5.5: Tasks to Target Psychedelic Drug Effects

This section presents the effects of psychedelics on perception and cognition and then pairs those effects with appropriate tasks. Cognitive behavioral tasks always involve some level of perceptual processing, therefore tasks were selected based on the function that they most prominently target. First, tasks that primarily focus on cognitive functions, such as attention, decision making, and problem solving will be discussed in relation to cognitive psychedelic effects. Second, tasks that focus primarily on perceptual processes, such as the ability to organize and identify sensory information will be discussed in relation to perceptual psychedelic effects.

Deciding which tasks may capture low-dose psilocybin-induced changes in perceptual and cognitive processing is difficult at this stage in the research, so initial studies will be largely exploratory. However, insights from medium- and high-dose neuroimaging research will be drawn upon.

Cognitive Effects

Psychedelic-induced alterations in brain activity increases cognitive flexibility while decreasing cognitive control and stability (Carhart-Harris, 2014, 2016), resulting in less controlled thought-processes, reduced performance in attentional tasks (Carter et al., 2005; Vollenweider et al., 2007), increased divergent thinking (Kuypers et al., 2016), expanded semantic activation (Family et al., 2016), and a tendency to attribute new meaning to perceptual stimuli (Preller et al., 2017). Long-term improvements in creative problem solving (Sweat et al., 2016), as well as increases in optimism, and trait ‘openness’ have also been reported in the literature (Maclean et al., 2011; Lebedev et al., 2016).

Enhanced focus, sustained attention, clarity of mind, and increased cognitive control have been anecdotally reported by microdosers. Perhaps it is the case that microdosing does not result in any impairments of stability or control, rather an enhancement of these processes. If this is the case, it is important to identify whether creativity and flexibility are also enhanced or impaired. If microdosing does produce clarity in thought processes, researchers may find improved performance in processes that are effected by mind-wandering such as attention (Tang et al., 2009) and inhibition (Zeiden & Faust, 2008).

The following tasks were chosen to target attention, control, and flexibility. Research on microdosing may be able to discover critical points at which cognitive impairments and cognitive enhancements emerge. Microdosing research should expand the upper limit to 1/10-2/5 of a standard dose in order to identify when cognitive impairments escalate to a point that hinders normal functioning.

Working-Memory and Inhibition Tasks

Working memory is a cognitive system or systems generally defined as the ability to hold information “on-line” and manipulating the information in processes of reason, comprehension, and/or learning (Baddeley, 2010). While there are many different theories about this function, what matters here is that it is a real process that allows human beings to hold information in the mind and think about it, and also that this ability has certain limitations.

One of the only studies that used cognitive tasks to investigate psychedelic effects on cognitive functioning was done by Bouso and colleagues (2013), who investigated the effects of ayahuasca on working memory in 24 ayahuasca users (11 long-term and 13 occasional users). The researchers used the Stroop task, The Sternberg Task, and Tower of London Task prior and following ayahuasca intake. Their results indicate that, while working memory was impaired (shown by more errors in the Sternberg), stimulus-response interference was decreased (shown by decreased reaction times in the Stroop). They also found impairments of working memory only had negative effects in the less experienced group.

The Stroop Color and Word Test (SCWT) was selected because it is a well-established and validated tool for investigating the ability to inhibit inappropriate responses and select appropriate responses (Scarpina & Tagini, 2017). This will also keep consistency in the research to be able to make inferences about effects across studies. The task requires the participant to select the color that a word is presented in when the word itself is a different color. For example, the word “RED” will be presented in green ink and the participant must select “GREEN” to be correct, this is the incongruent condition. The congruent condition is when a word is presented, “RED” for example, and it is presented in red ink. In the congruent condition, the participant clicks “RED” for a correct response. Because reading the word is the more automatic response, the longer reaction times in incongruent trials is known as the Stroop effect (Stroop, 1935).

The “n-back task” is widely used in cognitive science as a measure of working memory ability. The task requires participants to attend to a series of objects (typically numbers or words) presented on the computer screen, and to respond when an object is the same as the one that was presented n trials back (usually 2- or 3-back) (Meule, 2017). Here, the participant has to hold the previously presented objects in the mind while paying attention to the object that is currently being presented. In some n-back tasks, the participant is required to press one key when the object presented is not a match with the object n-back and another when it is a match. As to limit the number of cognitive functions required to perform, participants should be required to press a button only when the object presented is a match. Dependent variables that will be compared between groups is accuracy and reaction times.

