Perception

Let’s focus first on sensory perception. The five primary senses are sight, sound, taste, touch, and smell. In addition to that, we also have lesser known senses such as vestibular perception which manages head movement and balance, proprioception which manages the location of the body, and interoception manages visceral sensing and the nervous system generally. We have chronoception, the subjective experience of the passage of time.

For each sense, you can provide a simple suggestion by providing something at the edge of perception. This is surprisingly easy to do, as you can produce hallucination without suggestion through classical conditioning.

Some classic hypnotic suggestions are immediately apparent once we organize by sensory perception.

Memory is not commonly thought of as a perception, but we unconsciously rely on memory to navigate environments and immediately become confused if we don’t have immediate access to memory. There are several different types of memory, but they can be broadly categorized as follows:

Memory depends on attention, and losing attention can cause us to completely lose track of events. It is also very easy to misremember or even confabulate memories completely. Imagination and past experiences paper over the gaps in memory and cause us to recall events differently or place events in a different order.

A number of classic hypnotic suggestions are related to memory. The most common is amnesia, the inability to recall a memory. The simplest example is to forget being hypnotized, but you can also suggest forgetting the number five and then have them count their fingers.

But suggestions can also involve modification of memory, an enhanced recall of an existing memory, or even the creation or confabulation of false memory. These suggestions can also apply to any of the different types of memory, which can lead to some interesting suggestions.

You can give someone recognition amnesia, where they may know who you are but not recognize your face or voice. You can give someone episodic amnesia but leave their procedural memory intact, so that they are surprised by the fact that they immediately know how to play piano or ride a bike. This is especially interesting in the context of the Stroop effect, a delay in processing when colors and words are incongruent. By giving a post hypnotic suggestion to see a particular word as meaningless, one study found that the Stroop effect could be minimized.

You can also apply memory suggestions to hypnosis, i.e. you can give people false memories of successfully following a suggestion during hypnosis, or have them recognize a new suggestion as a familiar one.

Emotions are perceived as being real and immediate, but are not directly products of the senses. Instead, emotions are constructed by the mind based on perception, including memories of past experiences and anticipation of future events. Some studies have suggested six emotional dimensions, but a more recent study identified 27 distinct categories of emotion:

Again, some common hypnotic suggestions pop up immediately when looking at this list. The emotion of entrancement is obviously elicited during inductions, but stage hypnotists commonly suggest amusement, excitement, craving, or disgust.

Suggesting an emotion is usually done through imagining or remembering a situation where the emotion takes center stage. Different people have different emotional reactions to situations, so the best way to suggest an emotion is to ask about a time when the hypnotee felt that emotion really strongly, and have them describe and recall the scene and placing themselves in that scenario. Alternatively, an imagery induction can be used to prepare the emotion about to be elicited.

Emotions are typically used to create a mental association with other thoughts or beliefs, such as associating cookies with nostalgia, or associating spirals with entrancement. The association between a situation and an emotion can also be disassociated through desensitization.

Mental perception is an integration of sensory perception, emotional perception, memory perception, and attention; everything that the person is aware of when making an appraisal of the environment and making decisions.

Everything we perceive about our environment and ourselves is categorized as concepts based on past experience. We have to, because the brain has no direct line to the raw physical world — it only deals with concepts. The brain resolves ambiguity and uncertainty by conceptualizing an internal model, and then uses that model to construct instances. Everything we perceive is filtered, biased, and appraised through our internal mental models, also called intentions or response expectancies. For the sake of brevity, let’s just call them beliefs.

Mental perception doesn’t mean that conscious thought is leading the decision. In fact, conscious thought is usually the last link in the chain of perception, and may not be involved at all. What really matters are beliefs and emotions.

In every day decision making, sensory perception and attention are processed through beliefs, and an emotional perception is produced, producing a value judgement for your environment and determining the range of available decisions. For example, you may see some paper money on the ground. Depending on your beliefs (how rich you are) this will cause an emotional response that produces the conscious thought of what to do — do you scramble for the money or keep walking?

Likewise, much of our every day interactions don’t require thought, only recognition of a situation that requires action. The doorbell rings, you open the door. An ad scrolls up on Tiktok, and you flick past it. There is recognition and response.

Conscious thought in decision making is usually limited to selecting from the available decisions. If there is only one good decision, conscious thought is usually involved in the plan of action than in thinking about a decision. Because conscious thought is focused on execution and implementation in decision making, it is inherently forward looking rather than backward looking. Once people feel that they have made a decision, they are thinking about how to implement it, rather than on why they are implementing it.

Hypnotic suggestions that alter existing beliefs or add new beliefs are the basis for changing behavior and decision making. Hypnotic suggestion is an application of belief.

This applies even to the sense of agency, the feeling of controlling actions in the world. Hypnotic suggestions reduce the sense of agency by suggesting that the arm is "lifting by itself" or can’t bend, leading the hypnotee ascribing agency to the suggestion or the hypnotist.

The sense of ownership is also a mental perception that is experienced as sensory. Although we have a sense of ourselves and our bodies, our practical experience of body identity changes whenever we drive a car, play a video game, or wear a costume. It is very easy to produce body transfer illusions by confusing and interfering with sensory input, so there is evidence of integration of sensory channels.

Belief is complex. We implicitly understand how to play make-believe as children, and consciously applying beliefs is something we do all the time as adults , but it’s important to know that we are talking about harmless and fun beliefs. Some beliefs, such as body dysmorphia or self-loathing, are deeply held and will not move as easily. We can nudge and mask beliefs temporarily in hypnosis, but changing complex beliefs are best dealt with by trained professionals in therapy.