Entrainment

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Synopsis

Changing the player’s internal rhythms through acoustic stimulation, eventually inducing emotions and behaviour.

Relationships

Contexts:
Emotional Script , Trance , R-A-E-D Iterations , Relaxation , Anticipation , Engagement , Decay , Window of Opportunity , Hurry Up! .
May use:
Heartbeat , Breath , Footsteps , Music , Rhythm Gameplay , Foley , Ambiance .

Description

Entrainment is a technique that enables tackling emotions at a physiological level, and consequently for which no conscious interpretation is required. Entrainment can be used to support the maintenance or the change of emotional states, by influencing the player to progressively move from one state of resonance into another. Sound is one prominent way to implement entrainment, benefiting from the way humans resonate to auditory stimuli. The principles of entrainment and resonance have been exploited by music through the ages.

Entrainment techniques that can be achieved through (or built in) other sound explorations, with the ultimate goal of influencing the Emotional Script.

Specific examples of sound explorations in games that are commonly used to implement Entrainment include:

• Music: one major role of Music in a game is, precisely, to contribute to Entrainment. For instance, distinctive Music is typically designed for each of the phases Relaxation, Anticipation, Engagement and Decay. The fact that there is a great body of knowledge in this matter in close domains (as music itself, cinema, ...) influences the exploration of Music in games. Yet, it is important to acknowledge the specificity of games, to adapt and go beyond the "imported" explorations .
• Heartbeat and Breath: they are very direct approaches to Entrainment, considering that hearthbeat and breath are two of the human body's resonant systems (see below). Again, this techniques also have been long explored in the domain of music and cinema.
• Rhythm Gameplay: if the gameplay demands that the player performs an action subject to a beat it is conceivable that such player may entrains with that beat.
• other more subtle – and possibly more complex – instances, such as rhythmic Foley (e.g. a machine, a "hacked" clock, etc...) or elements in the Ambiance are also used.

Despite techniques based in Entrainment create opportunities that are less dependent on context, it should be recognised that experiencing emotions is still an individual and context dependent process. Emotion cannot be designed: a designer can only create conditions for players to reach themselves the intended emotions.

Examples

Beat Hazard:The output of the cannons is dictated by the intensity of the selected Music. As a consequence, players adapt behaviour to the variations in Music.

Far Cry 2: Notice in this experiment that the shot is followed by an activation Music that contributes to achieve an arousal state that is more consonant with the true meaning of firing a gun.

Patapon: In this game Entrainment is not only a consequence but also a requisite of the Rhythm Gameplay. The player voluntary seeks to keep in sync with the beat of the game. The exteriorization of the game's beat in the player's body language is a common testimony. The game's tempo is 120 bpm (4/4).

Sonic the Hedgehog: Some power-ups change the characteristics of the Music and effectively induce a higher arousal level.

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Pond:

Additional Comments

Entrainment refers to the synchronization of resonant systems. Breath, heartbeat, and brainwaves are examples of resonant systems for which entrainment may be explored as studied in psychoacoustics. There are two types of entrainment: internal-to-internal and external-to-internal. Internal-to-internal refers to entrainment among one person’s pulse systems, namely heart, breath, and brain. For instance, when heartbeat increases so does breath rate. External-to-internal has to do with the changing of internal rhythms through external stimulation, in our case, through sound. The latter is what allows for entrainment through design; the former augments the opportunities regarding the system at which that entrainment is target.

External Resources

• First presentation of the pattern Entrainment
• On the concept and physics of entrainment
  • some demonstrations of entrainment, at a mechanical level .
• Entrainment in Sound Design in Games

References