Latency and frequency reports to the Necker cube illusion: effects of hypnotic susceptibility and mental arithmetic

An experiment (N = 32) was conducted to assess latency of first apparent reversal (AR) and AR frequency while observing the Necker cube illusion. Subjects who were either high in hypnotic susceptibility (susceptibles) or low in hypnotic susceptibility (resistant subjects) observed the cube either while performing or not performing mental addition problems. Susceptibles reported perceiving the first AR more quickly and a greater frequency of ARs than did resistant subjects. Also, latency of the first AR was negatively correlated with AR frequency. These results were interpreted in terms of the ability of susceptibles to allocate concentrative or selective attention in a manner that was conducive to faster performance, when faced with competing tasks.     

Hypnotic susceptibility, visual distraction, and reports of Necker cube apparent reversals

Subjects, either susceptible (n = 50) or resistant (n = 50) to hypnotic suggestion, were asked to report on frequency of apparent reversals (ARs) to the Necker cube illusion. Such reports were made in the presence or absence of various types of visual, geometric surrounds (squares, triangles, crosses, or parallelograms). In agreement with a number of previous experiments, susceptible subjects reported perceiving more ARs than did resistant subjects. This difference held whether visual surrounds were present or absent. The presence of surrounds did serve to reduce AR reports regardless of hypnotic susceptibility level. The results are examined in terms of the ability of subjects to selectively attend when confronted with potential visual distractors.     

EEG gamma-band response during the perception of Necker cube reversals

In two former studies our research group reported frontal gamma-band enhancement during multistable visual perception and reversal rate dependent differences in the gamma-band. In these studies, a dynamic reversible figure was used which was based on the phenomenon of apparent motion. The aim of this study was to examine whether the results obtained with a dynamic motion paradigm can be replicated with the static Necker cube. The results demonstrate a general frontal gamma-band enhancement and higher induced gamma activity for subjects with a relatively high reversal rate in comparison to subjects with a relatively low reversal rate. This pattern of results fits well to the findings obtained with the dynamic motion paradigm. Therefore, the important role of frontal gamma activity for figure reversals has received further evidence. The results support the involvement of attentional top-down processing of figure reversal that is not directly related to binding processes.     

Hypnotic susceptibility and familial handedness

The possible relationship between hypnotic susceptibility and familiar handedness was examined. In a mass-testing session of students enrolled in introductory psychology classes, subjects were administered the Harvard Group Scale of Hypnotic Susceptibility, Form A and were also required to complete a questionnaire that ascertained information on their dominant handedness and that of their immediate family relatives. Subjects who had immediate sinistral relatives scored significantly lower in hypnotic susceptibility compared to those who had a history of familial dextrality. When immediate relatives of the original subject pool were tested on hypnotic susceptibility level, sinistral relatives scored lower in susceptibility than dextral relatives. This may indicate the existence of a familial component in hypnotic susceptibility.     

Hypnotic susceptibility, baseline attentional functioning, and the Stroop task

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.     

Sex differences in susceptibility to the Poggendorff illusion

This study presents experimental results indicating that there are sex differences in the susceptibility to a geometric optical illusion. Participants (57 male and 39 female undergraduate students) performed 3 trials on a test involving the Poggendorff illusion. Analysis indicated that the magnitude of the illusion diminished significantly with each trial and that the percent perceived error was significantly larger for women than for men. This finding is consistent with the numerous studies which have indicated better visuospatial abilities for men than for women.     

Proactive interference and spontaneous alternation in rats

Two pairs of trials were given to naive rats in a T-maze. The first trial of a pair was forced to one arm, the second was free, and the delay between trials was 25 min. or 10 hr. Rats left in the maze for 15 sec. following the forced choice showed increased alternation on the second pair of trials at the 25-min. delay as compared with the 10-hr. delay. This was interpreted as due to a decline in alternation with delay on this pair of trials, together with an overall increase in alternation between the first and second pairs, and is consistent with the proactive interference theory of forgetting. Rats left in for 2 min. showed a decline in alternation with delay on the first pair of trials, but not on the second; this is inconsistent with the proactive interference theory.     

