Psychological Investigations of Humor and Laughter: Honoring the Research Contributions of Professor Rod Martin

Welcome to this special issue of Europe’s Journal of Psychology (EJOP), which honors the many psychological research contributions on humor and laughter made by Professor Rod Martin. After completing his graduate training at the University of Waterloo in 1984, Dr. Martin became a faculty member in the clinical psychology program at the University of Western Ontario. Professor Martin then remained at Western for many years, conducting research on humor and laughter, until his very recent retirement in the summer of 2016.

. This table is organized accordingly to the various topic areas within the domains of humor and laughter research that Professor Martin has explored since the early to mid-1980s.
What is immediately apparent, even from a cursory examination of whereas other studies have focused on the degree to which sense of humor may display cross-cultural variations.
Further aspects of Professor Martin's work has addressed the nature versus nurture distinctions by examining humor styles from a behavioral genetics perspective, as well as considering how professional comedians may differ from non-comedians in their upbringing, the expression of certain personality traits and their humor production ability. Dr. Martin has also advanced our understanding of how humor and laughter may be involved in social interactions and close relationships, as well as the use of humor as a possible intervention technique.
Overall, this very brief synopsis of Professor Martin's many research activities and accomplishments over the past 30 or so years clearly reveals both the breadth and depth of his contributions to our psychological understanding of humor and laugher. In turn, his contributions now provide a robust theoretical-empirical framework that can be built upon by future investigators, as they continue to explore psychological aspects of humor and laughter.
Professor Martin's legacy in the humor research domain is very strong, and this special issue honors his contributions by presenting an in-depth interview with Dr. Martin (Martin & Kuiper, 2016, this issue). In this interview, Professor Martin discusses several of his main humor research contributions over the past 30 years, and provides both a personal and historical perspective on his career highlights and accomplishments. In addition, Dr. Martin also provides many insightful comments regarding some of the most significant issues facing contemporary humor and laughter researchers today. Table 1 Humor
[Translated into Spanish, Korean, Japanese and Russian]

Articles in the Current Special Issue
In further recognition of Dr. Martin's many research achievements, this special humor issue of Europe's Journal of Psychology offers a set of contemporary psychological studies investigating various aspects of humor and laughter. Table 2 provides a brief summary of several key characteristics for each of the papers in this special issue. These characteristics include the humor constructs being investigated in that study, the sample employed, and the main issues under consideration. As can be seen in Table 2, the majority of the studies in this special issue (see the first 9 listed in this table) build upon Dr. Martin's prominent humor styles model. In turn, the last 3 papers listed in Table 2 provide samples of additional contemporary work in the humor domain that does not derive directly from Professor Martin's work, but rather focuses on laughter research, therapeutic medical clowning, and the semiotic analysis of jokes.
What is quite evident across all of the papers in this special issue is the extensive nature of the humor research now being conducted. As shown in Table 2, participants are drawn from many different countries (Canada, Germany, Norway Switzerland, United Kingdom, and United States), and include samples composed of children, adolescents, adults, and couples. The novel themes examined in these studies include associations of humor styles with: (1) happiness and other personality characteristics (Ford, Lappi, & Holden, 2016, this issue), (2)  Moving beyond a focus on the humor styles, the remaining studies in this special issue explore: (10) links between laughter, trunk compression and cortical activation (Svebak, 2016, this issue), (11) the effects of medical clowning on patients and staff (Dionigi & Canestrari, 2016, this issue), and (12) the use of a typology of 45 different techniques to analyze jokes (Berger, 2016, this issue).
More generally, as you read through these articles presented in this special humor issue of EJOP, I hope you find them to be enjoyable, informative and enlightening. In addition to honoring Professor Rod Martin's research work, this collection of articles also provides an intriguing slice of contemporary theory and research on various psychological aspects of humor and laughter. As such, reading about this work may inspire you to also conduct further research on some of the topics described herein. However, in doing so, it should be remembered that the topics covered in this special issue represent only a very small portion of the exponentially increasing number of psychologically-based studies on humor and laughter published in the past few years. This additional research also warrants further detailed consideration as the field moves forward.

Concluding Comments
While preparing this special issue, I received many positive comments from other humor investigators about the stellar quality and high impact of the many research contributions made by Professor Martin throughout his career.
Notably, many of these investigators also spontaneously commented on the very gracious interpersonal style that is a hallmark of Professor Martin's professional interactions with others. His positive demeanor, coupled with a strong ability and desire to unravel the many mysteries still surrounding our use of humor and laughter, helps make Professor Martin a truly outstanding humor scholar. His work has greatly advanced our knowledge and understanding of many different facets of humor and laughter, and we would all like to wish him the best as he begins his retirement.
I would also like to thank all of the reviewers and contributors to this special humor issue for their assistance throughout the many stages of this project. Their co-operation, patience and thoughtfulness certainly helped to make this special issue a very fitting tribute to Professor Martin's research career and accomplishments. Finally, I would also like to offer considerable thanks to the chief editor of EJOP, Vlad Glăveanu, who has very capably helped me throughout this special issue project. It should be noted that this is the third in a series of special humor issues that Europe's Journal of Psychology has published (see also Kuiper, 2010 andKuiper 2014). For all three issues, the chief editor's encouragement and unwavering support has made this editorial task immensely easier.

Funding
The author has no funding to report.

Competing Interests
The author has declared that no competing interests exist.