Promoting Critical Thinking in Undergraduate Sensation and Perception

Nicole D Anderson^*

• MacEwan University, Edmonton, Canada

Psychology is well positioned to foster critical thinking, due to its emphasis on scientific reasoning and evidence evaluation. Psychology students must learn to analyze research methods and assess the validity of experimental designs, making critical thinking essential to their training. The discipline also offers opportunities to confront misinformation, particularly in the form of "pop psychology." The book 50 Great Myths of Popular Psychology (Lilienfeld et al., 2010) provides a compelling framework, presenting widely accepted but flawed beliefs that can be deconstructed through critical analysis. Using familiar examples that students may already believe or recognize captures their interest and provides an engaging entry point into evidence-based reasoning. Thus, psychology serves as an ideal vehicle for introducing and reinforcing critical thinking at the undergraduate level through active engagement.One area of psychology that strongly benefits from active engagement is sensation and perception. This course can feel intimidating for many psychology students because of its interdisciplinary nature (Aivar, 2024), but much of that concern can be mitigated using instructor-led demonstrations and student-centered in-class activities. Demonstrations provide direct, observable illustrations of perceptual phenomena, while activities invite students to apply those principles through guided exploration and analysis. Both approaches help clarify abstract concepts and make the material more concrete. The value of demonstrations for sensation and perception is underscored by a recent special issue of Visual Cognition devoted to highlighting demonstrations that instructors can use (see Kosovicheva, Strand, & Balas, 2024, for an overview). As emphasized throughout this issue, shared collections of teaching resources that include demonstrations accompanied by readings, discussion prompts, and creative projects improve teaching effectiveness and promote deep thinking. Importantly, both demonstrations and activities serve as powerful vehicles for fostering critical thinking.Consumer products that claim to influence perception serve as effective tools for in-class critical thinking activities in sensation and perception. Their natural appeal to students and the general public is evident in the popularity of products marketed to enhance or restore sensory abilities, whether for vision, pain, or other perceptual conditions. Many of these products lack scientific support, and analyzing their claims in relation to established sensory mechanisms deepens students' understanding. Conversely, products that appear implausible yet prove effective are especially engaging, as they prompt students to reason through why they work. Such contrasts between pseudoscientific and evidence-based tools both reinforce core concepts and foster critical thinking.Here, I present a selection of real-world products, some grounded in scientific evidence and others not, that claim to influence various aspects of sensory functioning. These examples are intended as flexible resources for instructors who wish to design critical thinking activities. Legitimate products can be used to illustrate and reinforce key principles of sensory processing by exploring the scientific rationale behind their effectiveness, whereas pseudoscientific items offer opportunities for students to apply their knowledge to identify why such claims are unsupported. In my classes, students work in groups to evaluate a list of products, researching whether each claim aligns with what we have learned about that sensory system and then discussing their conclusions as a class. These same products could also be adapted for a "Psychbusters"-style assignment (Blessing, 2023), in which students investigate the accuracy of perceptual claims as a term project, or for a refutational infographic activity where students design an evidence-based infographic to debunk the product's claims (Laurin & Kelly, 2025). Even a brief analysis of these products can prompt meaningful reflection on the principles of sensory processing while encouraging students to develop evidence-based reasoning skills and the kind of critical analysis that is essential in both scientific and everyday contexts. In this section, I provide descriptions of two evidence-based and two pseudoscientific products. Each example includes a discussion of how it can be used as a teaching tool in sensation and perception. A broader list of additional products, with brief notes on their scientific viability, is provided in Table 1. It is important to emphasize that the effectiveness of some products may be condition-specific; evidence of benefit in one context does not necessarily generalize to others. Dark adaptation goggles are red-tinted glasses marketed to promote rapid dark adaptation. These goggles allow primarily long-wavelength light to pass through, creating a red-filtered visual environment. The claim is that wearing the goggles under normal lighting conditions enables users to enter a dark environment fully adapted, bypassing the typical 25-to-30minute adjustment period required for dark adaptation. This can be advantageous in contexts that require a quick transition from light to dark, such as in military operations, hunting, or astronomy. These goggles are an example of a legitimate sensory product grounded in well-established principles of vision. A foundational concept in sensation and perception is the dark adaptation curve, a nonlinear function describing how light sensitivity changes over time in darkness. The early phase of the curve reflects cone adaptation, which adapt quickly but are not very light-sensitive. The later phase reflects rod adaptation. Rods take longer to adapt but ultimately become far more sensitive to low light. Full dark adaptation is reached once rod adaptation is complete.Because rods are insensitive to long-wavelength light, wearing red-filtered goggles minimizes their stimulation, allowing them to regenerate even under otherwise lit conditions. Meanwhile, cones remain active, allowing users to function visually in red light without disrupting rod adaptation.Using dark adaptation goggles as a teaching example enables students to critically examine the physiology of photoreceptor regeneration, the functional distinctions between rods and cones, and the spectral