David Mallard

“Um, I can tell you're lying”: Linguistic markers of deception versus truth-telling in speech

Lying is a deliberate attempt to transmit messages that mislead others. Analysis of language behaviors holds great promise as an objective method of detecting deception. The current study reports on the frequency of use and acoustic nature of “um” and “like” during laboratory-elicited lying versus truth-telling. Results obtained using a within-participants false opinion paradigm showed that instances of “um” occur less frequently and are of shorter duration during lying compared to truth-telling. There were no significant differences in relation to “like.” These findings contribute to our understanding of the linguistic markers of deception behavior. They also assist in our understanding of the role of “um” in communication more generally. Our results suggest that “um” may not be accurately conceptualized as a filled pause/hesitation or speech disfluency/error whose increased usage coincides with increased cognitive load or increased arousal during lying. It may instead carry a lexical status similar to interjections and form an important part of authentic, effortless communication, which is somewhat lacking during lying.

Seeing is believing: The reality of hypnotic hallucinations

Two experiments investigated the reality attributed to hypnotic suggestion through subtle projection of a visual image during simultaneous suggestion for a visual hallucination that resembled the projected image. In Experiment 1, high and low hypnotizable participants were administered either a hypnotic induction or wake instructions, given a suggestion to hallucinate a shape, and then the projected image was subsequently introduced. Although highs in both conditions rated the projected image more vividly than lows, highs in the hypnosis (but not wake) condition made comparable reality ratings when the projected image was absent and present. In Experiment 2, high hypnotizable participants were administered a suggestion to see a shape on a wall. For half the participants the suggested image was projected on the wall and then removed, and for half the projection was initially absent and then introduced. Participants who had the projection absent and then present reported comparable reality and vividness ratings when the projection was absent and present. These findings indicate that elevated hypnotizability and hypnosis are associated with attributions of external reality to suggested experiences.

Reality Monitoring in Hypnosis: A Real-Simulating Analysis

Abstract The extent to which hypnotic suggestions are perceived as real is central to understanding hypnotic response. This study indexed the reality attributed to hypnotic suggestion through subtle projection of a visual image during simultaneous suggestion for a visual hallucination that resembled the projected image. Twenty real hypnotized and 20 simulating nonhypnotized participants were administered a hypnotic induction and given a suggestion to hallucinate a shape, and then the projected image was introduced. Following the hypnosis session, an Experiential Analysis Technique was employed to index experiential responses. Real, but not simulating, participants made comparable reality ratings when the projected image was absent and present. Reals, but not simulators, also reported more effort in maintaining belief in the suggestion when the projection was absent. These findings suggest that the reality attributed to a hypnotic suggestion cannot be attributed to demand characteristics. This research was funded by an Australian Research Council grant.

Posthypnotic amnesia for material learned before hypnosis

The impact of a suggestion for posthypnotic amnesia on material learned either before or during hypnosis was investigated across 2 experiments. In Experiment 1, very high, high, and low hypnotizable participants learned a word list either before or immediately after a hypnotic induction. During hypnosis, participants were given a suggestion for posthypnotic amnesia for the word list. After hypnosis, they were tested on recall, word-fragment, and word-recognition tasks. Experiment 2 replicated and extended Experiment 1 through application of the real-simulating paradigm. Across the 2 experiments, there was no difference in the performance of participants who learned the word list either before or during hypnosis. Although amnesia on direct memory measures was associated with high hypnotizability (Experiment 1), an explanation based on demand characteristics could not be excluded (Experiment 2). The implications of these findings for the use of post-hypnotic amnesia as a laboratory analog of disorders of autobiographical memory are discussed.