The heat illusion test and its relevance to susceptibility to hypnosis

The Heat Illusion test is of interest because of the equivocal nature of the evidence concerning both what aspects of behaviour it measures and its power to predict hypnotic susceptibility. This test was administered to 99 subjects who were also tested for susceptibility to hypnosis. The power of the test to predict hypnotic susceptibility was found to be poor, when scoring was done in the classical manner, but, using the decrement of the threshold of perception, an alternative means of scoring was discovered which improved the predictive power of the test. The results are discussed in the light of this new aspect of the test.     

Thinking disposition,thinking style,and susceptibility to causal illusion predict fake news discriminability

Acceptance of fake news is probably modulated by an intricate interplay of social, cultural, and political factors. In this study, we investigated whether individual-level cognitive factors related to thinking and decision making could influence the tendency to accept fake news. A group of volunteers responded to a COVID19-related fake news discrimination scale as well as to questionnaires assessing their thinking style (reflective vs. intuitive) and thinking disposition (actively open-mindedness). Furthermore, they completed a computerized contingency learning task aimed at measuring their tendency to develop a causal illusion, a cognitive bias leading to perceive causal connections between non-contingent events. More actively open-minded and more reflective individuals presented higher fake news discrimination scores. In addition, those who developed weaker causal illusions in the contingency learning task were also more accurate at differentiating between fake and legitimate news. Actively open-minded thinking was the main contributor in a regression model predicting fake news discrimination.     

Necker cube and autokinetic illusions after awakening from REM and NONREM sleep: lack of effect.

Earlier studies demonstrated differential perceptions of the visual illusions, beta movements and spiral aftereffect, following awakening from REM and NONREM sleep. The present study tested the effects of awakening from the two phases of sleep on two additional visual illusions, the Necker cube and autokinetic illusions. 12 young adults were wakened from REM and NONREM sleep and tested on both illusions for three 1-min. trials, within 1 to 2 min. of the awakening. Comparison of the post-REM and post-NONREM illusions indicated a nonsignificant difference between the two waking conditions in the passive spontaneous reversal rates of the Necker cube. Data for the autokinetic illusion were not reported as they were unreliable.     

Hypnotic susceptibility and the perception of afterimages and dot stimuli

Three experiments were conducted to determine the relationship between hypnotic susceptibility level and the susceptibility to several perceptual phenomena. Experiment I required subjects to observe an induced afterimage in a light-proofed environment and to report the frequency of direction and color changes. In addition, subjects reported the persistence of the afterimage. Experiment II involved the observation of a black dot against a white background, with frequency of observed movement being the dependent measure. Experiment III was similar to the second experiment except that the stimulus was encompassed by a frame. In Experiments I and II, subjects judged high in hypnotic susceptibility reported perceiving the strongest effect. This phenomenon was virtually eliminated in the third experiment. These results were interpreted as supporting a process whereby subjects judged high in hypnotic susceptibility are better able to selectively attend to relevant cues in a stimulus array during conditions of perceptual impoverishment.     

Story contexts increase susceptibility to the DRM illusion in 5-year-olds

False recognition in children aged 5, 8, and 11 years was investigated using the standard version of the Deese-Roediger-McDermott (DRM) procedure and an alternative version in which the DRM stimuli were embedded in stories designed to emphasize their overall theme. Relative to the 8- and 11-year-olds, the 5-year-olds falsely recognized fewer critical lures when the DRM stimuli were presented in lists, but falsely recognized more critical lures when the stimuli were presented in stories. Levels of false recognition in the 8- and 11-year-olds were not affected by study format. We argue that the story context enhanced the ability of the 5-year-olds to make inferences based on the theme of the DRM stimuli. The 5-year-olds then showed higher levels of false recognition than the older children owing to their inability to reject lure words consistent with the stories.