Standing up to threats: Translating the two-system model of fear to balance control in older adults

Abstract

The ‘two-system’ view of fear builds on traditional conceptualisations of emotion; proposing that the mechanism(s) responsible for behavioural and physiological responses to threat may be distinct from that underpinning the (conscious) emotional experience itself. We empirically tested this notion within a novel, applied context of social and economic importance: fear of falling in older adults. Older adults stood on the edge of a raised platform and were stratified based on whether they reported fear in response to this postural threat. Irrespective of whether participants reported fear, we observed behaviours indicative of postural ‘stiffening’ during the threat condition. Self-reports indicated that participants cognitively monitored these changes in balance, and fear of falling was experienced in those who interpreted these behaviours to imply that harm was likely to occur. Fearful participants exhibited additional changes in balance (increased movement complexity and altered utilisation of sensory feedback) – behaviours likely influenced by attempts to consciously control balance. Taken together, these findings provide novel insight into the systems that regulate behavioural and emotional responses to postural threats. The novel conceptual framework developed from these findings helps identify specific mechanisms that might be targeted for clinical intervention.