When skiing, we tend to quickly respond to a stimulus with a single response. When more than one stimulus is presented, our reaction time takes longer.
The psychological refractory period is a delay of the response time to a second stimulus as a consequence of our brain still processing the first one when both stimuli are presented in quick succession. An example of this might be when we dangerously approach an object and another skier or snowboarder appears, our first reaction is turning to avoid the object, but simultaneously try to stop to elude a collision with the other skier/snowboarder. In this case, the second execution will be less effective because our brain has a limited capacity and both reaction responses overlap.
Skiers with lower reaction skills due to a limitation in their speed information processing will exhibit this feature more markedly than quicker reactive skiers, limiting their decision to one at a time. If we are descending on a slope and another person cuts off in front of us, and at the avoiding moment we perceive the sound of a second person approaching from behind, then our motor response to avoid the person crossing will be longer. In this situation, we have to decide to avoid the person cutting off by deviating from his path or by stopping so, at having two options, our decision time delays our reaction time.
Reaction Time and Motion Speed of Others
It is difficult to calculate the speed of other people on the slope if at the same time we move because our visual system must separate on the retina the image of the other persons’ motion from our image of our own motion. Also, there is to consider that it is easier to estimate someone’s speed moving laterally that if it does lengthwise facing us.
Reaction Time and the Number of Stimuli and Responses
Based on the proposal of the Dutch scientist Franciscus Donders, currently it is recognized the following classification:
- Simple reaction time occurs when we perform a single response to just one stimulus.
- Choice reaction time occurs when existing several stimuli, we have a response for each one of them.
- Recognition reaction time is when various stimuli appear and each one is associated with several possible responses but only some should be responded. The Hicks’ law would apply here, which postulates that the more response options, the more reaction time increases.
Reaction Phases and Types
Reacting to a stimulus could be divided into three phases:
- In the perception phase we assign sensory detection time of the stimulus by vision, hearing, or touch.
- The decision phase implies the time to determine the appropriate response.
- The execution phase is when we apply the chosen response.
Reaction types are:
- The reflex reaction, which is an instinctive reaction like blinking.
- The simple reaction needs a single response like stopping before a drop-off.
- The complex reaction is when we have to choose between several possible responses, taking longer decision and reaction time.
- The discriminating reaction is applied when we must choose between several responses that are not usual for us.
Neuroscientific Framework Matrix for Skiing Motor Control and Reaction Time
| Concept / Phenomenon | Neural / Cognitive Mechanism | Processing Phase | Behavioral Reaction | Skiing Scenario / Trigger | Skiing Outcome & Efficiency |
| Psychological Refractory Period (PRP) | Central bottleneck; serial processing limit overlaps two rapid responses. | Overlapping Phases: Decision & Execution | Dual motor commands overlap; second action is delayed. | Approaching an object while another skier suddenly appears. | Severely Reduced: Second execution (stopping) is less effective. |
| Information Processing Limitation | Fixed speed capacity in neural signal transmission and decoding. | All Phases: Perception through Execution | Cognitive overload restricts decision-making to one choice at a time. | Descending a slope with low innate reaction skills. | Markedly Lowered: Inability to handle rapid, successive changes. |
| Relative Motion Differen-tiation | Optic flow separation; distinguishing retinal image motion from self-motion. | Perception Phase: Visual cortex decoding | Prolonged gaze fixation or delayed speed estimation. | Attempting to calculate another skier’s speed while moving. | Impaired: Speed estimation is highly inaccurate or delayed. |
| Spatial Vector Bias | Higher neural sensitivity to lateral angular displacement vs. sagittal expansion. | Perception Phase: Retinal image translation | Quicker visual calculation and faster motor preparation. | Observing a skier moving across (laterally) vs. facing lengthwise. | Optimized: Higher accuracy tracking lateral skiers than head-on ones. |
| Simple Reaction Time | Direct 1:1 sensorimotor mapping; minimal cortical loop filtering. | Abbreviated Phase: Fast Perception to Execution | Immediate, single, pre-planned motor response. | Encountering a single, isolated stimulus on an open slope. | Maximum Speed: Fastest possible response time. |
| Choice Reaction Time | Multiple parallel neural activations requiring competitive selection. | Extended Phase: Prolonged Decision | Selection of one specific response for each distinct stimulus. | Facing several distinct obstacles, each needing a unique maneuver. | Delayed Speed: Reaction time scales up with stimulus count. |
| Recognition Reaction Time | Logarithmic increase in cortical processing as response options multiply. | Maximized Phase: Deep Decision filtering | Selective inhibition of incorrect responses; executing only one. | Facing various stimuli with multiple potential movement paths. | Slower Speed: Total reaction time increases as choices multiply. |
| Perception Phase | Activation of primary sensory cortices (visual, auditory, somato-sensory). | Perception Phase: Sensory detection | Transducing external physical stimuli into neural signals. | Seeing an obstacle, hearing a skier behind, or feeling ice. | Initial Baseline: Sets up the raw speed for the next phases. |
| Decision Phase | Frontal and prefrontal cortex integration to evaluate motor plans. | Decision Phase: Motor planning | Selecting the single most appropriate physical maneuver. | Choosing whether to turn left, turn right, or drop into a stop. | Bottleneck Zone: Delays the entire chain if choices are ambiguous. |
| Execution Phase | Motor cortex activation sending efferent signals to skeletal muscles. | Execution Phase: Physical application | Activation of specific muscle groups to execute the turn/stop. | Physically applying pressure to ski edge to initiate a turn. | Final Realization: Reflects the accumulated delays of prior phases. |
| Reflex Reaction | Subcortical or spinal monosynaptic reflex arc bypassing conscious thought. | Bypassed: Instantaneous sensory-motor loop | Involuntary, automatic, protective motor twitch. | Getting snow sprayed in the eyes or losing sudden balance. | Instantaneous: Maximum safety; zero conscious delay (e.g., blinking). |
| Simple Reaction Type | Low-complexity cortical routing for a single known threat. | Linear Phases: Fast Perception to Decision to Execution | A single, rehearsed, protective motor execution. | Spotting a sudden drop-off or cliff edge immediately ahead. | High Efficiency: Swift, clean stopping or clearing of the hazard. |
| Complex Reaction Type | Multi-layered cortical loop processing with competitive inhibition. | Elongated Phases: Heavy Decision burden | Hesitant or calculated multi-step motor response. | Hearing someone behind while trying to avoid someone in front. | Compromised: Longer decision-making significantly delays reaction. |
| Discrimi-nating Reaction Type | High cognitive control; overrides default pathways for unusual motor habits. | Maximized Phases: Unfamiliar Decision & Execution | Non-habitual, highly calculated motor adjustment. | Recovering from an atypical wipeout or executing an unpracticed turn. | Lowest Efficiency: Extremely long processing time due to novelty. |
