Amygdala damage eliminates monetary loss aversion

In the paper

“This analysis yielded λ = 0.76 for S.M., and a mean λ for the S.M. control group of 1.52 (SEM = 0.19). For A.P., λ = 1.06 whereas the mean λ for the A.P. control group was 1.76 (SEM = 0.12).”

• Also stated in: § Results · plain

  “The values of λ estimated by our analysis show that neither amygdala-lesioned participant exhibits loss aversion whereas the control participant λ estimates are close to those found in previous studies (17, 18).”

What the sources say

• Not checked yetcites [17] Sokol-Hessner P, et al. Thinking like a trader selectively reduces individuals’ loss aversion. Proc Natl Acad Sci USA. 2009;106(13):5035–5040. doi: 10.1073/pnas.0806761106. [DOI] [PMC free article] [PubMed] [Google Scholar] source
• Not checked yetcites [18] Tom SM, Fox CR, Trepel C, Poldrack RA. The neural basis of loss aversion in decision-making under risk. Science. 2007;315:515–518. doi: 10.1126/science.1134239. [DOI] [PubMed] [Google Scholar] source

In the paper

“Critically, both lesion participants exhibited a marked dislike for increasing outcome variance, given a constant level of expected value. This was manifested in a reduction in gamble acceptance rates as a function of increases in the gamble’s variance (Fig. 6). Most importantly, their dislike for increased variance was no different from that of the controls.”

In the paper

“Critically, both participants retained a monotonic sensitivity to reward magnitude (i.e., they preferred larger gains and smaller losses).”

In the paper

“Loss aversion has been well documented in the laboratory and in many field settings (2), including high-stakes game show decisions (3), financial markets (4), politics (5), trade policy for declining industries (6), rate of organ donation for transplant cases (7) and has also been evident in monkey behavior (8).”

What the sources say

• Not checked yetcites [2] Kahneman D, Tversky A. Choices, values, and frames. Am Psychol. 1984;39:341–350. [Google Scholar] source
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In the paper

“The two participants were each compared to a separate group of 6 healthy controls (12 in total) matched to that participant on age, gender, monetary income, and education.”

In the paper

“The first participant, S.M., is a 43-year-old woman with a high school education whose lesions encompass the entire amygdala plus subjacent white matter and anterior entorhinal cortex. The second participant, A.P., is a 23-year-old woman with a college education whose lesions are entirely confined to the amygdala and encompass roughly 50% of the amygdala.”

In the paper

“loss aversion appears to increase with affective enrichment of “hedonic” consumer goods (e.g., music CDs versus computer disks) (11) and more generally with emotional attachment (12).”

What the sources say

• Not checked yetcites [11] Dhar R, Wertenbroch K. Consumer choice between hedonic and utilitarian goods. J Mark Res. 2000;37:60–71. [Google Scholar] source
• Not checked yetcites [12] Ariely D, Huber J, Wertenbroch K. When do losses loom larger than gains? J Mark Res. 2005;42:134–138. [Google Scholar] source

In the paper

“Across many studies, losses typically loom about 1.5–2 times as large as gains: for instance, people will avoid gambles in which they are equally likely to either lose $10 or win $15, even though the expected value of the gamble is positive ($2.50).”

What the sources say

• Not checked yetcites [1] Kahneman D, Tversky A. Prospect theory: An analysis of decision under risk. Econometrica. 1979;47:263–292. [Google Scholar] source

In the paper

“recent theories of amygdala function argue that the amygdala subserves an abstract function in detecting uncertainty (13) or ambiguity (14) in the environment and in triggering arousal and vigilance as a consequence.”

What the sources say

• Not checked yetcites [13] Whalen PJ. The uncertainty of it all. Trends Cogn Sci. 2007;11:499–500. doi: 10.1016/j.tics.2007.08.016. [DOI] [PubMed] [Google Scholar] source
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In the paper

“a recent study found that increased cognitive control of the autonomic emotional responses normally elicited by losses significantly reduced the susceptibility to loss aversion (17).”