sensitivity of the visual system. It also encourages students to evaluate real-world applications of sensory science and the evidence behind marketed perceptual products. Pinhole glasses are marketed as a non-prescription alternative to standard optical lenses. They consist of opaque black surfaces perforated with a grid of small holes that restrict incoming light. Manufacturers claim that wearing these glasses for extended periods will train the eyes to see more clearly over time. Some even suggest that consistent use will eliminate the need for prescription lenses altogether.Although the concept of pinhole optics is based on valid optical principles, these glasses lack scientific support. In clinical settings, pinhole lenses are sometimes used to temporarily improve acuity by minimizing the effects of refractive error during diagnostic evaluations. However, this effect is purely optical and temporary. Pinhole glasses do not cause structural changes in the eye and cannot correct or improve vision once they are removed. Furthermore, because they block a large portion of the visual field, they significantly limit peripheral vision and light intake, making them impractical for daily use.Critically examining the claims behind pinhole glasses provides students with an opportunity to explore how optical correction works, and why structural problems like refractive errors require structural solutions. This discussion reinforces key concepts in physiological optics, including how the cornea and lens shape incoming light and how visual acuity is affected by focal length errors. It also prompts reflection on how easily real scientific principles can be misapplied or misrepresented in the marketing of sensory products. Vibration therapy (also known as transcutaneous electrical nerve stimulation or TENS) applies mechanical oscillations to the skin to reduce pain. It is used for chronic pain, arthritis, neuropathic pain, and short-term relief in acute injuries. While many commercial products are marketed for home use, the technique is also applied in clinical settings.Although vibration therapy may seem questionable because vibrations do not directly target nociceptors, it is a legitimate treatment supported by perceptual science. The key insight is that pain perception can be modulated without directly suppressing pain pathways.Several theoretical explanations for its effectiveness have been proposed, all of which are grounded in concepts commonly taught in sensation and perception. One potential mechanism is the gate control theory of pain, which proposes that non-nociceptive input (i.e., tactile stimulation) can inhibit pain signals at the spinal cord. In this context, mechanical vibrations activate mechanoreceptors that may inhibit nociceptive transmission through lateral inhibition. Another possibility is that vibrations serve as a distraction, reducing attentional focus on the painful stimulus. This aligns with research on the modulatory role of cognitive processes in pain perception. For a deeper review of the mechanisms behind vibratory analgesia, see Hollins, McDermott, and Harper (2014).Discussing vibration therapy in the classroom provides an opportunity for students to explore how pain perception can be shaped by competing sensory input, spinal processing, and cortical modulation. It also encourages them to critically examine how real perceptual principles can explain the effectiveness of treatments that may initially seem implausible. Magnetic bracelets are wearable accessories marketed to relieve pain and inflammation through magnetic fields. A common claim is that the magnets influence the alignment or behavior of iron in the blood, thereby improving circulation and ultimately reducing pain. Magnetic elements are also embedded in other products such as socks, belts, and athletic wear, but bracelets remain among the most widely marketed and accessible forms. Despite these claims, there is no scientific evidence supporting the use of magnetic bracelets for pain relief. Neurons in the human body are not responsive to magnetic energy in a way that would modulate pain. Even if magnets did influence blood flow, circulation is not the primary mechanism underlying pain perception, and the iron in blood is not magnetic. Furthermore, the magnetic fields used in consumer products are too weak to meaningfully affect biological processes. Therefore, the central claims of magnetic therapy products lack both biological plausibility and empirical support.Discussing the viability of magnetic bracelets encourages students to critically examine the neural basis of pain and the kinds of environmental stimuli that can be transduced by the sensory systems. It also highlights the importance of distinguishing between biologically meaningful mechanisms and marketing claims. In this paper, I have presented examples of products that can be used to promote critical thinking in a sensation and perception course. A broader selection of products, with brief descriptions of their scientific viability, is provided in Table 1. Although this discussion has focused on products claiming to affect vision and pain perception, many others relate to the remaining senses. In the chemical senses, one particularly interesting example is the "miracle fruit" pill, available online, which offers a vivid demonstration of taste modulation. This example allows for discussion of the chemotransductive nature of gustation and how chemical properties of food can directly alter sensory experience. Another valuable category of products to examine is homeopathic treatments for sensory issues (e.g., Chininum Sulphuricum and Argentum Nitricum), which are particularly instructive given both the pseudoscientific foundations of homeopathy and the extraordinary claims these products make when considered in light of sensory processes.Because students are often exposed to such products through social media, advertising, and online sources that lack peer review, they tend to find it especially engaging to evaluate these claims through a scientific lens. Critically examining these products not only helps reinforce key course concepts but also equips students with valuable real-world skills. In particular, it helps them learn how to assess health-related claims and become more informed consumers. Whether a product is evidence-based or pseudoscientific, using it as a teaching tool encourages deeper conceptual understanding and supports the development of scientific reasoning.