While it may not yield any significant differences, it would be interesting to modify the n-back to see whether or not the valence of a word would affect performance in the n-back task. In this case, a within-subjects variable would be the valence of words, with some trials being low in meaningfulness (chair, cup, hairbrush, toothpick, etc.), some trials with high positive valence (love, trust, beauty, honesty), and some trials being high in negative valence (hate, bully, outcast, violence). Although there’s not any direct evidence from psychedelic research that lends one to believe there would be differences, some exploration in this task could yield interesting results.

Cognitive Flexibility Tasks

The ability to appropriately and efficiently adjust cognitive processing in response to a changing condition is perhaps the root of adaptability. Cognitive flexibility is this capacity, whereby an individual is able to switch from one strategy or mindset to another, in response to new or changing conditions, to achieve a desired goal. While tasks in the previous section focused on more automatic cognitive functions, tasks that measure cognitive flexibility must capture changes in more complex cognition or behavior after a person has been performing a task for some time (Cañas, Fajardo, & Salmerón, 2018). Tasks must therefore have several elements such as an acquisition to a task, some environmental changes, and then a required adjustment to those changes in order to successfully perform.

An individual’s cognitive flexibility is predictive factor for a range of adaptive outcomes (Zeytinoglu, Calkins, & Leerkes, 2018). Individuals with high cognitive flexibility have shown higher levels of resiliency, (Genet & Siemer, 2011) creativity, (Chen et al., 2014), and quality of life (Davis et al., 2010). The inability to shift strategies or mindsets when a current behavior or psychological state is not helpful can be described as cognitive rigidity (cognitive inflexibility). Cognitive rigidity can manifest mildly in unhealthy habits of mind and body that leave an individual in harmful loops and repetitions. It can also take more severe forms such as obsessive compulsive disorder and depressive rumination, both of which are characterized by rigid cognition (Meiran, Diamond, Toder, & Nemets, 2010). Research on generalized anxiety disorder also reports cognitive rigidity underlies perseverative cognition (i.e. worry or rumination) (Ottaviani et al., 2015, 2016). In addition, research on eating disorders and social anxiety have both shown strong positive correlations with cognitive rigidity (Arlt et al., 2016).

Microdosers report access to a greater repertoire of mindsets and perspectives, reflecting a shift from rigidity to flexibility. Bringing validity to these claims is a great challenge for cognitive scientists and deserves great efforts, as enhancing this ability could have positive effects in other aspects of mental life and wellbeing. A good assessment of whether or not microdoses of psychedelic substances can enhance cognitive flexibility would be tasks that require an individual to switch from one strategy or mindset to another to achieve a goal. Two tasks are presented that target different levels of cognitive processing. The first is a test of a more automatic ability to switch from one set of rules to another and respond very quickly. The second requires one to switch between higher-order processing strategies from identifying details of a story to comprehension of the overarching message of a story.

The Simon Switch Task (SST) requires individuals to respond differently depending on the type of stimuli presented (adopted from Liu et al., 2016, originally Simon & Barbaum, 1988, 1990). The task starts with a fixation point for about 800 ms, followed by an arrow that is either red or blue. If the arrow is red, participants must hit the arrow key that is the same as the direction of the arrow presented (congruent). If the arrow is blue, participants must hit the arrow key that is the opposite direction of the one presented (incongruent). Some blocks of trials will require a switch from blue to red arrows, while others will not. Switching involves the inhibition of a previously activated rule and the activation of the appropriate rule to employ the appropriate response. This type of switching can be considered a form of attentional flexibility, which is more automatic and requires less complex cognitions compared to the following task.

The second task was selected to capture how microdosing psychedelics may alter one’s ability to perform complex cognitive flexibility tasks. Cañas and colleagues (2004) designed a cognitive flexibility task that requires participants to select the optimal strategy for solving a complex problem. The task is designed such that the participant must act quickly to put out a wild fire while considering the instruments and resources available to them, as well as environmental constraints such as wind speed and type of land. The researchers gave the participants several blocks with different task scenarios in which they had to adaptively adjust strategies given resource and environmental constraints. In every scenario, there was an optimal strategy that would successfully cover the most land in the shortest time. In order to capture the level of adjustment to new conditions, participants will get acclimated to responding in a certain scenario, and then switch the resources and constraints to see how quickly and effectively they solve the problem.

