THE EFFECTS OF PRESENTING SUBOPTIMAL EMOTIONAL STIMULI ON SUBSEQUENT EVALUATIVE JUDGMENTS BY ELENA ADRIAN BALZAC A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 1993 ACKNOWLEDGEMENTS There are many people who have helped me to achieve this goal. First, I would like to thank my dissertation chair. Dawn Bowers, Ph.D., for her advice and encouragement, and for always being as enthusiastic about my project as I was. I would also like to thank my cochair, Bruce Crosson, Ph.D., who gave generously of his wisdom and support, not only during this endeavour but throughout our work together. I am also grateful to my other committee members for their individual and valuable contributions: Rus Bauer, Ph.D., for his humor and challenging ideas; Howard Rothman, Ph.D., for his warmth and support, and for always making Shabbat morning minyan such a pleasure; Tiana Leonard, Ph.D., for her help and her interest; and, Hugh Davis, Ph.D., for helping me to grow during my years of graduate school, and for teaching me his love of language and laughter. I could not have completed this work without the help of Lyana Doty. She was responsible, reliable and dedicated, as well as fun to work with, and she saved me from many sleepless nights. I am very grateful for everything she so good-naturedly did. I also thank 11 Barbara Hawes, who graciously shared her mechanical and computer knowledge (which far exceeds mine) with me. There are many friends who helped and supported me, and kept me sane while my dissertation threatened to consume me. I'd like to thank Larry Freedman, Allen Silken, and David Greene, who cheerfully agreed to be guinea pigs. I'd also like to thank Sharon Chase, Randi Lincoln, Jennifer Oglesby, and Christina Rodriguez, just for being there when I needed them. I apologize to my cats, Thelma and Louise, for all the times I neglected them for this dissertation. I am also grateful to my family, for the love and support they have always given me. I'd like to thank them all for always encouraging me (and I especially thank my sister, for not finishing school before I did) . Last, but not least, I'd like to thank everyone who put on a garbage bag, leaned against a chalkboard and made funny faces, for the sake of science. Ill TABLE OF CONTENTS page ACKNOWLEDGMENTS ii ABSTRACT vi INTRODUCTION AND REVIEW OF LITERATURE 1 Mechanisms Underlying Implicit vs. Explicit Memory Processing 3 Impact of Subliminal Events on Behavior 10 Affective Primacy: Emotional Reactions to Stimuli 21 Neuroanatomical Evidence 31 Rationale for Study 35 STUDY 1 42 Hypotheses 42 Methods 43 Analyses 49 Results 50 Discussion 51 STUDY II 62 Hypotheses 62 Methods 62 Analyses 64 Results 64 Discussion 65 STUDY III 71 Hypotheses 71 Methods 72 Analyses 74 Results 74 Discussion 77 STUDY IV 88 Hypotheses 88 Methods 89 iv Analyses 96 Results 96 Discussion 100 GENERAL DISCUSSION 124 REFERENCES 138 BIOGRAPHICAL SKETCH 146 Abstract of Dissertation Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy THE EFFECTS OF PRESENTING SUBOPTIMAL EMOTIONAL STIMULI ON SUBSEQUENT EVALUATIVE JUDGMENTS By Elena Adrian Balzac August, 1993 Chairperson: Dawn Bowers, Ph.D. Major Department: Clinical and Health Psychology Four different studies were conducted to determine the effects of suboptimal affective stimuli, in an attempt to replicate Murphy's (1990) findings that suboptimal emotional faces can influence a subsequent liking rating. Right- handed males of college age served as subjects. In Study I, subjects saw happy faces, angry faces or neutral polygons as prime stimuli, followed by a Chinese ideograph serving as a backward mask and as a target stimulus. Subjects rated how much they liked the ideograph on a 1-7 scale. Sixteen subjects saw the primes optimally, for 1000 msec, and sixteen subjects saw them suboptimally for approximately 1 , msec. Liking ratings did not differ between conditions. Study II was almost identical to Study I, except that an increased suboptimal exposure time was used. Ten subjects saw the primes for approximately 4 msec. There was again no VI effect of primes on liking ratings. In Study III a different set of face primes, specifically rated for emotional expression and intensity was used. Neutral faces were added to serve as a neutral prime stimulus. In the suboptimal condition, sixteen subjects saw the primes for 4 msec, followed by the target ideograph. There was a significant effect of prime condition, such that ideographs preceded by neutral shapes were preferred to all other conditions. In the optimal