phones, their use to support healthcare in the Indian context is inevitable. It is however necessary to assess end-user perceptions regarding mobile health interventions especially in the rural Indian context prior to its use in healthcare. This would contextualize the use of mobile phone communication for health to 70% of the country's population that resides in rural India.ObjectivesTo explore the acceptability of delivering healthcare interventions through mobile phones among users in a village in rural Bangalore.MethodsThis was an exploratory study of 488 mobile phone users, residing in a village, near Bangalore city, Karnataka, South India. A pretested, translated, interviewer-administered questionnaire was used to obtain data on mobile phone usage patterns and acceptability of the mobile phone, as a tool for health-related communication. The data is described using basic statistical measures.ResultsThe primary use of mobile phones was to make or receive phone calls (100%). Text messaging (SMS) was used by only 70 (14%) of the respondents. Most of the respondents, 484 (99%), were willing to receive health-related information on their mobile phones and did not consider receiving such information, an intrusion into their personal life. While receiving reminders for drug adherence was acceptable to most 479 (98%) of our respondents, 424 (89%) preferred voice calls alone to other forms of communication. Nearly all were willing to use their mobile phones to communicate with health personnel in emergencies and 367 (75%) were willing to consult a doctor via the phone in an acute illness. Factors such as sex, English literacy, employment status, and presence of chronic disease affected preferences regarding mode and content of communication.ConclusionThe mobile phone, as a tool for receiving health information and supporting healthcare through mHealth interventions was acceptable in the rural Indian context.

Is health literacy related to health behaviors and cell phone usage patterns among the text4baby target population?

BackgroundText4baby provides educational text messages to pregnant and postpartum women and targets underserved women. The primary purpose of this study is to examine the health behaviors and cell phone usage patterns of a text4baby target population and the associations with health literacy.MethodsPregnant and postpartum women were recruited from two Women, Infant and Children clinics in Atlanta. Women were asked about their demographics, selected pregnancy or postpartum health behaviors, and cell phone usage patterns. Health literacy skills were measured with the English version of the Newest Vital Sign. Multivariable logistic regression was used to examine health behaviors and cell usage patterns by health literacy classification, controlling for commonly accepted confounders.ResultsFour hundred sixty-eight women were recruited, and 445 completed the Newest Vital Sign. Of these, 22% had inadequate health literacy, 50% had intermediate health literacy, and 28% had adequate health literacy skills. Compared to adequate health literacy, limited literacy was independently associated with not taking a daily vitamin during pregnancy (OR 3.6, 95% CI: 1.6, 8.5) and never breastfeeding their infant (OR 1.4, 95% CI: 1.1, 1.8). The majority (69.4%) of respondents received nine or more text messages a day prior to enrollment, one in four participants (24.6%) had changed their number within the last six months, and 7.0% of study participants shared a cell phone. Controlling for potentially confounding factors, those with limited health literacy were more likely to share a cell phone than those with adequate health literacy (OR 2.57, 95% CI: 1.79, 3.69).ConclusionsText4baby messages should be appropriate for low health literacy levels, especially as this population may have higher prevalence of targeted unhealthy behaviors. Text4baby and other mhealth programs targetting low health literacy populations should also be aware of the different ways that these populations use their cell phones, including: sharing cell phones, which may mean participants will not receive messages or have special privacy concerns; frequently changing cell phone numbers which could lead to higher drop-off rates; and the penetrance of text messages in a population that receives many messages daily.