Judgement bias may be explained by shifts in stimulus response curves

Abstract

Judgement bias, or ‘optimism’ and ‘pessimism’, has been demonstrated across many taxa, yet the cognitive mechanisms underlying this behaviour remain unclear. In an optimism paradigm, animals are trained to an association, and, if given a positive experience, behave more favourably towards ‘ambiguous’ stimuli. We tested whether this effect could be explained by changes to stimulus response gradients by giving bees a task where their response was tested across a wider gradient of stimuli than typically tested. In line with previous work, we found that bees given a positive experience demonstrated judgement bias, being more likely to visit ambiguous stimuli. However, bees were also less likely to visit a stimulus on the other side of the rewarded stimulus (S+), and as such had a shifted stimulus response curve, showing a diminished peak shift response. In two follow-up experiments we tested the hypothesis that our manipulation altered bees’ stimulus response curves via changes to the peak shift response by reducing peak shift in controls. We found that, in support of our hypothesis, elimination of peak shift also eliminated differences between treatments. Our results point towards a cognitive explanation of ‘optimistic’ behaviour in non-human animals and offer a new paradigm for considering emotion-like states.

Motivational modulation of flight speed in foraging bumblebees

“…Here, such a "liking" effect as concentration increased did not produce significant changes in flight behaviour. While this is similar to what has been reported in experiments on cognitive bias tasks (37,38), the positive cognitive bias reported by these studies when bees are in a (supposedly) high hedonic state suggests that such a "liking" effect on flight behaviour is possible, perhaps in terms of trajectory (which betrays the search of alternatives within the environment). Importantly, by virtue of happening before reward consumption, any behavioural change in the flight characteristics of a bee flying toward a reward could be interpreted not as evidence of liking, but rather of the "expected pleasantness" of the reward (90).…”

“…While these studies suggest a simple correlation between reward value and behavioural vigour, the relative importance of the reward intrinsic value and its value modulators is unclear. Moreover, two studies using judgment bias tasks have revealed that although an unexpected reward before a foraging flight reduces the sampling latencies of bees towards ambiguous stimuli, latency before choice to known options is unaffected (37,38). This suggests that changes in a bee's motivational state do not systematically translate into changes in behavioural vigour.…”

I. The Era Beyond Eisemann et al. (1984): Insect pain in the 21st century

“…Insects' behavioral flexibility also plays a role in their possible affective responses to noxious or aversive stimuli, resulting in state-dependent judgment biases (Bateson et al, 2011;Deakin et al, 2018;Perry & Baciadonna, 2017;Procenko et al, 2023;Strang & Muth, 2023), neophobia (Cohen et al, 2015), and anxiety-like and depression-like behaviors in response to tests designed for eliciting anxiety and depression in mammals (reviewed in Gibbons et al 2022a). Further, we have documented throughout this paper the many ways insects respond flexibly, and sometimes site-and contextspecifically, to injuries.…”

“…Just as striking, brains of many sizes share a capacity to produce a number of seemingly complex abilities, such as numerical cognition, social learning, facial recognition, and various cognitive biases (all insects: Bateson et al, 2011;Bridges et al, 2023;Dacke & Srinivasan, 2008;Fellers & Fellers, 1976;Frisch & Seeley, 1967;Giurfa, 2012Giurfa, , 2015Giurfa et al, 2001;Howard et al, 2019;Leadbeater & Chittka, 2007;Mirwan & Kevan, 2013;Perry & Baciadonna, 2017;Perry & Barron, 2013;Strang & Muth, 2023;Tibbetts et al, 2021;Weise et al, 2022). Insects may even be capable of faster reversal learning than most vertebrates (evidence reviewed in Gibbons et al, 2022a).…”

Pain and Suffering in Farmed Animals: First Steps Towards Better Understanding and Management (Musk and Clutton, 2024) - Insects

“…The impressive cognitive abilities of social insects have been (relative to solitary insects) well studied, hence our focus here. These abilities include: counting in bees (Dacke and Srinivasan 2008), numerical cognition that enables addition and subtraction in bees (Howard et al 2019), abstract concepts of same and different in wasps and bees (Giurfa et al 2001;Weise et al 2022), facial recognition in wasps (Tibbetts et al 2021), tool use in ants (Fellers and Fellers 1976), play-like behavior in bees and flies (Galpayage Dona et al 2022;Triphan and Huetteroth 2023), social information transfer (Frisch and Seeley 1967;Leadbeater and Chittka 2007;Mirwan and Kevan 2013;Bridges et al 2023), metacognitive-like processes (Perry and Barron 2013;Giurfa 2015), attention (Perry et al 2017), emotion-like states and judgment bias (Bateson et al 2011;Perry and Baciadonna 2017;Strang and Muth 2023), and self-medication (de Roode and Hunter 2019). There is an entire field of insect 'personality' (or, if you like, consistent individual behavioral differences) research (Jandt et al 2014).…”