Use of “um” in the deceptive speech of a convicted murderer

Previous studies have demonstrated a link between language behaviors and deception; however, questions remain about the role of specific linguistic cues, especially in real-life high-stakes lies. This study investigated use of the so-called filler, “um,” in externally verifiable truthful versus deceptive speech of a convicted murderer. The data revealed significantly fewer instances of “um” in deceptive speech. These results are in line with our recent study of “um” in laboratory elicited low-stakes lies. Rather than constituting a filled pause or speech disfluency, “um” may have a lexical status similar to other English words and may be under the strategic control of the speaker. In an attempt to successfully deceive, humans may alter their speech, perhaps in order to avoid certain language behaviors that they think might give them away.

Hypnotic color blindness and performance on the stroop test

Abstract A suggestion for hypnotic color blindness was investigated by administering a reverse Stroop color-naming task. Prior to the suggestion for color blindness, participants learned associations between color names and shapes. Following the color blindness suggestion, participants were required to name the shapes when they appeared in colors that were either congruent or incongruent with the learned associations. The 18 high hypnotizable participants who passed the suggestion were slower to name (a) shapes in which the color name was incongruent with the color in which it was printed, (b) “unseen” rather than “seen” shapes, and (c) color-incongruent shapes that were printed in the color in which they were “color-blind.” These patterns are discussed in terms of potential cognitive and social mechanisms that may mediate responses to hypnotic color blindness.

Preventing Cross-Cultural Bias in Deception Judgments: The Role of Expectancies About Nonverbal Behavior

The expectancy violation model proposes that people infer deception when the communicator violates social norms without obvious cause. However, social norms are culture specific. Therefore, discrepant norms between a communicator and an observer in a cross-cultural interaction might increase the likelihood of inferring deception and thus result in bias. The present study investigated whether informing people about cultural differences in nonverbal behavior could counteract cross-cultural bias in deception judgments. Sixty-nine Australian students were randomly assigned to receive no information, general information, or specific information about culture-specific behavioral norms prior to making credibility judgments of 10 video clips (5 norm consistent and 5 norm inconsistent). The results suggest that cross-cultural biases in deception judgments can occur but may also be prevented by providing appropriate information. These findings require further investigation but have potentially significant implications in law enforcement, customs, immigration, and broader societal interactions.

Hypnotic Conflict: A Brief Report

Abstract Two studies investigated management of conflict in hypnosis by subtly increasing the brightness of a visual stimulus during a suggestion for hypnotic blindness to the stimulus. In Study 1, 23 high hypnotizable participants were administered a hypnotic suggestion for blindness to a projected light. For half the participants, the brightness of the light was intensified during the suggestion. Behavioral ratings and online analog-dial measurement indicated that participants reported decreased hypnotic blindness during the increased conflict condition. In Study 2, 20 participants were administered the nonexperimental procedure to investigate the impact of demand characteristics in this paradigm. Parallel findings in Studies 1 and 2 indicated that demand characteristics may explain the response to hypnotic conflict. Limitations in applying the nonexperimental procedure to this paradigm and the need for further investigation are discussed. We Are Grateful To Helen Bibby And Kasey Metcalf For Assistance In Data Collection.

Reality Monitoring in Hypnosis: A Pilot Investigation

In a pilot investigation of reality monitoring in hypnosis, 10 high and 10 low hypnotizable participants were administered a hypnotic suggestion to hallucinate a visual shape on a wall. For half the participants, an image was subtly projected onto the wall at the commencement of the suggestion and then subsequently removed. For the remaining participants, the projected image was initially absent and subsequently projected. Participants completed ratings of belief in the suggestion during hypnosis and also provided subjective reports of the suggestion during a subsequent Experiential Analysis Technique session. High hypnotizable participants who had the projected image introduced at the end of the suggestion provided comparable belief ratings when the image was present and absent. In contrast, highs who had the projected image presented first reported less belief when the image was absent than when it was present. Low hypnotizable participants rated the hallucination more strongly when the image was projected than when it was not projected. These pilot data are discussed in terms of developing a paradigm to objectively index the perceived reality of hypnotically suggested experiences.