Galvanic Skin Response | Lab Report

Short Solution

Discussion: Galvanic Skin Response (GSR) Lab Report

Summary of Results

The galvanic skin response (GSR) experiment measured changes in skin conductance as an indicator of physiological arousal. In general, the results showed that skin conductance increased when participants were exposed to emotionally or cognitively stimulating conditions, compared to a resting baseline. This pattern reflects the activation of the sympathetic nervous system, which increases sweat gland activity and reduces skin resistance.

Across individual trials, there was a clear upward shift in conductance during stimulus exposure, followed by a gradual return toward baseline once the stimulus ended. However, the magnitude of response varied between participants, suggesting differences in physiological sensitivity, emotional reactivity, or attentional engagement.

Comparison of Individual Results to Class Data

When comparing individual results to the wider class dataset, the overall trend remained consistent. Most participants showed increased skin conductance under stimulus conditions, confirming that the experimental design successfully triggered autonomic arousal responses.

However, variation was observed in the strength and speed of response. Some individuals showed sharp spikes in conductance, while others displayed more gradual or muted changes. In the class data, this created a wide distribution of peak responses, although the general direction of change remained the same.

The individual results in this report were broadly aligned with the class mean, sitting within one standard deviation of the average response. This suggests that while physiological responses are consistent at a group level, individual variability is significant and expected in psychophysiological measures such as GSR.

Interpretation: What Do the Results Mean?

The findings support the idea that GSR is a reliable indicator of emotional or cognitive arousal. Increased skin conductance reflects activation of the sympathetic nervous system, particularly sweat gland activity controlled by autonomic responses.

This means that when participants experienced stimuli (such as images, tasks, or emotional cues depending on the experiment), their bodies reacted automatically even if they were not consciously aware of it. The results therefore suggest that physiological responses can provide insight into internal emotional states that may not always be visible through behaviour alone.

However, the results do not distinguish between types of arousal. For example, increased conductance could reflect stress, excitement, concentration, or surprise. This limits the specificity of GSR as a standalone measure.

Alternative Explanations

Although the results appear to reflect genuine emotional arousal, there are several alternative explanations that may have influenced the data.

One possibility is movement artefact. Small finger movements or pressure changes on the electrodes can alter skin conductance readings, creating artificial spikes that are not related to emotional state.

Another factor is environmental conditions, such as room temperature or humidity. Warmer conditions increase sweating, which could artificially elevate conductance levels across all participants.

Individual differences also play a role. Participants may differ in baseline anxiety levels, skin properties, or familiarity with experimental settings. For example, more anxious individuals may show higher baseline conductance regardless of stimulus exposure.

Finally, attention and engagement levels may have varied. Participants who were more focused on the task likely showed stronger responses than those who were distracted.

These factors suggest that while the trend is valid, the results should be interpreted with caution.

Critical Comparison with Geldreich (1941)

Geldreich (1941) conducted early research into skin conductance responses, focusing on physiological reactions to emotional and sensory stimuli. His work involved measuring changes in electrical resistance of the skin under controlled laboratory conditions, using relatively simple and less sensitive equipment compared to modern systems.

In his study, participants were typically exposed to basic stimuli, and responses were recorded manually or with early electrical recording devices. The emphasis was primarily on establishing that emotional arousal could be objectively measured through changes in skin conductance.

Differences from the Current Study

The current study differs significantly in both methodology and precision. Modern GSR equipment provides continuous digital data collection with high sensitivity, allowing for more detailed and time-accurate measurements. In contrast, Geldreich’s system was more limited in resolution and likely captured broader, less precise changes.

Additionally, the present study includes group comparison and statistical interpretation, whereas early work like Geldreich’s was more exploratory and focused on establishing foundational physiological principles.

Another key difference is experimental control. Modern studies typically control environmental variables such as temperature and electrode placement more strictly, reducing noise in the data. Earlier research had less control over these factors, increasing the likelihood of variability.

Advantages of Geldreich (1941)

Despite its limitations, Geldreich’s work had important strengths. It was pioneering, helping to establish the scientific basis for psychophysiology and demonstrating that emotional states could be measured objectively. It also laid the groundwork for modern autonomic nervous system research.

Disadvantages of Geldreich (1941)

However, the study lacked modern precision, standardisation, and statistical analysis. Equipment limitations meant lower sensitivity, and results were more prone to measurement error. Ethical standards and sample diversity were also less developed compared to contemporary research.