The fire-fighter task could be an emotionally arousing experience for some individuals, leading to a decrease in performance as a result of physiological arousal. Research has shown decreased right-amygdala reactivity to negative and neutral stimuli after psilocybin administration, which was related to increases in positive mood. It could be that, for this task, the increased performance is partially or fully resulting from less emotional and physiological arousal, rather than an enhancement of cognitive flexibility. It is important that this task is counter-balanced with a task that is equally as cognitively demanding, but lacks any negative valence. While other cognitive functions are employed to perform these tasks, and other factors such as emotional arousal may be influencing the results, performance of task switching is reliably known to capture the varying levels of cognitive flexibility between individuals.

Creativity Task

Research looking at the brain activity of schizotypal individuals have found that a greater spread of cortical activation is an important factor for creative thought processes (Park, Roberts, Kirk, and Waldie, 2015). This is also consistent with previously mentioned neuroimaging work that has shown diversification of functional networks after psychedelic administration, anecdotal reports of enhanced creative thinking, and increased activation of indirect semantic associations under psilocybin (Spitzer, 1996). Taken together, these findings lend some indirect support for the hypothesis that microdoses of psychedelics may enhance creative thinking by altering the communication of existing neural circuits to generate novel combinations of information.

There are many different conceptualizations of creativity, but they essentially describe the ability for an individual to engage in conceptual and abstract thinking that goes beyond obvious or typical patterns to adopt a novel idea or perspective (Dietrich, 2004). A cognitive neuroscience approach will be used to operationalize this process. Creativity is considered here as a form of cognitive flexibility, constituted by the ability to generate novel and appropriate combinations of information, and is employed in any station where an individual has to adapt to a novel situation, context, or solve a problem (Dietrich, 2004).

Kuypers and colleagues (2016) found that the psychedelic substance, Ayahuasca, enhances divergent cognition, a style of thinking whereby an individual is generating new ideas in a context where more than one solution is correct. This study used the Pattern/Line Meaning Task (PLMT) and the Picture Concept Task (PCT) to measure divergent thinking. The ability to think divergently is highly adaptive, as individuals need to generate a multitude of solutions to select the one that is the most appropriate. It is also important to generate alternative solutions when an existing behavior or thought process has become maladaptive or harmful.

The task selected to assess whether microdosing a psychedelic substance (psilocybin or LSD) enhances creativity is the Alternative Uses Task (Guilford, 1967). This task is one of the classic measures of divergent thinking and is explorative and easy to employ. Participants must generate as many uses as possible for a given item within 45 seconds. Because these tasks will be online, the participant must type out as many uses as possible. Some examples of items include a shoe, snow, a car tire, a brick, a paperclip, a chair, a coffee mug, or any item that has a function but can be used for other purposes.

Assessment techniques are adopted from a previous study and scored based on fluency (number of uses generated), flexibility (number of distinct groups responses could be placed in), appropriateness (1 for appropriate, 0 for inappropriate), originality (comparing each response to the responses of all other participants) (Addis et al., 2014). Because these judgments are done by researchers, it is important to have several raters and run inter-rater reliability checking. Outcomes on these four measures have significant inter-correlations, so it is possible to generate a mean divergent thinking score to compare between groups (Addis et al., 2014).

Perceptual Effects

Psychedelic substances alter the way sensory information is processed and represented in the brain, possibly by altering the excitability of neurons in the visual cortex (Moreau et al., 2010). This alteration in visual processing results in distortions of external stimuli, (objects and their motion, shape, space, and distance) as well as the production of a sensory experience in the absence of external stimuli, which has all of the qualities of real perception, known as hallucinations (Kometer et al., 2013). Other perceptual effects include intensifications of textures, colors, lights, and sounds, as well as a higher level of detail perception, (Kometer & Vollenweider, 2016) and synaesthesia (Ward, 2013).

While microdoses are by definition ‘sub-perceptual’ and will not produce hallucinations or visual distortions, they may have subtle and/or unconscious effects on perceptual processing. Put another way, while microdoses will not alter the way the brain represents physical characteristics of external stimuli (the object itself), anecdotal reports of enhanced awareness to the environment suggest they may alter the ability to detect a stimuli and/or identify subtle changes in a visual scene. Because it is still unclear the exact nature of the disturbances in functional network connectivity, tasks that have already been linked to specific networks would help researchers identify which perceptual mechanisms are effected by LSD or psilocybin.

