This is from a Toronto MS thesis:
High dietary sodium intake is hypothesized to increase food intake (FI), fluid intake and glycemic response. Two short-term randomized repeated-measures studies measured the effects of acute sodium intake on FI, water intake (WI), subjective appetite (SA), thirst, and blood glucose (BG) in young men. Sodium additions were 740 and 1480 mg to a solid food (beans) in Experiment 1; and 500, 1000, 1500 and 2000 mg to a beverage (tomato juice) in Experiment 2. FI and WI were measured at ad libitum pizza meals 120 and 30 min later, respectively. SA, thirst and BG were measured at intervals before and after pizza. Compared with controls, treatments with added-sodium had no effect on dependent measures. In conclusion, acute intake of sodium in a solid or liquid matrix does not increase subjective ratings of appetite or thirst, ad libitum food or water intakes, or blood glucose in healthy young adults.
So neither subjective nor objective measures of thirst were increased by sodium in this study. It's not terribly clear to me how sodium was added in these experiments, but I presume it was common salt.
Anyway, is this finding consistent with other studies on the topic? Does sodium (or salt) not affect subjective thirst or subsequent water intake?
The first google hit on this topic is a page "Why Salt Makes You Thirsty"
Let’s follow salt into the digestive system and see what happens. In the wall of the small intestine, the salt is absorbed into your bloodstream, making your blood saltier than it was before.
As the saltier blood circulates through the body, it makes the fluid outside of our body cells saltier than the fluid inside the cells.
There are also sensors in the thirst center in the brain that keep tabs on the saltiness of the blood. When the thirst center goes on alert because things are too salty and the body needs water to dilute the salt, that’s when you start to feel thirsty.
So they can't both be right without some quantification or further context.
Also, a 2015 Israeli study seem to contradict the high-school science lesson as well:
However, according to Prof. Leshem, despite our gut feeling that salt increases drinking, this relationship has not been studied in conditions simulating salt-rich foods such as savory appetizers. Therefore, in the present study involving 58 student participants, Prof. Leshem sought to investigate the effect of salt in solid foods on drinking. Participants were scheduled to come to the lab every few days after not having eaten or drunk anything except water, and not having smoked, for two hours. On the days they came, they were asked to taste nuts -- one time sugary candied nuts, another time salted nuts, and yet a third time nuts with no additives. They rated their level of thirst and, during a couple of hours in which they responded to various questionnaires, they got bottles of water. Each subject could drink as much water as he or she wanted.
The main finding was that the level of reported thirst and the actual quantity of water that the subjects drank after eating salty nuts were not different than following consumption of candied nuts or nuts without added flavors. To more deeply examine a possible correlation, the researchers selected the 10 male and 10 female students who had consumed the largest quantities of salt (an average of 4.4 grams and 3.7 grams respectively) and sought to determine whether within this subgroup there was a connection between thirst and drinking, but here too no such correlation was found. This means that even those subjects who consumed larger quantities of salt did not drink more.
So, is high-school science wrong on water consumption following sodium/salt intake?
N.B. there's also a 2017 study that challenges that in the long run (months) salt increases water consumption. But since the latter study seems rather unique insofar, let's stick with shorter time frames, for which more studies probably exist (and perhaps some meta-analyses).