The present study investigated how the magnitude the word blindness suggestion effect on Stroop interference depended on hypnotic suggestibility when given as an imaginative suggestion and under conditions in which hypnosis was not mentioned. Hypnotic suggestibility is shown to be a significant predictor of the magnitude of the imaginative word blindness suggestion effect under these conditions. This is therefore the first study to show a linear relationship between the imaginative word blindness suggestion effect and hypnotic suggestibility across the whole hypnotizability (...) spectrum. The results replicate previous findings showing that highs respond to the word blindness suggestion to a greater extent than lows but extend previous work by showing that the advantage for those higher on the hypnotizability spectrum occurs even in a non-hypnotic context. Negative attitudes about hypnosis may not explain the failure to observe similar effects of the word blindness suggestion in less hypnotizable individuals. (shrink)

The present work aimed at assessing whether the interference exerted by task-irrelevant spatial information is comparable in high- and low-susceptible individuals and whether it may be eliminated by means of a specific posthypnotic suggestion. To this purpose high- and low-susceptible participants were tested using a Simon-like interference task after the administration of a suggestion aimed at preventing the processing of the irrelevant spatial information conveyed by the stimuli. The suggestion could be administered either in the absence or following a standard (...) hypnotic induction. We showed that, outside from the hypnotic context, the Simon effect was similar in high and low-susceptible participants and it was significantly reduced following the posthypnotic suggestion in high-susceptible participants only. These results show that a specific posthypnotic suggestion can alter information processing in high-susceptible individuals and reduce the interfering effect exerted by arrow stimuli. (shrink)

According to the theoretical framework relating hypnosis to attention, baseline attentional functioning in highly hypnotizable individuals should be more efficient than in low hypnotizable individuals. However, previous studies did not find differences in Stroop-like tasks in which the measure indicative of the Stroop interference effect was based on response latencies. This study was designed to determine whether subjects with different levels of hypnotic susceptibility show differences in baseline attentional functioning. To assess this hypothesis, high, medium, and low hypnotizable subjects performed (...) a Stroop task designed to evaluate accuracy performance, before being subjected to hypnotic induction. Results showed that the Stroop interference effect was smaller in high hypnotizable subjects than in low hypnotizable subjects, whereas it was not different between high, and medium hypnotizable subjects. This outcome supports the notion that baseline attentional functioning is related to hypnotic susceptibility. (shrink)

Can suggestion, particularly hypnotic suggestion, influence cognition? Addressing this intriguing question experimentally is on the rise in cognitive research, nowhere more prevalently than in the domain of cognitive control and attention. This may well rest on the intuitive connection between hypnotic suggestion and attention, where the hypnotist controls the subject’s attention. Particularly impressive has been the work of Raz and his colleagues demonstrating the modulation and even the complete elimination of classic Stroop color–word interference when subjects are given a posthypnotic (...) suggestion that words are meaningless. Overriding a highly practiced, possibly even automatic response like reading is testament to the attentional control that can be exerted under hypnotic suggestion. What else do we need to know—in the Stroop context and more broadly—to obtain a clear picture of how suggestion can orchestrate attention? (shrink)

have recently provided a compelling demonstration of enhanced attentional control under post-hypnotic suggestion. Using the classic color-word interference paradigm, in which the task is to ignore a word and to name the color in which it is printed (e.g., RED in green, say ''green''), they gave a post-hypnotic instruction to participants that they would be unable to read. This eliminated Stroop interference in high suggestibility participants but did not alter interference in low suggestibility participants. replicated this pattern and further demonstrated (...) that it is not due to a visual strategy (such as blurring or looking at a different location). As a historical footnote, we describe a ''case study'' from 18 years ago in which we observed the same result using a hypnotic instruction to a single highly suggestible individual that he could not read. The elimination of Stroop interference has important implications for both the study of attention and the study of hypnosis. (shrink)

Using the Stroop paradigm, we have previously shown that a specific suggestion can remove or reduce involuntary conflict and alter information processing in highly suggestible individuals . In the present study, we carefully matched less suggestible individuals to HSIs on a number of factors. We hypothesized that suggestion would influence HSIs more than LSIs and reduce the Stroop effect in the former group. As well, we conducted secondary post hoc analyses to examine negative priming – the apparent disruption of the (...) response to a previously-ignored item. Our present findings indicate that suggestion reduces Stroop effects in HSIs. Secondary analyses show that LSIs had an NP effect at baseline and that suggestion influenced the NP condition. Thus, at least in this experimental context, suggestion seems to dampen a deeply-engrained and largely automatic process – reading – by wielding a larger influence on HSIs relative to comparable LSIs. (shrink)

Research by Raz and his associates has repeatedly found that suggestions for hypnotic agnosia, administered to highly hypnotizable subjects, reduce or even eliminate Stroop interference. The present paper sought unsuccessfully to extend these findings to negative priming in the Stroop task. Nevertheless, the reduction of Stroop interference has broad theoretical implications, both for our understanding of automaticity and for the prospect of de-automatizing cognition in meditation and other altered states of consciousness.

Cognitive scientists distinguish between automatic and controlled mental processes. Automatic processes are either innately involuntary or become automatized through extensive practice. For example, reading words is a purportedly automatic process for proficient readers and the Stroop effect is consequently considered the “gold standard” of automated performance. Although the question of whether it is possible to regain control over an automatic process is mostly unasked, we provide compelling data showing that posthypnotic suggestion reduced and even removed Stroop interference in highly hypnotizable (...) individuals. Drawing on a large sample of highly hypnotizable participants, we examined the effects of suggestion on Stroop performance both with and without a posthypnotic suggestion to perceive the input stream as meaningless symbols. We show that suggestion administered to highly hypnotizable persons significantly reduced Stroop interference and derailed a seemingly automatic process. (shrink)