Freezing promotes perception of coarse visual features.

Abstract

Freezing is an evolutionarily preserved defensive behavior, characterized by immobility and heart rate deceleration, which is thought to promote visual perception. Rapid perceptual assessment of threat is crucial in life-threatening situations; for example, when policemen need to make split-second decisions about the use of deadly force. Here, we hypothesized that freezing is specifically associated with better perception of rapidly processed coarse, low-spatial frequency (LSF) features. We used a visual discrimination task in which participants determined the orientation of LSF and high-spatial frequency (HSF) gratings under threat of shock and safe conditions. As predicted, threat anticipation improved perception of LSF at the expense of HSF gratings. Crucially, stronger decrease in heart rate, a parasympathetic physiological index of freezing, was linked to better perception of LSF. These results provide empirical evidence for the comobilization of physiological and perceptual processes, which may play an important role in decision making under acute stress.

Human defensive freezing is associated with acute threat coping, long term hair cortisol levels and trait anxiety

“…This variability could be due to task demands (active vs. passive tasks) or subject-specific factors. Bradycardia reactions have been often studied in the context of (threat) anticipation processes that are associated with optimized perceptual and motor processes for subsequent actions (Lojowska et al, 2015;Löw, Lang, Smith, & Bradley, 2008;Löw et al, 2015;Porges, 2003). Our result of an association between bradycardia and reaction times is therefore in line with this literature.…”

“…Upon distal threat detection and in anticipation of potential threat, human freezing is typically accompanied by heart rate deceleration (or: bradycardia) (Azevedo et al, 2005;Facchinetti, Imbiriba, Azevedo, Vargas, & Volchan, 2006;Hagenaars, Oitzl, & Roelofs, 2014). Prolonged bradycardia responses have been suggested to enhance sensory processing to optimize the detection of threatening information in the environment (Campbell, Wood, & McBride, 1997;Graham & Clifton, 1966;Lojowska, Gladwin, Hermans, & Roelofs, 2015;Vila et al, 2007). At this stage, freezing reactions are thought to facilitate risk assessment and prepare subsequent defensive actions while minimizing the chance of being detected by predators or conspecifics (Eilam, 2005;Fanselow, 1994;Roelofs, 2017).…”

Anticipatory versus reactive spatial attentional bias to threat

“…This aspect of predictive attentional biases involving emotional stimuli appears to have been understudied thus far, relative to reactive attentional biases. However, relatively recent lines of research have focused on anticipatory psychophysiological states under threat (Gladwin et al ., ; Lojowska, Gladwin, Hermans, & Roelofs, ; Löw, Weymar, & Hamm, ; Mobbs et al ., ; Nieuwenhuys & Oudejans, ; Wendt, Löw, Weymar, Lotze, & Hamm, ). For instance, in a task with a purely anticipatory period in which participants viewed a static screen but awaited a potential virtual attack, heart rate and body sway decreased, reflecting preparatory freezing (Gladwin et al ., ).…”

Elevated arousal levels enhance contrast perception

“…This gain profile plays a primary role in determining what we can and cannot see in our visual environment, and the shape of this function has already proven itself to be malleable to a number of cognitive processes, including attention (Cameron, Tai & Carrasco, 2002;Carrasco, Ling, & Read, 2004;Herrmann, Montaser-Kouhsari, Carrasco, & Heeger, 2010;Ling & Carrasco, 2006a, 2006bReynolds & Chelazzi, 2004;Reynolds & Heeger, 2009) and competition (Ling & Blake, 2012;Moradi & Heeger, 2009). Although there is evidence to suggest that arousal states alter human perception (Keil et al, 2003; T.-H. Lee, Baek et al, 2014; T. H. Lee, Sakaki et al, 2014;Lojowska, Gladwin, Hermans, & Roelofs, 2015;Phelps et al, 2006;Woods, Philbeck, & Wirtz, 2013), very little work has directly explored how arousal levels might influence the contrast response profile (Cano et al, 2006;Zhuang et al, 2014), particularly in humans (Song & Keil, 2014). Some theorize that the slope of a response profile becomes steeper with arousal level (Aston-Jones & Cohen, 2005a), which would increase discriminability straddling a certain range of intensities.…”