What the sources say

• Not checked yetcites [17] Sokol-Hessner P, et al. Thinking like a trader selectively reduces individuals’ loss aversion. Proc Natl Acad Sci USA. 2009;106(13):5035–5040. doi: 10.1073/pnas.0806761106. [DOI] [PMC free article] [PubMed] [Google Scholar] source

In the paper

“a tendency for amygdala-lesioned monkeys to approach stimuli that healthy monkeys avoid (15)”

What the sources say

• Not checked yetcites [15] Mason WA, Capitanio JP, Machado CJ, Mendoza SP, Amaral DG. Amygdalectomy and responsiveness to novelty in rhesus monkeys (Macaca mulatta): Generality and individual consistency of effects. Emotion. 2006;6:73–81. doi: 10.1037/1528-3542.6.1.73. [DOI] [PubMed] [Google Scholar] source

In the paper

“an idea motivated by a large literature implicating this brain structure in processing fear and threat (9), as well as in anticipation and experience of monetary loss (10).”

What the sources say

• Not checked yetcites [9] Adolphs R, Tranel D, Damasio H, Damasio AR. Fear and the human amygdala. J Neurosci. 1995;15:5879–5891. doi: 10.1523/JNEUROSCI.15-09-05879.1995. [DOI] [PMC free article] [PubMed] [Google Scholar] source
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In the paper

“a recent fMRI study (18 ) did not find amygdala activation associated with loss aversion”

What the sources say

• Not checked yetcites [18] Tom SM, Fox CR, Trepel C, Poldrack RA. The neural basis of loss aversion in decision-making under risk. Science. 2007;315:515–518. doi: 10.1126/science.1134239. [DOI] [PubMed] [Google Scholar] source

In the paper

“A plausible explanation that reconciles our findings with the previous fMRI study is that an initial negative anticipatory response is generated in the amygdala, influences the striatal computation of the gamble’s net value, and consequently leads to behavioral loss aversion through striatal mediation of instrumental behavior.”

In the paper

“lesion studies are one of the few methods in human neuroscience to investigate causal relationships between brain function and behavior.”

In the paper

“this is a standard procedure used in behavioral economics, which ensures that participants evaluate each gamble independently.”

In the paper

“More specifically, lesions to the amygdala would result in a reduced input to downstream regions that compute value through integrating across multiple inputs.”

In the paper

“Note that the sample size of lesion participants (n = 2) is common in neuropsychological studies—indeed, many famous studies used only a single participant. The reason is that individuals with focal brain lesions such as the bilateral amygdala lesions here are very rare.”

In the paper

“This procedure (i.e., bootstrapping at individuals level) was chosen because it is a more conservative procedure than the bootstrap at trial level, as it preserves the intersubject variability present in the control group.”

In the paper

“In this view, the amygdala produces an output signal in response to prospective loss, which is conveyed to other value-sensitive brain structures such as the ventral striatum and orbitofrontal cortex.”

In the paper

“Amygdala and striatum have a well-documented anatomic connectivity (29) and show a tight functional coupling in stimulus–reward association and stimulus–cue devaluation (30).”

What the sources say

• Not checked yetcites [29] Amaral DG, Price JL, Pitkanen A, Carmichael ST. in The Amygdala: Neurobiological Aspects of Emotion, Memory and Mental Dysfunction. In: Aggleton JP, editor. New York: Wiley−Liss; 1992. pp. 1–66. [Google Scholar]
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In the paper

“In the case of evaluation of mixed gambles, this could result in a reduced aversive signal elicited by the prospect of potential loss together with normal appetitive signals triggered by the prospect of potential gain. As a consequence (in particular when the EV of the gamble is close to zero), the appetitive response to the gain component of the gamble may outweigh the aversive component in the”

In the paper

“In those examples, the amygdala is not the locus of memory or of choice, but it passes a signal to other brain regions for integration of such processes.”

In the paper

“Our findings could also shed some light on the nature of individual differences in loss aversion observed in many behavioral studies.”

In the paper

“In this regard, the amygdala’s role in mediating loss aversion may be analogous to its role in modulating caudate- or hippocampal-dependent memory (31), and choice in reversal tasks (20).”

What the sources say

• Not checked yetcites [31] Packard MG, Cahill L, McGaugh JL. Amygdala modulation of hippocampal-dependent and caudate nucleus-dependent memory processes. Proc Natl Acad Sci USA. 1994;91:8477–8481. doi: 10.1073/pnas.91.18.8477. [DOI] [PMC free article] [PubMed] [Google Scholar] source
• Not checked yetcites [20] Hampton AN, Adolphs R, Tyszka MJ, O’Doherty JP. Contributions of the amygdala to reward expectancy and choice signals in human prefrontal cortex. Neuron. 2007;55:545–555. doi: 10.1016/j.neuron.2007.07.022. [DOI] [PubMed] [Google Scholar] source