condition, where 16 subjects viewed the primes for 1000 msec, there was also a significant prime effect. Ideographs preceded by happy faces or neutral shapes were preferred to ideographs preceded by angry or neutral faces. In Study IV, three different suboptimal exposure durations, 4, 16 and 32 msec, were used. Primes consisted of happy and angry faces rated for emotional expression and intensity, and neutral polygons. There was no effect of prime condition at any suboptimal exposure duration. In the optimal condition, ideographs preceded by angry faces were liked significantly less than ideographs in all other conditions. Overall, there was no evidence that the affective nature of suboptimal stimuli is processed when presented in this type of format. The implications of these findings within the field of subliminal and emotional processing are discussed. Vll INTRODUCTION AND REVIEW OF LITERATURE What is consciousness? Attempts to answer this question have been a continuing theme throughout the history of humankind. Philosophers and psychologists have struggled to understand consciousness and the role it plays in our lives. Is consciousness necessary for all aspects of cognition, or can there be knowledge without awareness? The empiricists and materialists of the 1700s and early 1800s postulated all cognitive activity and behavior to be within the domain of conscious awareness, although they did not agree on the specific mechanisms involved. Later, structuralists such as Wundt and Titchener asserted that all mental activity was accessible by introspection, and thus was conscious. It was Helmholtz in the 1800s who first proposed the idea of "unconscious inference," the idea that some degree of cognitive processing occurred outside of consciousness. Although this idea was surrounded by controversy, its popularity quickly spread. Freud proposed the domain of the unconscious, containing thoughts, memories, and feelings which are 2 hidden from conscious awareness because of their potential emotional impact. According to Freud, this unconscious knowledge affects conscious behavior through many mechanisms, including dreams, slips of the tongue, and jokes. Ebbinghaus suggested the possibility of cognitive, rather than simply emotional, knowledge without conscious awareness. He showed that early learning trials of nonsense syllables facilitated learning in later trials, even when he did not have a conscious memory of what he had learned. More recently, Claperede (1951) demonstrated what appeared to be an example of learning without awareness. He reported on an amnesic patient who refused to shake his hand after he pricked her with a hidden pin. When questioned, she had no conscious memory of having been pricked by the pin, yet her "avoidance" behavior indicated some level of knowledge of what had occurred. These are not isolated examples. Research over the past two decades has clearly established the existence of knowledge without awareness in both normal and neurologically impaired individuals. This has been empirically approached from two different perspectives. One approach has focused on findings that normal individuals and those with specific neuropsychological 3 disorders have "implicit" knowledge about consciously experienced events for which they demonstrate failure on "explicit" tasks. The second approach has examined the impact of subliminally or "suboptimally" presented events on subsequent behavior. In the sections which follow, each of these approaches will be reviewed. Mechanisms Underlying Implicit vs. Explicit Memory Processing Explicit memory is the overt recall or recognition of a previous experience, e.g. recognizing words that were seen on a previous list. Implicit memory accounts for those instances when the initial exposure is "forgotten" (is no longer conscious or explicit), yet it still exerts an impact on subsequent behavior. For example, when compared to novel words, subjects can make lexical judgments about familiar words more quickly (Forbach, Stanners, & Hochhaus, 1974), can read them in more degraded form (Jacoby & Dallas, 1981) and , they are more likely to complete word stems with these words (Tulving, Schacter, & Stark, 1982) in the absence of conscious recollection of exposure to these words. In general, explicit memory is tapped by "direct" tasks, where a conscious reference is made to the learning situation (e.g. subject is told "complete the word stem with a word from the list") while implicit , memory is tapped by "indirect" tasks, where no