Perceptual Processing Tasks

Psychedelic users report somewhat paradoxical effects of psychedelics on perceptual processing. In some cases, users report having enhanced detail perception and other reports reflect a more ‘gestalt’ processing of the environment. Therefore, the first task seeks to target these seemingly contradicting reports of changes in perceptual processing. It may be the case that how psychedelics alter processing of a visual scene depends on prior processing style, (Witkin, 1981; Walter & Dassonville, 2011) in which case researchers can investigate the nature of the impact of these substances on processing style with this task as well, or just control for these individual differences.

The Embedded Figures Task (EFT) targets the ability to find a particular shape within a more complex figure composed of many intersecting lines by breaking down the figure into its structural components (Manjaly et al., 2007). Neuroimaging research on this task have shown a recruitment of the frontoparietal network of brain regions (superior parietal cortex, precuneus, and middle frontal gyrus). Significant positive correlations between a portion of the right parietal cortex and processing speed were found, as well as strong correlations between processing speed and activation in the frontal gyrus (Walter & Dassonville, 2011).

This line of research suggests that healthy individuals rely on the integrity of the frontoparietal network is essential for proper EFT performance. Researchers interested in autism spectrum disorder (ASD) find that healthy individuals rely on working memory to suppress contextual information and search for the target shape, while the underconnectivity of frontoparietal regions in ASD cause individuals to rely more heavily on the parietal-occipital system for feature analysis (Ring et al., 1999; Damarla et al., 2010).

Muthukumaraswamy and colleagues (2013) report decreased frontoparietal connectivity after psilocybin administration, which is also consistent with fMRI results (Carhart-Harris et al., 2012). Research on low-dose effects of psychedelics should employ this task in a between samples (grouped by dosage) design in order to identify when these substances begin to exert their effects on this functional network, as well as what processing styles are employed if frontoparietal connectivity is compromised.

While the first task requires a shape be held in the mind and searched for in a complex embedded figure, the second task targets the ability to identify change in a scene with many visual elements. The Change Blindness Task (CBT) is more explorative and naturalistic compared to the EFT, and can perhaps capture more nuanced changes in perceptual processing. Change blindness is the inability to spot a change in a visual scene that is easily seen when pointed out (Hocchauser, Aran, & Grynszpan, 2017). Tasks that target this phenomenon have been classified as a measure of explorative processing, or a controlled and innate type of selective attention (Enns & Trick, 2006).

The task involves the presentation of a visual scene, followed by a blank screen presented for (at least) 100 ms, and then the same scene with a missing (or changed) element. The participants must notice that a change has occurred and identify which element has changed or is missing, an outcome that varies by the degree of interest or relevance of this element within its context (Hocchauser, Aran, & Grynszpan, 2017; Rensink, 2002).

For a CBT on the effects of low-dose psychedelics, it would be important for visual scenes to vary in content. It has been found that psychedelics enhance a sense of connectedness with nature, animals, other people, therefor naturalistic or social scenes may just be of greater interest in general for the psychedelic group compared to the control group. Studies that employ this task should generate a series of visual scenes that vary in content in order to compare the level of change detection across scenes and between groups.

As mentioned in the previous section, psychedelics have been subjectively reported to alter the way perceptual information is processed at both local levels (element and detail oriented) and global levels (holistic and meaning oriented). The CBT will be a particularly interesting task to employ because it is flexible, meaning the researcher can be a bit creative in order to investigate and control for many variables that may explain differences between groups. Research employing CBT should investigate changes in perceptual processing by manipulating the content of the visual scene (natural, social, industrial, etc.), level of relevance and meaning amongst elements (high connection/low connection), as well as the meaning saliency of the target element (high importance/low importance), and see how this correlates with detection rates.

It will not be enough to say increased detection rates means an enhancement local processing. Increased detection rates could result from an enhanced global processing because of a heightened perception to meaning or relevance between elements. If one of the elements changes or goes missing, it can be detected by its “void of meaning” left behind as a function of its level of connection with other meaningful elements. This can be teased apart by systematically manipulating the level of connection between elements in the visual scenes and the level of importance of the changed/missing elements.

Perhaps the type of processing, either local or global, that is employed will depend on the content and narrative of the visual scene itself. It is possible that the influence of psychedelics on perceptual processing may be contingent upon what and how content is presented, guiding the brain to employ the processing style that is most appropriate in a flexible and adaptive way. For example, if a visual scene has a bunch of elements that are not connected by meaning or relevance, perhaps a more local processing is employed to identify change. If a visual scene with high relevance between elements, perhaps a more global processing is employed.