Source
Damasio (1996), LIT-384 (Phil. Trans. R. Soc. Lond. B 351: 1413–1420), read in full in NOTE-332. Bechara, Damasio, Tranel and Damasio (1997), LIT-383 (Science 275: 1293–1295), read in full in NOTE-331. NOTE-332 says a THEORY should not rest on the 1996 paper alone, because it reports its evidence secondhand; LIT-383 is the primary report it previews.
What was actually shown
The hypothesis (LIT-384, §2b). Ventromedial prefrontal cortex holds “dispositional” links between a class of situation and the emotional state that went with it. When the situation recurs, the link reactivates the state, through the body (“body loop”) or directly in somatosensory cortex (“as if body loop”). The re-enacted state, co-displayed with the imagined scenario, “marks the scenario as good or bad” (p. 1415): overtly as an alarm or incentive, covertly as a bias. The marks let some option-outcome pairs be “rapidly rejected or endorsed”, which makes reasoning tractable. The paper says this is “not … a general theory for how prefrontal cortices work” (p. 1414).
The evidence the 1996 paper summarises (§5), without statistics. Ventromedial patients keep IQ, knowledge, language, attention and working memory and still decide badly in life. They give no skin conductance responses (SCRs) to emotionally charged pictures, though their SCRs to startle are normal. In the gambling task (44 controls against 6 patients) controls drift to the decks with smaller rewards and smaller penalties and patients do not.
The 1997 experiment (LIT-383, NOTE-331). 10 controls and 6 patients.
- All controls and no patients generated anticipatory SCRs: Fisher’s exact test, one-sided P < 0.001; group × period F(1,14) = 16.24, P < 0.001 (note 8). This is the robust result.
- Three patients who reached the stage of stating the right strategy still did not switch to the good decks.
- Before the “hunch” stage, controls’ preference for the good decks was not significant (note 9). It became significant once they reported a hunch.
- The pre-hunch SCR effect reported is a group-by-period interaction. No bad-deck against good-deck test is reported for that period, and deck differences were not significant later either (note 8).
What could have come out otherwise. Patients could have developed anticipatory SCRs and still chosen badly, or controls could have chosen well without them. Neither happened in these samples.
What this does not say
- That the marker causes the choice. SCRs index a body state. Nothing measured shows that it marks options or drives selection (NOTE-332, Limitations). The 1997 model is stated, not tested (NOTE-331, C7).
- That people choose well before they know. The statistics carry “before the articulated strategy”, not “before any awareness”. The awareness probe is coarse and starts at card 20 (NOTE-331, C3–C5).
- That the deficit is specifically somatic. The reversed-task evidence against reward hypersensitivity and punishment insensitivity is a conference abstract (C8). Response inhibition and reversal learning are set aside by argument, not experiment.
- That the body is needed. The “as if” loop bypasses the body, and the author believes it is the usual adult mode, on no evidence offered (C6). An argument from this account to “affect needs a body” would have to rest on the developmental claim that the body loop came first.
- That it survives its critics. Maia and McClelland (2004) and the later critiques of the gambling task are not held in the record and were not read.
Connections
- THEORY-603 states what the 1997 Iowa gambling study showed, with its limits: anticipatory SCRs in controls and not in patients, and no advantageous choice or deck-specific signal shown before awareness. The covert half of this account gets no support from it.
- Damasio’s later account, in which feelings are hybrid, partly the body state itself, is THEORY-093. Barrett’s felt affect as a prediction about the body is THEORY-045. This account puts body-state signals at the centre of decision and sets consciousness aside.
- Gross’s review of emotion regulation (LIT-554) cites the book version for prefrontal cortex lending emotional meaning to processing (THEORY-680).
- Overt markers have the same shape as a felt processing quality entering a judgement about its source (THEORY-662), with a body state as the feeling.